Compounds for treatment of cancer

Abstract

The present invention relates to novel compounds of formula (I) having anti-cancer activity, pharmaceutically acceptable salts thereof as well as pharmaceutical compositions comprising the same and the use of such compounds for the treatment of cancer wherein --A-- represents a peptide chain, wherein said peptide chain consists of 4 to 9 amino acids, wherein preferably said amino acids are selected from a-aminoisobutyric acid (Aib), leucine (Leu), preferably (S)-leucine, or β-alanine (β-Ala); R1 is (A), wherein the arrow indicates the attachment to the NH-moiety depicted in formula (I), and wherein R5 is selected from H, C1-C16alkyl, C1-C16alkenyl, carbocyclyl, heterocyclyl,,C1-C3alkylene-carbocyclyl or C1-C3alkylene-heterocyclyl, wherein said C1-C16alkyl and said C1-C16alkenyl each independently optionally substituted with halogen, OR18, NR19R20, -[O-C2H4]n-OCH3 wherein n=2-20; and wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C4alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5 substituted with halogen, C1-C3alkyl, OR18, NR19R20, wherein R18, R19, R20 are independently at each occurrence H, C1-C3alkyl, and wherein R6, R7, R8, R9, R10, R11 are independently at each occurrence selected from H, C1-C6alkyl, C1-C6alkenyl, carbocyclyl, heterocyclyl, C1-C3alkylene-carbocyclyl, C1- C3alkylene-heterocyclyl, halogen, C1-C2haloalkyl, OR21 or NR22R23, wherein said R21, R22, R23 are independently at each occurrence selected from H, C1-C6alkyl, C1-C6alkenyl, C(O)O-C1-C6alkyl, C(O)-C1-C6alkyl, C(O)O-C1-C6alkenyl, C(O)-C1-C6alkenyl, carbocyclyl, heterocyclyl, C1-C3alkylene-carbocyclyl or C1-C3alkylene-heterocyclyl, wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C3alkyl, halogen, oxo, C1-C2haloalkyl, OR18, NR19R20, C6H5, C6H5 substituted with halogen, C1-C3alkyl, OR18, NR19R20; or wherein two of said R6, R7, R8, R9, R10, and R11 together with the carbon atom to which they are attached form a carbocycle or heterocycle, preferably a carbocycle; said carbocycle and said heterocycle optionally substituted with C1-C3alkyl, halogen, CF3, OR18, NR19R20; and wherein at least one of said R6, R7, R8, R9, R10, and R11 is not H; and R2 is selected from C4-C12alkyl, C4-C10alkoxy, C1-C3alkylene-cycloalkyl, C1-C3alkylene-aryl or C1-C3alkylene-heteroaryl, wherein independently in said C1-C3alkylene one -CH2- moiety is optionally replaced by -CH(NH)- or -O-; and wherein said alkyl, cycloalkyl, aryl and heteroaryl are each independently optionally substituted with one or more, preferably one or two, substituents selected from C1-C2alkyl, C1-C2haloalkyl, oxo, OH, halogen, C1-C2alkoxy, C6H5 or C6H5 substituted with C1-C3alkyl or OC1-C3alkyl; R3 is (B), preferably (C), wherein the arrow indicates the attachment to the A-moiety in formula (I), and wherein R12, R13, R14 and R15 are independently at each occurrence selected from H or C1-C3alkyl, preferably H or methyl, or two of said R12, R13, R14 and R15 together with the carbon atom to which they are attached form a carbocycle or heterocycle, preferably a carbocycle, and wherein R16 and R17 are independently of each other selected from H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a heteroaryl or a heterocyclyl, each independently optionally substituted with halogen, C1-C4alkyl, OR18, NR19R20; or a pharmaceutically acceptable salt of said compound of formula (I).

