New target affinity and specificity of anti sfas-l antibody, pc111

Abstract

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Description

[0001] NEW TARGET AFFINITY AND SPECIFICITY OF ANTI SFAS-L ANTIBODY, PC111

[0002] Description

[0003] The present disclosure refers to antibodies having high affinity and specificity to the soluble form of the human Fas ligand (sFasL; also named CD95Lor CD178 orApo1 L) and uses thereof.

[0004] Background of the invention

[0005] Fas ligand is a 40-kDa homotrimeric, type II transmembrane protein that belongs to the tumor necrosis factor (TNF) superfamily. FasL is predominantly expressed on activated immune cells, such as T cells, B cells, dendritic cells, and NK cells. FasL- expressing immune cells recognize the Fas death receptor (Fas) on the surface of a target cell, which upon binding with Fas ligand (FasL), triggers apoptosis in many cell systems (Sharma et al, 2000).

[0006] FasL exists in membrane-bound form (mFasL) and soluble form (sFasL). The soluble Fas ligand (sFasL) is generated and released by proteolytical cleavage of the extracellular domain of mFasL expressed at the plasma membrane (mFasL) by zinc- regulated matrix metal loprotease (MMP). The soluble form (sFasL) displays both apoptotic and non-apoptotic activities.

[0007] The Fas-FasL interaction and the signalling pathway triggered thereby have been shown to play an important role in the physiological regulation of the immune system and have been implicated in the pathogenesis and progression of various malignancies and immune-inflammatory and infectious conditions. The implication of the Fas-FasL pathway, for example, has been shown to be a critical mediator of keratinocyte apoptosis and acantholysis in pemphigus (Lotti et al., 2018). Further studies have demonstrated that the Fas-FasL system plays a crucial role in the development of severe cutaneous conditions, such as Stevens-Johnson-Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) (Viard et al, 1998; Abe et al., 2003, Chang et al., 2004, Murata et al, 2008).

[0008] The Fas / Fas ligand system, however, also plays a critical role in immune cell homeostasis, prevention of autoimmunity and progression of cancer. For maintaining homeostasis in the immune system, the membrane-bound mFasL expressed on cytotoxic lymphocytes, binds to Fas receptor (Fas) and induces lysis of infected cells, hyperprol iterative T lymphocytes as well as cancer cells via apoptosis (O’Reilly at al., Nature, 2009 Oct 1 , 461 (7264):659-63). Defects of the Fas / FasL pathway may limit the efficiency of the immune surveillance and lead to lymphoproliferative disorders, autoimmunity and cancer (Tuomela et al., Front Immunol. 2022 Mar 23;13:867098).

[0009] Cell-to-cell interactions between activated immune cells carrying membrane-bound FasL and target cells carrying membrane-bound Fas are required to maintain a homeostasis in the immune system. Inhibiting these Fas-mFasL interactions may thus limit the efficiency of the immune surveillance and lead to initiation and / or progression of lymphoproliferative disorders, autoimmunity and / or cancer.

[0010] Thus, while inhibition of the Fas-FasL apoptotic pathway is a crucial target in the treatment of several diseases, the cell-to-cell interaction of mFasL with the Fas receptor is also essential in maintaining homeostasis of the immune system. Thus, inhibitors inhibiting the mFasL-Fas interaction may cause undesired physiological effects.

[0011] Therefore, it is crucial to develop inhibitors targeting FasL, but which do not affect the surveillance and homeostasis pathway regulated by the Fas / mFasL system. Accordingly, there is a need for an agent capable of selectively inhibiting the interaction between Fas and the soluble form of FasL (sFasL) without inhibiting the interaction between Fas and the membrane-bound form of FasL (mFasL).

[0012] Thus, it is an object of the present disclosure to provide an agent that specifically targets the soluble form of FasL (sFasL) with high affinity and selectivity for preventing and treating a disorder associated and / or mediated by soluble FasL (sFasL).

[0013] Summary of the invention

[0014] The present disclosure provides an agent specific for the soluble form of Fas ligand protein (sFasL), particularly human Fas ligand protein (hsFasL) as an active agent for treating a subject, particularly a human subject affected by a disease mediated and / or triggered by soluble FasL (sFasL-mediated disorder).

[0015] In a first aspect, the subject, particularly the human subject, is affected by a sFasL- mediated disorder and additionally suffers from a dysfunction of immunological homeostasis and / or has an increased risk of developing a dysfunction of immunological homeostasis.

[0016] In a second aspect, the subject, particularly a human subject, is affected by a sFasL- mediated disorder and additionally suffers from a secondary co-morbidity.