Description

[0001] COMPOUNDS FOR TREATMENT OF CANCER The present invention relates to novel compounds of formula (I) having anti-cancer activity, pharmaceutically acceptable salts thereof as well as pharmaceutical compositions comprising the same and the use of such compounds for the treatment of cancer. RELATED ART Cancer is a leading cause of death worldwide, accounting for nearly 10 million deaths in 2020 or nearly one in six deaths (WHO Cancer Fact Sheet 2022). The most common in 2020, in terms of new cases of cancer, were: breast cancer, lung cancer, colon and rectum cancer, prostate cancer, skin cancer, in particular non-melanoma cancer, and stomach cancer, which in addition to liver cancer also caused the most vases of cancer death. Despite the enormous activities, development and achievements, new treatment options are highly needed. A majority of the anticancer drugs used clinically are natural products or are derived from compounds found in nature. Leucinostatins, lipophilic peptide antibiotics produced as microbial metabolites, has generated interest in exploring their applications in human health and agriculture. The leucinostatins are noted to exhibit antimicrobial activities against several types of bacteria and fungi as well as trypanosomes (Kil Y-S et al., J Nat Prod. 2020, 83(6):2010– 2024; and references cited therein). Moreover, leucinostatin A has reported to inhibit the growth of DU-145 human prostate cancer cells in vitro and in vivo only when co-cultured with prostate stromal cells through a proposed mechanism of reduced insulin-like growth factor signaling (Momose I et al., Biochem. Biophys. Res. Commun 2010, 392:460–466). A new class of synthetic leucinostatin derivatives and its use for the treatment of protozoan infections, and further in particular for treatment of skin diseases associated with a protozoan disease, a bacterial infection or a fungal infection, has been described (EP3345917A1, WO2022 / 167656A1), while synthetic peptide compounds and its assessment for antiproliferative activity against 3 breast cancer cell lines (MDA-MB-468, SKBR3 and T47D), as well as a non-small cell lung cancer line NCI-H460 are disclosed in WO 2020 / 095253A1. SUMMARY OF THE INVENTION We have surprisingly found that the inventive compounds show strong activity against a plurality of different cancer cells including skin cancer cells such as cutaneous squamous cell carcinoma cells, epithelial skin cancer cells and melanoma skin cancer cells as well as breast cancer cells, colorectal cancer cells, hematopoietic cancer cell lines, cancer cells of the female genitourinary (GU) system, lung cancer cells, head and neck cancer cells, pancreas cancer cells, prostate cancer cells, bladder cancer cells, CNS cancer cells, stomach cancer cells, endocrine cancer cells and kidney cancer cells. This strong activity of the inventive compounds has been demonstrated not only over a structurally similar prior art reference compound but in addition it has been compared to staurosporine which typically serves as a suitable and very potent comparator for those skilled in the art. In particular, it has been surprisingly found that the combination of structural modifications of the inventive compounds, namely the substitution of the pyrrolidine ring system, as present in the inventive compounds, and the substitution of the amino acid threo-β-hydroxy-L-leucine, as being present, for example, in naturally occurring leucinostatins, by leucine preferably (S)-leucine, and thus by omitting the hydroxyl group at the specific position and replacement with hydrogen, resulted not only in a substantial increase of the activity of the inventive compounds, but further to a highly reduced toxicity thereby overcoming one of the main challenges that has been hampering the development to commercialization of such compounds. Moreover, the tailoring and reduction of the amino acid chain length of the inventive compounds to preferred compounds of an amino acid chain length of a total of eight, while reducing costs of goods of such compounds and drugs, respectively, additionally further led to an additional increase in efficacy. These findings have further been confirmed by the significant efficacy of a preferred inventive compound in experiments using fresh ex vivo infiltrative cSCC patient materials. Thus, in a first aspect, the present invention provides a compound of formula (I) wherein --A-- represents a peptide chain, wherein said peptide chain consists of 4 to 9 amino acids, wherein preferably said amino acids are selected from α-aminoisobutyric acid (Aib), leucine (Leu), preferably (S)-leucine, or β-alanine (β-Ala); , wherein the arrow indicates the attachment to the NH-moiety depicted in formula (I), and wherein R5is selected from H, C1-C16alkyl, C1-C16alkenyl, carbocyclyl, heterocyclyl,,C1-C3alkylene-carbocyclyl or C1-C3alkylene-heterocyclyl, wherein said C1-C16alkyl and said C1-C16alkenyl each independently optionally substituted with halogen, OR18, NR19R20, -[O-C2H4]n-OCH3wherein n=2-20; and wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C4alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl, and wherein R6, R7, R8, R9,R10,R11are independently at each occurrence selected from H, C1-C6alkyl, C1-C6alkenyl, carbocyclyl, heterocyclyl, C1-C3alkylene-carbocyclyl, C1- C3alkylene-heterocyclyl, halogen, C1-C2haloalkyl, OR21or NR22R23, wherein said R21, R22, R23are independently at each occurrence selected from H, C1-C6alkyl, C1- C6alkenyl, C(O)O-C1-C6alkyl, C(O)-C1-C6alkyl, C(O)O-C1-C6alkenyl, C(O)-C1- C6alkenyl, carbocyclyl, heterocyclyl, C1-C3alkylene-carbocyclyl or C1-C3alkylene- heterocyclyl, wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C3alkyl, halogen, oxo, C1- C2haloalkyl, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20; or wherein two of said R6, R7, R8, R9,R10,and R11together with the carbon atom to which they are attached form a carbocycle or heterocycle, preferably a carbocycle; said carbocycle and said heterocycle optionally substituted with C1- C3alkyl, halogen, CF3, OR18, NR19R20; and wherein at least one of said R6, R7, R8, R9,R10,and R11is not H; and R2is selected from C4-C12alkyl, C4-C10alkoxy, C1-C3alkylene‒cycloalkyl, C1- C3alkylene‒aryl or C1-C3alkylene‒heteroaryl, wherein independently in said C1- C3alkylene one -CH2- moiety is optionally replaced by –CH(NH)- or -O-; and wherein said alkyl, cycloalkyl, aryl and heteroaryl are each independently optionally substituted with one or more, preferably one or two, substituents selected from C1-C2alkyl, C1- C2haloalkyl, oxo, OH, halogen, C1-C2alkoxy, C6H5or C6H5substituted with C1-C3alkyl or OC1-C3alkyl; R3is wherein the arrow indicates the attachment to the A-moiety in formula (I), and wherein R12, R13, R14and R15are independently at each occurrence selected from H or C1-C3alkyl, preferably H or methyl, or two of said R12, R13, R14and R15together with the carbon atom to which they are attached form a carbocycle or heterocycle, preferably a carbocycle, and wherein R16and R17are independently of each other selected from H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a heteroaryl or a heterocyclyl, each independently optionally substituted with halogen, C1-C4alkyl, OR18, NR19R20; or a pharmaceutically acceptable salt of said compound of formula (I). In a further aspect, the present invention provides a pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof as defined herein, and a pharmaceutically acceptable carrier or adjuvant. In another aspect, the present invention provides a compound of formula (I) for use in a method of treating a cancer of a mammal, preferably of a human, wherein said method comprises administration of said compound to said mammal, preferably to said human. In a further aspect, the present invention provides a pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof as defined herein, and a pharmaceutically acceptable carrier or adjuvant, for use in a method of treating a cancer of a mammal, preferably of a human, wherein said method comprises administration of said pharmaceutical composition to said mammal, preferably to said human. In another aspect, the present invention provides a method of treating a cancer of a mammal, preferably of a human, wherein said method comprises administration of a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition comprising said compound of formula (I) or a pharmaceutically acceptable salt thereof, to said mammal, preferably to said human, and wherein preferably said method comprises administration of an effective amount of said compound to said mammal, preferably to said human. In a further aspect, the present invention provides for the use of a compound of formula (I) of the present invention, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition comprising said compound of formula (I) or a pharmaceutically acceptable salt thereof, for the preparation of a medicament for treating a cancer of a mammal, preferably of a human, wherein said method comprises administration of said compound of formula (I), or said pharmaceutically acceptable salt thereof, or said pharmaceutical composition of the invention, to said mammal, preferably to said human, and wherein preferably said method comprises administration of an effective amount of said compound, or said pharmaceutically acceptable salt thereof, or said pharmaceutical composition, to said mammal, preferably to said human. Further aspects and embodiments of the present invention will be become apparent as this description continues. DESCRIPTION OF THE FIGURES FIG. 1A: Half maximal inhibitory concentrations (IC50) of the preferred inventive compound 23526 as compared to reference compound 6027 in SCC13 skin squamous cell carcinoma cell line as reported in Example 4 showing a statistically significant increase in efficacy (P value: 0.005). FIG.1B: Half maximal inhibitory concentrations (IC50) of the preferred inventive compound 23526 as compared to reference compound 6027 in A31 skin squamous cell carcinoma cell line as reported in Example 4 showing a statistically significant increase in efficacy (P value: 0.03). FIG.1C: Half maximal inhibitory concentrations (IC50) of the preferred inventive compound 23526 as compared to reference compound 6027 in KERTr immortalized keratinocyte cell line as reported in Example 4 showing a statistically significant increase in efficacy (P value: 0.03). FIG.2A: Half maximal inhibitory concentrations (IC50) of the preferred inventive compound 23526 as compared to reference compound 6027 in M150672 melanoma cell line as reported in Example 6 showing a statistically significant increase in efficacy (P value: 0.0039). FIG.2B: Half maximal inhibitory concentrations (IC50) of the preferred inventive compound 23526 as compared to reference compound 6027 in M010817 melanoma cell line as reported in Example 6 showing a statistically significant increase in efficacy (P value: 0.01). FIG.2C: Half maximal inhibitory concentrations (IC50) of the preferred inventive compound 23526 as compared to reference compound 6027 in B16 F10 melanoma cell line as reported in Example 6 showing a statistically significant increase in efficacy (P value: 0.004). FIG.3A: Ex vivo example Immunohistochemistry stainings (HE, ki67) of patient derived cSCC tumor treated for 4 days with 500 nM of 23526 or with DMSO as negative control. FIG.3B: Quantification of ki67 positive cells is indicated. A significant reduction in proliferative tumor cells was observed compared to negative control (DMSO) after treatment with inventive compound 23526 (500 nM; **p<0.0035) in ex vivo infiltrative cSCC patient material. FIG.4A: Ex vivo example Immunohistochemistry stainings (HE, panCK, ki67) of patient derived cSCC tumor treated for 4 days with 500 nM of 6027 or 23526 or with DMSO as negative control.. FIG.4B: Quantification of panCK and ki67 positive cells are indicated. Significant reduction of proliferative tumor cells compared to negative control (DMSO) after treatment with the reference compound 6027 (500 nM; *p<0.03) but in particular after treatment with the inventive compound 23526 (500 nM; **p<0.004) in ex vivo infiltrative cSCC patient material was observed. DETAILED DESCRIPTION OF THE INVENTION Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this invention belongs. The herein described and disclosed embodiments, preferred embodiments and very preferred embodiments should apply to all aspects and other embodiments, preferred embodiments and very preferred embodiments irrespective of whether is specifically again referred to. The articles “a” and “an” are used in this disclosure to refer to one or more than one (i.e., to at least one) of the grammatical object of the article unless the context clearly dictates otherwise. By way of example, “an element” means one element or more than one element. The term “and / or” is used in this disclosure to mean either “and” or “or” unless indicated otherwise. Each alkyl moiety either alone or as part of a larger group such as alkoxy, aminoalkyl or haloalkoxy refers to a monovalent saturated acyclic (i.e., non-cyclic) hydrocarbon group which may be straight or branched. Accordingly, an "alkyl" group does not comprise any carbon-to- carbon double bond or any carbon-to-carbon triple bond. A "C1-6alkyl" denotes an alkyl group having 1 to 6 carbon atoms. Examples include methyl, ethyl, n-propyl, prop-2-yl, n-butyl, but- 2-yl, 2-methyl-prop-1-yl or 2-methyl-prop-2-yl. Examples of an alkoxy include methoxy, ethoxy, propoxy, iso-propoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentoxy, neo-pentoxy, n- hexoxy. Examples of aminoalkyl include aminomethyl, aminoethyl, dimethylaminomethyl, dimethylaminoethyl. Haloalkoxy refers to alkoxy with further substitution of halogen. As used herein, the terms "alkylene" or “alkylenyl,” refer to an alkanediyl group, i.e. a straight or branched hydrocarbon chain bi-radical derived from alkyl, as defined herein, wherein one hydrogen of said alkyl is cleaved off generating the second radical of said alkylene. A "C1-6alkylene" denotes an alkylene group having 1 to 6 carbon atoms. Preferred exemplary alkylene groups are methylene (-CH2-), ethylene (e.g., -CH2-CH2- or -CH(-CH3)-), propylene (e.g., -CH2-CH2-CH2-, -CH(-CH2-CH3)-, -CH2-CH(-CH3)-, or -CH(-CH3)-CH2-), or butylene (e.g., -CH2-CH2-CH2-CH2-). Each haloalkyl moiety either alone or as part of a larger group such as haloalkoxy is an alkyl group substituted by one or more of the same or different halogen atoms. Haloalkyl include for example 1 to 5 halo substituents, or 1 to 3 halo substituents. Examples include in particular fluoromethyl, difluoromethyl, trifluoromethyl, chlorodifluoromethyl and 2,2,2- trifluoro-ethyl. Each alkenyl moiety either alone or as part of a larger group such as alkenyloxy or alkenylene refers to a straight or branched-chain monovalent hydrocarbon radical with at least one site of unsaturation, i.e., a carbon-carbon double bond, wherein the alkenyl radical may be optionally substituted independently with one or more substituents described herein, and includes radicals having (E)- or (Z)-configurations, wherein preferably said alkenyl is a C2- C16alkenyl, more preferably a C2-C14alkenyl. Preferred Examples include vinyl and allyl. A compound of the present invention comprising an alkenyl moiety thus may include, if applicable, either said compound with said alkenyl moiety in its (E)-configuration, said compound with said alkenyl moiety in its (Z)-configuration and mixtures thereof in any ratio. Halogen is fluorine, chlorine, bromine, or iodine. As used herein, the terms "carbocyclyl" or “carbocycle” refers to a monovalent hydrocarbon ring group including monocyclic rings as well as bridged ring, spiro ring and / or fused ring systems (which may be composed, e.g., of two or three rings), wherein said ring group may be saturated, partially unsaturated (i.e., unsaturated but not aromatic) or aromatic. The number of carbon atoms in the carbocyclyl is preferably 3 to 14, more preferably 4 to 12 or 5 to 10. In a preferred embodiment, said carbocyclyl is an aryl, a cycloalkyl or a cycloalkenyl. As used herein, the term "heterocyclyl" or “heterocycle” refers to a monovalent ring group including monocyclic rings as well as bridged ring, spiro ring and / or fused ring systems (which may be composed, e.g., of two or three rings), wherein said ring group comprises one or more (such as, e.g., one, two, three, four or five) ring heteroatoms independently selected from O, S and N, and the remaining ring atoms are carbon atoms, wherein one or more S ring atoms (if present) and / or one or more N ring atoms (if present) may optionally be oxidized, wherein one or more carbon ring atoms may optionally be oxidized (i.e., to form an oxo group), and further wherein said ring group may be saturated, partially unsaturated (i.e., unsaturated but not aromatic) or aromatic. The number of atoms (including carbon and heteroatoms) in the heterocyclyl group is preferably 5 to 14, more preferably 5 to 12 or 5 to 10. In a preferred embodiment, said heterocyclyl is a heteroaryl, a heterocycloalkyl or a heterocycloalkenyl. The term “aryl”, as used herein, refers to a monovalent aromatic hydrocarbon radical of 6-18 carbon atoms (C6-C18). Aryl includes monocyclic, bicyclic, tricyclic or tetracyclic, preferably monocyclic or bicyclic, further preferably monocyclic radicals comprising an aromatic ring to which saturated, partially unsaturated or aromatic carbocycle(s) or heterocycle(s) are fused or bridged. Aryl groups are optionally substituted independently with one or more substituents, typically and preferably with one or two substituents, wherein said substituents are typically and preferably independently at each occurrence selected from C1- C4alkyl, halogen, oxo, C1-C2haloalkyl preferably CF3, OH, OC1-C3alkyl, NH2, NH(C1- C3alkyl), N(C1-C3alkyl)2, C6H5, C6H5substituted with halogen, C1-C3alkyl, OH, OC1-C3alkyl, NH2, NH(C1-C3alkyl), N(C1-C3alkyl)2. Typical aryl groups include, but are not limited to, phenyl, naphthyl, 1,2-dihydronapthalenyl, 1,2,3,4-tetrahydronaphthenyl, anthracenyl, phenanthrenyl, biphenyl, indenyl and indanyl. In a preferred embodiment, said aryl is phenyl or phenyl substituted by one or two substituents, preferably by one substituent, said substituents independently selected from C1-C4alkyl, halogen, C1-C2haloalkyl preferably CF3, OH, OC1- C3alkyl, NH2, NH(C1-C3alkyl), N(C1-C3alkyl)2, C6H5, C6H5substituted with halogen, C1- C3alkyl, OH, OC1-C3alkyl, NH2, NH(C1-C3alkyl), N(C1-C3alkyl)2. As used herein, the term "heteroaryl" refers to an aromatic ring group including monocyclic aromatic rings as well as bridged ring and / or fused ring systems containing at least one aromatic ring (e.g., ring systems composed of two or three fused rings, wherein at least one of these fused rings is aromatic; or bridged ring systems composed of two or three rings, wherein at least one of these bridged rings is aromatic), wherein said aromatic ring group comprises one or more (such as, e.g., one, two, three, four or five) ring heteroatoms independently selected from O, S and N, and the remaining ring atoms are carbon atoms, wherein one or more S ring atoms (if present) and / or one or more N ring atoms (if present) may optionally be oxidized, and further wherein one or more carbon ring atoms may optionally be oxidized (i.e., to form an oxo group). Heteroaryl groups are optionally substituted independently with one or more substituents, typically and preferably with one or two substituents independently selected from C1-C4alkyl, halogen, oxo, C1-C2haloalkyl preferably CF3, OH, OC1-C3alkyl, NH2, NH(C1-C3alkyl), N(C1-C3alkyl)2, C6H5, C6H5substituted with halogen, C1-C3alkyl, OH, OC1-C3alkyl, NH2, NH(C1-C3alkyl), N(C1-C3alkyl)2. Unless defined otherwise, a "heteroaryl" preferably has 5 to 14 ring atoms, more preferably 5 to 12 or 5 to 10 ring atoms. In a preferred embodiment, said heteroaryl is a monovalent monocyclic aromatic or bicyclic aromatic ring group, wherein said aromatic ring group comprises one or more (such as, e.g., one, two, three, or four) ring heteroatoms independently selected from O, S and N, and the remaining ring atoms are carbon atoms, and wherein said aromatic ring group is optionally substituted independently with one or more substituents, typically and preferably with one or two substituents independently selected from C1-C4alkyl, halogen, oxo, C1-C2haloalkyl preferably CF3, OH, OC1-C3alkyl, NH2, NH(C1-C3alkyl), N(C1-C3alkyl)2, C6H5, C6H5substituted with halogen, C1-C3alkyl, OH, OC1-C3alkyl, NH2, NH(C1-C3alkyl), N(C1-C3alkyl)2, wherein said monocyclic or bicyclic heteroaryl preferably has 5 to 12, preferably 5 to 10 ring atoms. Examples of heteroaryl groups are pyridinyl, imidazolyl, imidazopyridinyl, pyrimidinyl, pyrazolyl, triazolyl, pyrazinyl, tetrazolyl, furyl, thienyl, isoxazolyl, thiazolyl, oxadiazolyl, oxazolyl, isothiazolyl, pyrrolyl, quinolinyl, isoquinolinyl, tetrahydroisoquinolinyl, indolyl, benzimidazolyl, benzofuranyl, cinnolinyl, indazolyl, indolizinyl, phthalazinyl, pyridazinyl, triazinyl, isoindolyl, pteridinyl, purinyl, thiadiazolyl, furazanyl, benzofurazanyl, benzopyranyl, benzothiophenyl, benzothiazolyl, benzooxazolyl, coumarinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, and furopyridinyl, wherein said heteroaryl are optionally substituted independently with one or more, preferably one or two substituents independently selected from C1-C4alkyl, halogen, oxo, C1-C2haloalkyl preferably CF3, OH, OC1-C3alkyl, NH2, NH(C1- C3alkyl), N(C1-C3alkyl)2, C6H5, C6H5substituted with halogen, C1-C3alkyl, OH, OC1-C3alkyl, NH2, NH(C1-C3alkyl), N(C1-C3alkyl)2. Further examples of such monocyclic heteroaryl radicals include, but are not limited to: 2-pyridyl, 3-pyridyl, 4-pyridyl, 3-isoxazolyl, 4- isoxazolyl, 5-isoxazolyl, 2-imidazolyl, 4-imidazolyl, 3-pyrazolyl, 4-pyrazolyl, 2-pyrrolyl, 3- pyrrolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 3-pyridazinyl, 4-pyridazinyl, 5-pyridazinyl, 2- pyrimidinyl, 5-pyrimidinyl, 6-pyrimidinyl, 2-pyrazinyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 2- furanyl, 3-furanyl, 2-thienyl, 3-thienyl, 3-triazolyl, 1-triazolyl, 5-tetrazolyl, 1-tetrazolyl, and 2- tetrazolyl, which are optionally substituted independently with one or more substituents, typically and preferably with one or two substituents, wherein said substituents are independently at each occurrence independently selected from C1-C4alkyl, halogen, oxo, CF3, OH, OC1-C3alkyl, NH2, NH(C1-C3alkyl), N(C1-C3alkyl)2, C6H5, C6H5substituted with halogen, C1-C3alkyl, OH, OC1-C3alkyl, NH2, NH(C1-C3alkyl), N(C1-C3alkyl)2. As used herein, the term "cycloalkyl" refers to a monovalent saturated hydrocarbon ring group including monocyclic rings as well as bridged ring, spiro ring and / or fused ring systems (which may be composed, e.g., of two, three or four rings; such as, e.g., a fused ring system composed of two or three fused rings). Cycloalkyl groups are optionally substituted independently with one or more substituents, typically and preferably with one or two substituents independently selected from C1-C4alkyl, halogen, oxo, C1-C2haloalkyl preferably CF3, OH, OC1-C3alkyl, NH2, NH(C1-C3alkyl), N(C1-C3alkyl)2, C6H5, C6H5substituted with halogen, C1-C3alkyl, OH, OC1-C3alkyl, NH2, NH(C1-C3alkyl), N(C1-C3alkyl)2. Unless defined otherwise, "cycloalkyl" preferably refers to a C3-14cycloalkyl. Examples of cycloalkyl are cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, or adamantyl. As used herein, the term "heterocycloalkyl" refers to a monovalent saturated ring group, including monocyclic rings as well as bridged ring, spiro ring and / or fused ring systems (which may be composed, e.g., of two or three rings; such as, e.g., a fused ring system composed of two or three fused rings), wherein said ring group contains one or more (such as, e.g., one, two, three, or four) ring heteroatoms independently selected from O, S and N, and the remaining ring atoms are carbon atoms, wherein one or more S ring atoms (if present) and / or one or more N ring atoms (if present) may optionally be oxidized, and further wherein one or more carbon ring atoms may optionally be oxidized (i.e., to form an oxo group). Heterocycloalkyl groups are optionally substituted independently with one or more substituents, typically and preferably with one or two substituents independently selected from C1-C4alkyl, halogen, oxo, C1- C2haloalkyl preferably CF3, OH, OC1-C3alkyl, NH2, NH(C1-C3alkyl), N(C1-C3alkyl)2, C6H5, C6H5substituted with halogen, C1-C3alkyl, OH, OC1-C3alkyl, NH2, NH(C1-C3alkyl), N(C1- C3alkyl)2. Unless defined otherwise, "heterocycloalkyl" preferably refers to a 3 to 14 membered saturated ring group, which is a monocyclic ring or a fused ring system (e.g., a fused ring system composed of two fused rings), wherein said ring group contains one or more (e.g., one, two, three, or four) ring heteroatoms independently selected from O, S and N, wherein one or more S ring atoms (if present) and / or one or more N ring atoms (if present) are optionally oxidized, and wherein one or more carbon ring atoms are optionally oxidized; more preferably, "heterocycloalkyl" refers to a 5 to 7 membered saturated monocyclic ring group containing one or more (e.g., one, two, or three) ring heteroatoms independently selected from O, S and N, wherein one or more S ring atoms (if present) and / or one or more N ring atoms (if present) are optionally oxidized, and wherein one or more carbon ring atoms are optionally oxidized. As used herein, the term "cycloalkenyl" refers to an unsaturated alicyclic (non-aromatic) hydrocarbon ring group, including monocyclic rings as well as bridged ring, spiro ring and / or fused ring systems (which may be composed, e.g., of two or three rings; such as, e.g., a fused ring system composed of two or three fused rings), wherein said hydrocarbon ring group comprises one or more (e.g., one or two) carbon-to-carbon double bonds and does not comprise any carbon-to-carbon triple bond. Cycloalkenyl groups are optionally substituted independently with one or more substituents, typically and preferably with one or two substituents, wherein said substituents are typically and preferably independently at each occurrence selected from C1-C4alkyl, halogen, oxo, C1-C2haloalkyl preferably CF3, OH, OC1-C3alkyl, NH2, NH(C1- C3alkyl), N(C1-C3alkyl)2, C6H5, C6H5substituted with halogen, C1-C3alkyl, OH, OC1-C3alkyl, NH2, NH(C1-C3alkyl), N(C1-C3alkyl)2. "Cycloalkenyl" may, e.g., refer to cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cyclohexadienyl, cycloheptenyl, or cycloheptadienyl. Unless defined otherwise, "cycloalkenyl" preferably refers to a C3-14cycloalkenyl, and more preferably refers to a C3-7cycloalkenyl. As used herein, the term "heterocycloalkenyl" refers to an unsaturated alicyclic (non-aromatic) ring group, including monocyclic rings as well as bridged ring, spiro ring and / or fused ring systems (which may be composed, e.g., of two or three rings; such as, e.g., a fused ring system composed of two or three fused rings), wherein said ring group contains one or more (such as, e.g., one, two, three, or four) ring heteroatoms independently selected from O, S and N, and the remaining ring atoms and carbon atoms, wherein one or more S ring atoms (if present) and / or one or more N ring atoms (if present) may optionally be oxidized, wherein one or more carbon ring atoms may optionally be oxidized (i.e., to form an oxo group), and further wherein said ring group comprises at least one double bond between adjacent ring atoms and does not comprise any triple bond between adjacent ring atoms. Heterocycloalkenyl groups are optionally substituted independently with one or more substituents, typically and preferably with one or two substituents, wherein said substituents are typically and preferably independently at each occurrence selected from C1-C4alkyl, halogen, oxo, C1-C2haloalkyl preferably CF3, OH, OC1-C3alkyl, NH2, NH(C1-C3alkyl), N(C1-C3alkyl)2, C6H5, C6H5substituted with halogen, C1-C3alkyl, OH, OC1-C3alkyl, NH2, NH(C1-C3alkyl), N(C1-C3alkyl)2. Unless defined otherwise, "heterocycloalkenyl" preferably refers to a 3 to 14 membered unsaturated alicyclic ring group, which is a monocyclic ring or a fused ring system (e.g., a fused ring system composed of two fused rings), wherein said ring group contains one or more (e.g., one, two, three, or four) ring heteroatoms independently selected from O, S and N, wherein one or more S ring atoms (if present) and / or one or more N ring atoms (if present) are optionally oxidized, wherein one or more carbon ring atoms are optionally oxidized, and wherein said ring group comprises at least one double bond between adjacent ring atoms and does not comprise any triple bond between adjacent ring atoms. Where a group or a chemical moiety is said to be “optionally substituted” shall mean that said group or said chemical moiety has the potential to contain other (functional) groups or moieties, but does not necessarily have any further (functional) groups or moieties. Where a group or a chemical moiety is said to be “optionally substituted”, preferably there are optionally 1-5 substituents, more preferably optionally 1-3 substituents, and again more preferably optionally one or two substituents. The term “amino acid”, as used herein, refers to organic compounds containing the functional groups amine (-NH2) and carboxylic acid (-COOH) and its zwitterions, typically and preferably, along with a side chain specific to each amino acid. The term “amino acid” typically and preferably includes amino acids that occur naturally, such as proteinogenic amino acids (produced by RNA-translation), non-proteinogenic amino acids (produced by other metabolic mechanisms, e.g. posttranslational modification), standard or canonical amino acids (that are directly encoded by the codons of the genetic code) and non-standard or non-canonical amino acids (not directly encoded by the genetic code). Naturally occurring amino acids include non- eukaryotic and eukaryotic amino acids. The term “amino acid”, as used herein, also includes unnatural amino acids that are chemically synthesized. Moreover, the term covers alpha- (α-), beta- (β-), gamma- (γ-) and delta- (δ-) etc. amino acids as well as mixtures thereof in any ratio, and any isomeric form of an amino acid, i.e. D- and L-stereoisomers (alternatively addressed by the (R) and (S) nomenclature) as well as mixtures thereof in any ratio, preferably in a racemic ratio of 1:1. Amino acids in this invention are preferably in L-configuration. The term “D- stereoisomer”, “L-stereoisomer”, “D-amino acid” or “L-amino acid” refers to the chiral alpha carbon of the amino acids. Certain compounds of formula (I) of the present invention may contain one or two or more centers of chirality and such compounds may be provided as pure enantiomers or pure diastereoisomers as well as mixtures thereof in any ratio. The compounds of the invention also include all tautomeric forms of the compounds of formula (I). The compounds of formula (I) may also be solvated, especially hydrated, which are also included in the compounds of formula (I). The term "chiral" refers to compounds, which have the property of non-superimposability of the mirror image partner, while the term "achiral" refers to compounds, which are superimposable on their mirror image partner. The term "stereoisomers" refers to compounds, which have identical chemical constitution, but differ with regard to the arrangement of the atoms or groups in space. "Diastereomer" refers to a stereoisomer with two or more centers of chirality in which the compounds are not mirror images of one another. Diastereomers have different physical properties, e.g. melting points, boiling points, spectral properties, and chemical and biological reactivities. Mixtures of diastereomers may be separated under high resolution analytical procedures such as electrophoresis and chromatography. "Enantiomers" refer to two stereoisomers of a compound which are non-superimposable mirror images of one another. Stereochemical definitions and conventions used herein generally follow S.P. Parker, Ed., McRaw-Hiff Dictionary of Chemical Terms (1984), McGraw-Hill Book Company, New York; and Eliel, E. and Wilen, S., "Stereochemistry of Organic Compounds", John Wiley & Sons, Inc., New York, 1994. The compounds of the invention may contain asymmetric or chiral centers, and therefore exist in different stereoisomeric forms. It is intended that all stereoisomeric forms of the compounds of the invention, including but not limited to, diastereomers, enantiomers and atropisomers, as well as mixtures thereof such as racemic mixtures, form part of the present invention. Many organic compounds exist in optically active forms, i.e., they have the ability to rotate the plane of plane-polarized light. In describing an optically active compound, the prefixes D and L, or R and S, are used to denote the absolute configuration of the molecule about its chiral center(s). The prefixes d and l or (+) and (−) are employed to designate the sign of rotation of plane-polarized light by the compound, with (−) or l meaning that the compound is levorotatory. A compound prefixed with (+) or d is dextrorotatory. For a given chemical structure, these stereoisomers are identical except that they are mirror images of one another. A specific stereoisomer may also be referred to as an enantiomer, and a mixture of such isomers is often called an enantiomeric or a scalemic mixture. A 50:50 mixture of enantiomers is referred to as a racemic mixture or a racemate. The term "tautomer" or "tautomeric form" refers to structural isomers of different energies, which are interconvertible via a low energy barrier. For example, proton tautomers include interconversions via migration of a proton, such as keto-enol and imine-enamine isomerizations. The phrase "pharmaceutically acceptable salt" as used herein, refers to pharmaceutically acceptable organic or inorganic salts of a compound of the invention, in particular acid addition salts. Exemplary salts include, but are not limited to, sulfate, citrate, acetate, oxalate, chloride, bromide, iodide, nitrate, bisulfate, phosphate, acid phosphate, isonicotinate, lactate, salicylate, acid citrate, tartrate, oleate, tannate, pantothenate, bitartrate, ascorbate, succinate, maleate, gentisinate, fumarate, gluconate, glucuronate, saccharate, formate, benzoate, glutamate, methanesulfonate (mesylate), ethanesulfonate, benzenesulfonate, p-toluenesulfonate, and pamoate salts. A pharmaceutically acceptable salt may involve the inclusion of another molecule such as an acetate ion, a succinate ion or other counter ion. The counter ion may be any organic or inorganic moiety that stabilizes the charge on the parent compound. Furthermore, a pharmaceutically acceptable salt may have more than one charged atom in its structure. Instances where multiple charged atoms are part of the pharmaceutically acceptable salt can have multiple counter ions. Hence, a pharmaceutically acceptable salt can have one or more charged atoms and / or one or more counter ion. If the compound of the invention is a base, the desired pharmaceutically acceptable salt may be prepared by any suitable method available in the art, for example, treatment of the free base with an inorganic acid, such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, methanesulfonic acid, phosphoric acid and the like, or with an organic acid, such as acetic acid, trifluoroacetic acid, maleic acid, succinic acid, mandelic acid, fumaric acid, malonic acid, pyruvic acid, oxalic acid, glycolic acid, salicylic acid, a pyranosidyl acid, such as glucuronic acid or galacturonic acid, an alpha hydroxy acid, such as citric acid or tartaric acid, an amino acid, such as aspartic acid or glutamic acid, an aromatic acid, such as benzoic acid or cinnamic acid, a sulfonic acid, such as p-toluenesulfonic acid or ethanesulfonic acid, or the like. The term "mammal" includes, but is not limited to, humans, mice, rats, guinea pigs, monkeys, dogs, cats, horses, cows, pigs, and sheep. The term "mammal", as used herein, preferably refers to humans. The term "treatment" of a disorder or disease as used herein (e.g., "treatment" of a skin cancer such as melanoma) is well known in the art. "Treatment" of a disorder or disease implies that a disorder or disease is suspected or has been diagnosed in a patient / subject. A patient / subject suspected of suffering from a disorder or disease typically shows specific clinical and / or pathological symptoms which a skilled person can easily attribute to a specific pathological condition (i.e., diagnose a disorder or disease). The "treatment" of a disorder or disease may, for example, lead to a halt in the progression of the disorder or disease (e.g., no deterioration of symptoms) or a delay in the progression of the disorder or disease (in case the halt in progression is of a transient nature only). The "treatment" of a disorder or disease may also lead to a partial response (e.g., amelioration of symptoms) or complete response (e.g., disappearance of symptoms) of the subject / patient suffering from the disorder or disease. Accordingly, the "treatment" of a disorder or disease may also refer to an amelioration of the disorder or disease, which may, e.g., lead to a halt in the progression of the disorder or disease or a delay in the progression of the disorder or disease. Such a partial or complete response may be followed by a relapse. It is to be understood that a subject / patient may experience a broad range of responses to a treatment. The treatment of a disorder or disease may, inter alia, comprise curative treatment (preferably leading to a complete response and eventually to healing of the disorder or disease) and palliative treatment (including symptomatic relief). The "amelioration" of a disorder or disease may, for example, lead to a halt in the progression of the disorder or disease or a delay in the progression of the disorder or disease. "Treatment" can also mean prolonging survival as compared to expected survival if not receiving treatment. The term "effective amount" means an amount of a compound of the present invention or an inventive pharmaceutical composition that (i) treats the particular disease or disorder or (ii) attenuates, ameliorates, or eliminates one or more symptoms of the particular disease or disorder. In the case of a skin cancer, in particular in case of a cancer is a melanoma or a cutaneous squamous cell carcinoma, the effective amount of the drug may reduce the tumor volume and / or reduce clinical symptoms. The terms "cancer" and "cancerous" includes the physiological condition in mammals that is typically characterized by unregulated cell growth. A "tumor" comprises one or more cancerous cells. The term “skin cancer” as used herein, refers to a skin cancer such as a melanoma skin cancer and non-melanoma skin cancer (NMSC) but also refers and includes precancer and pre- invasive neoplastic skin proliferations such as cutaneous squamous cell carcinoma in situ (cSCCis or Bowen’s disease) or Actinic Keratosis (AK, also called "solar keratosis" and "senile keratosis"). Moreover, the term “skin cancer” as used herein, shall also include cutaneous lymphomas such as cutaneous T-cell lymphoma (CTCL) or cutaneous B-cell lymphoma (CBCL), or a pre-invasive form thereof. Bowen’s disease is a neoplastic skin disease which can be considered as an early stage or intraepidermal form of squamous cell carcinoma. Actinic keratosis is characterized by pre-cancerous patches of thick, scaly, or crusty skin, which are usually formed when skin gets damaged by ultraviolet (UV) radiation from the sun or indoor tanning beds. The term “non-melanoma skin cancer”, (abbreviated as “NMSC”) is used herein to refer to a group of diseases in particular including cutaneous squamous cell carcinoma (cSCC), basal cell carcinoma (BCC), Merkel Cell carcinoma (MCC), Bowen's Disease (BD) and Actinic Keratosis (AK), as well as any precancer and pre-invasive forms thereof. In a first aspect, the present invention provides for a compound of formula (I) wherein --A-- represents a peptide chain, wherein said peptide chain consists of 4 to 9 amino acids, wherein preferably said amino acids are selected from α-aminoisobutyric acid (Aib; 2- amino-2-methylpropionic acid), leucine (Leu), preferably (S)-leucine, or β-alanine (β- Ala); R1is , wherein the arrow indicates the attachment to the NH-moiety depicted in formula (I), and wherein R5is selected from H, C1-C16alkyl, C1-C16alkenyl, carbocyclyl, heterocyclyl,,C1-C3alkylene-carbocyclyl or C1-C3alkylene-heterocyclyl, wherein said C1-C16alkyl and said C1-C16alkenyl each independently optionally substituted with halogen, OR18, NR19R20, -[O-C2H4]n-OCH3wherein n=2-20; and wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C4alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl, and wherein R6, R7, R8, R9,R10,R11are independently at each occurrence selected from H, C1-C6alkyl, C1-C6alkenyl, carbocyclyl, heterocyclyl, C1-C3alkylene-carbocyclyl, C1- C3alkylene-heterocyclyl, halogen, C1-C2haloalkyl, OR21or NR22R23, wherein said R21, R22, R23are independently at each occurrence selected from H, C1-C6alkyl, C1- C6alkenyl, C(O)O-C1-C6alkyl, C(O)-C1-C6alkyl, C(O)O-C1-C6alkenyl, C(O)-C1- C6alkenyl, carbocyclyl, heterocyclyl, C1-C3alkylene-carbocyclyl or C1-C3alkylene- heterocyclyl, wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C3alkyl, halogen, oxo, C1- C2haloalkyl, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20; or wherein two of said R6, R7, R8, R9,R10,and R11together with the carbon atom to which they are attached form a carbocycle or heterocycle, preferably a carbocycle; said carbocycle and said heterocycle optionally substituted with C1- C3alkyl, halogen, CF3, OR18, NR19R20; and wherein at least one of said R6, R7, R8, R9,R10,and R11is not H; and R2is selected from C4-C12alkyl, C4-C10alkoxy, C1-C3alkylene‒cycloalkyl, C1- C3alkylene‒aryl or C1-C3alkylene‒heteroaryl, wherein independently in said C1- C3alkylene one -CH2- moiety is optionally replaced by –CH(NH)- or -O-; and wherein said alkyl, cycloalkyl, aryl and heteroaryl are each independently optionally substituted with one or more, preferably one or two, substituents selected from C1-C2alkyl, C1- C2haloalkyl, oxo, OH, halogen, C1-C2alkoxy, C6H5or C6H5substituted with C1-C3alkyl or OC1-C3alkyl; R3is wherein the arrow indicates the attachment to the A-moiety in formula (I), and wherein R12, R13, R14and R15are independently at each occurrence selected from H or C1-C3alkyl, preferably H or methyl, or two of said R12, R13, R14and R15together with the carbon atom to which they are attached form a carbocycle or heterocycle, preferably a carbocycle, and wherein R16and R17are independently of each other selected from H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a heteroaryl or a heterocyclyl, each independently optionally substituted with halogen, C1-C4alkyl, OR18, NR19R20; or a pharmaceutically acceptable salt of said compound of formula (I). In a further aspect, the present invention provides a pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof as defined herein, and a pharmaceutically acceptable carrier or adjuvant. In a further aspect, the present invention provides a compound of formula (I) for use in a method of treating a cancer of a mammal, preferably of a human, wherein said method comprises administration of said compound to said mammal, preferably to said human. In a further aspect, the present invention provides a pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof as defined herein, and a pharmaceutically acceptable carrier or adjuvant, for use in a method of treating a cancer of a mammal, preferably of a human, wherein said method comprises administration of said pharmaceutical composition to said mammal, preferably to said human. In another aspect, the present invention provides a method of treating a cancer of a mammal, preferably of a human, wherein said method comprises administration of a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition comprising said compound of formula (I) or a pharmaceutically acceptable salt thereof, to said mammal, preferably to said human, and wherein preferably said method comprises administration of an effective amount of said compound to said mammal, preferably to said human. In a further aspect, the present invention provides for the use of a compound of formula (I) of the present invention, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition comprising said compound of formula (I) or a pharmaceutically acceptable salt thereof, for the preparation of a medicament for treating a cancer of a mammal, preferably of a human, wherein said method comprises administration of said compound of formula (I), or said pharmaceutically acceptable salt thereof, or said pharmaceutical composition of the invention, to said mammal, preferably to said human, and wherein preferably said method comprises administration of an effective amount of said compound, or said pharmaceutically acceptable salt thereof, or said pharmaceutical composition, to said mammal, preferably to said human. In a further aspect, the present invention provides a compound of formula (I) for use in a method of treating a skin cancer of a mammal, preferably of a human, wherein said method comprises administration to said mammal, preferably to said human, of a compound of formula (I), or a pharmaceutically acceptable salt thereof, as defined herein, in particular as in any one of the appended claims, wherein preferably said method comprises administration of an effective amount of said compound, or said pharmaceutically acceptable salt thereof, to said mammal, preferably to said human. In a further aspect, the present invention provides a pharmaceutical composition for use in a method of treatment of a skin cancer of a mammal, preferably of a human, wherein said pharmaceutical composition comprises a compound of formula (I), or a pharmaceutically acceptable salt thereof, as defined herein, in particular as in any one of the appended claims, and a pharmaceutically acceptable carrier or adjuvant, and wherein said method comprises administration of said pharmaceutical composition to said mammal, preferably to said human, and wherein preferably said pharmaceutical composition comprises an effective amount of said compound. Thus, in particular, the present invention provides compounds and pharmaceutical compositions for use in methods of treatment of skin cancer of a mammal, preferably of a human, in particular for use in methods of treatment of melanoma and non-melanoma skin cancer, and preferably for melanoma and cutaneous squamous cell carcinoma, wherein said methods comprise administration of an effective amount of a compound of formula (I), or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition comprising said compound of formula (I), or a pharmaceutically acceptable salt thereof, to said mammal, preferably to said human. In another aspect, the present invention provides a method for treating a skin cancer of a mammal, preferably of a human, wherein said method comprises administration of a compound of formula (I) of the present invention, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition comprising said compound of formula (I), or a pharmaceutically acceptable salt thereof, to said mammal, preferably to said human, and wherein preferably said method comprises administration of an effective amount of said compound, or said pharmaceutically acceptable salt thereof, or said pharmaceutical composition to said mammal, preferably to said human. In a further aspect, the present invention provides for the use of a compound of formula (I) of the present invention, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition comprising said compound of formula (I), or a pharmaceutically acceptable salt thereof, for the preparation of a medicament for treating a skin cancer of a mammal, preferably of a human, wherein said method comprises administration of said compound of formula (I), or said pharmaceutically acceptable salt thereof, or said pharmaceutical composition of the invention, to said mammal, preferably to said human, and wherein preferably said method comprises administration of an effective amount of said compound, or said pharmaceutically acceptable salt thereof, or said pharmaceutical composition, to said mammal, preferably to said human. In another aspect, the present invention provides a compound of formula (II) wherein --B-- represents a peptide chain, wherein said peptide chain consists of 0 to 5 amino acids, wherein preferably said amino acids are selected from α-aminoisobutyric acid (Aib; 2- amino-2-methylpropionic acid), leucine (Leu), preferably (S)-leucine, or β-alanine (β- Ala); R1is , wherein the arrow indicates the attachment to the NH-moiety depicted in formula (I), and wherein R5is selected from H, C1-C16alkyl, C1-C16alkenyl, carbocyclyl, heterocyclyl,,C1-C3alkylene-carbocyclyl or C1-C3alkylene-heterocyclyl, wherein said C1-C16alkyl and said C1-C16alkenyl each independently optionally substituted with halogen, OR18, NR19R20, -[O-C2H4]n-OCH3wherein n=2-20; and wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C4alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl, and wherein R6, R7, R8, R9,R10,R11are independently at each occurrence selected from H, C1-C6alkyl, C1-C6alkenyl, carbocyclyl, heterocyclyl, C1-C3alkylene-carbocyclyl, C1- C3alkylene-heterocyclyl, halogen, C1-C2haloalkyl, OR21or NR22R23, wherein said R21, R22, R23are independently at each occurrence selected from H, C1-C6alkyl, C1- C6alkenyl, C(O)O-C1-C6alkyl, C(O)-C1-C6alkyl, C(O)O-C1-C6alkenyl, C(O)-C1- C6alkenyl, carbocyclyl, heterocyclyl, C1-C3alkylene-carbocyclyl or C1-C3alkylene- heterocyclyl, wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C3alkyl, halogen, oxo, C1- C2haloalkyl, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20; or wherein two of said R6, R7, R8, R9,R10,and R11together with the carbon atom to which they are attached form a carbocycle or heterocycle, preferably a carbocycle; said carbocycle and said heterocycle optionally substituted with C1- C3alkyl, halogen, CF3, OR18, NR19R20; and wherein at least one of said R6, R7, R8, R9,R10,and R11is not H; and R2is selected from C4-C12alkyl, C4-C10alkoxy, C1-C3alkylene‒cycloalkyl, C1- C3alkylene‒aryl or C1-C3alkylene‒heteroaryl, wherein independently in said C1- C3alkylene one -CH2- moiety is optionally replaced by –CH(NH)- or -O-; and wherein said alkyl, cycloalkyl, aryl and heteroaryl are each independently optionally substituted with one or more, preferably one or two, substituents selected from C1-C2alkyl, C1- C2haloalkyl, oxo, OH, halogen, C1-C2alkoxy, C6H5or C6H5substituted with C1-C3alkyl or OC1-C3alkyl; R3is wherein the arrow indicates the attachment to the A-moiety in formula (I), and wherein R12, R13, R14and R15are independently at each occurrence selected from H or C1-C3alkyl, preferably H or methyl, or two of said R12, R13, R14and R15together with the carbon atom to which they are attached form a carbocycle or heterocycle, preferably a carbocycle, and wherein R16and R17are independently of each other selected from H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a heteroaryl or a heterocyclyl, each independently optionally substituted with halogen, C1-C4alkyl, OR18, NR19R20; or a pharmaceutically acceptable salt of said compound of formula (I). In a preferred embodiment, said compound of formula (I) is a compound of formula (II). In another preferred embodiment, said compound of formula (I) is a compound selected from any one of the formulas (III) to (VIII) as depicted below. In another preferred embodiment, said compound of formula (II) is a compound selected from any one of the formulas (III) to (VIII) In another preferred embodiment, said compound of formula (II) is a compound selected from any one of the formulas (IV) to (VI). In another preferred embodiment, said compound of formula (II) is a compound selected from any one of the formulas (IV) to (V). In another preferred embodiment, said compound of formula (II) is a compound of formula (V). In another preferred embodiment, said compound of formula (II) is a compound of formula (VI). In another very preferred embodiment, said compound of formula (II) is a compound of formula (IV). In a further aspect, the present invention provides a compound of formula (IV) wherein --B-- represents a peptide chain, wherein said peptide chain consists of 0 to 5 amino acids, wherein preferably said amino acids are selected from α-aminoisobutyric acid (Aib; 2- amino-2-methylpropionic acid), leucine (Leu), preferably (S)-leucine, or β-alanine (β- Ala); R1is , wherein the arrow indicates the attachment to the NH-moiety depicted in formula (I), and wherein R5is selected from H, C1-C16alkyl, C1-C16alkenyl, carbocyclyl, heterocyclyl,,C1-C3alkylene-carbocyclyl or C1-C3alkylene-heterocyclyl, wherein said C1-C16alkyl and said C1-C16alkenyl each independently optionally substituted with halogen, OR18, NR19R20, -[O-C2H4]n-OCH3wherein n=2-20; and wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C4alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl, and wherein R6, R7, R8, R9,R10,R11are independently at each occurrence selected from H, C1-C6alkyl, C1-C6alkenyl, carbocyclyl, heterocyclyl, C1-C3alkylene-carbocyclyl, C1- C3alkylene-heterocyclyl, halogen, C1-C2haloalkyl, OR21or NR22R23, wherein said R21, R22, R23are independently at each occurrence selected from H, C1-C6alkyl, C1- C6alkenyl, C(O)O-C1-C6alkyl, C(O)-C1-C6alkyl, C(O)O-C1-C6alkenyl, C(O)-C1- C6alkenyl, carbocyclyl, heterocyclyl, C1-C3alkylene-carbocyclyl or C1-C3alkylene- heterocyclyl, wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C3alkyl, halogen, oxo, C1- C2haloalkyl, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20; or wherein two of said R6, R7, R8, R9,R10,and R11together with the carbon atom to which they are attached form a carbocycle or heterocycle, preferably a carbocycle; said carbocycle and said heterocycle optionally substituted with C1- C3alkyl, halogen, CF3, OR18, NR19R20; and wherein at least one of said R6, R7, R8, R9,R10,and R11is not H; and R2is selected from C4-C12alkyl, C4-C10alkoxy, C1-C3alkylene‒cycloalkyl, C1- C3alkylene‒aryl or C1-C3alkylene‒heteroaryl, wherein independently in said C1- C3alkylene one -CH2- moiety is optionally replaced by –CH(NH)- or -O-; and wherein said alkyl, cycloalkyl, aryl and heteroaryl are each independently optionally substituted with one or more, preferably one or two, substituents selected from C1-C2alkyl, C1- C2haloalkyl, oxo, OH, halogen, C1-C2alkoxy, C6H5or C6H5substituted with C1-C3alkyl or OC1-C3alkyl; R3is wherein the arrow indicates the attachment to the A-moiety in formula (I), and wherein R12, R13, R14and R15are independently at each occurrence selected from H or C1-C3alkyl, preferably H or methyl, or two of said R12, R13, R14and R15together with the carbon atom to which they are attached form a carbocycle or heterocycle, preferably a carbocycle, and wherein R16and R17are independently of each other selected from H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a heteroaryl or a heterocyclyl, each independently optionally substituted with halogen, C1-C4alkyl, OR18, NR19R20; or a pharmaceutically acceptable salt of said compound of formula (I). In another preferred embodiment, said R5is selected from cycloalkyl, aryl, heteroaryl, C5-C12alkyl, C5-C12alkenyl or C1-C4alkylene–[O-C2H4]n-OCH3wherein n=5-15, wherein said aryl, heteroaryl, cycloalkyl each independently optionally substituted with C1-C4alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20. In another preferred embodiment, said R5is selected from C6-C7alkyl, C6-C7alkenyl, C1- C4alkylene–[O-C2H4]n-OCH3wherein n=8-12, phenyl or a monocyclic heteroaryl comprising one or two heteroatoms selected from N, O and S, preferably oxazolyl, wherein said phenyl or said monocyclic heteroaryl preferably said oxazolyl, each independently optionally substituted with C1-C4alkyl, halogen, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1- C3alkyl, OR18, NR19R20. In another preferred embodiment, said R5is selected from cycloalkyl, aryl, heteroaryl, C5-C12alkyl, or C5-C12alkenyl, wherein said aryl, heteroaryl, cycloalkyl each independently optionally substituted with C1-C4alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20. In another preferred embodiment, said R5is selected from C6-C7alkyl, C6-C7alkenyl, phenyl or a monocyclic heteroaryl comprising one or two heteroatoms selected from N, O and S, preferably oxazolyl, wherein said phenyl or said monocyclic heteroaryl preferably said oxazolyl, each independently optionally substituted with C1-C4alkyl, halogen, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20. In another preferred embodiment, said R5is selected from C5-C12alkyl or C5- C12alkenyl, preferably from C6-C7alkyl or C6-C7alkenyl. In another preferred embodiment, said R5is ((S,E)-4-methylhex-2-enoyl. In another preferred embodiment, said R5is selected from cycloalkyl, aryl or heteroaryl, each independently optionally substituted with C1-C4alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, said R5is selected from cycloalkyl, monocyclic or bicyclic aryl or monocyclic or bicyclic heteroaryl, each independently optionally substituted with C1-C4alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, said R5is selected from phenyl, naphthyl, 1,2- dihydronapthalenyl, 1,2,3,4-tetrahydronaphthenyl, anthracenyl, phenanthrenyl, biphenyl, indenyl, indanyl, pyridinyl, imidazolyl, imidazopyridinyl, pyrimidinyl, pyrazolyl, triazolyl, pyrazinyl, tetrazolyl, furyl, thienyl, isoxazolyl, thiazolyl, oxadiazolyl, oxazolyl, isothiazolyl, pyrrolyl, quinolinyl, isoquinolinyl, tetrahydroisoquinolinyl, indolyl, benzimidazolyl, benzofuranyl, cinnolinyl, indazolyl, indolizinyl, phthalazinyl, pyridazinyl, triazinyl, isoindolyl, pteridinyl, purinyl, thiadiazolyl, furazanyl, benzofurazanyl, benzopyranyl, benzothiophenyl, benzothiazolyl, benzooxazolyl, coumarinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, furopyridinyl, cyclopentyl, cyclopentenyl, cyclohexyl, cyclohexenyl, adamantanyl, each independently optionally substituted with C1-C4alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, said R5is selected from cycloalkyl, monocyclic or bicyclic aromatic aryl or monocyclic or bicyclic heteroaryl, each independently optionally substituted with C1-C4alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, said R5is selected from phenyl or a monocyclic or bicyclic heteroaryl comprising one or two heteroatoms selected from N, O and S, preferably from phenyl, coumarinyl or oxazolyl, further preferably phenyl or oxazolyl; each independently optionally substituted with C1-C4alkyl, halogen, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, said R5is selected from phenyl or monocyclic or bicyclic heteroaryl, each independently optionally substituted with C1-C4alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, said R1is selected from phenyl or monocyclic or bicyclic aromatic heteroaryl, each independently optionally substituted with C1-C4alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, said R5is selected from phenyl, imidazolyl, furyl, thienyl, isoxazolyl, thiazolyl, oxazolyl, isothiazolyl, pyrrolyl, quinolinyl, isoquinolinyl, indolyl, benzimidazolyl, benzopyranyl, benzothiophenyl, benzothiazolyl, benzooxazolyl, each independently optionally substituted with C1-C4alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, said R5is selected from phenyl, imidazolyl, furyl, thienyl, isoxazolyl, thiazolyl, oxazolyl, isothiazolyl, pyrrolyl, quinolinyl, isoquinolinyl, indolyl, benzimidazolyl, benzopyranyl, benzothiophenyl, benzothiazolyl, benzooxazolyl, coumarinyl, each independently optionally substituted with methyl, ethyl, chlorine, fluorine, oxo, CF3, OC1-C2alkyl, NR19R20, C6H5, C6H5substituted with methyl, ethyl, chlorine, fluorine, OC1-C2alkyl, NR19R20, wherein R19, R20are independently at each occurrence H, methyl, ethyl. In a further preferred embodiment, said R5is selected from phenyl, imidazolyl, furyl, thienyl, isoxazolyl, thiazolyl, oxazolyl, isothiazolyl, pyrrolyl, indolyl, coumarinyl, each independently optionally substituted with C1-C4alkyl, halogen, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, said R5is selected from phenyl, thienyl, oxazolyl, pyrrolyl, coumarinyl, each independently optionally substituted with C1-C4alkyl, halogen, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, said R5is selected from phenyl, thienyl, oxazolyl, pyrrolyl, coumarinyl, each independently optionally substituted, preferably mono- substituted, with methyl, ethyl, chlorine, fluorine, CF3, OC1-C2alkyl, NR5R6, C6H5, C6H5substituted with methyl, ethyl, chlorine, fluorine, OC1-C2alkyl, NR19R20, wherein R19, R20are independently at each occurrence H, methyl, ethyl. In a further preferred embodiment, said R5is selected from the formula wherein R indicates the attachment to the C(O)-moiety depicted in formula (I). In a further preferred embodiment, said R5is phenyl or oxazolyl, each independently optionally substituted with C1-C4alkyl, halogen, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, said R5is phenyl, coumarinyl or oxazolyl, each independently optionally substituted, preferably mono-substituted, with methyl, ethyl, chlorine, fluorine, CF3, OC1-C2alkyl, NR5R6, C6H5, C6H5substituted with methyl, ethyl, chlorine, fluorine, OC1-C2alkyl, NR19R20, wherein R19, R20are independently at each occurrence H, methyl, ethyl. In a further preferred embodiment, said R5is phenyl, coumarinyl or oxazolyl, each independently optionally substituted, preferably mono-substituted, with methyl, chlorine, fluorine, CF3, OCH3C6H5, C6H5substituted, preferably mono-substituted, with methyl or fluorine. In a further very preferred embodiment, said R5 is , wherein R indicates the attachment to the C(O)-moiety depicted in formula (I). In a preferred embodiment, said R6, R7, R8, R9,R10,R11are independently at each occurrence selected from H, C1-C4alkyl, C1-C4alkenyl, carbocyclyl, heterocyclyl, C1- C2alkylene-carbocyclyl, C1-C2alkylene-heterocyclyl, halogen, CF3, OR21or NR22R23, wherein said R21, R22, R23are independently at each occurrence selected from H, C1-C4alkyl, C1- C4alkenyl, C(O)O-C1-C4alkyl, C(O)-C1-C4alkyl, C(O)O-C1-C4alkenyl, C(O)-C1-C4alkenyl, carbocyclyl, heterocyclyl, C1-C2alkylene-carbocyclyl or C1-C2alkylene-heterocyclyl, wherein said carbocyclyl and said heterocyclyl is mono- or bicyclic, and wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C3alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1- C3alkyl, OR18, NR19R20; or wherein two of said R6, R7, R8, R9,R10,and R11together with the carbon atom to which they are attached form a mono- or bicyclic carbocycle or heterocycle, preferably a mono- or bicyclic carbocycle; wherein said carbocycle and said heterocycle each independently optionally substituted with C1-C3alkyl, halogen, CF3, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl, In another preferred embodiment, said R6, R7, R8, R9,R10,R11are independently at each occurrence selected from H, C1-C4alkyl, C1-C4alkenyl, carbocyclyl, heterocyclyl, C1- C2alkylene-carbocyclyl, C1-C2alkylene-heterocyclyl, halogen, CF3, OR21or NR22R23, wherein said R21and R22, are independently at each occurrence selected from C1-C4alkyl, C1-C4alkenyl, C(O)O-C1-C4alkyl, C(O)-C1-C4alkyl, C(O)O-C1-C4alkenyl, C(O)-C1-C4alkenyl, carbocyclyl, heterocyclyl, C1-C2alkylene-carbocyclyl or C1-C2alkylene-heterocyclyl, and wherein R23is selected from H, C1-C4alkyl, C1-C4alkenyl, C(O)O-C1-C4alkyl, C(O)-C1-C4alkyl, C(O)O-C1- C4alkenyl, C(O)-C1-C4alkenyl, carbocyclyl, heterocyclyl, C1-C2alkylene-carbocyclyl or C1- C2alkylene-heterocyclyl, wherein said carbocyclyl and said heterocyclyl is mono- or bicyclic, and wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C3alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20; or wherein two of said R6, R7, R8, R9,R10,and R11together with the carbon atom to which they are attached form a mono- or bicyclic carbocycle or heterocycle, preferably a mono- or bicyclic carbocycle; wherein said carbocycle and said heterocycle each independently optionally substituted with C1-C3alkyl, halogen, CF3, OR18, NR19R20, wherein preferably R18and R19are independently at each occurrence C1- C3alkyl, and wherein preferably R20is H or C1-C3alkyl. In another preferred embodiment, said R6, R7, R8, R9,R10,R11are independently at each occurrence selected from H, C1-C3alkyl, C1-C3alkenyl, carbocyclyl, heterocyclyl, C1- C2alkylene-carbocyclyl, C1-C2alkylene-heterocyclyl, halogen, CF3, OR21or NR22R23, wherein said R21, R22, R23are independently at each occurrence selected from H, C1-C3alkyl, C1- C3alkenyl, C(O)O-C1-C3alkyl, C(O)-C1-C3alkyl, C(O)O-C1-C3alkenyl, C(O)-C1-C3alkenyl, carbocyclyl, heterocyclyl, C1-C2alkylene-carbocyclyl or C1-C2alkylene-heterocyclyl, wherein said carbocyclyl and said heterocyclyl is monocyclic, and wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C3alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20; or wherein two of said R6, R7, R8, R9,R10,and R11together with the carbon atom to which they are attached form a monocyclic carbocycle or heterocycle, preferably a monocyclic carbocycle; wherein said carbocycle and said heterocycle each independently optionally substituted with C1-C3alkyl, halogen, CF3, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, said R6, R7, R8, R9,R10,R11are independently at each occurrence selected from H, C1-C3alkyl, C1-C3alkenyl, carbocyclyl, heterocyclyl, C1- C2alkylene-carbocyclyl, C1-C2alkylene-heterocyclyl, halogen, CF3, OR21or NR22R23, wherein said R21and R22are independently at each occurrence selected from C1-C3alkyl, C1-C3alkenyl, C(O)O-C1-C3alkyl, C(O)-C1-C3alkyl, C(O)O-C1-C3alkenyl, C(O)-C1-C3alkenyl, carbocyclyl, heterocyclyl, C1-C2alkylene-carbocyclyl or C1-C2alkylene-heterocyclyl, and wherein R23is selected from H, C1-C3alkyl, C1-C3alkenyl, C(O)O-C1-C3alkyl, C(O)-C1-C3alkyl, C(O)O-C1- C3alkenyl, C(O)-C1-C3alkenyl, carbocyclyl, heterocyclyl, C1-C2alkylene-carbocyclyl or C1- C2alkylene-heterocyclyl, wherein said carbocyclyl and said heterocyclyl is monocyclic, and wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C3alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20; or wherein two of said R6, R7, R8, R9,R10,and R11together with the carbon atom to which they are attached form a monocyclic carbocycle or heterocycle, preferably a monocyclic carbocycle; wherein said carbocycle and said heterocycle each independently optionally substituted with C1-C3alkyl, halogen, CF3, OR18, NR19R20, wherein preferably R18and R19are independently at each occurrence C1-C3alkyl, and wherein preferably R20is H or C1-C3alkyl. In a further preferred embodiment, said R6, R7, R8, R9,R10,R11are independently at each occurrence selected from H, C1-C2alkyl, C1-C3alkenyl, carbocyclyl, heterocyclyl, C1alkylene- carbocyclyl, C1alkylene-heterocyclyl, halogen, CF3, OR21or NR22R23, wherein said R21, R22, R23are independently at each occurrence selected from H, C1-C2alkyl, C1-C3alkenyl, C(O)O- C1-C2alkyl, C(O)-C1-C2alkyl, C(O)O-C1-C3alkenyl, C(O)-C1-C3alkenyl, carbocyclyl, heterocyclyl, C1alkylene-carbocyclyl or C1alkylene-heterocyclyl, wherein said carbocyclyl and said heterocyclyl is monocyclic, and wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C2alkyl, halogen preferably F, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen preferably F, C1-C2alkyl, OR18, NR19R20; or wherein two of said R6, R7, R8, R9,R10,and R11together with the carbon atom to which they are attached form a monocyclic carbocycle or heterocycle, preferably a monocyclic carbocycle; wherein said carbocycle and said heterocycle each independently optionally substituted with C1-C2alkyl, halogen preferably F, CF3, OR18, NR19R20, wherein preferably R18and R19are independently at each occurrence C1-C2alkyl, and wherein preferably R20is H or C1-C2alkyl. In a further preferred embodiment, said R6, R7, R8, R9,R10,R11are independently at each occurrence selected from H, C1-C2alkyl, C1-C3alkenyl, carbocyclyl, heterocyclyl, C1alkylene- carbocyclyl, C1alkylene-heterocyclyl, halogen, CF3, OR21or NR22R23, wherein said R21and R22are independently at each occurrence selected from C1-C2alkyl, C1-C3alkenyl, C(O)O-C1- C2alkyl, C(O)-C1-C2alkyl, C(O)O-C1-C3alkenyl, C(O)-C1-C3alkenyl, carbocyclyl, heterocyclyl, C1alkylene-carbocyclyl or C1alkylene-heterocyclyl, and wherein R23is selected from H, C1-C2alkyl, C1-C3alkenyl, C(O)O-C1-C2alkyl, C(O)-C1-C2alkyl, C(O)O-C1-C3alkenyl, C(O)-C1-C3alkenyl, carbocyclyl, heterocyclyl, Calkylene-carbocyclyl or C1alkylene- heterocyclyl, wherein said carbocyclyl and said heterocyclyl is monocyclic, and wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C2alkyl, halogen preferably F, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen preferably F, C1-C2alkyl, OR18, NR19R20; or wherein two of said R6, R7, R8, R9,R10,and R11together with the carbon atom to which they are attached form a monocyclic carbocycle or heterocycle, preferably a monocyclic carbocycle; wherein said carbocycle and said heterocycle each independently optionally substituted with C1-C2alkyl, halogen preferably F, CF3, OR18, NR19R20, wherein preferably R18and R19are independently at each occurrence C1-C2alkyl, and wherein preferably R20is H or C1-C2alkyl. In a preferred embodiment, said R18, R19, R20are independently at each occurrence H, C1- C3alkyl. In a preferred embodiment, said R18and R19are independently at each occurrence C1- C3alkyl, and wherein preferably R20is H or C1-C3alkyl. In a preferred embodiment, said R18and R19are independently at each occurrence C1- C2alkyl, and wherein preferably R20is H or C1-C2alkyl. In a preferred embodiment, said R18and R19are independently at each occurrence methyl, and wherein preferably R20is H or methyl. In a preferred embodiment, at least one of said R6, R7, R8, R9,R10,and R11is H, and at least one of said R6, R7, R8, R9,R10,and R11is not H. In a preferred embodiment, at least two of said R6, R7, R8, R9,R10,and R11is H, and at least one of said R6, R7, R8, R9,R10,and R11is not H. In a preferred embodiment, at least three of said R6, R7, R8, R9,R10,and R11is H, and at least one of said R6, R7, R8, R9,R10,and R11is not H. In a preferred embodiment, at least four of said R6, R7, R8, R9,R10,and R11is H, and at least one of said R6, R7, R8, R9,R10,and R11is not H. In a preferred embodiment, at least five of said R6, R7, R8, R9,R10,and R11is H, and at least one of said R6, R7, R8, R9,R10,and R11is not H. In a preferred embodiment, said R10is H. In a preferred embodiment, said R11is H. In a further preferred embodiment, said R10and said R11is H. In a preferred embodiment, said R6is not H. In a preferred embodiment, said R7is not H. In a preferred embodiment, said R8is not H. In a preferred embodiment, said R9is not H. In a further preferred embodiment, said R8and said R9is not H. In a further preferred embodiment, at least two of said R6, R7, R8and R9are not H. In a further preferred embodiment, said R6and said R8are not H. In a further preferred embodiment, said R7and said R9are not H. In a preferred embodiment, one of said R8or said R9is not H, wherein the stereochemistry at the carbon atom substituted by either R8or R9has the (S)-stereochemistry. In a further preferred embodiment, said R6, R7, R8, R9,R10,R11are independently at each occurrence selected from H, methyl, C1-C3alkenyl, carbocyclyl, heterocyclyl, C1alkylene- carbocyclyl, C1alkylene-heterocyclyl, F, CF3, OR21or NR22R23, wherein said R21, R22, R23are independently at each occurrence selected from H, methyl, C1-C3alkenyl, C(O)O-CH3, C(O)- CH3, C(O)O-C1-C3alkenyl, C(O)-C1-C3alkenyl, carbocyclyl, heterocyclyl, C1alkylene- carbocyclyl or C1alkylene-heterocyclyl, wherein said carbocyclyl and said heterocyclyl is monocyclic, and wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with methyl, F, CF3, OR18, NR19R20, C6H5, C6H5substituted with F, methyl, OR18, NR19R20; or wherein two of said R6, R7, R8, R9,R10,and R11, preferably R8and R9, R7and R9or R6and R8, further preferably R8and R9or R6and R8, together with the carbon atom to which they are attached form a monocyclic carbocycle or heterocycle, preferably a monocyclic carbocycle; wherein said carbocycle and said heterocycle each independently optionally substituted with methyl, F, CF3, OR18, NR19R20, wherein preferably R18and R19are independently at each occurrence methyl, and wherein preferably R20is H or methyl. In a further preferred embodiment, said R6, R7, R8, R9,R10,R11are independently at each occurrence selected from H, methyl, C1-C3alkenyl, carbocyclyl, heterocyclyl, C1alkylene- carbocyclyl, C1alkylene-heterocyclyl, F, CF3, OR21or NR22R23, wherein said R21and R22are independently at each occurrence selected from methyl, C1-C3alkenyl, C(O)O-CH3, C(O)-CH3, C(O)O-C1-C3alkenyl, C(O)-C1-C3alkenyl, carbocyclyl, heterocyclyl, C1alkylene-carbocyclyl or C1alkylene-heterocyclyl, and wherein said R23is selected from H, methyl, C1-C3alkenyl, C(O)O-CH3, C(O)-CH3, C(O)O-C1-C3alkenyl, C(O)-C1-C3alkenyl, carbocyclyl, heterocyclyl, C1alkylene-carbocyclyl or C1alkylene-heterocyclyl, wherein said carbocyclyl and said heterocyclyl is monocyclic, and wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with methyl, F, CF3, OR18, NR19R20, C6H5, C6H5substituted with F, methyl, OR18, NR19R20; or wherein two of said R6, R7, R8, R9,R10,and R11, preferably R8and R9, R7and R9or R6and R8, further preferably R8and R9or R6and R8, together with the carbon atom to which they are attached form a monocyclic carbocycle or heterocycle, preferably a monocyclic carbocycle; wherein said carbocycle and said heterocycle each independently optionally substituted with methyl, F, CF3, OR18, NR19R20, wherein preferably R18and R19are independently at each occurrence methyl, and wherein preferably R20is H or methyl. In a further preferred embodiment, said R6, R7, R8, R9,R10,R11are independently at each occurrence selected from H, methyl, C1-C3alkenyl, phenyl, benzyl, C3-C6cycloalkyl, C1alkylene-C3-6cycloalkyl, F, CF3, OR21or NR22R23, wherein said R21, R22, R23are independently at each occurrence selected from H, methyl, C1-C3alkenyl, C(O)O-CH3, C(O)- CH3, C(O)O-C1-C3alkenyl, C(O)-C1-C3alkenyl, phenyl, benzyl, C3-C6cycloalkyl, C1alkylene- C3-6cycloalkyl, and wherein each of said phenyl, benzyl, C3-C6cycloalkyl independently at each occurrence optionally substituted with methyl, F, CF3, OR18, NR19R20, C6H5, C6H5substituted with F, methyl, OR18, NR19R20; or wherein two of said R6, R7, R8, R9,R10,and R11, preferably R8and R9, R7and R9or R6and R8, further preferably R8and R9or R6and R8, together with the carbon atom to which they are attached form a C3-C6cycloalkyl; wherein said C3-C6cycloalkyl is optionally substituted with methyl, F, CF3, OR18, NR19R20, wherein preferably R18and R19 are independently at each occurrence methyl, and wherein preferably R20is H or methyl. In a further preferred embodiment, said R6, R7, R8, R9,R10,R11are independently at each occurrence selected from H, methyl, C1-C3alkenyl, phenyl, benzyl, C3-C6cycloalkyl, C1alkylene-C3-6cycloalkyl, F, CF3, OR21or NR22R23, wherein said R21and R22are independently at each occurrence selected from methyl, C1-C3alkenyl, C(O)O-CH3, C(O)-CH3, C(O)O-C1-C3alkenyl, C(O)-C1-C3alkenyl, phenyl, benzyl, C3-C6cycloalkyl, C1alkylene-C3-6cycloalkyl, and wherein R23is selected from H, methyl, C1-C3alkenyl, C(O)O-CH3, C(O)-CH3, C(O)O-C1-C3alkenyl, C(O)-C1-C3alkenyl, phenyl, benzyl, C3-C6cycloalkyl, C1alkylene-C3-6cycloalkyl, and wherein each of said phenyl, benzyl, C3-C6cycloalkyl independently at each occurrence optionally substituted with methyl, F, CF3, OR18, NR19R20, C6H5, C6H5substituted with F, methyl, OR18, NR19R20; or wherein two of said R6, R7, R8, R9,R10,and R11, preferably R8and R9, R7and R9or R6and R8, further preferably R8and R9or R6and R8, together with the carbon atom to which they are attached form a C3-C6cycloalkyl; wherein said C3-C6cycloalkyl is optionally substituted with methyl, F, CF3, OR18, NR19R20, wherein preferably R18and R19are independently at each occurrence methyl, and wherein preferably R20is H or methyl. In a preferred embodiment, one, two, three or four of said R6, R7, R8, R9,R10,R11are methyl, wherein the other five, four, three or two of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, one or two of said R6, R7, R8, R9,R10,R11are methyl, wherein the other five or four of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, one of said R6, R7, R8, R9,R10,R11is methyl, wherein the other five of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, two of said R6, R7, R8, R9,R10,R11are methyl, wherein the other four of said R6, R7, R8, R9,R10,R11are H. In a very preferred embodiment, said R6and R7are methyl, wherein said R8, R9,R10and R11are H. In a preferred embodiment, said R8and R9are methyl, wherein said R6, R7,R10and R11are H. In a preferred embodiment, said R10and R11are methyl, wherein said R6, R7,R8and R9are H. In a preferred embodiment, said R6is methyl, wherein R7, R8,R9,R10and R11are H. In a preferred embodiment, said R7is methyl, wherein R6, R8,R9,R10and R11are H. In a very preferred embodiment, said R8is methyl, wherein R6, R7, R9,R10and R11are H. In a preferred embodiment, said R9is methyl, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, said R10is methyl, wherein R6, R7, R8,R9and R11are H. In a preferred embodiment, said R11is methyl, wherein R6, R7, R8,R9and R10are H. In a preferred embodiment, said R8is OH, wherein R6, R7, R9,R10and R11are H. In a preferred embodiment, said R9is OH, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, said R6and R8together with the carbon atom to which they are attached form a cyclohexyl, wherein R7, R9, R10and R11are H. In a preferred embodiment, said R7and R9together with the carbon atom to which they are attached form a cyclohexyl, wherein R6, R8, R10and R11are H. In a preferred embodiment, one of said R6, R7, R8, R9,R10,R11is O-phenyl optionally substituted with methyl, F, CF3, wherein the other five of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, said R8is O-phenyl, optionally substituted with methyl, F, CF3, wherein R6, R7, R9,R10and R11are H. In a preferred embodiment, said R9is O-phenyl optionally substituted with methyl, F, CF3, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, one of said R6, R7, R8, R9,R10,R11is O-phenyl, wherein the other five of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, said R8is O-phenyl, wherein R6, R7, R9,R10and R11are H. In a preferred embodiment, said R9is O-phenyl, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, one of said R6, R7, R8, R9,R10,R11is benzyl optionally substituted with methyl, F, CF3, wherein the other five of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, said R8is benzyl optionally substituted with methyl, F, CF3, wherein R6, R7, R9,R10and R11are H. In a preferred embodiment, said R9is benzyl optionally substituted with methyl, F, CF3, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, one of said R6, R7, R8, R9,R10,R11is benzyl substituted with F, wherein the other five of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, said R8is benzyl substituted with F, wherein R6, R7, R9,R10and R11are H. In a preferred embodiment, said R9is benzyl substituted with F, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, said R8is benzyl substituted with F at the para position, wherein R6, R7, R9,R10and R11are H. In a preferred embodiment, said R9is benzyl substituted with F at the para position, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, one or two of said R6, R7, R8, R9,R10,R11are F, wherein the other five or four of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, one of said R6, R7, R8, R9,R10,R11is F, wherein the other five of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, two of said R6, R7, R8, R9,R10,R11are F, wherein the other four of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, said R8is F, wherein R6, R7, R9,R10and R11are H. In a preferred embodiment, said R9is F, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, said R8and said R9are F, wherein R6, R7, R10and R11are H. In a preferred embodiment, one of said R6, R7, R8, R9,R10,R11is CF3, wherein the other five of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, said R8is CF3, wherein R6, R7, R9,R10and R11are H. In a preferred embodiment, said R9is CF3, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, said R6and R7together with the carbon atom to which they are attached form a cyclopropyl, wherein R8, R9, R10and R11are H. In a preferred embodiment, said R8and R9together with the carbon atom to which they are attached form a cyclopropyl, wherein R6, R7, R10and R11are H. In a preferred embodiment, one of said R6, R7, R8, R9,R10,R11is phenyl optionally substituted with methyl, F, CF3, wherein the other five of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, said R8is phenyl, optionally substituted with methyl, F, CF3, wherein R6, R7, R9,R10and R11are H. In a very preferred embodiment, said R9is phenyl optionally substituted with methyl, F, CF3, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, one of said R6, R7, R8, R9,R10,R11is phenyl, wherein the other five of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, said R8is phenyl, wherein R6, R7, R9,R10and R11are H. In a very preferred embodiment, said R9is phenyl, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, one of said R6, R7, R8, R9,R10,R11is phenyl substituted with F, wherein the other five of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, said R8is phenyl optionally substituted with F, wherein R6, R7, R9,R10and R11are H. In a very preferred embodiment, said R9is phenyl substituted with F, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, said R8is phenyl, optionally substituted with F at the para position, wherein R6, R7, R9,R10and R11are H. In a preferred embodiment, said R9is phenyl substituted with F at the para position, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, one of said R6, R7, R8, R9,R10,R11is cyclohexyl optionally substituted with methyl, F, CF3, wherein the other five of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, said R8is cyclohexyl optionally substituted with methyl, F, CF3, wherein R6, R7, R9,R10and R11are H. In a preferred embodiment, said R9is cyclohexyl optionally substituted with methyl, F, CF3, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, said R8is cyclohexyl, wherein R6, R7, R9,R10and R11are H. In a preferred embodiment, said R9is cyclohexyl, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, one of said R6, R7, R8, R9,R10,R11is O-benzyl optionally substituted with methyl, F, CF3, wherein the other five of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, said R8is O-benzyl, optionally substituted with methyl, F, CF3, wherein R6, R7, R9,R10and R11are H. In a preferred embodiment, said R9is O-benzyl optionally substituted with methyl, F, CF3, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, one of said R6, R7, R8, R9,R10,R11is O-benzyl, wherein the other five of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, said R8is O-benzyl, wherein R6, R7, R9,R10and R11are H. In a preferred embodiment, said R9is O-benzyl, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, one of said R6, R7, R8, R9,R10,R11is NHC(O)O-allyl, wherein the other five of said R6, R7, R8, R9,R10,R11are H. In a preferred embodiment, said R8is NHC(O)O-allyl, wherein R6, R7, R9,R10and R11are H. In a preferred embodiment, said R9is NHC(O)O-allyl, wherein R6, R7, R8,R10and R11are H. In a preferred embodiment, said R1is selected from the formula wherein R indicates the attachment to the NH-moiety depicted in formula (I). In another preferred embodiment, said wherein R indicates , wherein R indicates the attachment to the NH-moiety depicted in formula (I). In another preferred embodiment, said R1is , wherein R indicates the attachment to the NH-moiety depicted in formula (I). attachment to the NH-moiety depicted in formula In another preferred embodiment, said R1 wherein R indicates the attachment to the NH-moiety depicted in formula (I). In another preferred embodiment, said wherein R indicates the , wherein R indicates the , wherein R indicates the attachment to the NH-moiety depicted in formula In another preferred embodiment, said R1 wherein R indicates the attachment to the NH-moiety depicted in formula (I). In another preferred embodiment, said R1is , wherein R indicates the attachment to the NH-moiety depicted in formula (I). the attachment to the NH-moiety depicted in formula (I). In another preferred embodiment, said , wherein R indicates the attachment to the NH-moiety depicted in formula (I). In another preferred embodiment, said , wherein R indicates the attachment to the NH-moiety depicted in formula (I). In another preferred embodiment, said , wherein R indicates the attachment to the NH-moiety depicted in formula (I). the attachment to the NH-moiety depicted in formula (I). In another preferred embodiment, said wherein R indicates the attachment to the NH-moiety depicted in formula (I). In another preferred embodiment, said wherein R indicates the attachment to the NH-moiety depicted in formula (I). In another preferred embodiment, said R1is , wherein R indicates the attachment to the NH-moiety depicted in formula (I). In a further preferred embodiment, said R2is selected from C5-C12alkyl, C4-C10alkoxy, C1-C3alkylene‒cycloalkyl, C1-C3alkylene‒aryl, C1-C3alkylene‒heteroaryl, wherein independently in said C1-C3alkylene one -CH2- moiety is optionally replaced by –CH(NH)- or -O-; and wherein said alkyl, cycloalkyl, aryl and heteroaryl are each independently optionally and preferably substituted with one or more, typically and preferably one or two, substituents selected from C1-C2alkyl, C1-C2haloalkyl, oxo, OH, halogen, C1-C2alkoxy, C6H5or C6H5substituted with C1-C3alkyl or OC1-C3alkyl. In a further preferred embodiment said R2is selected from C5-C12alkyl, C4-C10alkoxy, C1-C3alkylene‒C5-C6cycloalkyl, C1-C3alkylene‒phenyl, C1-C3alkylene‒biphenyl, C1- C3alkylene‒(mono- or bicyclic-heteroaryl), wherein independently in said C1-C3alkylene one - CH2- moiety is optionally replaced by –CH(NH)- or -O-, and wherein said phenyl, biphenyl, C5-C6-cycloalkyl, and mono- or bicyclic-heteroaryl are each independently optionally substituted with one or more, typically and preferably one or two, substituents selected from methyl, ethyl, fluorine, chlorine, methoxy, wherein preferably said mono- or bicyclic-heteroaryl is selected from imidazolyl, furyl, thienyl, isoxazolyl, thiazolyl, oxazolyl, isothiazolyl, pyrrolyl, quinolinyl, isoquinolinyl, indolyl, benzimidazolyl, benzopyranyl, benzothiophenyl, benzothiazolyl, benzooxazolyl. In a further preferred embodiment said R2is selected from C5-C12alkyl, C4-C10alkoxy, C1-C2alkylene‒C5-C6cycloalkyl, C1-C2alkylene‒phenyl, C1-C2alkylene‒biphenyl, C1- C2alkylene‒(mono- or bicyclic-heteroaryl), wherein independently in said C1-C2alkylene one - CH2- moiety is optionally replaced by –CH(NH)- or -O-, and wherein said phenyl, biphenyl, C5-C6-cycloalkyl, and mono- or bicyclic-heteroaryl are each independently optionally substituted with one or more, typically and preferably one or two, substituents selected from methyl, ethyl, fluorine, chlorine, methoxy, wherein preferably said mono- or bicyclic-heteroaryl is selected from imidazolyl, furyl, thienyl, isoxazolyl, thiazolyl, oxazolyl, isothiazolyl, pyrrolyl, quinolinyl, isoquinolinyl, indolyl, benzimidazolyl, benzopyranyl, benzothiophenyl, benzothiazolyl, benzooxazolyl, and