[0017] In a third aspect, the subject, particularly a human subject, is characterized by a combination of the first and the second aspects, i.e. the subject, particularly the human subject, is affected by a sFasL-mediated disorder, additionally suffers from a dysfunction of immunological homeostasis and / or has an increased risk of developing a dysfunction of immunological homeostasis and further additionally suffers from a secondary co-morbidity. In particular embodiments, the agent is an antibody or an antigen-binding fragment thereof which is directed against FasL, particularly human FasL, and which shows a selective high affinity binding to the soluble form of FasL while not substantially inhibiting the binding of mFasL to Fas. Selective binding to sFasL allows the targeted inhibition of the pathological form sFasL without substantially inhibiting the homeostatic form mFasL. Thus, interactions of mFasL with Fas receptor are not substantially affected, thereby avoiding undesired effects on immunological homeostasis. In certain embodiments, the undesired effects on immunological homeostasis include an inhibition of the function of activated immune cells carrying mFasL, which may lead to lymphoproliferative disorders, autoimmunity disorders, cancer diseases and an aberrant immune response at immune privileged sites.

[0018] Consequently, the present disclosure provides a highly selective and targeted therapy for soluble FasL-mediated disorders with an improved safety profile, minimizing the risk of undesired effects triggered by inhibiting the interaction of mFasL and Fas. This risk may include causing and / or increasing a dysfunction of immunological homeostasis which may lead to the development and / or progression of a lymphoproliferative disorder, an autoimmunity disorder and / or cancer.

[0019] The term “immunological homeostasis” particularly refers to an adequate and / or balanced functioning of the immune system of the subject to be treated. The term “dysfunction” particularly refers to a disturbance of the immune system, e.g., of the functionality of immune cells carrying membrane-bound FasL, and more particularly to the capability of those immune cells to interact with target cells carrying a Fas receptor.

[0020] According to a particular aspect, the disclosure relates to an efficient and safe treatment of a subject suffering from a soluble FasL-mediated disorder, such as pemphigus and other skin-blistering diseases, wherein the subject additionally suffers from an immune system-related dysfunction or having an increased risk of developing an immune system-related dysfunction, e.g., an immuno-inflammatory disorder, an autoimmune disorder and / or cancer. In certain embodiments, the subject suffers from an immune-compromising disorder, e.g., a HIV infection, a HBV infection and / or a HCV infection, and / or receives immunosuppressive medication, e.g. cyclosporin. In further embodiments, the subject suffers from an immune-inflammatory disorder, e.g., autoimmune lymphoproliferative syndrome (ALPS). In further embodiments, the subject suffers from an autoimmune disorder, e.g., Hashimoto’s thyroiditis. In further embodiments, the subject suffers from cancer, e.g., lymphoma. In further embodiments, the subject has an increased risk of developing a condition as described above.

[0021] According to a further preferred aspect of the present invention, the disclosure relates to an efficient and safe treatment of a subject suffering from a sFasL-mediated disorder, such as pemphigus or another skin-blistering disease, wherein the subject additionally suffers from a secondary co-morbidity disorder.

[0022] The term “co-morbidity disorder” particularly refers to a secondary disorder which affects the subject simultaneous with the sFasL-mediated disorder. In certain embodiments, the co-morbidity disorder is an additional sFasL-mediated disorder. In certain embodiments, the co-morbidity disorder is a non-sFasL-mediated disorder. In certain embodiments, the co-morbidity disorder is triggered by the sFasL-mediated disorder. In certain embodiments, the co-morbidity disorder is unrelated to and / or independentfrom the soluble FasL-mediated disorder. In certain embodiments, the comorbidity disorder is an iatrogenic-induced co-morbidity, i.e. a co-morbidity caused and / or induced by a treatment, e.g., a previous or concomitant treatment of the sFasL- mediated disorder, specifically an immunosuppressive treatment of the sFasL- mediated disorder.

[0023] The therapeutic utility of the antibody or an antigen-binding fragment is based on a combination of high binding affinity and selectivity for the soluble form of human FasL.

[0024] In a particular embodiment of the present disclosure, the agent is a monoclonal antibody or an antigen-binding fragment thereof comprising a VH region having complementary determining regions CDR H1 , CDR H2 and CDR H3 as assigned in SEQ ID NOs: 1 , 3 and 5 and a VL region having complementary determining regions CDR L1 , CDR L2 and CDR L3 as assigned in SEQ ID N Os: 7-9. In a more particular embodiment, the antibody has an IgG heavy chain constant region, e.g., a human IgG heavy chain constant region, preferably an lgG1 or lgG4 heavy chain constant region.