wherein further preferably said mono- or bicyclic- heteroaryl is selected from isoxazolyl, thiazolyl, oxazolyl, isothiazolyl, indolyl, benzimidazolyl, benzothiazolyl, benzooxazolyl. In a further preferred embodiment said R2is selected from C5-C12alkyl, C4-C10alkoxy, C1-C2alkylene‒C5-C6cycloalkyl, C1-C2alkylene‒phenyl, C1-C2alkylene‒biphenyl, C1- C2alkylene‒(mono- or bicyclic-heteroaryl), wherein independently in said C1-C2alkylene one - CH2- moiety is optionally replaced by –CH(NH)- or -O-, and wherein said phenyl, biphenyl, C5-C6-cycloalkyl, and mono- or bicyclic-heteroaryl are each independently optionally substituted with one or more, typically and preferably one or two, substituents selected from methyl, ethyl, fluorine, chlorine, methoxy, wherein said mono- or bicyclic-heteroaryl is selected from isoxazolyl, thiazolyl, oxazolyl, isothiazolyl, indolyl, benzimidazolyl, benzothiazolyl, benzooxazolyl. In a further preferred embodiment said R2is selected from C5-C12alkyl, C4-C10alkoxy, C1-C2alkylene‒C5-C6cycloalkyl, CH2‒phenyl, CH2‒biphenyl, CH2‒O-biphenyl, CH2‒(mono- or bicyclic-heteroaryl), wherein said phenyl, biphenyl, C5-C6-cycloalkyl, and mono- or bicyclic-heteroaryl are each independently optionally substituted with one or more, typically and preferably one or two, substituents selected from methyl, ethyl, fluorine, chlorine, methoxy, wherein preferably said mono- or bicyclic-heteroaryl is selected from isoxazolyl, thiazolyl, oxazolyl, isothiazolyl, indolyl, benzimidazolyl, benzothiazolyl, benzooxazolyl, and wherein further preferably said mono- or bicyclic-heteroaryl is selected from, thiazolyl, indolyl, benzothiazolyl and benzooxazolyl. In a further preferred embodiment said R2is selected from C5-C12alkyl, C4-C10alkoxy, C1-C2alkylene‒C5-C6cycloalkyl, CH2‒phenyl, CH2‒biphenyl, CH2‒O-biphenyl, CH2‒(mono- or bicyclic-heteroaryl), wherein said phenyl, biphenyl, C5-C6-cycloalkyl, and mono- or bicyclic-heteroaryl are each independently optionally substituted with one or more, typically and preferably one or two, substituents selected from methyl, ethyl, fluorine, chlorine, methoxy, wherein said mono- or bicyclic-heteroaryl is selected from, thiazolyl, indolyl, benzothiazolyl and benzooxazolyl. In a further preferred embodiment, said R2is selected from C5-C12alkyl, C1-C2alkylene‒C5-C6cycloalkyl, CH2‒biphenyl and CH2‒O-biphenyl and a bicyclic-heteroaryl selected from benzothiazolyl and benzooxazolyl. In a further very preferred embodiment, said R2is selected from and wherein R indicates the attachment to the CH-moiety depicted in formula (I). In a further very preferred embodiment, said R2 is ,wherein R indicates the attachment to the CH-moiety depicted in formula (I). In a further very preferred embodiment, said R2 is ,wherein R indicates the attachment to the CH-moiety depicted in formula (I). In a further very preferred embodiment, said R2 is , wherein R indicatesthe attachment to the CH-moiety depicted in formula (I). In a further preferred embodiment, said R3is wherein the arrow indicates the attachment to the A-moiety in formula (I), and wherein R12, R13, R14and R15are independently at each occurrence selected from H or C1-C3alkyl, preferably H or methyl, or two of said R12, R13, R14and R15together with the carbon atom to which they are attached form a carbocycle or heterocycle, preferably a carbocycle, and wherein R16and R17are independently of each other selected from H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a heteroaryl or a heterocyclyl, each independently optionally substituted with halogen, C1-C4alkyl, OR18, NR19R20; wherein said R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, said R3is . In a further preferred embodiment, said R12, R13, R14and R15are independently at each occurrence H or C1-C3alkyl, preferably H or methyl, or independently at each occurrence two of said R12, R13, R14and R15together with the carbon atom to which they are attached form a carbocyclic or heterocyclic ring, preferably a carbocyclic ring, and wherein R16and R17are independently of each other H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a mono- or bicyclic heteroaryl or a a mono- or bicyclic heterocyclyl, preferably selected from a pyridinyl, imidazolyl, imidazopyridinyl, pyrimidinyl, pyrazolyl, triazolyl, pyrazinyl, tetrazolyl, isoxazolyl, thiazolyl, oxadiazolyl, oxazolyl, isothiazolyl, pyrrolyl, quinolinyl, isoquinolinyl, tetrahydroisoquinolinyl, indolyl, benzimidazolyl, indazolyl, indolizinyl, pyridazinyl, triazinyl, isoindolyl, purinyl, pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl, homopiperazinyl, 2-pyrrolinyl, 3- pyrrolinyl, indolinyl, dihyrooxazolyl, pyrazolinyl, pyrazolidinyl, imidazolinyl, imidazolidinyl, each independently optionally substituted with halogen, C1-C4alkyl, OR18, NR19R20; wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, R12, R13, R14and R15are independently at each occurrence H or C1-C3alkyl, preferably H or methyl, or independently at each occurrence two of said R12, R13, R14and R15together with the carbon atom to which they are attached form a monocyclic carbocyclic or monocyclic heterocyclic ring, preferably a monocyclic carbocyclic ring, wherein further preferably said monocyclic carbocyclic ring is selected from cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl, and wherein again further preferably said monocyclic carbocyclic ring is cyclobutyl or cyclopentyl, and wherein R16and R17are independently of each other H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a mono- or bicyclic heteroaryl or a mono- or bicyclic heterocyclyl, preferably selected from a pyridinyl, imidazolyl, imidazopyridinyl, pyrimidinyl, pyrazolyl, triazolyl, pyrazinyl, tetrazolyl, isoxazolyl, thiazolyl, oxadiazolyl, oxazolyl, isothiazolyl, pyrrolyl, quinolinyl, isoquinolinyl, tetrahydroisoquinolinyl, indolyl, benzimidazolyl, indazolyl, indolizinyl, pyridazinyl, triazinyl, isoindolyl, purinyl, pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl, homopiperazinyl, 2-pyrrolinyl, 3-pyrrolinyl, indolinyl, dihyrooxazolyl, pyrazolinyl, pyrazolidinyl, imidazolinyl, imidazolidinyl, each independently optionally substituted with halogen, C1-C4alkyl, OR18, NR19R20; wherein said R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, R12, R13, R14and R15are independently at each occurrence H or C1-C3alkyl, preferably H or methyl, or independently at each occurrence two of said R12, R13, R14and R15together with the carbon atom to which they are attached form a monocyclic carbocyclic or monocyclic heterocyclic ring, preferably a monocyclic carbocyclic ring, wherein further preferably said monocyclic carbocyclic ring is selected from cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl, and wherein again further preferably said monocyclic carbocyclic ring is cyclobutyl or cyclopentyl, and wherein R16and R17are independently of each other H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a monocyclic heteroaryl or a monocyclic heterocyclyl, each independently optionally substituted with halogen, C1-C4alkyl, OR18, NR19R20; wherein said R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, R12, R13, R14and R15are independently at each occurrence H or C1-C3alkyl, preferably H or methyl, or independently at each occurrence two of said R12, R13, R14and R15together with the carbon atom to which they are attached form a monocyclic carbocyclic or monocyclic heterocyclic ring, preferably a monocyclic carbocyclic ring, wherein further preferably said monocyclic carbocyclic ring is selected from cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl, and wherein again further preferably said monocyclic carbocyclic ring is cyclobutyl or cyclopentyl, and wherein R16and R17are independently of each other H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a monocyclic heteroaryl or a monocyclic heterocyclyl, wherein said monocyclic heteroaryl or said monocyclic heterocyclyl comprise one or two heteroatoms (including said nitrogen atom to which R16and R17are attached) selected from nitrogen, oxygen and sulphur, each independently optionally substituted with halogen, C1-C4alkyl, OR18, NR19R20; wherein said R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, R12, R13, R14and R15are independently at each occurrence H or C1-C3alkyl, preferably H or methyl, or independently at each occurrence two of said R12, R13, R14and R15together with the carbon atom to which they are attached form a monocyclic carbocyclic or monocyclic heterocyclic ring, preferably a monocyclic carbocyclic ring, wherein further preferably said monocyclic carbocyclic ring is selected from cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl, and wherein again further preferably said monocyclic carbocyclic ring is cyclobutyl or cyclopentyl, and wherein R16and R17are independently of each other H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a monocyclic heteroaryl or a monocyclic heterocyclyl selected from a pyridinyl, imidazolyl, pyrimidinyl, pyrazolyl, triazolyl, pyrazinyl, tetrazolyl, isoxazolyl, thiazolyl, oxadiazolyl, oxazolyl, isothiazolyl, pyrrolyl, pyridazinyl, triazinyl, pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl, 2-pyrrolinyl, 3-pyrrolinyl, dihyrooxazolyl, pyrazolinyl, pyrazolidinyl, imidazolinyl, imidazolidinyl, each independently optionally substituted with halogen, C1-C4alkyl, OR18, NR19R20; wherein said R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, R12, R13, R14and R15are independently at each occurrence H or C1-C3alkyl, preferably H or methyl, or independently at each occurrence two of said R12, R13, R14and R15together with the carbon atom to which they are attached form a monocyclic carbocyclic ring, wherein further preferably said monocyclic carbocyclic ring is selected from cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl, and wherein again further preferably said monocyclic carbocyclic ring is cyclobutyl or cyclopentyl, and wherein R16and R17are independently of each other H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a monocyclic heterocyclic ring, each independently optionally substituted with halogen, C1-C4alkyl, OR18, NR19R20; wherein said R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, R12, R13, R14and R15are independently at each occurrence H or C1-C3alkyl, preferably H or methyl, or independently at each occurrence two of said R12, R13, R14and R15together with the carbon atom to which they are attached form a monocyclic carbocyclic or monocyclic heterocyclic ring, preferably a monocyclic carbocyclic ring, wherein further preferably said monocyclic carbocyclic ring is selected from cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl, and wherein again further preferably said monocyclic carbocyclic ring is cyclobutyl or cyclopentyl, and wherein R16and R17are independently of each other H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a monocyclic heterocyclyl, wherein said monocyclic heterocyclyl comprise one or two heteroatoms (including said nitrogen atom to which R16and R17are attached) selected from nitrogen, oxygen and sulphur, each independently optionally substituted with halogen, C1- C4alkyl, OR18, NR19R20; wherein said R18, R19, R20are independently at each occurrence H, C1- C3alkyl. In a further preferred embodiment, R12, R13, R14and R15are independently at each occurrence H or C1-C3alkyl, preferably H or methyl, or independently at each occurrence two of said R12, R13, R14and R15together with the carbon atom to which they are attached form a monocyclic carbocyclic ring, wherein further preferably said monocyclic carbocyclic ring is selected from cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl, and wherein again further preferably said monocyclic carbocyclic ring is cyclobutyl or cyclopentyl, and wherein R16and R17are independently of each other H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a monocyclic heterocyclic ring selected from imidazolyl, pyrimidinyl, pyrazolyl, triazolyl, pyrazinyl, tetrazolyl, isoxazolyl, thiazolyl, oxadiazolyl, oxazolyl, isothiazolyl, pyrrolyl, pyridazinyl, triazinyl, pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl, 2-pyrrolinyl, 3-pyrrolinyl, dihyrooxazolyl, pyrazolinyl, pyrazolidinyl, imidazolinyl, imidazolidinyl, each independently optionally substituted with halogen, C1-C4alkyl, OR18, NR19R20; wherein said R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, said R14and R15are H, and said R12and R13are independently at each occurrence H or C1-C3alkyl, preferably H or methyl, or said R12and R13, together with the carbon atom to which they are attached form a monocyclic carbocyclic ring, wherein further preferably said monocyclic carbocyclic ring is selected from cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl, and wherein again further preferably said monocyclic carbocyclic ring is cyclobutyl or cyclopentyl, and wherein R16and R17are independently of each other H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a monocyclic heterocyclic ring selected from imidazolyl, pyrimidinyl, pyrazolyl, triazolyl, pyrazinyl, tetrazolyl, isoxazolyl, thiazolyl, oxadiazolyl, oxazolyl, isothiazolyl, pyrrolyl, pyridazinyl, triazinyl, pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl, 2-pyrrolinyl, 3-pyrrolinyl, dihyrooxazolyl, pyrazolinyl, pyrazolidinyl, imidazolinyl, imidazolidinyl, each independently optionally substituted with halogen, C1- C4alkyl, OR18, NR19R20; wherein said R18, R19, R20are independently at each occurrence H, C1- C3alkyl. In a further preferred embodiment, R12, R13, R14and R15are independently at each occurrence H or C1-C3alkyl, preferably H or methyl, or independently at each occurrence two of said R12, R13, R14and R15together with the carbon atom to which they are attached form a monocyclic carbocyclic ring selected from cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl, preferably said monocyclic carbocyclic ring is cyclobutyl or cyclopentyl, and wherein R16and R17are independently of each other H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a monocyclic heterocyclic ring selected from piperidinyl, morpholinyl, thiomorpholinyl, preferably from piperidinyl or morpholinyl, and further preferably from morpholinyl, each independently optionally substituted with halogen, C1-C4alkyl, OR18, NR19R20; wherein said R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, said R14and R15are H, and said R12and R13are independently at each occurrence H or C1-C3alkyl, preferably H or methyl, or said R12and R13, together with the carbon atom to which they are attached form a monocyclic carbocyclic ring selected from cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl, preferably said monocyclic carbocyclic ring is cyclobutyl or cyclopentyl, and wherein R16and R17are independently of each other H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a monocyclic heterocyclic ring selected from piperidinyl, morpholinyl, thiomorpholinyl, preferably from piperidinyl or morpholinyl, and further preferably from morpholinyl, each independently optionally substituted with halogen, C1-C4alkyl, OR18, NR19R20; wherein said R18, R19, R20are independently at each occurrence H, C1-C3alkyl. In a further preferred embodiment, said R3is selected from the attachment to the A-moiety in formula (I). In a further preferred embodiment, said R3is selected from wherein R indicates the attachment to the C(O)-moiety depicted in formula (I). In a further preferred embodiment, said R3is , wherein R indicates the attachment to the C(O)-moiety depicted in formula (I). In a further very preferred embodiment, said R3is , wherein R indicates the attachment to the C(O)-moiety depicted in In a further preferred embodiment, said R3is wherein R indicates the attachment to the C(O)-moiety depicted in formula (I). H In a further preferred embodiment, said R3is , wherein R indicates the attachment to the C(O)-moiety depicted in formula (I). In a further preferred embodiment, said wherein R indicates the attachment to the C(O)-moiety depicted in formula (I). H In a further preferred embodiment, said R3is , wherein R indicates the attachment to the C(O)-moiety depicted in formula (I). In a further preferred embodiment, said R3is , wherein R indicates the attachment to the C(O)-moiety depicted in formula (I). In a further preferred embodiment, said R3is , wherein R indicates the attachment to the C(O)-moiety depicted in formula (I). H In a further preferred embodiment, said R3is , wherein R indicates the attachment to the C(O)-moiety depicted in formula (I). In a further very preferred embodiment, said compound of formula (I) is selected from 20762: allyl ((3S,5S)-5-(((12S,15S,21S,24S)-26-cyclohexyl-1-((1- ((dimethylamino)methyl)cyclobutyl)amino)-12,15,21-triisobutyl-6,6,9,9,18,18-hexamethyl- 1,5,8,11,14,17,20,23-octaoxo-4,7,10,13,16,19,22-heptaazahexacosan-24-yl)carbamoyl)-1-(4- fluorobenzoyl)pyrrolidin-3-yl)carbamate 22178:(2S,4S)-N-((4S,17S,20S,26S,29S)-31-cyclohexyl-17,20,26-triisobutyl- 2,4,11,11,14,14,23,23-octamethyl-6,10,13,16,19,22,25,28-octaoxo-2,5,9,12,15,18,21,24,27- nonaazahentriacontan-29-yl)-4-methyl-1-((S,E)-4-methylhex-2-enoyl)pyrrolidine-2- carboxamide 22179:(2S,4S)-N-((4S,17S,20S,26S,29S)-31-cyclohexyl-17,20,26-triisobutyl- 2,4,11,11,14,14,23,23-octamethyl-6,10,13,16,19,22,25,28-octaoxo-2,5,9,12,15,18,21,24,27- nonaazahentriacontan-29-yl)-1-(4-fluorobenzoyl)-4-methylpyrrolidine-2-carboxamide 23103:(2S,4S)-N-((12S,15S,21S,24S)-26-cyclohexyl-1-((1- ((dimethylamino)methyl)cyclobutyl)amino)-12,15,21-triisobutyl-6,6,9,9,18,18-hexamethyl- 1,5,8,11,14,17,20,23-octaoxo-4,7,10,13,16,19,22-heptaazahexacosan-24-yl)-4-methyl-1- ((S,E)-4-methylhex-2-enoyl)pyrrolidine-2-carboxamide 23491:(2S,4S)-N-((12S,15S,21S,24S)-26-cyclohexyl-1-((1- ((dimethylamino)methyl)cyclobutyl)amino)-12,15,21-triisobutyl-6,6,9,9,18,18-hexamethyl- 1,5,8,11,14,17,20,23-octaoxo-4,7,10,13,16,19,22-heptaazahexacosan-24-yl)-1-(4- fluorobenzoyl)-4-methylpyrrolidine-2-carboxamide 23525:(2S,4S)-N-((17S,20S,26S,29S)-31-cyclohexyl-17,20,26-triisobutyl- 2,4,4,11,11,14,14,23,23-nonamethyl-6,10,13,16,19,22,25,28-octaoxo- 2,5,9,12,15,18,21,24,27-nonaazahentriacontan-29-yl)-1-(4-fluorobenzoyl)-4- methylpyrrolidine-2-carboxamide 23526:(2S,4S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-1-(4-fluorobenzoyl)-4-methylpyrrolidine-2-carboxamide 23538:(2S,4S)-N-((17S,20S,26S,29S)-31-cyclohexyl-17,20,26-triisobutyl- 2,4,4,11,11,14,14,23,23-nonamethyl-6,10,13,16,19,22,25,28-octaoxo- 2,5,9,12,15,18,21,24,27-nonaazahentriacontan-29-yl)-4-methyl-1-((S,E)-4-methylhex-2- enoyl)pyrrolidine-2-carboxamide 23542:(2S,4S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-4-methyl-1-((S,E)-4-methylhex-2-enoyl)pyrrolidine-2-carboxamide 23549:(2S,4R)-N-((4S,17S,20S,26S,29S)-31-cyclohexyl-17,20,26-triisobutyl- 2,4,11,11,14,14,23,23-octamethyl-6,10,13,16,19,22,25,28-octaoxo-2,5,9,12,15,18,21,24,27- nonaazahentriacontan-29-yl)-1-(4-fluorobenzoyl)-4-hydroxypyrrolidine-2-carboxamide 23552:(1S,3aS,7aR)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-2-(4-fluorobenzoyl)octahydro-1H-isoindole-1-carboxamide 23577:(2S,4R)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-1-(4-fluorobenzoyl)-4-hydroxypyrrolidine-2-carboxamide 23585:(2S,4S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-1-(4-fluorobenzoyl)-4-(trifluoromethyl)pyrrolidine-2-carboxamide 23586:(2S,4R)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-1-(4-fluorobenzoyl)-4-methylpyrrolidine-2-carboxamide 23594:(2S,4S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-1-(4-fluorobenzoyl)-4-phenoxypyrrolidine-2-carboxamide 23595:(2S,4R)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-4-fluoro-1-(4-fluorobenzoyl)pyrrolidine-2-carboxamide 23596:(2S,4R)-4-(benzyloxy)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22- triisobutyl-2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-1-(4-fluorobenzoyl)pyrrolidine-2-carboxamide 23612:(2S,4S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-1-(4-fluorobenzoyl)-4-phenylpyrrolidine-2-carboxamide 23687:(2S,4S)-N-((4S,10S,13S,19S,22S)-24-cyclohexyl-10,13,19-triisobutyl- 2,4,7,7,16,16-hexamethyl-6,9,12,15,18,21-hexaoxo-2,5,8,11,14,17,20-heptaazatetracosan-22- yl)-1-(4-fluorobenzoyl)-4-methylpyrrolidine-2-carboxamide 23692:(2S,4S)-N-((4S,11S,20S,23S,29S,32S)-34-cyclohexyl-11,20,23,29- tetraisobutyl-2,4,14,14,17,17,26,26-octamethyl-6,10,13,16,19,22,25,28,31-nonaoxo- 2,5,9,12,15,18,21,24,27,30-decaazatetratriacontan-32-yl)-1-(4-fluorobenzoyl)-4- methylpyrrolidine-2-carboxamide 23693:(2S,4S)-N-((4S,11S,14S,23S,26S,32S,35S)-37-cyclohexyl-11,14,23,26,32- pentaisobutyl-2,4,17,17,20,20,29,29-octamethyl-6,10,13,16,19,22,25,28,31,34-decaoxo- 2,5,9,12,15,18,21,24,27,30,33-undecaazaheptatriacontan-35-yl)-1-(4-fluorobenzoyl)-4- methylpyrrolidine-2-carboxamide 23705:(2S,4S)-N-((4S,14S,17S,26S,29S,35S,38S)-40-cyclohexyl-14,17,26,29,35- pentaisobutyl-2,4,11,11,20,20,23,23,32,32-decamethyl-6,10,13,16,19,22,25,28,31,34,37- undecaoxo-2,5,9,12,15,18,21,24,27,30,33,36-dodecaazatetracontan-38-yl)-1-(4- fluorobenzoyl)-4-methylpyrrolidine-2-carboxamide 23717:(2S,5S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-1-(4-fluorobenzoyl)-5-methylpyrrolidine-2-carboxamide 23718:(S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-1-(4-fluorobenzoyl)-5,5-dimethylpyrrolidine-2-carboxamide 23720:(2S,4R)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-1-(4-fluorobenzoyl)-4-phenylpyrrolidine-2-carboxamide 23736:(S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-1-(4-fluorobenzoyl)-3,3-dimethylpyrrolidine-2-carboxamide 23738:(2S,4S)-4-cyclohexyl-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22- triisobutyl-2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-1-(4-fluorobenzoyl)pyrrolidine-2-carboxamide 23739:(2S,5R)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-1-(4-fluorobenzoyl)-5-phenylpyrrolidine-2-carboxamide 23742:(2S,4R)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-1-(4-fluorobenzoyl)-4-(4-fluorobenzyl)pyrrolidine-2-carboxamide 23794:(S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-4,4-difluoro-1-(4-fluorobenzoyl)pyrrolidine-2-carboxamide 23795:(S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-5-(4-fluorobenzoyl)-5-azaspiro[2.4]heptane-6-carboxamide, or 23826:(2S,4S)-N-((13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 7,7,10,10,19,19-hexamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-1-(4-fluorobenzoyl)-4-methylpyrrolidine-2-carboxamide. 24879:(2S)‐2‐[(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl)‐4‐[4‐(2‐ methylpropyl)‐1H‐1,2,3‐triazol‐1‐yl]pyrrolidin‐2‐yl]formamido}butanamido]‐N‐(1‐{[(1S)‐1‐ {[(1S)‐1‐({1‐[(1‐{[(2S)‐1‐(dimethylamino)propan‐2‐yl]carbamoyl}‐1‐ methylethyl)carbamoyl]‐1‐methylethyl}carbamoyl)‐3‐methylbutyl]carbamoyl}‐3‐ methylbutyl]carbamoyl}‐1‐methylethyl)‐4‐methylpentanamide 25041:(2S)‐2‐[(2S)‐2‐{2‐[(2S)‐2‐[(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl) 4‐methylpyrrolidin‐2‐yl]formamido}butanamido]‐4‐methylpentanamido]‐2‐ methylpropanamido}‐4‐methylpentanamido]‐4‐methyl‐N‐{1‐methyl‐1‐[(1‐methyl‐1‐{[(2S)‐1‐ (morpholin‐4‐yl)propan‐2‐yl]carbamoyl}ethyl)carbamoyl]ethyl}pentanamide 25042:(2S)‐2‐[(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl)‐4‐ methylpyrrolidin‐2‐yl]formamido}butanamido]‐4‐methyl‐N‐(1‐methyl‐1‐{[(1S)‐3‐methyl‐1‐ {[(1S)‐3‐methyl‐1‐({1‐methyl‐1‐[(1‐methyl‐1‐{[2‐(4‐methylpiperazin‐1‐ yl)ethyl]carbamoyl}ethyl)carbamoyl]ethyl}carbamoyl)butyl]carbamoyl}butyl]carbamoyl}eth yl)pentanamide 25088:(2S)‐2‐[(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl)‐4‐ methylpyrrolidin‐2‐yl]formamido}butanamido]‐N‐(1‐{[(1S)‐1‐{[(1S)‐1‐({1‐[(1‐{[2‐ (dimethylamino)ethyl]carbamoyl}‐1‐methylethyl)carbamoyl]‐1‐methylethyl}carbamoyl)‐3‐ methylbutyl]carbamoyl}‐3‐methylbutyl]carbamoyl}‐1‐methylethyl)‐4‐methylpentanamide 25126:(2S)‐2‐[(2S)‐2‐{2‐[(2S)‐2‐[(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl)‐ 4‐methylpyrrolidin‐2‐yl]formamido}butanamido]‐4‐methylpentanamido]‐2‐ methylpropanamido}‐4‐methylpentanamido]‐4‐methyl‐N‐{1‐methyl‐1‐[(1‐methyl‐1‐{[(2S)‐1‐ (piperazin‐1‐yl)propan‐2‐yl]carbamoyl}ethyl)carbamoyl]ethyl}pentanamide, and 25157:(2S)‐2‐[(2S)‐2‐{2‐[(2S)‐2‐[(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl)‐ 4‐methylpyrrolidin‐2‐yl]formamido}butanamido]‐4‐methylpentanamido]‐2‐ methylpropanamido}‐4‐methylpentanamido]‐4‐methyl‐N‐{1‐methyl‐1‐[(1‐methyl‐1‐{[(2S)‐1‐ (methylamino)propan‐2‐yl]carbamoyl}ethyl)carbamoyl]ethyl}pentanamide. In a further very preferred embodiment, said compound of formula (I) is 23526: (2S,4S)- N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-1-(4- fluorobenzoyl)-4-methylpyrrolidine-2-carboxamide. In a further very preferred embodiment, said compound of formula (I) is 23542:(2S,4S)- N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-4- methyl-1-((S,E)-4-methylhex-2-enoyl)pyrrolidine-2-carboxamide. In a further very preferred embodiment, said compound of formula (I) is 23612:(2S,4S)- N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-1-(4- fluorobenzoyl)-4-phenylpyrrolidine-2-carboxamide. In a further very preferred embodiment, said compound of formula (I) is 23736:(S)-N- ((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19-octamethyl- 6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-1-(4- fluorobenzoyl)-3,3-dimethylpyrrolidine-2-carboxamide. In a further very preferred embodiment, said compound of formula (I) is 24879:(2S)‐2‐ [(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl)‐4‐[4‐(2‐methylpropyl)‐1H‐1,2,3‐triazol‐ 1‐yl]pyrrolidin‐2‐yl]formamido}butanamido]‐N‐(1‐{[(1S)‐1‐{[(1S)‐1‐({1‐[(1‐{[(2S)‐1‐ (dimethylamino)propan‐2‐yl]carbamoyl}‐1‐methylethyl)carbamoyl]‐1‐ methylethyl}carbamoyl)‐3‐methylbutyl]carbamoyl}‐3‐methylbutyl]carbamoyl}‐1‐ methylethyl)‐4‐methylpentanamide. In a further very preferred embodiment, said compound of formula (I) is 25041:(2S)‐2‐ [(2S)‐2‐{2‐[(2S)‐2‐[(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl)-4‐methylpyrrolidin‐2‐ yl]formamido}butanamido]‐4‐methylpentanamido]‐2‐methylpropanamido}‐4‐ methylpentanamido]‐4‐methyl‐N‐{1‐methyl‐1‐[(1‐methyl‐1‐{[(2S)‐1‐(morpholin‐4‐ yl)propan‐2‐yl]carbamoyl}ethyl)carbamoyl]ethyl}pentanamide. In a further very preferred embodiment, said compound of formula (I) is 25042:(2S)‐2‐ [(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl)‐4‐methylpyrrolidin‐2‐yl]formamido} butanamido]‐4‐methyl‐N‐(1‐methyl‐1‐{[(1S)‐3‐methyl‐1‐{[(1S)‐3‐methyl‐1‐({1‐methyl‐1‐ [(1‐methyl‐1‐{[2‐(4‐methylpiperazin‐1‐yl)ethyl]carbamoyl}ethyl)carbamoyl]ethyl} carbamoyl)butyl]carbamoyl}butyl]carbamoyl}ethyl)pentanamide In a further very preferred embodiment, said compound of formula (I) is 25088:(2S)‐2‐ [(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl)‐4‐methylpyrrolidin‐2‐yl]formamido} butanamido]‐N‐(1‐{[(1S)‐1‐{[(1S)‐1‐({1‐[(1‐{[2‐(dimethylamino)ethyl]carbamoyl}‐1‐ methylethyl)carbamoyl]‐1‐methylethyl}carbamoyl)‐3‐methylbutyl]carbamoyl}‐3‐ methylbutyl]carbamoyl}‐1‐methylethyl)‐4‐methylpentanamide. In a further very preferred embodiment, said compound of formula (I) is 25126:(2S)‐2‐ [(2S)‐2‐{2‐[(2S)‐2‐[(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl)‐4‐methylpyrrolidin‐2‐ yl]formamido}butanamido]‐4‐methylpentanamido]‐2‐methylpropanamido}‐4‐methylpentan- amido]‐4‐methyl‐N‐{1‐methyl‐1‐[(1‐methyl‐1‐{[(2S)‐1‐(piperazin‐1‐yl)propan‐2‐ yl]carbamoyl}ethyl)carbamoyl]ethyl}pentanamide. In a further very preferred embodiment, said compound of formula (I) is 25157:(2S)‐2‐ [(2S)‐2‐{2‐[(2S)‐2‐[(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl)‐4‐methylpyrrolidin‐2‐ yl]formamido}butanamido]‐4‐methylpentanamido]‐2‐methylpropanamido}‐4‐ methylpentanamido]‐4‐methyl‐N‐{1‐methyl‐1‐[(1‐methyl‐1‐{[(2S)‐1‐(methylamino)propan‐ 2‐yl]carbamoyl}ethyl)carbamoyl]ethyl}pentanamide. In a further very preferred embodiment, said compound of formula (I) is selected from 20762: 23103: 5 23526: 5 23549: 5 23585: 5 23595: 5 23687: 5 23717: 5 23736: 5 23742: 5 23826: 5 25042: 5 25157: In a further very preferred embodiment, said compound of formula (I) is 23526: . In a further very preferred embodiment, said compound of formula (I) is 23542: . In a further very preferred embodiment, said compound of formula (I) is 23612: . In a further very preferred embodiment, said compound of formula (I) is 23736: In a further very preferred embodiment, said compound of formula (I) is 24879: In a further very preferred embodiment, said compound of formula (I) is 25041: In a further very preferred embodiment, said compound of formula (I) is 25042: In a further very preferred embodiment, said compound of formula (I) is In a further very preferred embodiment, said compound of formula (I) is 25126: In a further very preferred embodiment, said compound of formula (I) is 25157: . In a further aspect, the present invention provides for the use of a compound of formula (I) of the present invention, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition comprising said compound of formula (I) or a pharmaceutically acceptable salt thereof, for the preparation of a medicament for treating a cancer of a mammal, preferably of a human, wherein said method comprises administration of said compound of formula (I), or said pharmaceutically acceptable salt thereof, or said pharmaceutical composition of the invention, to said mammal, preferably to said human, and wherein preferably said method comprises administration of an effective amount of said compound, or said pharmaceutically acceptable salt thereof, or said pharmaceutical composition, to said mammal, preferably to said human. In a preferred embodiment, said cancer is selected from the group consisting of skin cancer, breast cancer, colorectal cancer, hematopoietic cancer, cancer of the female genitourinary (GU) system, lung cancer, head and neck cancer, pancreas cancer, prostate cancer, bladder cancer cells, CNS cancer, stomach cancer, endocrine cancer and kidney cancer. In a preferred embodiment, said cancer is a solid tumor. In a further aspect, the present invention provides the use of a compound of formula (6027) or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition comprising said compound 6027 or a pharmaceutically acceptable salt thereof, for the preparation of a medicament for treating a cancer of a mammal, preferably of a human, wherein said method comprises administration of said compound 6027, or said pharmaceutically acceptable salt thereof, to said mammal, preferably to said human, and wherein preferably said method comprises administration of an effective amount of said compound 6027, or said pharmaceutically acceptable salt thereof, to said mammal, preferably to said human, provided that said use is not a method of topical treatment of a skin cancer of a mammal, wherein said method comprises topical administration of said compound to said mammal. In a preferred embodiment, said cancer is selected from the group consisting of skin cancer, breast cancer, colorectal cancer, hematopoietic cancer, cancer of the female genitourinary (GU) system, lung cancer, head and neck cancer, pancreas cancer, prostate cancer, bladder cancer cells, CNS cancer, stomach cancer, endocrine cancer and kidney cancer. In a preferred embodiment, said cancer is a solid tumor. In a further aspect, the present invention provides the use of 6027:(S)-N- ((12S,15S,21S,24S)-26-cyclohexyl-1-((1-((dimethylamino)methyl)cyclobutyl)amino)- 12,15,21-triisobutyl-6,6,9,9,18,18-hexamethyl-1,5,8,11,14,17,20,23-octaoxo- 4,7,10,13,16,19,22-heptaazahexacosan-24-yl)-1-(4-fluorobenzoyl)pyrrolidine-2-carboxamide or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition comprising said compound 6027 or a pharmaceutically acceptable salt thereof, for the preparation of a medicament for treating a cancer of a mammal, preferably of a human, wherein said method comprises administration of said compound 6027, or said pharmaceutically acceptable salt thereof, to said mammal, preferably to said human, and wherein preferably said method comprises administration of an effective amount of said compound 6027, or said pharmaceutically acceptable salt thereof, to said mammal, preferably to said human provided that said use is not a method of topical treatment of a skin cancer of a mammal, wherein said method comprises topical administration of said compound to said mammal. In a preferred embodiment, said cancer is selected from the group consisting of skin cancer, breast cancer, colorectal cancer, hematopoietic cancer, cancer of the female genitourinary (GU) system, lung cancer, head and neck cancer, pancreas cancer, prostate cancer, bladder cancer cells, CNS cancer, stomach cancer, endocrine cancer and kidney cancer. In a preferred embodiment, said cancer is a solid tumor. The present invention provides a compound of formula (I) for use in a method of treatment of a skin cancer of a mammal, wherein said method comprises administration of an effective amount of said compound, or a pharmaceutically acceptable salt thereof, to said mammal. In a preferred embodiment, said mammal is a human. In a further preferred embodiment, said skin cancer is selected from a melanoma skin cancer, a non-melanoma skin cancer and a cutaneous lymphoma, and any pre-invasive form thereof. In a further preferred embodiment, said skin cancer is selected from a melanoma, a non-melanoma skin cancer, and any pre-invasive form thereof, wherein preferably said non- melanoma skin cancer is a basal cell carcinoma, Merkel cell carcinoma or a cutaneous squamous cell carcinoma, and wherein further preferably said non-melanoma skin cancer is a basal cell carcinoma or a cutaneous squamous cell carcinoma, or any precancer form thereof. In a further preferred embodiment, said skin cancer is selected from a melanoma skin cancer, a non-melanoma skin cancer and a cutaneous lymphoma, and any pre-invasive form thereof, wherein preferably said non-melanoma skin cancer is a basal cell carcinoma, Merkel cell carcinoma or a cutaneous squamous cell carcinoma, and wherein further preferably said non- melanoma skin cancer is a basal cell carcinoma or a cutaneous squamous cell carcinoma, or any pre-invasive form thereof. In a further preferred embodiment, said skin cancer is selected from a melanoma, a non-melanoma skin cancer, and any pre-invasive form thereof, wherein preferably said non-melanoma skin cancer is a basal cell carcinoma, Merkel cell carcinoma or a cutaneous squamous cell carcinoma, and wherein further preferably said non-melanoma skin cancer is a basal cell carcinoma or a cutaneous squamous cell carcinoma, or any pre-invasive form thereof. In a further preferred embodiment, said skin cancer is selected from a melanoma and a non-melanoma skin cancer, wherein preferably said non-melanoma skin cancer is a basal cell carcinoma or a cutaneous squamous cell carcinoma. In a further preferred embodiment, said skin cancer is a melanoma. In a further preferred embodiment, said skin cancer is a non- melanoma skin cancer, wherein preferably said non-melanoma skin cancer is a basal cell carcinoma, Merkel cell carcinoma or a cutaneous squamous cell carcinoma, or any pre-invasive form thereof, and wherein further preferably said non-melanoma skin cancer is a basal cell carcinoma or a cutaneous squamous cell carcinoma, or any pre-invasive form thereof. In a further preferred embodiment, said skin cancer is a basal cell carcinoma. In a further preferred embodiment, said skin cancer is a cutaneous squamous cell carcinoma. In a preferred embodiment, said skin cancer is a pre-invasive form of non-melanoma skin cancer. In another preferred embodiment, said skin cancer is a non-melanoma skin cancer. In another preferred embodiment, said skin cancer is a cutaneous lymphoma. In a further preferred embodiment, said cutaneous squamous cell carcinoma (cSCC) is an invasive cSCC. In a further preferred embodiment, said cutaneous squamous cell carcinoma (cSCC) is a metastatic cSCC. In a further preferred embodiment, said basal cell carcinoma is selected from the group consisting of superficial basal cell carcinoma (also known as “in situ basal cell carcinoma” or “superficial multicentric basal-cell carcinoma”), infiltrative basal cell carcinoma and nodular basal cell carcinoma. In a preferred embodiment, said basal cell carcinoma is a superficial basal cell carcinoma (also known as “in situ basal cell carcinoma” or “superficial multicentric basal-cell carcinoma”). In a further preferred embodiment, said basal cell carcinoma is an infiltrative basal cell carcinoma. In a further preferred embodiment, said basal cell carcinoma is a nodular basal cell carcinoma. In another embodiment, said basal cell carcinoma is selected from the group consisting of cystic basal cell carcinoma, cicatricial basal cell carcinoma (also known as “morpheaform basal cell carcinoma” or “morphoeic basal cell carcinoma”), micronodular basal cell carcinoma, pigmented basal cell carcinoma, rodent ulcer (also known as “Jacob’s ulcer”), fibroepithelioma of Pinkus, polypoid basal cell carcinoma, pore-like basal cell carcinoma and aberrant basal cell carcinoma. In another preferred embodiment, said skin cancer is a pre-invasive form of a non- melanoma skin cancer, wherein said pre-invasive form is selected from the group consisting of cutaneous squamous cell carcinoma in situ (cSCCis, also known as “Bowen’s disease”) and precancerous actinic keratosis (AK). In another preferred embodiment, said skin cancer is a pre-invasive form of a non-melanoma skin cancer, wherein said pre-invasive form is cutaneous squamous cell carcinoma in situ (cSCCis, also known as “Bowen’s disease”). In a further preferred embodiment, said skin cancer is a pre-invasive form of a non-melanoma skin cancer, wherein said pre-invasive form is precancerous actinic keratosis (AK). In another preferred embodiment, said skin cancer is actinic keratosis (AK). In another preferred embodiment, said skin cancer is cutaneous squamous cell carcinoma in situ (cSCCis). In another preferred embodiment, said skin cancer is a cutaneous lymphoma, wherein preferably said cutaneous lymphoma is a cutaneous T-cell lymphoma (CTCL) or a cutaneous B-cell lymphoma (CBCL). In another preferred embodiment, said skin cancer is a cutaneous lymphoma, wherein said cutaneous lymphoma is a cutaneous T-cell lymphoma (CTCL). In another preferred embodiment, said skin cancer is a cutaneous lymphoma, wherein said cutaneous lymphoma is a cutaneous B-cell lymphoma (CBCL). In another preferred embodiment, said skin cancer is a pre-invasive form of a non-melanoma skin cancer, and wherein said pre-invasive form is actinic keratosis (AK). In another preferred embodiment, said skin cancer is a pre-invasive form of a non-melanoma skin cancer, and said pre-invasive form is cSCC in situ (cSCCis). The compounds and methods described herein are advantageously used to inhibit proliferation of skin cancer cells. Preferably, the compounds and methods provide treatment of a mammal, preferably a human, against skin cancer. The methods provides treatment against the various types of skin cancer, in particular of basal cell carcinoma, cutaneous squamous cell carcinoma or melanoma or cutaneous lymphoma. Thus, administering of a compound of formula (I) or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition comprising the same provide treatment of a patient against skin cancer. EXAMPLES All reagents and solvents used in the synthesis were purchased from Sigma Aldrich, Bachem, Iris Biotech, Fluorochem, Enamine, Combi-Blocks, Merck, Alchem Pharmatech and used as received. Solvents were stored over molecular sieves 4 Å. Peptides were synthesized on a 0.25-mmol or 0.10-mmol scale on Fmoc-β-Ala Wang resin (0.72 mmol g−1) or Fmoc-Aib Wang resin (0.49 mmol g−1) using a Liberty Blue microwave peptide synthesizer (CEM Corp., Matthews, NC) employing Fmoc solid-phase techniques with repeated steps of coupling, deprotection, and washing, as further described in Example 1. Mass and purity of final compounds was determined by UHPLC-MS using a Thermo Scientific UltiMate 3000 System equipped with a Accucore™ C18 column and diode array detector (254 nm). The mobile phase consisted of H2O-Acetonitrile (solvent A, 97:3 v / v, LC- MS Ultra Chromasolv®, UHPLC grade, Sigma-Aldrich, Germany) and 0.1 % Formic acid (LC- MS grade, Sigma-Aldrich, Germany) and Acetonitrile-H2O (solvent B, 97:3 v / v, LC-MS Ultra Chromasolv®, UHPLC grade, Sigma-Aldrich, Germany) and 0.1 % Formic acid (LC-MS grade, Sigma-Aldrich, Germany) with a 3 min run time, 1.3 ml / min flow rate, 5 µL injection volume and a gradient elution according to the following program: linear increment starting with 100 % A to 100 % Bin 1.35 min and holding 100 % B for 0.9 min before returning to the initial conditions within the next 0.75 min. MS detection of analytes was performed on a Thermo Scientific single quadrupole mass spectrometer equipped with electrospray ionization (ESI) interface (Thermo Scientific, MSQ Plus Mass Detector) in positive and negative ion mode with mass range from 100-1700 m / z. EXAMPLE 1 General procedure for the synthesis for compounds of formula (I) The peptides were synthesized using a Liberty Blue microwave peptide synthesizer (CEM Corp., Matthews, NC) starting from Fmoc-Aib-OH or Fmoc-beta-Ala linked to Wang resin employing Fmoc solid-phase techniques with repeated steps of coupling, deprotection, and washing. Coupling was performed as follows: Fmoc-L-amino acids or the capping group (5.0 equiv., 0.2M in DMF), DIC (5.0 equiv., 0.5M in DMF), and Oxyma (5.0 equiv., 0.5M in DMF) for 4 minutes with microwave irradiation at 90°C. For the second Aib coupling, a double coupling with each 15 minutes microwave irradiation at 90°C was performed. Fmoc deprotection was performed as follows: 10% piperazine in NMP / ethanol (9:1, v / v) for 1 minute with microwave irradiation at 90°C. By employing sequentially the amino acid building blocks listed in Table 1 and free acid derivatives listed in Table 2, the different peptides were assembled on solid phase support. Said syntheses are illustrated for inventive octa- and nonapeptides in Scheme 1A and Scheme 1B, wherein the numbering is depicted accordingly, namely the amino acids used in steps 1 to 8 (Scheme 1A) or in steps 1 to 9 (Scheme 1B) and the free acid derivatives used in step 9 (Scheme 1A) or in step 10 (Scheme 1B). The corresponding shorter or longer peptide chains were synthesized and numbered accordingly. Following synthesis, the peptide was cleaved from the resin by treatment with a cleavage mixture (1mL / 0.1g resin) consisting of TFA / H2O (95:5, v / v) for 90 minutes at ambient temperature. The suspended resin was removed by filtration and the filtrate was concentrated in vacuo. The crude peptides were dissolved in acetonitrile and were purified by ISCO chromatography system using as mobile phase H2O / acetonitrile (95:5, v / v) and acetonitrile / H2O (95:5, v / v), gradient ACN 10% to 100%, to give peptide acids with ≥ 90% purity. The purified peptide acid (1.0 equiv.) was coupled in solution (DMF) with the respective amine (2.0 equiv.) listed in Table 3 in presence of DIPEA (3.0 equiv.) and HATU (2.0 equiv.) to give the final peptide (illustrated as step 10 in Scheme 1A and step 11 in Scheme 1B. The final peptide was then diluted with ethyl acetate and washed with an aqueous HCl (1M) solution, followed by an aqueous NaOH (1M) solution and a saturated NaCl solution. The organic phase was dried over Na2SO4, filtered and concentrated in vacuo. The crude peptide was purified on Gilson PLC 2020 Personal Purification System, as described above, to give final products with ≥ 90% purity, typically with ≥ 95% purity. In two cases the remaining protection group was removed in an HCl solution and once with Palladium on carbon under a hydrogen atmosphere. Scheme 1A: Scheme for the synthesis of the respective inventive compounds of formula (I) comprising an octapeptide Scheme 1B: Scheme for the synthesis of the respective inventive compounds of formula (I) comprising a nonapeptide

[0002] Table 1: Amino acid building blocks used for the synthesis of compounds of formula (I) AMINO ACIDS Short Name Structure IUPAC Name 3-{[(9H-fluoren-9- FmocNCOOHFmoc-β-Ala-OH H ylmethoxy)carbonyl]amino}propa noic acid 2-((((9H-fluoren-9-yl)methoxy) Fmoc-Aib-OHFmoc NCOOHcarbonyl)amino)-2- H methylpropanoic acid (((9H-fluoren-9- Fmoc-Leu-OH Fmoc OH N yl)methoxy)carbonyl)-L-leucine H O (S)-2-((((9H-fluoren-9-yl) Fmoc-L- methoxy)carbonyl)amino)-4- homocyclohexylalanine FmocNOHcyclohexylbutanoic acid H O (S)-2-((((9H-fluoren-9- (S)-2-((((9H-fluoren-9- yl)methoxy)carbonyl)amin yl)methoxy)carbonyl)amino)decan o)decanoic acid oic acid O (((9H-fluoren-9-yl)methoxy) Fmoc-L-Pro-OH OH N carbonyl)-L-proline Fmoc O (2S,4S)-1-(((9H-fluoren-9- Fmoc-L-Pro(4S-Methyl)- OH yl)methoxy)carbonyl)-4- OH N methylpyrrolidine-2-carboxylic Fmoc acid H2C (2S,4R)-1-(((9H-fluoren-9- Fmoc-L-Pro(4-NH-Alloc)- O O O yl)methoxy)carbonyl)-4- OH (2S, 4R) HN R (((allyloxy)carbonyl)amino)pyrrol N Fmoc idine-2-carboxylic acid O (2S,4R)-1-(((9H-fluoren-9- yl)methoxy)carbonyl)-4-(tert- Fmoc-Hyp(tBu)-OH O OH N butoxy)pyrrolidine-2-carboxylic Fmoc acid (2S)‐1‐{[(9H‐fluoren‐9‐ Fmoc-L-Octahydroindole- yl)methoxy]carbonyl}‐2-carboxylic acidNOH octahydro‐1H‐indole‐2‐carboxylic FmocOacid Fmoc N O (2S,4R)‐4‐(benzyloxy)‐1‐{[(9H‐ Fmoc-Hyp(Bzl)-OH OH O fluoren‐9‐ yl)methoxy]carbonyl}pyrrolidine‐ 2‐carboxylic acid O (2S,4S)-1-(((9H-fluoren-9- F yl)methoxy)carbonyl) oc-L-Pro(4-CF3)-OH O -4- Fm F H F N (trifluoromethyl)pyrrolidine-2- Fmoc carboxylic acid O (2S,4R)-1-(((9H-fluoren-9- Fmoc-L-Pro(4R-Methyl)- OH yl)methoxy)carbonyl)-4- OH N methylpyrrolidine-2-carboxylic Fmoc acid O (2S,4S)-1-(((9H-fluoren-9- (2S, 4S)-Fmoc-4-phenoxy- O OH yl)methoxy)carbonyl)-4- pyrrolidine-2-carboxylic N phenoxypyrrolidine-2-carboxylic acid Fmoc acid O (2S,4R)-1-(((9H-fluoren-9- Fmoc-L-Pro(4-F)-OH yl)methoxy)carbonyl)-4- F OH (2S,4R) N fluoropyrrolidine-2-carboxylic Fmoc acid O (2S,4S)-1-(((9H-fluoren-9- Fmoc-(2S,4S)-4- yl)methoxy)carbonyl)-4- phenylpyrrolidine-2- OH N phenylpyrrolidine-2-carboxyliccarboxylic acidFmoc acid O OH (2S)‐1‐{[(9H‐fluoren‐9‐ Fmoc-L-4,4,- Fmoc yl)methoxy]carbonyl}‐4,4‐ N difluoroproline difluoropyrrolidine‐2‐carboxylic FFacid O (2S,4R)-1-(((9H-fluoren-9- Fmoc-(2S,4R)-4- yl)methoxy)carbonyl) nylpyrrolidine-2- O -4- phe H N phenylpyrrolidine-2-carboxyliccarboxylic acidFmoc acid O (2S,5S)-1-(((9H-fluoren-9- Fmoc-L-Pro(5-Me)-OH OH yl)methoxy)carbonyl)-5- (2S,5S) N methylpyrrolidine-2-carboxylic Fmoc acid O (S)-1-(((9H-fluoren-9- OH yl)methoxy)carbonyl)-5,5- Fmoc-5,5-dmP-OH (S) N dimethylpyrrolidine-2-carboxylic Fmoc acid O (S)-1-(((9H-fluoren-9- yl)methoxy)carbonyl)-3,3- Fmoc-3,3-dmP-OH (S) OH N dimethylpyrrolidine-2-carboxylic Fmoc acid O (2S,4S)-1-(((9H-fluoren-9- Fmoc-L-Pro(4Chx)-OH OH yl)methoxy)carbonyl)-4- (2S,4S) N cyclohexylpyrrolidine-2- Fmoc carboxylic acid O (2S,5R)-1-(((9H-fluoren-9- OH Fmoc-L-Pro(5-Ph)-OH N yl)methoxy)carbonyl)-5- (2S,5R) Fmoc phenylpyrrolidine-2-carboxylic acid O (2S,4R)-1-(((9H-fluoren-9- OH Fmoc-L-Pro(4-p-F-Ph)- yl)methoxy)carbonyl)-4-(4- N OH (2S,4R) Fmoc fluorobenzyl)pyrrolidine-2- carboxylic acid F (S)-5-(((9H-fluoren-9- O (S)-5-(((9H-fluoren-9- yl)methoxy)carbonyl)-5- yl)methoxy)carbonyl)-5- OH azaspiro[2.4]heptane-6- N azaspiro[2.4]heptane-6-carboxyliccarboxylic acidFmoc acid (2S,4S)‐1‐{[(9H‐fluoren‐ 9‐yl)methoxy]carbonyl}‐ (2S,4S)‐1‐{[(9H‐fluoren‐9‐ 4‐[4‐(2‐methylpropyl)‐1H‐ N yl)methoxy]carbonyl}‐4‐[4‐(2‐ N 1,2,3‐triazol‐1‐ NOmethylpropyl)‐1H‐1,2,3‐triazol‐1‐ yl]pyrrolidine‐2‐ N OH yl]pyrrolidine‐2‐carboxylic acid Fmoc carboxylic acid (2S,3R)-2-((((9H-fluoren- (2S,3R)-2-((((9H-fluoren-9- 9-yl)methoxy)carbonyl)- O TBDMS yl)methoxy)carbonyl)amino)-3- amino)-3-((tert- Fmoc OH N ((tert-butyldimethylsilyl)oxy)-4- butyldimethylsilyl)oxy)-4- H O methylpentanoic acid methylpentanoic acid Table 2: Free acids used for the synthesis of compounds of formula (I) ACIDS Short Name Structure IUPAC Name F 4-Fluorobenzoic acidOH4-Fluorobenzoic acid O (S,E)-4-methylhex-2-enoic OH (S,E)-4-methylhex-2-enoic acid acid O Table 3: Primary or secondary amines used for the synthesis of compounds of formula (I). AMINES Short Name Structure IUPAC Name H2N 1-[(dimethylamino)methyl] N 1-[(dimethylamino)methyl] cyclobutan-1-aminecyclobutan-1-amine [(2S)-2- H2N N (2S)-N1,N1-dimethylpropane- aminopropyl]dimethylamine1,2-diamine H N ,N -2-trimethylpropane-2N 11N N1,N1-2-trimethylpropane-1,2- 1,2-diaminediamine O tert-butyl (2-aminoethyl)- H2N N tert-butyl (2-aminoethyl)- (methyl)carbamateO(methyl)carbamate H2Ntert‐butyl 4‐[(2S)‐2‐Ntert‐butyl 4‐[(2S) nopropyl]piperazine‐1‐N‐2‐ amiOaminopropyl]piperazine‐1‐ carboxylateOcarboxylateH2N(2‐aminoethyl)dimethylamineN(2‐aminoethyl)dimethylamineH2N(2S)‐1‐(morpholin‐4‐N(2S)‐1‐(morpholin‐4‐yl)propan‐ yl)propan‐2‐amineO2‐amine H2N2‐(4‐methylpiperazin‐1‐N2‐(4‐methylpiperazin‐1‐ yl)ethan‐1‐amineNyl)ethan‐1‐amine O benzyl N‐[(2S)‐2‐H2Nbenzyl N‐[(2S)‐2‐ aminopropyl]‐N‐N Oaminopropyl]‐N‐ methylcarbamate methylcarbamate EXAMPLE 2 Synthesis of amino acids as building blocks for compounds of formula (I) Some amino acids needed for the synthesis of compounds of formula (I) were not commercially available. In this case, they were synthesized. In Scheme 2, Scheme 3, Scheme 4 and Scheme 5 these syntheses are presented. Scheme 2: Synthesis of not commercially available amino acid 2. 12The synthesis of the amino acids 2 is depicted at Scheme 2. To begin with, (4S)-4Methyl- L-Proline (1, 7.7 mmol, 1.0 equiv.) was suspended in THF (4 ml / mmol of 1) and water (2.5 ml / mmol of 1). A saturated solution of NaHCO3in water (1.5 ml / mmol of 1) was added. Fmoc- OSU (9.3 mmol, 1.2 equiv.) was added and the reaction was stirred at room temperature for 18 hours. The THF was removed in vacuo and the remaining mixture was diluted with an aqueous HCl (2 M, 25 ml) solution. The aqueous layer was extracted three times with ethyl acetate (3 x 50 ml). The combined organic layers were dried over Na2SO4, filtered and concentrated in vacuo. The residue was purified by reversed phase chromatography to obtain 2 as a white solid. Scheme 3: Synthesis of not commercially available amino acid 4. The synthesis of the amino acid 4 is depicted at Scheme 3. To begin with, compound 3 (2.5 mmol, 1.0 equiv.) was diluted in a HCl solution (4 M, 1 ml / 0.5 mmol of 3) in dioxane and stirred at room temperature for 3 hours. Then a saturated aqueous solution of NaHCO3(1 ml / 0.25 mmol of 3) and Fmoc-OSU (3.0 mmol, 1.2 equiv.) were added. The reaction mixture was stirred at room temperature for 18 hours. The dioxane was removed in vacuo and the remaining mixture was diluted with an aqueous HCl (2 M, 20 ml) solution. The aqueous layer was extracted three times with ethyl acetate (3 x 40 ml). The combined organic layers were dried over Na2SO4, filtered and concentrated in vacuo. The residue was purified by reversed phase chromatography to obtain 4 as a white solid. Scheme 4: Synthesis of not commercially available amino acid 7. The synthesis of the amino acid 7 is depicted in Scheme 4. To begin with, compound 5 (3.1 mmol, 1.0 equiv.) was dissolved in a mixture of THF (3 ml / mmol of 5) and water (3 ml / mmol of 5). A saturated aqueous NaHCO3solution was added until pH ~10 was reached. A solution of Fmoc-OSu (3.8 mmol, 1.2 equiv.) in THF (3 ml / mmol of 5) was added over 30 minutes at 0°C. After the addition, the suspension was allowed to warm to ambient temperature and stirred overnight. The reaction mixture was acidified to pH ~3 with an aqueous 10% citric acid solution. The mixture was extracted with ethyl acetate (3 x 100 ml). The combined organic layers were dried over Na2SO4, filtered and concentrated in vacuo. The crude product was purified by column chromatography to obtain 6. To a solution of 6 (3.1 mmol, 1.0 equiv.) in DCM (10 ml / mmol of 6), 2,6-Lutidine (15.6 mmol, 5.0 equiv.) and TBDMS-OTf (8.8 mmol, 2.5 equiv.) were added at 0 °C. The reaction mixture was allowed to warm to ambient temperature and was stirred overnight. The mixture was quenched with an aqueous saturated NH4Cl solution and the two phases seperated. The aqueous phase was extracted once with DCM (50 ml). The combined organic layers were washed with an aqueous 1 M HCl solution, brine and then dried over Na2SO4, filtered and concentrated in vacuo. The crude producte was purified by column chromatography to afford 7 as a solid. Scheme 5: Synthesis of not commercially available building block 10 The synthesis of the free acid 10 is depicted in Scheme 5. To begin with, a solution of dimethyl sulfoxide (34.0 mmol, 3.0 equiv.) in dichloromethane (1.5 ml / mmol of 8) was added to a solution of oxalyl chloride (22.7 mmol, 2.0 equiv.) in dichloromethane (1.75 ml / mmol of 8) at -78 °C. After stirring for 5 min at -78 °C, a solution of (S)-(-)-2-methyl-1-butanol (8, 11.3 mmol, 1.0 equiv.) in dichloromethane (2.4 ml / mmol of 8) was added. After stirring for 1 hour at -78 °C, a solution of triethylamine (68 mmol, 6.0 equiv.) was added and the mixture was warmed to room temperature. After stirring for 1 hour at room temperature, the reaction was quenched with water (50 ml). The two layers were separated and the aqueous one was extracted twice with dichloromethane (2 x 50 ml). The combined organic layers were washed with brine, dried over Na2SO4, filtered and concentrated in vacuo. The aldehyde was diluted in dichloromethane (5 ml / mmol of 8) and (carbethoxymethylene)triphenylphosphorane (14.7 mmol, 1.3 equiv.) was added. The reaction was stirred overnight at room temperature. The reaction mixture was diluted with hexane (50 ml) and the suspension was filtered through Celite®. The filtrate was concentrated in vacuo and the residue was purified by normal-phase column chromatography, to obtain 9 as a colorless oil. To a solution of 9 (6.8 mmol, 1.0 equiv.) in methanol and water (4:1, 3.5 ml / mmol of 9), lithium hydroxide monohydrate (13.6 mmol, 2.0 equiv.) was added. The reaction was stirred overnight at room temperature. The reaction mixture was basified with an aqueous NaOH (2 M, 0.5 ml / mmol of 9) solution and extracted with dichloromethane. The organic phase was discarded and the aqueous phase was acidified with an aqueous HCl (2 M, 2 ml / mmol of 9) solution and extracted with dichloromethane. The organic phase was dried over Na2SO4, filtered and concentrated in vacuo. The crude oil was purified by normal-phase chromatography to afford 10 as a yellowish oil. Scheme 6: Synthesis of not commercially available amino acid 13. The synthesis of the free acid 13 is depicted in Scheme 6. To begin with, compound 12 (7 µmol, 1.0 equiv.) was dissolved in H2O / iPrOH (1:1, 1 ml / 10 µmol of 12). Compound 11 (8 µmol, 1.1 equiv.), Copper(II) sulfate pentahydrate (1 µmol, 0.1 equiv.) and sodium ascorbate (4 µmol, 0.5 equiv.) were added to the solution of 12 in H2O / iPrOH at room temperature. The reaction mixture was stirred for 48 hours at room temperature. The reaction mixture was diluted with acetonitrile and directly purified by reversed-phase chromatography to afford 13 as a white solid. EXAMPLE 3 Synthesis of compounds of formula (I) The compounds of formula (I) have been synthesized in accordance with the general procedures described above and as depicted in Schemes 1A and 1B for the inventive octa- and nonapeptides. Each of the synthesized compounds are identified by its compound number (4 or 5-digit number), its structural formula and its IUPAC name as generated by the ChemDraw software. Furthermore, the synthesis is described by way of the building blocks, acids and amines used as disclosed in Tables 1-3. Moreover, the experimentally measured molecular mass is provided. Finally, for each specifically identified compound of formula (I) the characterization of the substituents R1, R2, and R3in accordance with formula (I) is given, wherein the residue R within said definition of said substituents R1, R2, and R3corresponds to and indicates the respective attachment within formula (I). The synthesis of the reference compound 6027 has been described in EP3345917. 20762: Allyl ((3S,5S)-5-(((12S,15S,21S,24S)-26-cyclohexyl-1-((1-((dimethylamino)methyl)cyclo- butyl)amino)-12,15,21-triisobutyl-6,6,9,9,18,18-hexamethyl-1,5,8,11,14,17,20,23-octaoxo- 4,7,10,13,16,19,22-heptaazahexacosan-24-yl)carbamoyl)-1-(4-fluorobenzoyl)pyrrolidin-3- yl)carbamate Cpd 1 2 3 4 5 6 20762 Fmoc-β- Fmoc-Aib- Fmoc-Aib-OH Fmoc-Leu-OH Fmoc-Leu- Fmoc-Aib- Ala-OH OH OH OH 7 8 9 10 11 Fmoc- Fmoc-L- Fmoc-L-Pro(4- 4- 1-[(dimethylamino)methyl] Leu-OH homocyclo NH-Alloc)-OH Fluorobenzoic cyclobutan-1-amine hexyl- (2S, 4R) acid alanine Cpd Molecular weight Experimentally measured mass 20762 [M+H]+ 1279.7 1280.2 Cpd R1 R2 R3 H2C O O O HN R 20762NO R NRN H F 22178: (2S,4S)-N-((4S,17S,20S,26S,29S)-31-cyclohexyl-17,20,26-triisobutyl-2,4,11,11,14,14,23,23- octamethyl-6,10,13,16,19,22,25,28-octaoxo-2,5,9,12,15,18,21,24,27-nonaazahentriacontan- 29-yl)-4-methyl-1-((S,E)-4-methylhex-2-enoyl)pyrrolidine-2-carboxamide Cpd 1 2 3 4 5 6 22178 Fmoc-β- Fmoc-Aib- Fmoc-Aib-OH Fmoc-Leu- Fmoc-Leu-OH Fmoc-Aib- Ala-OH OH OH OH 7 8 9 10 11 Fmoc- Fmoc-L- Fmoc-L-Pro(4S- 4- [(2S)-2- Leu-OH homocyclo Methyl)-OH Fluorobenz aminopropyl]dimethylamine hexyl- oic acid alanine Cpd Molecular weight Experimentally measured mass 22178 [M+]+ 1156.6 1156.6 Cpd R1 R2 R3 R N O 22178RNNORH 22179: (2S,4S)-N-((4S,17S,20S,26S,29S)-31-cyclohexyl-17,20,26-triisobutyl-2,4,11,11,14,14,23,23- octamethyl-6,10,13,16,19,22,25,28-octaoxo-2,5,9,12,15,18,21,24,27-nonaazahentriacontan- 29-yl)-1-(4-fluorobenzoyl)-4-methylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 6 22179 Fmoc-β- Fmoc-Aib- Fmoc-Aib- Fmoc-Leu- Fmoc-Leu-OH Fmoc-Aib- Ala-OH OH OH OH OH 7 8 9 10 11 Fmoc- Fmoc-L- Fmoc-L- 4- [(2S)-2- Leu-OH homocyclohe Pro(4S- Fluorobenz aminopropyl]dimethylamine xylalanine Methyl)-OH oic acid Cpd Molecular mass Experimentally measured mass 22179 [M+H]+ 1168.5 1169.2 Cpd R1 R2 R3 R 22179 N OR NN R H OF22180 (reference example): (2S,4S)-N-((4S,17S,20S,26S,29S)-31-cyclohexyl-26-((R)-1-hydroxy-2-methylpropyl)-17,20- diisobutyl-2,4,11,11,14,14,23,23-octamethyl-6,10,13,16,19,22,25,28-octaoxo- 2,5,9,12,15,18,21,24,27-nonaazahentriacontan-29-yl)-1-(4-fluorobenzoyl)-4- methylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 6 22180 Fmoc-β- Fmoc-Aib- Fmoc-Aib-OH Fmoc-Leu- Fmoc-Leu-OH Fmoc-Aib- Ala-OH OH OH OH 7 8 9 10 11 Fmoc- Fmoc-L- Fmoc-L- 4- [(2S)-2- Leu-OH homocyclo Pro(4S- Fluorobenz aminopropyl]dimethylamine hexylalanin Methyl)-OH oic acid e Cpd Molecular mass Experimentally measured mass 22180 [M+H+]+ 1184.5 1185.1 Cpd R1 R2 R3 R 22180 N OR NN R H OF22430 (reference example): (2S,4S)-N-((4S,17S,20S,26S,29S)-26-((R)-1-hydroxy-2-methylpropyl)-17,20-diisobutyl- 2,4,11,11,14,14,23,23-octamethyl-6,10,13,16,19,22,25,28-octaoxo-2,5,9,12,15,18,21,24,27- nonaazaheptatriacontan-29-yl)-4-methyl-1-((S,E)-4-methylhex-2-enoyl)pyrrolidine-2- carboxamide Cpd 1 2 3 4 5 6 22430 Fmoc-β- Fmoc-Aib- Fmoc-Aib-OH Fmoc-Leu- Fmoc-Leu-OH Fmoc-Aib- Ala-OH OH OH OH 7 8 9 10 11 (2S,3R)-2-((((9H- (S)-2-((((9H- Fmoc-L- (S,E)-4- [(2S)-2- fluoren-9- fluoren-9- Pro(4S- methylhex-2- aminopropyl] yl)methoxy)carbonyl)- yl)methoxy)- Methyl)- enoic acid dimethyl- amino)-3-((tert- carbonyl)ami- OH amine butyldimethylsilyl)oxy)- no)decanoic 4-methylpentanoic acid acid Cpd Molecular mass Experimentally measured mass 22430 [M+H]+ 1174.6 1175.7 Cpd R1 R2 R3 R N O 22430R NN ORH 22432 (reference example): (S)-N-((4S,17S,20S,26S,29S)-31-cyclohexyl-26-((R)-1-hydroxy-2-methylpropyl)-17,20- diisobutyl-2,4,11,11,14,14,23,23-octamethyl-6,10,13,16,19,22,25,28-octaoxo- 2,5,9,12,15,18,21,24,27-nonaazahentriacontan-29-yl)-1-((S,E)-4-methylhex-2- enoyl)pyrrolidine-2-carboxamide Cpd 1 2 3 4 5 6 22432Fmoc-β-Fmoc-Aib- Fmoc-Aib-OH Fmoc-Leu- Fmoc-Leu- Fmoc-Aib- Ala-OH OH OH OH OH 7 8 9 10 11 (2S,3R)-2-((((9H- Fmoc-L- Fmoc-L-Pro- (S,E)-4- [(2S)-2- fluoren-9- homocyclo- OH methylhex-2- amino- yl)methoxy)carbonyl)- hexylalanine enoic acid propyl]di- amino)-3-((tert- methylamine butyldimethylsilyl)oxy)- 4-methylpentanoic acid Cpd Molecular mass Experimentally measured mass 22432 [M+H+]+ 1158.6 1159.6 Cpd R1 R2 R3 22432R NN R H 22433 (reference example): (2S,4S)-N-((4S,17S,20S,26S,29S)-31-cyclohexyl-26-((R)-1-hydroxy-2-methylpropyl)-17,20- diisobutyl-2,4,11,11,14,14,23,23-octamethyl-6,10,13,16,19,22,25,28-octaoxo- 2,5,9,12,15,18,21,24,27-nonaazahentriacontan-29-yl)-4-methyl-1-((S,E)-4-methylhex-2- enoyl)pyrrolidine-2-carboxamide Cpd 1 2 3 4 5 6 22433 Fmoc-β- Fmoc-Aib- Fmoc-Aib-OH Fmoc-Leu- Fmoc-Leu- Fmoc-Aib-OH Ala-OH OH OH OH 7 8 9 10 11 (2S,3R)-2-((((9H- Fmoc-L- Fmoc-L- (S,E)-4- [(2S)-2- fluoren-9- homocyclohex Pro(4S- methylhex-2- aminopropyl]d yl)methoxy)carbonyl)- ylalanine Methyl)-OH enoic acid imethylamine amino)-3-((tert- butyldimethylsilyl)oxy)- 4-methylpentanoic acid Cpd Molecular mass Experimentally measured mass 22433 [M]+ 1172.6 1172.8 Cpd R1 R2 R3 R N O 22433RNNORH 23103: (2S,4S)-N-((12S,15S,21S,24S)-26-cyclohexyl-1-((1- ((dimethylamino)methyl)cyclobutyl)amino)-12,15,21-triisobutyl-6,6,9,9,18,18-hexamethyl- 1,5,8,11,14,17,20,23-octaoxo-4,7,10,13,16,19,22-heptaazahexacosan-24-yl)-4-methyl-1- ((S,E)-4-methylhex-2-enoyl)pyrrolidine-2-carboxamide Cpd 1 2 3 4 5 6 23103 Fmoc-β- Fmoc-Aib- Fmoc-Aib-OH Fmoc-Leu- Fmoc-Leu- Fmoc-Aib-OH Ala-OH OH OH OH 7 8 9 10 11 Fmoc- Fmoc-L- Fmoc-Pro(4S- (S,E)-4- 1-[(dimethylamino)methyl] Leu-OH homocyclohe Methyl)-OH methylhex-2- cyclobutan-1-amine xylalanine enoic acid Cpd Molecular mass Experimentally measured mass 23103 [M]+ 1182.6 1182.6 Cpd R1 R2 R3 R N O 23103R NORN H 23491: (2S,4S)-N-((12S,15S,21S,24S)-26-cyclohexyl-1-((1- ((dimethylamino)methyl)cyclobutyl)amino)-12,15,21-triisobutyl-6,6,9,9,18,18-hexamethyl- 1,5,8,11,14,17,20,23-octaoxo-4,7,10,13,16,19,22-heptaazahexacosan-24-yl)-1-(4- fluorobenzoyl)-4-methylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 6 23491 Fmoc-β- Fmoc-Aib- Fmoc-Aib-OH Fmoc-Leu-OH Fmoc-Leu- Fmoc-Aib- Ala-OH OH OH OH 7 8 9 10 11 Fmoc- Fmoc-L- Fmoc-Pro(4S- 4-Fluorobenzoic 1- Leu-OH homocyclohe Methyl)-OH acid [(dimethylamino)methyl] xylalanine cyclobutan-1-amine Cpd Molecular mass Experimentally measured mass 23491 [M]+ 1194.6 1194.7 Cpd R1 R2 R3 R 23491 N OR NRN H OF23525: (2S,4S)-N-((17S,20S,26S,29S)-31-cyclohexyl-17,20,26-triisobutyl-2,4,4,11,11,14,14,23,23- nonamethyl-6,10,13,16,19,22,25,28-octaoxo-2,5,9,12,15,18,21,24,27-nonaazahentriacontan- 29-yl)-1-(4-fluorobenzoyl)-4-methylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 6 23525 Fmoc-β- Fmoc-Aib-OH Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu- Fmoc-Aib- Ala-OH OH OH OH 7 8 9 10 11 Fmoc- Fmoc-L- Fmoc-L- 4- N1,N1-2-trimethylpropane- Leu-OH homocyclohex Pro(4S- Fluorobenzoic 1,2-diamine ylalanine Methyl)-OH acid Cpd Molecular mass Experimentally measured mass 23525 [M]+ 1182.6 1182.7 Cpd R1 R2 R3 R 23525 N OR NN R H OF23526: (2S,4S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-1-(4- fluorobenzoyl)-4-methylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23526 Fmoc-Aib- Fmoc-Aib-OH Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-L- 4-Fluorobenzoic [(2S)-2- OH homocyclohexyl Pro(4S- acid aminopropyl]di- alanine Methyl)-OH methylamine Cpd Molecular mass Experimentally measured mass 23526 [M]+ 1097.5 1097.6 Cpd R1 R2 R3 R 23526 N OR NN R H OF23538: (2S,4S)-N-((17S,20S,26S,29S)-31-cyclohexyl-17,20,26-triisobutyl-2,4,4,11,11,14,14,23,23- nonamethyl-6,10,13,16,19,22,25,28-octaoxo-2,5,9,12,15,18,21,24,27-nonaazahentriacontan- 29-yl)-4-methyl-1-((S,E)-4-methylhex-2-enoyl)pyrrolidine-2-carboxamide Cpd 1 2 3 4 5 6 23538 Fmoc-β- Fmoc-Aib- Fmoc-Aib-OH Fmoc-Leu-OH Fmoc-Leu- Fmoc-Aib- Ala-OH OH OH OH 7 8 9 10 11 Fmoc- Fmoc-L- Fmoc-Pro(4S- (S,E)-4- N1,N1-2- Leu-OH homocyclohe Methyl)-OH methylhex-2- trimethylpropane-1,2- xylalanine enoic acid diamine Cpd Molecular mass Experimentally measured mass 23538 [M]+ 1170.6 1170.7 Cpd R1 R2 R3 R N O 23538R NN ORH 23542: (2S,4S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-4- methyl-1-((S,E)-4-methylhex-2-enoyl)pyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23542 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-L- (S,E)-4- [(2S)-2- OH homocycloh Pro(4S- methylhex-2- aminopropyl]dimethyl exylalanine Methyl)-OH enoic acid amine Cpd Molecular mass Experimentally measured mass 23542 [M]+ 1085.5 1085.7 Cpd R1 R2 R3 R N O 23542R NN ORH 23549: (2S,4R)-N-((4S,17S,20S,26S,29S)-31-cyclohexyl-17,20,26-triisobutyl-2,4,11,11,14,14,23,23- octamethyl-6,10,13,16,19,22,25,28-octaoxo-2,5,9,12,15,18,21,24,27-nonaazahentriacontan- 29-yl)-1-(4-fluorobenzoyl)-4-hydroxypyrrolidine-2-carboxamide Cpd 1 2 3 4 5 6 23549 Fmoc-β- Fmoc-Aib-OH Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu- Fmoc- Ala-OH OH OH Aib-OH 7 8 9 10 11 Fmoc- Fmoc-L- Fmoc- 4- [(2S)-2- Leu-OH homocyclohex Hyp(tBu)- Fluorobenzoic aminopropyl]dimethyl- ylalanine OH acid amine Cpd Molecular mass Experimentally measured mass 23549 [M]+ 1170.5 1170.7 Cpd R1 R2 R3 HO R 23549 N OR NN R H OF23552: (1S,3aS,7aR)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-2-(4-fluorobenzoyl)octahydro-1H-isoindole-1-carboxamide Cpd 1 2 3 4 5 23552 Fmoc- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH Aib-OH OH 6 7 8 9 10 Fmoc- Fmoc-L- Fmoc-L- 4- [(2S)-2- Leu-OH homocyclohe Octahydroindole- Fluorobenzoic aminopropyl]di- xylalanine 2-carboxylic acid acid methylamine Cpd Molecular mass Experimentally measured mass 23552 [M+H]+ 1137.5 1138.6 Cpd R1 R2 R3 H R H 23552RNNN ORH OF23585: (2S,4S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-1-(4- fluorobenzoyl)-4-(trifluoromethyl)pyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23585 Fmoc- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH Aib-OH OH 6 7 8 9 10 Fmoc- Fmoc-L- Fmoc-L-Pro(4- 4-Fluorobenzoic [(2S)-2- Leu-OH homocyclohe CF3)-OH acid aminopropyl]di- xylalanine methylamine Cpd Molecular mass Experimentally measured mass 23585 [M]+ 1151.4 1151.6 (2S,4R)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-1-(4- fluorobenzoyl)-4-methylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23586 Fmoc- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH Aib-OH OH 6 7 8 9 10 Fmoc- Fmoc-L- Fmoc-L- 4-Fluorobenzoic [(2S)-2- Leu-OH homocyclohe Pro(4R- acid aminopropyl]dimethyl- xylalanine Methyl)-OH amine Cpd Molecular mass Experimentally measured mass 23586 [M]+ 1097.5 1097.6 Cpd R1 R2 R3 (2S,4S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-1-(4- fluorobenzoyl)-4-phenoxypyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23594 Fmoc- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH Aib-OH OH 6 7 8 9 10 Fmoc- Fmoc-L- (2S, 4S)-Fmoc-4- 4-Fluorobenzoic [(2S)-2- Leu-OH homocyclohe phenoxy- acid aminopropyl]dimeth xylalanine pyrrolidine-2- ylamine carboxylic acid Cpd Molecular mass Experimentally measured mass 23594 [M]+ 1175.5 1175.7 Cpd R1 R2 R3 O R 23594R NN H N ORO F 23595: (2S,4R)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-4- fluoro-1-(4-fluorobenzoyl)pyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23595 Fmoc- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH Aib-OH OH 6 7 8 9 10 Fmoc- Fmoc-L- Fmoc-L-Pro(4-F)- 4-Fluorobenzoic [(2S)-2- Leu-OH homocyclohe OH (2S,4R) acid aminopropyl]di- xylalanine methylamine Cpd Molecular mass Experimentally measured mass 23595 [M]+ 1101.4 1101.6 Cpd R1 R2 R3 F R 23595 N OR NN R H OF23596: (2S,4R)-4-(benzyloxy)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-1-(4-fluorobenzoyl)pyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23596 Fmoc-Aib- Fmoc-Aib-OH Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-Hyp(Bzl)- 4-Fluorobenzoic [(2S)-2- OH homocyclohex OH acid aminopropyl]di- ylalanine methylamine Cpd Molecular mass Experimentally measured mass 23596 [M]+ 1189.6 1189.7 Cpd R1 R2 R3 O R 23596RNNRH N O OF23612: (2S,4S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-1-(4- fluorobenzoyl)-4-phenylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23612 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-(2S,4S)-4- 4-Fluorobenzoic [(2S)-2- OH homocyclohe phenylpyrrolidine acid aminopropyl]di- xylalanine -2-carboxylic acid methylamine Cpd Molecular mass Experimentally measured mass 23612 [M]+ 1159.5 1159.7 Cpd R1 R2 R3 R 23612R NN N ORH OF23687: (2S,4S)-N-((4S,10S,13S,19S,22S)-24-cyclohexyl-10,13,19-triisobutyl-2,4,7,7,16,16- hexamethyl-6,9,12,15,18,21-hexaoxo-2,5,8,11,14,17,20-heptaazatetracosan-22-yl)-1-(4- fluorobenzoyl)-4-methylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23687 Fmoc-Aib-OH Fmoc-Leu- Fmoc-Leu-OH Fmoc-Aib-OH Fmoc-Leu- OH OH 6 7 8 9 Fmoc-L- Fmoc-L- 4- [(2S)-2- - homocyclohexyl Pro(4S- Fluorobenzoic aminopropyl]dimet alanine Methyl)-OH acid hylamine Cpd Molecular mass Experimentally measured mass 23687 [M]+ 1012.4 1012.6 Cpd R1 R2 R3 R 23687 N ORNNRH OF23688 (reference example): (2S,4S)-N-((4S,7S,10S,16S,19S)-21-cyclohexyl-7,10,16-triisobutyl-2,4,13,13-tetramethyl- 6,9,12,15,18-pentaoxo-2,5,8,11,14,17-hexaazahenicosan-19-yl)-1-(4-fluorobenzoyl)-4- methylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23688 Fmoc-Leu- Fmoc-Leu-OH Fmoc-Aib-OH Fmoc-Leu- Fmoc-L- OH OH homocyclohexyl- alanine 6 7 8 Fmoc- 4- [(2S)-2- - - Pro(4S- Fluorobenzoic aminopropyl]dim Methyl)-OH acid ethylamine Cpd Molecular mass Experimentally measured mass 23688 [M]+ 927.2 927.6 Cpd R1 R2 R3 R 23688 N ORNNRH OF23692: (2S,4S)-N-((4S,11S,20S,23S,29S,32S)-34-cyclohexyl-11,20,23,29-tetraisobutyl- 2,4,14,14,17,17,26,26-octamethyl-6,10,13,16,19,22,25,28,31-nonaoxo- 2,5,9,12,15,18,21,24,27,30-decaazatetratriacontan-32-yl)-1-(4-fluorobenzoyl)-4- methylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 6 23692 Fmoc-β- Fmoc- Fmoc-Aib-OH Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Ala-OH Leu-OH OH 7 8 9 10 11 12 Fmoc- Fmoc- Fmoc-L- Fmoc-L- 4- [(2S)-2- Aib-OH Leu-OH homocyclohex Pro(4S- Fluorobenzoic aminopropyl]di- ylalanine Methyl)-OH acid methylamine Cpd Molecular mass Experimentally measured mass 23692[M]+ 1281.7 1281.8 (2S,4S)-N-((4S,11S,14S,23S,26S,32S,35S)-37-cyclohexyl-11,14,23,26,32-pentaisobutyl- 2,4,17,17,20,20,29,29-octamethyl-6,10,13,16,19,22,25,28,31,34-decaoxo- 2,5,9,12,15,18,21,24,27,30,33-undecaazaheptatriacontan-35-yl)-1-(4-fluorobenzoyl)-4- methylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 6 7 23693 Fmoc- Fmoc- Fmoc-Leu- Fmoc-Aib- Fmoc- Fmoc-Leu-OH Fmoc- β-Ala- Leu-OH OH OH Aib-OH Leu-OH OH 8 9 10 11 12 13 Fmoc- Fmoc- Fmoc-L- Fmoc-L- 4- [(2S)-2- Aib-OH Leu-OH homocyclohe Pro(4S- Fluoroben aminopropyl]di xylalanine Methyl)-OH oic acid methylamine Cpd Molecular mass Experimentally measured mass 23693 [M]+ 1394.9 1394.9 Cpd R1 R2 R3 R 23693 N OR NN R H OF23704 (reference example): (2S,4S)-N-((4S,7S,13S,16S)-18-cyclohexyl-7,13-diisobutyl-2,4,10,10-tetramethyl-6,9,12,15- tetraoxo-2,5,8,11,14-pentaazaoctadecan-16-yl)-1-(4-fluorobenzoyl)-4-methylpyrrolidine-2- carboxamide Cpd 1 2 3 4 23704 Fmoc-Leu-OH Fmoc-Aib-OH Fmoc-Leu-OH Fmoc-L- homocyclohexylalanine 5 6 7 Fmoc-L-Pro(4S- 4-Fluorobenzoic [(2S)-2- Methyl)-OH acid aminopropyl]di methylamine Cpd Molecular mass Experimentally measured mass 23704 [M]+ 814.1 814.3 Cpd R1 R2 R3 R 23704 N ORNNRH OF23705: (2S,4S)-N-((4S,14S,17S,26S,29S,35S,38S)-40-cyclohexyl-14,17,26,29,35-pentaisobutyl- 2,4,11,11,20,20,23,23,32,32-decamethyl-6,10,13,16,19,22,25,28,31,34,37-undecaoxo- 2,5,9,12,15,18,21,24,27,30,33,36-dodecaazatetracontan-38-yl)-1-(4-fluorobenzoyl)-4- methylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 6 7 23705 Fmoc- Fmoc- Fmoc- Fmoc-Leu- Fmoc-Aib- Fmoc-Aib- Fmoc-Leu- β-Ala- Aib-OH Leu-OH OH OH OH OH OH 8 9 10 11 12 13 14 Fmoc- Fmoc- Fmoc- Fmoc-L- Fmoc-L- 4- [(2S)-2- Leu-OH Aib-OH Leu-OH homocyclohe Pro(4S- Fluorobeno aminopropyl xylalanine Methyl)-OH ic acid ]dimethylam ine Cpd Molecular mass Experimentally measured mass 23705 [M]+ 1480.0 1479.9 Cpd R1 R2 R3 R 23705 N ORNNRH OF23717: (2S,5S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-1-(4- fluorobenzoyl)-5-methylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23717 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-L-Pro(5- 4-Fluorobenzoic [(2S)-2- OH homocyclohe Me)-OH (2S,5S) acid aminopropyl]di- xylalanine methylamine Cpd Molecular mass Experimentally measured mass 23717 [M]+ 1097.5 1097.5 Cpd R1 R2 R3 R 23717 N OR NN R H OF23718:

[0003] (S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-1-(4- fluorobenzoyl)-5,5-dimethylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23718 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-5,5-dmP- 4-Fluorobenzoic [(2S)-2- OH homocyclohe OH (S) acid aminopropyl]di- xylalanine methylamine Cpd Molecular mass Experimentally measured mass 23718 [M]+ 1111.5 1111.6 Cpd R1 R2 R3 R 23718 N OR NN R H OF23720:

[0004] (2S,4R)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-1-(4- fluorobenzoyl)-4-phenylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23720 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-(2S,4R)-4- 4-Fluorobenzoic [(2S)-2- OH homocyclohe phenylpyrrolidine acid aminopropyl]di- xylalanine -2-carboxylic acid methylamine Cpd Molecular mass Experimentally measured mass 23720 [M]+ 1159.5 1159.7 Cpd R1 R2 R3 R 23720R NN N ORH OF23736: (S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-1-(4- fluorobenzoyl)-3,3-dimethylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23736 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-3,3-dmP- 4-Fluorobenzoic [(2S)-2- OH homocyclohe OH (S) acid aminopropyl]di- xylalanine methylamine Cpd Molecular mass Experimentally measured mass 23736 [M]+ 1111.5 1111.6 Cpd R1 R2 R3 R 23736 N OR NN R H OF23738:

[0005] (2S,4S)-4-cyclohexyl-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl- 2,4,7,7,10,10,19,19-octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23- octaazaheptacosan-25-yl)-1-(4-fluorobenzoyl)pyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23738 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-L- 4-Fluorobenzoic [(2S)-2- OH homocyclohe Pro(4Chx)-OH acid aminopropyl]di- xylalanine (2S,4S) methylamine Cpd Molecular mass Experimentally measured mass 23738 [M]+ 1165.6 1165.6 Cpd R1 R2 R3 R 23738R NN O N R H OF23739:

[0006] (2S,5R)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-1-(4- fluorobenzoyl)-5-phenylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23739 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-L-Pro(5- 4-Fluorobenzoic [(2S)-2- OH homocyclohe Ph)-OH (2S,5R) acid aminopropyl]d- xylalanine imethylamine Cpd Molecular mass Experimentally measured mass 23739 [M]+ 1159.5 1159.6 Cpd R1 R2 R3 R 23739 N OR NN R H OF23741 (reference example): Cpd 1 2 3 4 5 6 7 8 9 23741 Fmoc- Fmoc- Fmoc- Fmoc- Fmoc-Aib- Fmoc-Leu- Fmoc- Fmoc- Fmoc- β-Ala- Leu- Leu- Aib- OH OH Leu-OH Aib- Aib- OH OH OH OH OH OH 10 11 12 13 14 15 16 17 Fmoc- Fmoc- Fmoc- Fmoc- Fmoc-L- Fmoc-L- 4- [(2S)-2- Leu- Leu- Aib- Leu- homocycloh Pro(4S- Fluoroben aminopropyl]di OH OH OH OH exylalanine Methyl)-OH zoic acid methylamine Cpd + Molecular mass Experimentally measured mass 23741 ([M+2H ]2+) / 2 1791.4 896.6 ([M+2H+]2+) / 2 Cpd R1 R2 R3 R 23741 N OR NN R H OF23742: (2S,4R)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-1-(4- fluorobenzoyl)-4-(4-fluorobenzyl)pyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23742 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-L-Pro(4-p- 4-Fluorobenzoic [(2S)-2- OH homocyclohe F-Ph)-OH (2S,4R) acid aminopropyl]di- xylalanine methylamine Cpd Molecular mass Experimentally measured mass 23742 [M]+ 1191.4 1191.6 Cpd R1 R2 R3 F 23742 RR NN R H N O OF23794: (S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-4,4- difluoro-1-(4-fluorobenzoyl)pyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23794 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-L-4,4,- 4-Fluorobenzoic [(2S)-2- OH homocyclohe difluoroproline acid aminopropyl]di- xylalanine methylamine Cpd Molecular mass Experimentally measured mass 23794 [M]+ 1119.41 1119.17 Cpd R1 R2 R3 F F R 23794 N OR NN R H OF 23795: (S)-N-((4S,13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-2,4,7,7,10,10,19,19- octamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-5-(4- fluorobenzoyl)-5-azaspiro[2.4]heptane-6-carboxamide Cpd 1 2 3 4 5 23795 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- (S)-5-(((9H-fluoren-9- 4-Fluorobenzoic [(2S)-2- OH homocyclohe yl)methoxy)carbonyl)-5- acid aminopropyl]di- xylalanine azaspiro[2.4]heptane-6- methylamine carboxylic acid Cpd Molecular mass Experimentally measured mass 23795 [M]+ 1109.46 1109.17 Cpd R1 R2 R3 R 23795 N OR NN R H OF23826: (2S,4S)-N-((13S,16S,22S,25S)-27-cyclohexyl-13,16,22-triisobutyl-7,7,10,10,19,19- hexamethyl-6,9,12,15,18,21,24-heptaoxo-2,5,8,11,14,17,20,23-octaazaheptacosan-25-yl)-1- (4-fluorobenzoyl)-4-methylpyrrolidine-2-carboxamide Cpd 1 2 3 4 5 23826 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-L-Pro(4S- 4-Fluorobenzoic tert-butyl (2- OH homocyclohe Methyl)-OH acid aminoethyl)- xylalanine (methyl)carbamate Cpd Molecular mass Experimentally measured mass 23826 [M]+ 1069.40 1069.17 Cpd R1 R2 R3 R H 23826 N O R N N R H OF24879: (2S)‐2‐[(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl)‐4‐[4‐(2‐methylpropyl)‐1H‐1,2,3‐ triazol‐1‐yl]pyrrolidin‐2‐yl]formamido}butanamido]‐N‐(1‐{[(1S)‐1‐{[(1S)‐1‐({1‐[(1‐{[(2S)‐ 1‐(dimethylamino)propan‐2‐yl]carbamoyl}‐1‐methylethyl)carbamoyl]‐1- methylethyl}carbamoyl)‐3‐methylbutyl]carbamoyl}‐3‐methylbutyl]carbamoyl}‐1‐ methylethyl)‐4‐methylpentanamide Cpd 1 2 3 4 5 24879 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- (2S,4S)‐1‐ 4-Fluorobenzoic [(2S)-2- OH homocyclohe {[(9H‐fluoren‐ acid aminopropyl]di- xylalanine 9-yl)methoxy] methylamine carbonyl}‐4‐[4‐ (2-methyl- propyl)‐1H‐ 1,2,3triazol‐1‐ yl]pyrrolidine‐2‐ carboxylic acid Cpd Molecular mass Experimentally measured mass 24879 [M]+ 1206.58 1206.95 Cpd R1 R2 R3 N NN O24879R NN R N R H O F 25041: (2S)‐2‐[(2S)‐2‐{2‐[(2S)‐2‐[(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl)‐4‐ methylpyrrolidin‐2‐yl]formamido}butanamido]‐4‐methylpentanamido]‐2‐ methylpropanamido}‐4‐methylpentanamido]‐4‐methyl‐N‐{1‐methyl‐1‐[(1‐methyl‐1‐{[(2S)‐1‐ (morpholin‐4‐yl)propan‐2‐yl]carbamoyl}ethyl)carbamoyl]ethyl}pentanamide Cpd 1 2 3 4 5 25041 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-L-Pro(4S- 4-Fluorobenzoic (2S)‐1‐(morpholin‐ OH homocyclohe Methyl)-OH acid 4‐yl)propan‐2‐ xylalanine amine Cpd Molecular mass Experimentally measured mass 25041 [M+H+]+ 1139.49 1140.23 Cpd R1 R2 R3 R H N 25041 N O R N R O OF25042: (2S)‐2‐[(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl)‐4‐methylpyrrolidin‐2‐ yl]formamido}butanamido]‐4‐methyl‐N‐(1‐methyl‐1‐{[(1S)‐3‐methyl‐1‐{[(1S)‐3‐methyl‐1‐ ({1‐methyl‐1‐[(1‐methyl‐1‐{[2‐(4‐methylpiperazin‐1‐ yl)ethyl]carbamoyl}ethyl)carbamoyl]ethyl}carbamoyl)butyl]carbamoyl}butyl]carbamoyl}eth yl)pentanamide Cpd 1 2 3 4 5 25042 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-L-Pro(4S- 4-Fluorobenzoic 2‐(4- OH homocyclohe Methyl)-OH acid methylpiperazin‐1‐ xylalanine yl)ethan‐1‐amine Cpd Molecular mass Experimentally measured mass 25042 [M+H+]+ 1138.51 1139.13 Cpd R1 R2 R3 R H N 25042 N O R N R N OF25088: (2S)‐2‐[(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl)‐4‐methylpyrrolidin‐2‐ yl]formamido}butanamido]‐N‐(1‐{[(1S)‐1‐{[(1S)‐1‐({1‐[(1‐{[2- (dimethylamino)ethyl]carbamoyl}‐1‐methylethyl)carbamoyl]‐1‐methylethyl}carbamoyl)‐3‐ methylbutyl]carbamoyl}‐3‐methylbutyl]carbamoyl}‐1‐methylethyl)‐4‐methylpentanamide Cpd 1 2 3 4 5 25088 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-L-Pro(4S- 4-Fluorobenzoic (2‐ OH homocyclohe Methyl)-OH acid aminoethyl)dimeth xylalanine ylamine Cpd Molecular mass Experimentally measured mass 25088 [M+H+]+ 1083.43 1084.08 Cpd R1 R2 R3 R H 25088 N O N R N ORF25126: (2S)‐2‐[(2S)‐2‐{2‐[(2S)‐2‐[(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl)‐4‐ methylpyrrolidin‐2‐yl]formamido}butanamido]‐4‐methylpentanamido]‐2‐ methylpropanamido}‐4‐methylpentanamido]‐4‐methyl‐N‐{1‐methyl‐1‐[(1‐methyl‐1‐{[(2S)‐1‐ (piperazin‐1‐yl)propan‐2‐yl]carbamoyl}ethyl)carbamoyl]ethyl}pentanamide Cpd 1 2 3 4 5 25126 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-L-Pro(4S- 4-Fluorobenzoic tert‐butyl 4‐[(2S)‐ OH homocyclohe Methyl)-OH acid 2-aminopropyl]- xylalanine piperazine‐1‐ carboxylate Cpd Molecular mass Experimentally measured mass 25126 [M+H+]+ 1138.51 1139.29 Cpd R1 R2 R3 R H N 25126 N O R N NH ORF25157: (2S)‐2‐[(2S)‐2‐{2‐[(2S)‐2‐[(2S)‐4‐cyclohexyl‐2‐{[(2S,4S)‐1‐(4‐fluorobenzoyl)‐4‐ methylpyrrolidin‐2‐yl]formamido}butanamido]‐4‐methylpentanamido]‐2‐ methylpropanamido}‐4‐methylpentanamido]‐4‐methyl‐N‐{1‐methyl‐1‐[(1‐methyl‐1‐{[(2S)‐1‐ (methylamino)propan‐2‐yl]carbamoyl}ethyl)carbamoyl]ethyl}pentanamide vanadium Cpd 1 2 3 4 5 25157 Fmoc-Aib- Fmoc-Aib- Fmoc-Leu-OH Fmoc-Leu-OH Fmoc-Aib-OH OH OH 6 7 8 9 10 Fmoc-Leu- Fmoc-L- Fmoc-L-Pro(4S- 4-Fluorobenzoic benzyl N‐[(2S)‐2‐ OH homocyclohe Methyl)-OH acid aminopropyl]‐N‐ xylalanine methylcarbamate Cpd Molecular mass Experimentally measured mass 25157 [M+H+]+ 1138.51 1139.29 Cpd R1 R2 R3 R H 25157 N O N R N R H OFEXAMPLE 4 In vitro anti-proliferative effects of the inventive compounds against cutaneous squamous carcinoma cells and keratinocytes Cutaneous squamous cell carcinoma of the skin is a common form of skin cancer that develops in the squamous cells that make up the middle and outer layers of the skin. Cutaneous squamous cell carcinoma of the skin is usually not life-threatening, though it can be aggressive. Untreated, squamous cell carcinoma of the skin can grow large or spread to other parts of your body, causing serious complications. Most squamous cell carcinomas of the skin result from prolonged exposure to ultraviolet (UV) radiation, either from sunlight or from tanning beds or lamps. Avoiding UV light helps reduce your risk of squamous cell carcinoma of the skin and other forms of skin cancer. Squamous cells are found in many places in the body, and squamous cell carcinoma can occur anywhere squamous cells are found. Squamous cell carcinoma of the skin, and cutaneous squamous cell carcinoma (cSCC), respectively, refers to cancer that forms in the squamous cells found in the skin. Cutaneous squamous cell carcinoma is a malignant neoplasm formed from keratinocytes found in the squamous cell layer of the skin. The in vitro anti-proliferative effects of inventive compounds against cutaneous squamous carcinoma cells as well as keratinocytes have been tested. In particular, the in vitro anti-proliferative effects of inventive compounds against the cutaneous squamous cell carcinoma cell lines SCC13 and A431_SCC as well as CCD-1102 KERTr cell culture (KERTr) have been tested. 1. Representative and preferred inventive compounds have been tested and showed activities against cutaneous squamous cell carcinoma cell line SCC13 in vitro as depicted in Table 4. cSCC cell culture SCC13 has a TP53 as well as a NF2 mutation and is derived from an advanced stage female 56 years old patient. Methodology. The cutaneous squamous cell carcinoma cell culture SCC13 was cultivated in Dulbecco’s Modified Eagle Medium (DMEM, Cat#11966025, Gibco) supplemented with 10% heat-inactivated fetal bovine serum (Cat# S006420H01, BioWest). For the library screening, cells were distributed to 96-well plates in a cell density of 1,500 cells in 90μl / well and let to adhere over night at 37°C and 5% CO2in a cell culture incubator. Serial dilution of compounds in DMSO to 1000x was performed (10 mM, 5 mM, 1 mM, 500 μM, 250 μM, 100 μM, 10 μM , 1 μM). 2 μl of these dilutions were further diluted in 198 μl Dulbecco’s Modified Eagle Medium with supplements, mixed well and 10 μl were further dispensed in triplicates to the 96-well plates containing SCC cells in 90 μl. These dilutions resulted in a final compound concentration of 10 μM, 5 μM, 1μM, 500 nM, 250 nM, 100 nM, 10 nM, 1 nM on cells. Plates were incubated for additional 72 hours and cell culture medium was replaced to medium containing 0.1% of Resazurin-sodium salt stock solution (stock: 0.015mg / ml, in PBS, Cat# R7017, Sigma-Aldrich). Cell culture plates were incubated for 2-3 hours in cell culture incubator at 37°C and 5% CO2. With a fluorescence-based plate reader (Infinite M200 Pro, Tecan, Switzerland) using excitations between 530-560nM and emissions at 590nM the cell- culture plates were readout. The calculations and graphs are performed with GraphPad Prism program. Vehicle treated wells were set to 100% viability. Table 4: Half maximal inhibitory concentrations (IC50) of inventive compounds in cutaneous squamous cell carcinoma cell line SCC13. Compound IC50 (nM) 6027 (reference example) 191.0 20762 54.5 22178 68.4 22179 57.6 22180 (reference example) 134.5 23103 30.1 23491 43.9 23525 46.2 23526 18.0 23538 46.4 23542 12.9 23549 179.0 23552 27.9 23585 48.4 23586 48.5 23594 65.3 23595 52.5 23596 46.3 23612 10.1 23687 48.3 23688 (reference example) 286.9 23692 25.7 23693 45.3 23704 (reference example) 6341.6 23705 46.1 23717 46.4 23718 61.2 23720 36.7 23736 20.9 23738 40.1 23739 55.6 23741 (reference example) NA 23742 45.2 23794 46.9 23795 29.6 23826 74.3 Results. The inventive compounds showed significant activities and IC50 values in the double digit nM range against cutaneous squamous cell carcinoma SCC13 in vitro confirming its use as drugs for the treatment of skin cancers in particular cutaneous squamous skin cancer. In particular, the inventive compounds showed significant increased activities as compared to the reference compound 6027. The reduction to an amino acid chain length of a total of five (23704) or six (23688), or the increase to an amino acid chain length of a total of fifteen (23741) led to a significant decrease and / or of any measurable effectiveness (23741). Surprisingly, the reduction of the amino acid chain length of a total of eight, in particular as represented by formula (III) is considered to not only reduce costs of goods of such compounds and drugs, respectively, but further led to an additional increase in efficacy. Very preferred examples thereof are 23526, 23542, 23612 and 23736. The further provided reference example 22180 also shows reasonable efficacy. However, as described in the following Example 5, it has been found that the presence of 3-Hydroxy- Leucin within the amino acid chain, as it is the case in Leucinostatin A, led to a substantial not acceptable increase in toxicity. 2. The significant activity of the inventive compounds against cSCC has been confirmed in another in vitro anti-proliferative assay, wherein preferred inventive compounds have been tested in a further cutaneous squamous cell carcinoma cell line, namely A431_SCC. A431_SCC is a cSCC cell culture with a TP53 mutation derived from an advanced stage female 85 years old patient. The results are depicted in Table 5. Methodology. The cutaneous squamous cell carcinoma cell culture A431_SCC was cultivated in Dulbecco’s Modified Eagle Medium (DMEM, Cat#11966025, Gibco) supplemented with 10% heat-inactivated fetal bovine serum (Cat# S006420H01, BioWest). For the library screening, cells were distributed to 96-well plates in a cell density of 1,500 cells in 90μl / well and let to adhere over night at 37°C and 5% CO2in a cell culture incubator. Serial dilution of compounds in DMSO to 1000x was performed (10 mM, 5 mM, 1 mM, 500 μM, 250 μM, 100 μM, 10 μM , 1 μM).2 μl of these dilutions were further diluted in 198 μl keratinocyte growth medium with supplements, mixed well and 10 μl were further dispensed in triplicates to the 96-well plates containing SCC cells in 90 μl. These dilutions resulted in a final compound concentration of 10 μM, 5 μM, 1μM, 500 nM, 250 nM, 100 nM, 10 nM, 1 nM on cells. Plates were incubated for additional 72 hours and cell culture medium was replaced to medium containing 0.1% of Resazurin-sodium salt stock solution (stock: 0.015mg / ml, in PBS, Cat# R7017, Sigma-Aldrich). Cell culture plates were incubated for 2-3 hours in cell culture incubator at 37°C and 5% CO2. With a fluorescence-based plate reader (Infinite M200 Pro, Tecan, Switzerland) using excitations between 530-560nM and emissions at 590nM the cell- culture plates were readout. The calculations and graphs are performed with GraphPad Prism program. Vehicle treated wells were set to 100% viability. Table 5: Half maximal inhibitory concentrations (IC50) of inventive compounds in cutaneous squamous cell carcinoma cell line A431_SCC. Compound IC50 (nM) 6027 (reference example) 70.0 23526 15.0 23542 11.9 23585 47.8 23586 36.1 23594 53.1 23595 49.1 23596 28.1 23612 10.3 23688 (reference example) 328.1 23692 17.2 23693 32.5 23704 (reference example) 4700.7 23705 45.3 23717 45.0 23720 20.1 23736 9.9 23738 19.1 23739 50.3 23741 (reference example) NA 23742 40.8 23794 42.6 23826 46.9 3. The significant activities of the inventive compounds against utaneous squamous cell carcinoma cell lines cSCC and A431_SCC, as reported above, has additionally been confirmed in another in vitro anti-proliferative assay, wherein preferred inventive compounds were tested in CCD-1102 KERTr cell culture (KERTr), which is commonly used to study actinic keratosis due to its ability to mimic the characteristic of this precancerous skin condition effectively. It is an immortalized keratinocyte cell culture and as cSCC is a keratinocyte based disorder as well, we used this cell culture to proof general efficacy of inventive compounds in keratinocyte based cancerous cell disorders. The results are depicted in Table 6. Methodology. The immortalized keratinocyte cell culture CCD-1102 KERTr was cultivated in keratinocyte-SFM media (KSFM, Cat# 17005042, Gibco) supplemented with human recombinant epidermal growth factor 1-53 (EGF 1-53) and bovine pituitary extract (BFE). For the library screening, cells were distributed to 96-well plates in a cell density of 3000 cells in 90μl / well and let to adhere over night at 37°C and 5% CO2in a cell culture incubator. Serial dilution of compounds in DMSO to 1000x was performed (10 mM, 5 mM, 1 mM, 500 μM, 250 μM, 100 μM, 10 μM , 1 μM). 2 μl of these dilutions were further diluted in 198 μl keratinocyte growth medium with supplements, mixed well and 10 μl were further dispensed in triplicates to the 96-well plates containing SCC cells in 90 μl. These dilutions resulted in a final compound concentration of 10 μM, 5 μM, 1μM, 500 nM, 250 nM, 100 nM, 10 nM, 1 nM on cells. Plates were incubated for additional 72 hours and cell culture medium was replaced to medium containing 0.1% of Resazurin-sodium salt stock solution (stock: 0.015mg / ml, in PBS, Cat# R7017, Sigma-Aldrich). Cell culture plates were incubated for 2-3 hours in cell culture incubator at 37°C and 5% CO2. With a fluorescence-based plate reader (Infinite M200 Pro, Tecan, Switzerland) using excitations between 530-560nM and emissions at 590nM the cell-culture plates were readout. The calculations and graphs are performed with GraphPad Prism program. Vehicle treated wells were set to 100% viability. Table 6: Half maximal inhibitory concentrations (IC50) in nM of inventive compounds in immortalized keratinocyte cell culture (CCD-1102 KERTr (KERTr)). Compound KERTr 6027 (reference example) 82.3 23526 35.1 23704 (reference example) 7813.0 23720 70.3 23736 56.4 23738 44.6 23741 (reference example) NA 23742 47.1 23794 56.8 23795 41.8 23826 43.5 EXAMPLE 5 In vitro anti-proliferative effects of the inventive compounds against lung cancer and breast cancer cells The in vitro anti-proliferative effects of the inventive compounds against mouse lung carcinoma cells (LLC) as well as human mammary gland carcinoma cells (Du4475) have been tested in a resazurin-based viability assay. The resazurin-based viability assay is a homogeneous, fluorometric assay that uses resazurin indicator dye to measure the metabolic capability of cells. Viable cells are able to convert non-fluorescent resazurin to its fluorescent product, resorufin. Nonviable cells are unable to reduce resazurin and thus do not display a fluorescent signal. Reduction of resazurin to resorufin also involves a shift of the absorbance maximum from 605 nm to 573 nm, so viability may also be estimated using absorbance. However, fluorescence measurement is usually preferred, as it is more sensitive and requires fewer calculations The LL / 2 (LLC1) CRL-1642 lewis lung carcinoma is a cell line established from the lung of a C57BL mouse bearing a tumor resulting from an implantation of primary Lewis lung carcinoma. This cell line is widely used as a model for metastasis and studying the mechanisms of cancer chemotherapeutic agents. The Du4475 (HTB-123) cell line is a ductal adenocarcinoma breast cancer cell line, which was isolated from a 70-year-old female. Methodology: Before plating, the cells were first washed with DPBS and then trypsinized with trypsin solution in DPBS. The appropriate volume of culture medium was placed in a flask to stop trypsinization. Cells were centrifuged, resuspended, stained with Trypan Blue and counted using a counting chamber. The appropriate volume of the cell suspension was placed in the falcon tube containing plating medium RPMI 1640 with 1% FBS, 2 mM L-glutamine, 100 units / mL penicillin, and 100 µg / mL streptomycin. Cells at 125000 cells / ml density were seeded in sterile 384-well plates (Greiner Bio-One, Cat# 781091) in 40 µl / well (5000 cells / well) and covered with sterile transparent seals. Plates were left overnight in a humidified atmosphere at 37°C and 5% CO2 for adaptation. Cytotoxicity for the test compounds was assessed at the final concentrations ranging from 0.005 µM to 100.0 µM (10 points, 3-fold serial dilutions). Incubation was performed for 48 hours in a humidified atmosphere at 37°C and 5% CO2. The final concentration of DMSO in the assay was 0.5 %. Then resazurin (50 µM final concentration) was added and incubated for 3 hours in a humidified atmosphere at 37°C and 5% CO2. The presence of resorufin was quantified by measuring fluorescence Ex – 555 nm, Em – 585 nm, cut-off 570, bottom read. Results: The inventive compounds showed significant activities and IC50 values in the double to low triple digit nM range against mouse lung carcinoma cells (LLC) as well as human mammary gland carcinoma cells (Du4475) in vitro, confirming its use as drugs for the treatment of different types of cancer, such as lung and skin cancer. The change of the amine moiety shows good tolerance in the activity. Surprisingly most amine groups show a strong increase in activity in both cell lines. Especially the use of a morpholine moiety as exemplified in 25041, as well as a secondary amine as exemplified in 25157 showed an up to 10-fold increase in activity compared to 6027 in both cell lines. Table 7: Half maximal inhibitory concentrations (IC50) in nM of inventive compounds in mouse lung carcinoma cell line (LLC) and human mammary gland carcinoma cell line (Du4475) Compound LLC Du4475 6027 (reference sample) 391 223 24879 63 122 25041 32 32 25042 187 85 25088 99 27 25126 165 30 25157 56 21 EXAMPLE 6 Toxicity Studies Toxicity studies with mice were effected to test for systemic toxicity upon i.v. injection, as well as to test for skin irritation upon topical applications, wherein inventive compounds or corresponding reference compounds having a 3-Hydroxy-Leucin within the amino acid chain as it is the case for the natural product Leucinostatin A have been applied. Methodology: For the topical application to test for skin irritation, C57BI / 6 female mice bearing no tumor were treated once daily for a duration of seven (7) days (7 applications in total) with 20µl of a 0.5% (w / v) solution in a suitable carrier comprising either inventive compounds or corresponding reference compounds having a 3-Hydroxy-Leucin within the amino acid chain as it is the case for the natural product Leucinostatin A. The compounds were each time applied on the shaved neck region of the mice and the application site was monitored. For the injection to test for systemic toxicity, groups of each three C57BI / 6N female mice of 11-13 weeks of age bearing no tumor were treated once daily by i.v. injection at a dose of 3mg / kg in a single dose with a solution (5ml / kg) in a suitable carrier (DMSO:KolliphorHS15:Saline=5:10:85) comprising either inventive compounds or corresponding reference compounds having a 3-Hydroxy-Leucin within the amino acid chain as it is the case for the natural product Leucinostatin A. After injection the animals were monitored for clinical signs of toxicity and the observation is reported after 72 hours. Results. During the skin irritation, the inventive compounds were tolerated and no skin irritations could be observed neither within nor after the entire treatment, while the application of the reference compounds having a 3-Hydroxy-Leucin within the amino acid chain developed and led to very bad skin irritations even after 3-4 days of treatment which caused the halt of the treatment. The results are summarized in Table 8. This finding was further confirmed by applying an even ten times higher concentrated solution of an inventive compound (5% of 22178) which again was well tolerated and did not lead to any skin irritations, while even a 0.2% of Leucinostatin A led to said very bad skin irritations and the halt of the treatment. During the systemic toxicity testing the animals were monitored for clinical signs of toxicity and the observation 72 hours after injection reported. The results are summarized in Table 8. The animals treated with inventive compounds all showed good appearance and had no clinical symptoms, while the treatment with the reference compounds having a 3-Hydroxy- Leucin within the amino acid chain as it is the case for the natural product Leucinostatin A led to the death (---) or moribund (###) of the animals. Table 8: Toxicity study of inventive and reference compounds with C57BI / 6 female mice. CompoundPresence ofSkin irritation Systemic Toxicity 3-Hydroxy-Leucin [at 0,5 % in mice] [at 3mg / kg in mice] 6027 no none none 22178 no none none 22179 no none none 22717 no none none 23526 no none none Leucinostatin A yes bad --- 22430 yes bad --- 22432 yes bad ### 22433 yes bad --- EXAMPLE 7 In vitro anti-proliferative effect against various melanoma cells In vitro anti-proliferative effects by the inventive compounds against further various skin cancer cells have been tested. Hereby, significant activities against cutaneous melanoma cell cultures (M150672, M010817 and B16-F10) as well as acral lentiginous melanoma cell cultures (ALM) (ALM_M150207, ALM_M100513) have been observed as depicted in Tables 9-10. Cell cultures M150672 and M010817 are both human derived cutaneous melanoma cell cultures derived from a subcutaneous metastasis, while cell culture B16-F10 is a mouse derived cutaneous melanoma cell culture. Cell cultures M150672 and B16-F10 have BRAF(V600E) mutations, while cell culture M010817 is NRAS(Q61R) mutated. With the above mentioned cell cultures used the most frequent occurring mutations in cutaneous melanoma are covered. Cell culture M150672 and B16-F10 are MAPK pathway inhibition resistant, while cell culture M010817 is MAPK pathway inhibition sensitive. The acral lentiginous melanoma cell cultures ALM_M150207 and ALM_M100513 are cKIT (K642E) mutated. Methodology. For the library screening cells were distributed to 96-well plates (cell densities (cells / well): M150672 (2000), M010817 (2000) and B16-F10 (1500) in 90μl / well and let to adhere over night at 37°C and 5% CO2in a cell culture incubator. For the maintenance of cutaneous and acral lentiginous melanoma cell cultures RPMI- 1640 (Cat#R0883, Gibco) supplemented with L-glutamine (Cat# 25030-081, Gibco), 1mM sodium pyruvate (Cat# S8636, Sigma-Aldrich), 10% heat-inactivated fetal bovine serum (Cat# S006420H01, BioWest) and 1% Penicillin-Streptomycin (Cat#15140122, Gibco) was used. To determine the half maximal inhibitory concentrations (IC50’s) serial dilution of compounds in DMSO to 1000x was performed (10 mM, 5 mM, 1 mM, 500 μM, 250 μM, 100 μM, 10 μM , 1 μM).2 μl of these dilutions were further diluted in 198 μl growth medium with supplements, mixed well and 10 μl were further dispensed in triplicates to the 96-well plates containing cells in 90 μl. These dilutions resulted in a final compound concentration of 10 μM, 5 μM, 1μM, 500 nM, 250 nM, 100 nM, 10 nM, 1 nM. For each drug condition and cell culture (for each row of the triplicate) a well with only RPMI-1640 complete and one with media and DMSO were made as controls. DMSO was never at a higher concentration than 0.2% v / v. Triplicates were seeded for each condition. On the day of the assay, the medium was exchanged with cell culture media containing 0.1% of Resazurin- sodium salt stock solution (stock: 0.015mg / ml, in PBS, Cat# R7017, Sigma-Aldrich). Cell culture plates were incubated for 2-3 hours in cell culture incubator at 37°C and 5% CO2. With a fluorescence-based plate reader (Infinite M200 Pro, Tecan, Switzerland) using excitations between 530-560nM and emissions at 590nM the cell-culture plates were readout. The calculations and graphs are performed with GraphPad Prism program. Vehicle treated wells were set to 100% viability. Cytotoxic potency of inventive compounds shown as IC50 values in nM tested in cutaneous melanoma cell cultures (M150672, M010817 and B16-F10) are shown in Table 9. The corresponding cytotoxicity potencies of compounds in acral lentiginous melanoma cell cultures (ALM_M150207, ALM_M100513) are shown in Table 10. Table 9: Half maximal inhibitory concentrations (IC50) in nM of inventive compounds in various cutaneous melanoma cell cultures (M150672, M010817, B16-F10). Compound M150672 M010817 B16-F10 6027 (reference example) 122.0 60.0 215.9 23526 37.6 21.1 44.6 23542 50.0 56.1 23585 45.3 42.3 121.4 23586 49.4 38.3 120.3 23594 51.2 45.5 185.0 23595 44.2 184.6 23596 31.2 199.9 23612 30.2 21.2 45.3 23687 173.9 45.8 119.1 23688 (reference example) 438.1 430.9 412.3 23692 21.2 21.8 52.4 23693 36.2 348.8 62.9 23704 (reference example) NA NA NA 23717 62.8 43.9 59.7 23720 34.0 27.9 80.5 23736 9.1 50.0 147.7 23738 33.5 39.2 101.7 23739 56.1 67.5 164.5 23741 (reference example) NA NA NA 23794 49.4 42.8 79.6 23795 24.3 22.2 45.9 Table 10: Half maximal inhibitory concentrations (IC50) in nM of inventive compounds in various acral lentiginous melanoma (ALM) cell lines (ALM_M150207, ALM_M100513). Compound ALM_M150207 ALM_M100513 23526 33.8 48.3 23585 42.3 44.1 23586 40.3 23594 45.5 98.5 23595 60.7 23596 45.7 23612 21.2 42.9 23687 44.8 59.6 23688 (reference example) 426.9 661.8 23692 20.5 23693 349.0 Results. The results obtained for the preferred inventive compounds, as shown in Tables 9-10, demonstrate significant efficacy in the tested cell lines. These results confirm the data obtained from the assays conducted on cutaneous squamous cell carcinoma cell lines and keratinocytes, as described in Example 4. Figures 1A-1C and FIG.2A-C show the statistically significant increase in efficacy of the very preferred compound 23526 as compared to reference compound 6027 for the tested cutaneous squamous cell carcinoma cell lines, keratinocytes as well as for various melanoma cells as reported in Example 4 and within this Example 6. EXAMPLE 8 In vitro anti-proliferative effects of inventive compounds in a plurality of cancerous tissue cell panels Tumors are traditionally classified in primarily by tissue and organ type. One of the inventive compounds (23526) was tested in in vitro cellular models representing the most common and relevant tumor types in human disease according to this classification (types by tissue) using cell lines that are well accepted in cancer research and representative for each tumor type. Whenever possible models from the NCI-60 cancer cell line panel used by the National Cancer Institute (NCI) for the screening of compounds to detect potential anticancer activity were used. Broad in vitro anti-proliferative effects of the very preferred inventive compound 23526 were assessed in a series of specific cancer tissues and the proliferation response of those cancer cell lines to drug treatments were measured through bioluminescence. The tested cell lines are commercially available from depositories. Methodology. Cells were grown in RPMI 1640, 10% FBS, 2 mM L-alanyl-L-glutamine, 1 mM Na pyruvate, or a special medium. Cells were seeded into 384-well plates (96- well plate for 6027) and incubated in a humidified atmosphere of 5% CO2at 37oC. Compounds were added the day following cell seeding. At the same time, a time zero untreated cell plate was generated. After a 3-day incubation period, cells were lysed with cell viability detection reagent CellTiter-Glo® (Promega). Compounds tested were serially diluted in half-log steps (3 fold dilutions for 6027) from the highest test concentration of 3µM in DMSO (10µM in DMSO for 6027) and assayed over 10 concentrations with a maximum assay concentration of 0.1% DMSO (0.5% for 6027). Bioluminescence was read by a PerkinElmer Envision® microplate reader. Cell viability was measured by the bioluminescence signal generated by the production of ATP in viable cells. The output is referred to as the relative cell count, where measured bioluminescence intensity was transformed to percent of control (POC). Cell count EC50 is the test compound concentration at the curve inflection point or half the effective response. Curve- fitting, calculations, and report generation was performed using a custom data reduction engine and MathIQ based software (AIM). 1. Potency of 23526 in breast cancer. MCF-7 is a breast cancer cell line isolated in 1970 from a 69-year-old White woman. This cell line retained several characteristics of differentiated mammary epithelium, including the ability to process estradiol via cytoplasmic estrogen receptors and the capability of forming domes. MDA-MB-468 is a cell line that was isolated from a black 51-year-old female human with metastatic adenocarcinoma of the breast in 1977, and were extracted from a pleural effusion of mammary gland and breast tissues, and have proven useful for the study of metastasis, migration, and breast cancer proliferation. Both cell lines are widely used to test chemical breast cancer treatments and are considered representative for the disease and are part of the NCI reference panel of cell lines for cancer testing. Results. Table 11: Efficacy of the preferred inventive compound 23526 in breast cancer cells given as EC50 in nM. Cell line Tissue Group 23526 Staurosporine 6027 (Reference) MCF7 Breast 9.2 40.5 71.0 MDA MB 468 Breast 10.8 23.9 30.0 The inventive compound 23526 shows a strong anti-cancer response in the representative breast cancer cell lines of 9.2 nM against MCF7 and 10.8 nM against MDA MB 468 cells. This is multiple times stronger than the reference compound 6027 (71.0 nM against MCF7 and 30.0 nM against MDA MB 468 cells) and also multiple times more potent than Staurosporine (40.5 nM against MCF7 and 23.9 nM against MDA MB 468 cells) which serves as a suitable and very potent comparator for those skilled in the art. 2. Potency of 23526 in colorectal cancer HT-29 is a human colon cancer cell line used extensively in biological and cancer research. Initially derived in 1964 from a 44-year-old Caucasian female, HT-29 cells form a tight monolayer while exhibiting similarity to enterocytes from the small intestine. HT-29 cells have been studied for their ability to differentiate and thus simulate real colon tissue in vitro, a characteristic that has made HT-29 useful for epithelial cell research. The COLO 205 cell line is made up of epithelial cells isolated in 1975 from ascitic fluid derived from a 70-year-old, Caucasian, male with colon cancer. These cells exhibit epithelial cell morphology and come from a Dukes’ type D tumor. The patient had been treated with 5- fluorouracil for approximately five weeks before removal of the specimen. Both cell lines are widely used to test chemical colorectal cancer treatments and are considered representative for the disease and are part of the NCI reference panel of cell lines for cancer testing. Results. Table 12: Efficacy of the preferred inventive compound 23526 in colorectal cancer cells given as EC50 in nM. Cell line Tissue Group 23526 Staurosporine 6027 (Reference) HT-29 Colorectal 6.2 13.7 50.0 Colo 205 Colorectal 11.9 6.9 43.0 The inventive compound 23526 shows a strong anti-cancer response in the representative colorectal cancer cell lines of 6.2 nM against HT-29 and 11.9 nM against Colo 205 cells. This is multiple times stronger than the reference compound 6027 (50.0 nM against HT-29 and 43.0 nM against Colo 205 cells) and in the same range of potency as Staurosporine (13.7 nM against HT-29 and 6.9 nM against Colo 205 cells) which serves as a very potent and suitable comparator for those skilled in the art. 3. Potency of 23526 in hematopoietic cancer Tumors of the hematopoietic and lymphoid tissues are tumors that affect the blood, bone marrow, lymph, and lymphatic system. Because these tissues are all intimately connected through both the circulatory system and the immune system, a disease affecting one will often affect the others as well, making aplasia, myeloproliferation and lymphoproliferation (and thus the leukemias and the lymphomas) closely related and often overlapping problems. Hematological malignancies may derive from either of the two major blood cell lineages: myeloid and lymphoid cell lines. The myeloid cell line normally produces granulocytes, erythrocytes, thrombocytes, macrophages and mast cells; the lymphoid cell line produces B, T, NK and plasma cells. Lymphomas, lymphocytic leukemias, and myeloma are from the lymphoid line, while acute and chronic myelogenous leukemia, myelodysplastic syndromes and myeloproliferative diseases are myeloid in origin. SR cells were established from the pleural effusion of an 11-year-old boy with CD30+ (Ki-1) large T cell lymphoma in 1983. K-562 are lymphoblast cells isolated from the bone marrow of a 53-year-old chronic myelogenous leukemia patient. MOLT-4 cells are T cell leukemia established from the peripheral blood of a 19-year-old man with acute lymphoblastic leukemia (ALL) in relapse in 1971. CCRF-CEM are human T lymphoblasts isolated from the peripheral blood of a female, Caucasian 4-year-old with acute lymphoblastic leukemia (ALL). All cell lines are widely used to test chemical treatments of hematopoietic cancers and are considered representative for the disease and are part of the NCI reference panel of cell lines for cancer testing. To capture the variability within the group of hematopoietic cancers the following cell lines were used: Table 13: Hematopoietic cancer cell lines CELL LINE SPECIFIC TISSUE / TUMOR SUB-TYPE TUMOR TYPE TISSUE SUBTYPE SR Large cell immunoblastic lymphoma, Lymphoma Lymphoblast pleural effusion K562 Chronic myelogenous leukemia Leukemia Lymphoblast MOLT-4 Acute lymphoblastic leukemia Leukemia T-lymphoblast CCRFCEM Acute lymphoblastic leukemia Leukemia T-lymphoblast Results. Table 14: Efficacy of the preferred inventive compound 23526 in hematopoietic cancer cells given as EC50 in nM. Cell line Tissue Group 23526 Staurosporine 6027 (Reference) SR Hematopoietic 2.7 9.8 30.0 K562 Hematopoietic 7.1 63.7 29.0 MOLT-4 Hematopoietic 9.2 13.8 46.0 CCRFCEM Hematopoietic 14.2 36.4 73.0 The inventive compound 23526 shows a strong anti-cancer response in the representative hematopoietic cancer cell lines of 2.7 nM against SR and 7.1 nM against K562 cells and 9.2 nM against MOLT-4 cells and 14.2 nM against CCRFCEM cells. This is multiple times stronger than the reference compound 6027 (30.0 nM against SR and 29.0 nM against K562 cells and 46.0 nM against MOLT-4 cells and 73.0 nM against CCRFCEM cells) and also multiple times more potent than Staurosporine (9.8 nM against SR and 63.7 nM against K562 cells and 13.8 nM against MOLT-4 cells and 36.4 nM against CCRFCEM cells) which serves as a very potent and suitable comparator for those skilled in the art. 4. Potency of 23526 in cancers of the female genitourinary (GU) system OVCAR3 are epithelial cells that were isolated in 1982 from the malignant ascites of a patient with progressive adenocarcinoma of the ovary. Cells are used to study drug resistance in ovarian cancer. C-33 A are epithelial cells isolated from the cervix of a 66-year-old, white, uterine cancer patient. SiHa is a cell line isolated from fragments of a primary uterine tissue sample from a 55- year-old, female, Japanese patient with squamous cell carcinoma. All cell lines are widely used to test chemical treatments of cancers of the female genitourinary (GU) system and are considered representative for the disease. OVCAR3 is also part of the NCI reference panel of cell lines for cancer testing. Table 15: Cancer cell lines of the female genitourinary (GU) system CELL LINE TISSUE SUBTYPE TUMOR TYPE TUMOR SUB-TYPE OR STAGE OVCAR3 Ovary Adenocarcinoma C-33A Cervix Carcinoma Retinoblastoma SiHa Cervix Squamous cell carcinoma Grade II Results. Table 16: Efficacy of the preferred inventive compound 23526 female genitourinary (GU) system cells given as EC50 in nM. Cell line Tissue Group 23526 Staurosporine 6027 (Reference) OVCAR3 Female GU 3.5 12.7 14.0 C-33A Female GU 22.4 82.3 33.0 SiHa Female GU 58.1 71.4 67.0 The inventive compound 23526 shows a strong anti-cancer response in the representative cancer cell lines of the female genitourinary (GU) system of 3.5 nM against OVCAR3 and 22.4 nM against C-33A cells and 58.1 nM against SiHa cells. This is much stronger potency than the reference compound 6027 (14.0 nM against OVCAR3 and 33.0 nM against C-33A cells and 67.0 nM against SiHa cells) and Staurosporine (12.7 nM against OVCAR3 and 82.3 nM against C-33A cells and 71.4 nM against SiHa cells) which serves as a very potent and suitable comparator for those skilled in the art. 5. Potency of 23526 in lung cancer Calu-6 is a cell line exhibiting epithelial morphology that was derived from a 61-year- old, white female patient with anaplastic carcinoma. A549 cells were isolated from the lung tissue of a white, 58-year-old male with lung cancer. DMS 114 is a cell line that was isolated from the lung of a white, 68-year-old, male patient with carcinoma. NCI-H460 cells were isolated in 1982 from the pleural fluid of a male patient with large cell lung cancer. All cell lines are widely used to test chemical treatments of lung cancers, immuno- oncology, and toxicology research and are considered representative for the disease. A549 and NCI-460 and DMS114 are also part of the NCI reference panel of cell lines for cancer testing. Results. Table 17: Efficacy of the preferred inventive compound 23526 in lung cancer cells given as EC50 in nM. Cell line Tissue Group 23526 Staurosporine 6027 (Reference) Calu6 Lung 6.2 8.4 n.d. A549 Lung 9.0 2.3 44.0 DMS114 Lung 10.9 44.6 n.d. NCI-H460 Lung 16.8 15.0 51.0 The inventive compound 23526 shows a strong anti-cancer response in the representative lung cancer cell lines of 6.2 nM against Calu6 and 9.0 nM against A549 cells and 10.9 nM against DMS114 cells and 16.8 nM against NCI-H460 cell lines. For A549 and NCI-H460 (Calu6 and DMS114 not determined (n.d.) for this compound) this is multiple times stronger anti-cancer activity when compared to the reference compound 6027 (44.0 nM against A549 cells and 51.0 nM against NCI-H450) and also a higher potency than the reference Staurosporine against the Calu6 and DMS114 cell lines, which serves as a very potent and suitable comparator for those skilled in the art. 6. Potency of 23526 in cancers of the head and neck FaDu is a cell line with epithelial morphology that was established in 1968 from a punch biopsy of a hypopharyngeal tumor removed from a 56-year-old, white, male patient with squamous cell carcinoma (pharynx). A-253 cell line was isolated from tissue of a submandibular gland squamous cell carcinoma of the salivary glands. OE21 was established in 1993 from a squamous carcinoma of mid oesophagus of a 74 year-old male patient. The tumor was identified as pathological stage IIA(UICC) and showed moderate differentiation. All cell lines are widely used to test chemical treatments of cancers of the head and neck and are considered representative for the disease. Results. Table 18: Efficacy of the preferred inventive compound 23526 in head and neck cancer cells given as EC50 in nM. Cell line Tissue Group 23526 Staurosporine 6027 (Reference) FaDu Head and Neck 10.6 17.2 n.d. A-253 Head and Neck 10.8 120.0 n.d. OE21 Head and Neck 23.8 1.9 110.0 The inventive compound 23526 shows a strong anti-cancer response in the representative cell lines of cancer of the head and neck of 10.6 nM against FaDu cells and 10.8 nM against A- 253 cells and 23.8 nM against OE21 cells. In case of OE21 cells, This efficacy represents a multiple times stronger anti-cancer activity when compared to the reference compound 6027 (110.0 nM against OE21; FaDu and A-253 not determined (n.d.) for 6027) and also a much higher potency (with the exception of OE21) than the reference Staurosporine (17.2 nM against FaDu cells and 120.0 nM against A-253 cells and 1.9 nM against OE21 cells) which serves as a very potent and suitable comparator for those skilled in the art. 7. Potency of 23526 in pancreatic cancer MIA PaCa-2 is an epithelial cell line that was derived from tumor tissue of the pancreas obtained from a 65-year-old, white male. Capan-2 is a cell line with polygonal morphology that was isolated in 1975 from the pancreas of a 56-year-old, white, male patient with pancreatic adenocarcinoma. PANC-1 is a cell line exhibiting epithelial morphology that was isolated from the pancreatic duct of a 56-year-old, white, male with epithelioid carcinoma. All cell lines are widely used to test chemical treatments of pancreatic cancers and are considered representative for the disease. Results. Table 19: Efficacy of the preferred inventive compound 23526 in pancreatic cancer cell lines given as EC50 in nM. Cell line Tissue Group 23526 Staurosporine Mia PaCa-2 Pancreas11.3 17.1Capan-2 Pancreas38.2 42.9PANC-1 Pancreas38.3 83.0The inventive compound 23526 shows a strong anti-cancer response in the representative cell lines of pancreatic cancer of 11.3 nM against Mia PaCa-2 cells and 38.2 nM against Capan- cells and 38.3 nM against PANC-1 cells with a much higher potency than the reference Staurosporine (17.1 nM against Mia PaCa-2 cells and 42.9 nM against Capan-cells and 83.0 nM against PANC-1 cells) which serves as a very potent and suitable comparator for those skilled in the art. 8. Potency of 23526 in prostate cancer 22Rv1 is a human prostate carcinoma epithelial cell line that was derived from a human prostate carcinoma xenograft (CWR22R) that was serially propagated in nude mice after castration. DU 145 is a cell line with epithelial morphology that was isolated from a metastatic central nervous system lesion in the brain of a 69-year-old, white, male with prostate cancer. established in 1975 PC-3 is a cell line derived from a bone marrow metastasis isolated post-mortem from a 62-year-old, white, male with grade IV prostate cancer (poorly differentiated adenocarcinoma) after androgen suppression therap All cell lines are widely used to test chemical treatments of prostate cancers and are considered representative for the disease. DU145 and PC-3 are also part of the NCI reference panel of cell lines for cancer testing. Results. Table 20: Efficacy of the preferred inventive compound 23526 in lung cancer cell lines given as EC50 in nM. Cell line Tissue Group 23526 Staurosporine 6027 (Reference) 22Rv1 Prostate 6.7 35.6 n.d. DU145 Prostate 10.7 1.9 48.0 PC-3 Prostate 21.5 2.2 74.0 The inventive compound 23526 shows a strong anti-cancer response in the representative prostate cancer cell lines of 6.7 nM against 22Rv1 and 10.7 nM against DU145 cells and 21.5 nM against PC-3 cells. For DU145 and PC-3 (22Rv1 not determined (n.d.) for this compound) this is multiple times stronger anti-cancer activity when compared to the reference compound 6027 (48.0 nM against DU145 cells and 74.0 nM against PC-3 cells) and also a much higher potency than the reference Staurosporine for 22Rv1 (35.6 nM) which serves as a very potent and suitable comparator for those skilled in the art. Staurosporine exhibits a higher degree of anti-cancer activity against DU145 (1.9 nM) and PC-3 (2.2 nM) than 23526. 9. Potency of 23526 in bladder cancer 5637 is a cell line exhibiting epithelial morphology that was isolated from the urinary bladder of a 68-year-old, white male patient with grade II carcinoma. HT-1197 is a cell isolated from the urinary bladder of a white, 44-year-old, male with carcinoma. All cell lines are widely used to test chemical treatments of bladder cancers and are considered representative for the disease. Results. Table 21: Efficacy of the preferred inventive compound 23526 in bladder cancer cell lines given as EC50 in nM. Cell line Tissue Group 23526 Staurosporine 5637 Bladder 8.3 16.2 HT-1197 Bladder 11.4 94.0 The inventive compound 23526 shows a strong anti-cancer response in the representative bladder cancer cell lines of 8.3 nM against 5637 and 11.4 nM against HT-1197 cells. This is multiple times stronger anti-cancer activity when compared to Staurosporine (16.2 nM against 5637 and 94.0 nM against HT-1197 cells ) which serves as a very potent and suitable comparator for those skilled in the art. 10. Potency of 23526 in CNS cancer PFSK-1 is a cell line exhibiting fibroblast morphology that was isolated from the cerebral hemisphere of a 22-month-old, white male patient with malignant primitive neuroectodermal tumor. U-87 MG is a cell line with epithelial morphology that was isolated from malignant gliomas from a male patient, likely with Glioblastoma. All cell lines are widely used to test chemical treatments of CNS cancers – particularly cancers of the brain - and are considered representative for the disease. Results. Table 22: Efficacy of the preferred inventive compound 23526 in CNS cancer cell lines given as EC50 in nM. Cell line Tissue Group 23526 Staurosporine PFSK-1 CNS 9.6 19.3 U-87 MG CNS 18.5 91.4 The inventive compound 23526 shows a strong anti-cancer response in the representative CNS cancer cell lines of 9.6 nM against PFSK-1 and 18.5 nM against U-87MG cells. This is a multiple times stronger anti-cancer activity when compared to Staurosporine (19.3 nM against PFSK-1 and 91.4 nM against U-87MG cells) which serves as a very potent and suitable comparator for those skilled in the art. 11. Potency of 23526 in stomach cancer SNU-16 is a cell line exhibiting epithelial morphology that was isolated in 1987 from ascites derived from a 33-year-old, female, asian, stomach cancer patient prior to chemotherapy. The Hs746T epithelial cell line was isolated from a 74-year-adult caucasian male patient with gastric carcinoma. All cell lines are widely used to test chemical treatments of stomach cancers and are considered representative for the disease. Results. Table 23: Efficacy of the preferred inventive compound 23526 in stomach cancer cell lines given as EC50 in nM. Cell line Tissue Group 23526 Staurosporine SNU-16 Stomach 6.0 6.7 Hs 746T Stomach 6.8 31.7 The inventive compound 23526 shows a strong anti-cancer response in the representative stomach cancer cell lines of 6.0 nM against SNU-16 and 6.8 nM against HS746T cells. This is a much stronger anti-cancer activity when compared to Staurosporine (6.7 nM against SNU-16 and 31.7 nM against HS746T cells )which serves as a very potent and suitable comparator for those skilled in the art. 12. Potency of 23526 in further cancer types HuTu 80 is a cell line exhibiting epithelial morphology that was isolated from the small intestine (duodenum) of a 53-year-old, white male patient with adenocarcinoma TT is a cell line exhibiting epithelial-like morphology that was isolated from the medulla of a white, 77-year-old, female patient with carcinoma. SK-HEP-1 are endothelial cells that were isolated from the liver of a 52-year-old, white male patient with adenocarcinoma. Rhabdomyosarcoma (RD) cells are large, multinucleated, spindle-shaped cells isolated from muscle tissue. All cell lines are widely used to test chemical treatments in cancers and are considered representative for the disease. Results. Table 24: Efficacy of the preferred inventive compound 23526 in other cancer cell lines given as EC50 in nM. Cell line Tissue Group 23526 Staurosporine HuTu 80 Duodenum 3.1 3.1 TT Endocrine 15.1 28.5 SK-HEP-1 Kidney 23.2 48.0 RD Soft Tissue & Bone 8.1 11.9 The inventive compound 23526 shows a strong anti-cancer response in the representative cancer cell lines of 3.1 nM against HuTu 80 and 15.1 nM against TT cells and 23.2 nM against SK-HEP-1 cells and 8.1 nM against RD cells showing a similar (HuTu 80) or stronger anti- cancer activity when compared to Staurosporine (28.5 nM against TT cells and 48.0 nM against SK-HEP-1 cells and 11.9 nM against RD cells) which serves as a very potent and suitable comparator for those skilled in the art. Summary Results The inventive compound 23526 demonstrated strong anti-cancer activity in a broad range of cancer cell lines derived from human tissue types representative for many cancer types. The anti-cancer effect of 23526 was always multiple times stronger towards the cancer than the reference compound 6027 and typically also much stronger than Staurosporine, a very potent comparator used in the art. In comparison, the half inhibitory concentration in the response to treatment in healthy tissue fibroblasts were 795 nM for 23526 and 489.5 nM for 6027 showing that the inventive compound 23526 was better tolerated in healthy tissue cell lines than in the tumor cell lines, and even better than the reference compound 6027. In connection hereto and with respect to the above described effective concentration against healthy cell fibroblasts, the calculated target selectivity for the inventive compound 23526 (calculated as effective concentration in healthy cells divided by the effective concentration in the target cancer cells) is significantly high and typically multiple times higher than for the reference compound 6027 demonstrating the potential of the inventive compounds for the treatment of cancer as human disease. By way of example: For Molt-4 (Hemopoietic, Acute lymphoblastic leukemia; see Table 14) selectivity for 23526 is 86.4 and the absolute anti-cancer activity is 9.2 nM while for the reference compound 6027 the selectivity is 10.6 and the absolute anti-cancer activity is 46.0 nM. EXAMPLE 9 Efficacy of 23526 on ex vivo patient-derived cutaneous Squamous Cell Carcinoma (cSCC) of the patient’s capillitium The efficacy of inventive compound 23526 was confirmed in an experiment using fresh ex vivo infiltrative cSCC patient material. Patient material was taken from a cSCC lesion on the capillitium of a 87 year’s old male patient. Fresh tumour material of said patient was cut into similar sized pieces, put on cell culture inserts (0.4μM, Millicell cell culture; Millipore, Cat# PICM03050) and incubated with 1ml of co-culture media (3 parts DMEM (Gibco, Cat. # 41966052), 1 part Ham's F-12 Nutrient Mix (Gibco, Cat.# 11765054), 10% Fetal Bovine serum heat inactivated (Gibco, Cat.# 1050), 0.1 mg / ml of NormocinTM (Invivogen, Cat.# ant-nr-1), 21.8 μg / mL of Adenin (Sigma-Aldrich, Cat.# A2786), 5.45 μg / mL of Apotransferrin (Sigma-Aldrich, Cat.# T1147), 2.18 nM of Triiodothyronine (Sigma-Aldrich, Cat.# T6397), 0.44 μg / mL of Hydrocortisone (Sigma- Aldrich, Cat.# H0888), 0.11 nM of Cholera toxin (Sigma-Aldrich, Cat. # C8052), 5.50 μg / mL of Insulin (Sigma-Aldrich, Cat.# I6634) and 0.01 μg / mL of Epidermal growth factor (Sigma- Aldrich, Cat.# E4127)) from below for 24 hours at 37°C and 5% CO2to let the tissue piece recover. After 24 hours, the cell culture media was replaced with cell culture media containing drug conditions and incubated for another 4 days at 37°C and 5% CO2. One made sure that tissue piece is covered with a drop of media containing drugs (day 0 and day 2). After 4 days of treatment, tissue was fixed in 4% buffered formaldehyde followed by immunohistochemistry stainings for histopathological examination and comparison of treatment conditions to untreated controls (DMSO). Immunohistochemistry of ex vivo tumor pieces: Tumor slices were embedded into paraffin blocks. Consecutive cuts were stained with antibodies of interest. Following antibodies were used for stainings: Ki67 (Dako, clone MIB-1, Cat# M7240, Dilution 1:50, Antigen Retrieval: Leica Bond ER2: 30 min at 95°C) and HE (Hämalaun nach Mayer, Artechemis, Cat# T.865.3; Eosin 1% wässrig – Morphisto, Cat# 10177) The slides were scanned at Vectra Polaris Slide Scanner (Akoya Biosystems) and analyzed with Qpath software. KI-67 staining was used as an immunohistochemical cellular marker for proliferation to visualize regions of the slice with proliferating cells. Results: Incubation of patient-derived infiltrative cSCC tumors for 4 days demonstrated a significant reduction in cell proliferation of tumor cells when exposed to inventive compound 23526 (500 nM) compared to the negative control DMSO (Two-Way ANOVA; ** p<0.0035). The reduction of proliferating tumor cells is indicated by the % of ki67 positive cells (DMSO: 17.1; 23526 500nM: 1.7). Tumor region was localized by HE stainings with help of a histopathologist. See FIG.3A and FIG.3B. EXAMPLE 10 Efficacy of 23526 on ex vivo patient-derived cutaneous Squamous Cell Carcinoma (cSCC) of the patient’s ear The efficacy of inventive compound 23526 was confirmed in a further experiment using fresh ex vivo infiltrative cSCC patient material. Tumour material was harvested from an infiltrative cutaneous squamous cell carcinoma (cSCC) from a 97 years old male patient’s ear. Fresh tumour material of said patient was cut into similar sized pieces, put on cell culture inserts (0.4μM, Millicell cell culture; Millipore, Cat# PICM03050) and incubated with 1ml of co-culture media (3 parts DMEM (Gibco, Cat. # 41966052), 1 part Ham's F-12 Nutrient Mix (Gibco, Cat.# 11765054), 10% Fetal Bovine serum heat inactivated (Gibco, Cat.# 1050), 0.1 mg / ml of NormocinTM (Invivogen, Cat.# ant-nr-1), 21.8 μg / mL of Adenin (Sigma-Aldrich, Cat.# A2786), 5.45 μg / mL of Apotransferrin (Sigma-Aldrich, Cat.# T1147), 2.18 nM of Triiodothyronine (Sigma-Aldrich, Cat.# T6397), 0.44 μg / mL of Hydrocortisone (Sigma- Aldrich, Cat.# H0888), 0.11 nM of Cholera toxin (Sigma-Aldrich, Cat. # C8052), 5.50 μg / mL of Insulin (Sigma-Aldrich, Cat.# I6634) and 0.01 μg / mL of Epidermal growth factor (Sigma- Aldrich, Cat.# E4127)) from below for 24 hours at 37°C and 5% CO2to let the tissue piece recover. After 24 hours, the cell culture media was replaced with cell culture media containing drug conditions and incubated for another 4 days at 37°C and 5% CO2. One made sure that tissue piece is covered with a drop of media containing drugs (day 0 and day 2). After 4 days of treatment, tissue was fixed in 4% buffered formaldehyde followed by immunohistochemistry stainings for histopathological examination and comparison of treatment conditions to untreated controls (DMSO). Immunohistochemistry of ex vivo tumor pieces: Tumor slices were embedded into paraffin blocks. Consecutive cuts were stained with antibodies of interest. Following antibodies were used for stainings: Ki67 (Dako, clone MIB-1, Cat# M7240, Dilution 1:50, Antigen Retrieval: Leica Bond ER2: 30 min at 95°C). pan Cytokeratin (PanCK) (Santa Cruz Biotechnology, Sc-8018, Cat# L2420, Dilution 1:50, Antigen Retrieval: Leica Bond ER2: 30 min at 95°C) and HE (Hämalaun nach Mayer, Artechemis, Cat# T.865.3; Eosin 1% wässrig – Morphisto, Cat# 10177). The slides were scanned at Vectra Polaris Slide Scanner (Akoya Biosystems) and analyzed with Qpath software. KI-67 staining was used as an immunohistochemical cellular marker for proliferation to visualize regions of the slice with proliferating cells. Pan Cytokeratin (PanCK) is a marker for epithelial tumors as it stains the cytoplasmic keratins of keratinocytes (FIG. 4A. Results: Incubation of patient-derived infiltrative cSCC tumors for 4 days demonstrated a significant reduction in cell proliferation of tumor cells when exposed to the reference compound 6027 (500 nM) as compared to the negative control DMSO but even more significantly further after treatment with the inventive compound 23526 (500 nM) (Two-Way ANOVA; ** p<0.004 (23526); * p<0.03 (6027)). The reduction of proliferating tumor cells is indicated by the ki67 / PanCK ratios (DMSO: 0.75; 6027 500nM: 0.24; 23526 500nM: 0) as shown in FIG.4B.