[0025] The disclosure also relates to a nucleic acid molecule encoding a monoclonal antibody as disclosed herein or an antigen-fragment thereof for the use in the treatment of a subject, particularly a human subject affected by a disease mediated and / or triggered by sFasL. In a first aspect, the subject additionally suffers from a dysfunction of immunological homeostasis and / or has an increased risk of developing a dysfunction of immunological homeostasis. In a second aspect, the subject additionally suffers from a secondary co-morbidity disorder. In a third aspect, the subject is characterized by a combination of the first and second above aspects.

[0026] Still a further aspect of the disclosure is a pharmaceutical composition comprising the antibody or antigen-binding fragment or the nucleic acid molecule disclosed herein together with one or more pharmaceutical acceptable carriers for the use in the treatment of a subject, particularly a human subject affected by a disease mediated and / or triggered by soluble FasL. In a first aspect, the composition is for use in a subject who additionally suffers from a dysfunction of immunological homeostasis and / or has an increased risk of developing a dysfunction of immunological homeostasis. In a second aspect, the composition is for use in a subject who additionally suffers from a secondary co-morbidity disorder. In a third aspect, the subject is characterized by a combination of the first and second above aspects.

[0027] Detailed description of the invention

[0028] It is an object of the present disclosure to provide a therapeutic agent for diseases mediated by the soluble form of FasL (sFasL-mediated disorders). The development of an active agent which specifically blocks sFasL allows a targeted therapeutic approach, which minimizes the risks of triggering or enhancing a dysfunction of immunological homeostasis associated with the Fas / mFasL system. The present disclosure thus relates to a sFasL antagonist selectively inhibiting the biological effects of the soluble form of FasL (sFasL), particularly selected from anti- sFasL antibodies, even more particularly from human or humanized anti-sFasL antibodies. The expression "sFasL antagonists selectively inhibiting the biological effects of sFasL" used herein relates to an antagonist which can fully or at least substantially inhibit or neutralize the biological effects of sFasL without substantially affecting the interaction of mFasL and Fas. For example, the inhibitory or neutralizing effect may be based on blocking and / or suppressing the binding of sFasL to its natural cellularreceptor and thereby preventing and / or reducing physiological signals resulting from this binding.

[0029] The sFasL antagonist may be administered as a monotherapy or in combination with further medicaments, e.g., further medicaments suitable for the treatment of sFasL- mediated disorders.

[0030] In particular embodiments, the present disclosure provides a therapeutic agent for sFasL-mediated disorders, comprising an antibody against human sFas ligand, or an antigen-binding fragment thereof as an active ingredient. The antibody may comprise a monoclonal antibody, e.g., a chimeric, humanized or human anti-sFasL antibody or an antigen-binding fragment thereof, e.g., a recombinant single chain antibody. The antibody or antibody fragment may be monovalent or multivalent and may comprise modifications such as a specific glycosylation pattern, or a modification of the Fc region for modulating its physiological characteristics, including antibody dependent cellular cytotoxicity (ADCC) and / or complement-dependent cytotoxicity (CDC). The antigenbinding fragment of the anti-FasL antibody disclosed herein may be a recombinant single chain antibody or single chain variable fragment. In a particular embodiment, the antibody is a human or humanized full-length sFasL-antibody. If desired, the antibody may be conjugated to an effector molecule, e.g., a cytostatic, cytotoxic and / or radioactive compound. Preferred humanized antibodies suitable for the prevention and / or treatment of sFasL- mediated disorders are described in US 7,262,277 ("Antagonistic Anti -hFas ligand human antibodies and fragments thereof'), the content of which is herein incorporated by reference. US 7,262,277discloses isolated anti-hFasL human antibodies with high affinity to the hFasL polypeptide and which are useful for neutralizing the hFasL activity. US 7,262,277 particularly describes the anti -hFas human antibodies 3E1 (produced by the hybridoma cell with accession number ATCC PTA-4017) and 4G11 (produced by the hybridoma cell with accession number ATCC PTA-4018). The hybridoma cells under Accession No. ATCC PTA-4017 and ATCC PTA-4018 have been deposited on 29 January 2002 with the American Type Culture Collection, 10801 University Boulevard, Manassas, Virgina 20110-2209 (USA).

[0031] It has been surprisingly found that the antibody 3E1 as disclosed in US 7,262,277 has a high target affinity and specificity for the soluble form of FasL, however it fails to bind to the membrane-bound form of FasL (mFasL).

[0032] This finding provides novel therapeutic uses for these antibodies, in particular their administration to a subject who suffers from a dysfunction of immunological homeostasis and / or has an increased risk of developing a dysfunction of immunological homeostasis. In particular embodiments, the present disclosure provides uses for the antibodies in subjects who suffer from an immune system-related dysfunction or having an increased risk of developing an immune system -related dysfunction, e.g., an immuno-inflammatory disorder, an autoimmune disorder and / or cancer. Furthermore, this finding provides advantageous novel therapeutic uses for these antibodies, in particular their administration to a subject who additionally suffers from a secondary co-morbidity disorder.

[0033] In an especially preferred embodiment, the present disclosure is directed to the anti- FasL human antibodies, or antigen-binding portions thereof, for use in the prevention and / or treatment of sFasL-mediated disorders comprising a light chain variable region and / or a heavy chain variable region as described in US 7,262,277, the content of which is herein incorporated by reference. In particular, the preferred anti-FasL human antibodies suitable for the prevention and / or treatment of sFasL-mediated disorders according to the present disclosure comprise a light chain variable region comprising a polypeptide with the sequence shown in SEQ ID NO: 2 of US 7,262,277 (incorporated herein by reference) and further comprising a heavy chain variable region comprising a polypeptide with the sequence shown in SEQ ID NO: 10 or 18 of US 7,262,277 (incorporated herein by reference). More particularly, the disclosure refers to the use of the anti-hFas human antibody 3E1 (produced by the hybridoma cell with accession number ATCC PTA-4017) and / or 4G11 (produced by the hybridoma cell with accession number ATCC PTA-4018) as described in US 7,262,277 (incorporated herein by reference) in the prevention and / or treatment of sFasL-mediated disorders.

[0034] In the context of the present disclosure, the term “prevention of sFasL-mediated disorders” means the treatment of the diseases at diagnosis, e.g. in an early stage of the disease, in order to prevent the progression of the diseases to a more severe spectrum of severity. The term “treatment of sFasL-mediated disorders” means that the disease is managed to lessen and / or ameliorate the symptoms of the disease, preferably to the point of fully curing the disease.

[0035] Thus, according to a first aspect, the present disclosure relates to a monoclonal antibody or an antigen -binding fragmentthereof specific for the soluble form of human Fas ligand protein (sFasL) comprising at least one heavy chain variable (VH) region and at least one light chain variable (VL) region, wherein said antibody or an antigenbinding fragment is selected from:

[0036] (i) an antibody or an antigen -binding fragment comprising a VH region having complementary determining regions (CD Rs) of the heavy chain CDR H1 , CDR H2 and CDR H3 as follows:

[0037] (ai) CDR H1 : Arg His Gly lie Thr (SEQ ID NO: 1 ) or

[0038] (a2) CDR H1 : Ser His Gly He Ser (SEQ ID NO: 2);

[0039] (bi) CDR H2: Trp He Asn Ala Tyr Asn Gly Asn Thr Asn Tyr Ala Gin Lys Vai Gin Gly (SEQ ID NO: 3) or

[0040] (b2) CDR H2: Trp He Asn Ala Tyr Ser Gly Asn Thr Asn Tyr Ala Gin Lys Leu Gin

[0041] Gly (SEQ ID NO: 4); and (C1) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Leu Asp Tyr (SEQ ID NO: 5) or

[0042] (C2) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Cys Asp Tyr (SEQ ID NO: 6), and comprising a VL region having complementary determining regions (CDRs) of the light chain CDR L1 , CDR L2 and CDR L3 as follows:

[0043] (as) CDR L1 : Arg Ala Ser Gin Ser Vai Ser Ser Ser Tyr Leu Ala (SEQ ID NO: 7),

[0044] (bs) CDR L2: Gly Ala Ser Ser Arg Ala Thr (SEQ ID NO: 8), and

[0045] (cs) CDR L3: Gin Gin Tyr Gly Ser Ser Pro Trp Thr (SEQ ID NO: 9), or

[0046] (ii) an antibody or an antigen -binding fragment competing with the antibody or antigen-binding fragment of (i) in the binding to human soluble Fas ligand protein (sFasL); for use in the prevention and / ortreatment of a soluble FasL (sFasL)-mediated disorder in a subject, wherein the subject additionally suffers from a dysfunction of immunological homeostasis and / or has an increased risk of developing a dysfunction of immunological homeostasis, e.g. an immune system related disfunction, such as an immuno-inflammatory disorder, an autoimmune disorder and / or cancer.