Claims

CLAIMS 1. A compound of formula (I)wherein --A-- represents a peptide chain, wherein said peptide chain consists of 4 to 9 amino acids, wherein preferably said amino acids are selected from α-aminoisobutyric acid (Aib), leucine (Leu), preferably (S)-leucine, or β-alanine (β-Ala); R1is, wherein the arrow indicates the attachment to the NH-moiety depicted in formula (I), and wherein R5is selected from H, C1-C16alkyl, C1-C16alkenyl, carbocyclyl, heterocyclyl,,C1-C3alkylene-carbocyclyl or C1-C3alkylene-heterocyclyl, wherein said C1-C16alkyl and said C1-C16alkenyl each independently optionally substituted with halogen, OR18, NR19R20, -[O-C2H4]n-OCH3wherein n=2-20; and wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C4alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20, wherein R18, R19, R20are independently at each occurrence H, C1-C3alkyl, and wherein R6, R7, R8, R9,R10,R11are independently at each occurrence selected from H, C1-C6alkyl, C1-C6alkenyl, carbocyclyl, heterocyclyl, C1-C3alkylene-carbocyclyl, C1- C3alkylene-heterocyclyl, halogen, C1-C2haloalkyl, OR21or NR22R23, wherein said R21, R22, R23are independently at each occurrence selected from H, C1-C6alkyl, C1- C6alkenyl, C(O)O-C1-C6alkyl, C(O)-C1-C6alkyl, C(O)O-C1-C6alkenyl, C(O)-C1- C6alkenyl, carbocyclyl, heterocyclyl, C1-C3alkylene-carbocyclyl or C1-C3alkylene-heterocyclyl, wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C3alkyl, halogen, oxo, C1- C2haloalkyl, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20; or wherein two of said R6, R7, R8, R9,R10,and R11together with the carbon atom to which they are attached form a carbocycle or heterocycle, preferably a carbocycle; said carbocycle and said heterocycle optionally substituted with C1- C3alkyl, halogen, CF3, OR18, NR19R20; and wherein at least one of said R6, R7, R8, R9,R10,and R11is not H; and R2is selected from C4-C12alkyl, C4-C10alkoxy, C1-C3alkylene‒cycloalkyl, C1- C3alkylene‒aryl or C1-C3alkylene‒heteroaryl, wherein independently in said C1- C3alkylene one -CH2- moiety is optionally replaced by –CH(NH)- or -O-; and wherein said alkyl, cycloalkyl, aryl and heteroaryl are each independently optionally substituted with one or more, preferably one or two, substituents selected from C1-C2alkyl, C1- C2haloalkyl, oxo, OH, halogen, C1-C2alkoxy, C6H5or C6H5substituted with C1-C3alkyl or OC1-C3alkyl; R3iswherein the arrow indicates the attachment to the A-moiety in formula (I), and wherein R12, R13, R14and R15are independently at each occurrence selected from H or C1-C3alkyl, preferably H or methyl, or two of said R12, R13, R14and R15together with the carbon atom to which they are attached form a carbocycle or heterocycle, preferably a carbocycle, and wherein R16and R17are independently of each other selected from H or C1-C4alkyl optionally substituted with halogen, hydroxyl or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a heteroaryl or a heterocyclyl, each independently optionally substituted with halogen, C1-C4alkyl, OR18, NR19R20; or a pharmaceutically acceptable salt of said compound of formula (I).

2. The compound of formula (I), wherein said compound is a compound of formula (II)wherein --B-- represents a peptide chain, wherein said peptide chain consists of 0 to 5 amino acids, wherein preferably said amino acids are independently selected from α-aminoisobutyric acid (Aib), leucine (Leu), preferably (S)-leucine, or β-alanine (β-Ala); and wherein R1, R2and R3are as defined as in claim 1.

3. The compound of claim 2, wherein said compound of formula (II) is a compound selected from any one of the formulas (III) to (VIII)and wherein preferably said compound of formula (II) is a compound selected from any one of the formulas (IV) to (VI), and wherein further preferably said compound of formula (II) is a compound of formula (IV).

4. The compound of any one of the preceding claims, wherein said R5is selected from cycloalkyl, aryl, heteroaryl, C5-C12alkyl, C5-C12alkenyl or C1-C4alkylene–[O-C2H4]n- OCH3wherein n=5-15, wherein said aryl, heteroaryl, cycloalkyl each independently optionally substituted with C1-C4alkyl, halogen, oxo, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20.

5. The compound of any one of the preceding claims, wherein R5is selected from C6- C7alkyl, C6-C7alkenyl, C1-C4alkylene–[O-C2H4]n-OCH3wherein n=8-12, phenyl or a monocyclic heteroaryl comprising one or two heteroatoms selected from N, O and S, preferably oxazolyl, wherein said phenyl or said monocyclic heteroaryl preferably said oxazolyl, each independently optionally substituted with C1-C4alkyl, halogen, CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20.

6. The compound of any one of the preceding claims, wherein R6, R7, R8, R9,R10,R11are independently at each occurrence selected from H, C1-C3alkyl, C1-C3alkenyl, carbocyclyl, heterocyclyl, C1-C2alkylene-carbocyclyl, C1-C2alkylene-heterocyclyl, halogen, CF3, OR21or NR22R23, wherein said R21, R22, R23are independently at each occurrence selected from H, C1-C3alkyl, C1-C3alkenyl, C(O)O-C1-C3alkyl, C(O)-C1- C3alkyl, C(O)O-C1-C3alkenyl, C(O)-C1-C3alkenyl, carbocyclyl, heterocyclyl, C1- C2alkylene-carbocyclyl or C1-C2alkylene-heterocyclyl, wherein said carbocyclyl and said heterocyclyl is monocyclic, and wherein each of said carbocyclyl and said heterocyclyl independently at each occurrence optionally substituted with C1-C3alkyl, halogen, oxo,CF3, OR18, NR19R20, C6H5, C6H5substituted with halogen, C1-C3alkyl, OR18, NR19R20; or wherein two of said R6, R7, R8, R9,R10,and R11together with the carbon atom to which they are attached form a monocyclic carbocycle or heterocycle, preferably a monocyclic carbocycle; wherein said carbocycle and said heterocycle each independently optionally substituted with C1-C3alkyl, halogen, CF3, OR18, NR19R20.

7. The compound of any one of the preceding claims, wherein said R1is selected from the formula, ,, wherein R indicates the attachment to the NH-moiety depicted in formula (I).

8. The compound of any one of the preceding claims, wherein said R2is selected from C5- C12alkyl, C4-C10alkoxy, C1-C3alkylene‒C5-C6cycloalkyl, C1-C3alkylene‒phenyl, C1- C3alkylene‒(mono- or bicyclic-heteroaryl), wherein said phenyl, C5-C6-cycloalkyl, and mono- or bicyclic-heteroaryl are each independently optionally substituted with one or more, typically and preferably with one or two, substituents selected from C1-C2alkyl, C1- C2haloalkyl, halogen, C1-C2alkoxy.

9. The compound of any one of the preceding claims, wherein said R2is selected from C5- C12alkyl, C1-C2alkylene‒C5-C6cycloalkyl and CH2‒phenyl, wherein said phenyl isoptionally substituted with one or two substituents selected from methyl, ethyl, fluorine, chlorine and methoxy.

10. The compound of any one of the preceding claims, wherein said R2is selected fromwherein R indicates the attachment to the CH-moiety depicted informula (I).

11. The compound of any one of the preceding claims, wherein said R12, R13, R14and R15are independently at each occurrence H or C1-C3alkyl, preferably H or methyl, or independently at each occurrence two of said R7, R8, R9and R10together with the carbon atom to which they are attached form a monocyclic carbocyclic or monocyclic heterocyclic ring, preferably a monocyclic carbocyclic ring, and wherein R16and R17are independently of each other H or C1-C4alkyl optionally substituted with halogen, hydroxyl, methoxy or C3-C6cycloalkyl; or together with the nitrogen atom to which they are attached form independently at each occurrence a monocyclic heteroaryl or a monocyclic heterocyclyl, each independently optionally substituted with halogen, C1- C4alkyl, OR18, NR19R20.

12. The compound of any one of the preceding claims, wherein said R3is selected fromA-moiety in formula (I).

13. The compound according to claim 1, wherein said compound is selected from20762:23103:523526:523549:523585:523595:523687:523717:523736:523742:523826:525042:525157:

14. A pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof as defined in any one of the claims 1 to 13, and a pharmaceutically acceptable carrier or adjuvant 15. The compound of any one of the claims 1 to 13, or the pharmaceutical composition of claim 14 for use in a method of treating a cancer of a mammal, preferably a human, wherein said method comprises administration of said compound or said pharmaceutical composition to said mammal, preferably to said human, and wherein preferably said method comprises administration of an effective amount of said compound or said pharmaceutical composition to said mammal, preferably to said human.

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