[0047] In a still further aspect, the present disclosure relates to a monoclonal antibody or an antigen-binding fragment thereof specific for the soluble form of human Fas ligand protein (sFasL) comprising at least one heavy chain variable (VH) region and at least one light chain variable (VL) region, wherein said antibody or an antigen -binding fragment is selected from:

[0048] (i) an antibody or an antigen -binding fragment comprising a VH region having complementary determining regions (CDRs) of the heavy chain CDR H1 , CDR H2 and CDR H3 as follows:

[0049] (ai) CDR H1 : Arg His Gly He Thr (SEQ ID NO: 1 ) or

[0050] (a2) CDR H1 : Ser His Gly He Ser (SEQ ID NO: 2);

[0051] (bi) CDR H2: Trp He Asn Ala Tyr Asn Gly Asn Thr Asn Tyr Ala Gin Lys Vai Gin Gly (SEQ ID NO: 3) or (b2) CDR H2: Trp He Asn Ala Tyr Ser Gly Asn Thr Asn Tyr Ala Gin Lys Leu Gin Gly (SEQ ID NO: 4); and

[0052] (ci) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Leu Asp Tyr (SEQ ID NO: 5) or

[0053] (C2) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Cys Asp Tyr (SEQ ID NO: 6), and comprising a VL region having complementary determining regions (CDRs) of the light chain CDR L1 , CDR L2 and CDR L3 as follows:

[0054] (as) CDR L1 : Arg Ala Ser Gin Ser Vai Ser Ser Ser Tyr Leu Ala (SEQ ID NO: 7),

[0055] (bs) CDR L2: Gly Ala Ser Ser Arg Ala Thr (SEQ ID NO: 8), and

[0056] (cs) CDR L3: Gin Gin Tyr Gly Ser Ser Pro Trp Thr (SEQ ID NO: 9), or

[0057] (ii) an antibody or an antigen -binding fragment competing with the antibody or antigen-binding fragment of (i) in the binding to human sFas ligand protein (sFasL); for use in the prevention and / ortreatment of a soluble FasL (sFasL)-mediated disorder in a subject, wherein the subject additionally suffers and / or is at risk of developing a lymphoproliferative disorder, an autoimmune disorder and / or cancer.

[0058] According to the second aspect, the present disclosure relates to a monoclonal antibody or an antigen -binding fragment thereof specific for the soluble form of human Fas ligand protein (sFasL) comprising at least one heavy chain variable (VH) region and at least one light chain variable (VL) region, wherein said antibody or an antigenbinding fragment is selected from:

[0059] (i) an antibody or an antigen -binding fragment comprising a VH region having complementary determining regions (CDRs) of the heavy chain CDR H1 , CDR H2 and CDR H3 as follows:

[0060] (ai) CDR H1 : Arg His Gly He Thr (SEQ ID NO: 1 ) or

[0061] (a2) CDR H1 : Ser His Gly He Ser (SEQ ID NO: 2);

[0062] (bi) CDR H2: Trp He Asn Ala Tyr Asn Gly Asn Thr Asn Tyr Ala Gin Lys Vai Gin Gly (SEQ ID NO: 3) or (b2) CDR H2: Trp He Asn Ala Tyr Ser Gly Asn Thr Asn Tyr Ala Gin Lys Leu Gin Gly (SEQ ID NO: 4); and

[0063] (ci) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Leu Asp Tyr (SEQ ID NO: 5) or

[0064] (C2) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Cys Asp Tyr (SEQ ID NO: 6), and comprising a VL region having complementary determining regions (CDRs) of the light chain CDR L1 , CDR L2 and CDR L3 as follows:

[0065] (as) CDR L1 : Arg Ala Ser Gin Ser Vai Ser Ser Ser Tyr Leu Ala (SEQ ID NO: 7),

[0066] (bs) CDR L2: Gly Ala Ser Ser Arg Ala Thr (SEQ ID NO: 8), and

[0067] (cs) CDR L3: Gin Gin Tyr Gly Ser Ser Pro Trp Thr (SEQ ID NO: 9), or

[0068] (ii) an antibody or an antigen -binding fragment competing with the antibody or antigen-binding fragment of (i) in the binding to human soluble Fas ligand protein (sFasL); for use in the prevention and / ortreatment of a soluble FasL (sFasL)-mediated disorder in a subject, wherein the subject additionally suffers from a secondary co-morbidity disorder.

[0069] Furthermore, according to the third aspect, the present disclosure relates to a monoclonal antibody or an antigen -binding fragment thereof specific for the soluble form of human Fas ligand protein (sFasL) comprising at least one heavy chain variable (VH) region and at least one light chain variable (VL) region, wherein said antibody or an antigen-binding fragment is selected from:

[0070] (i) an antibody or an antigen -binding fragment comprising a VH region having complementary determining regions (CDRs) of the heavy chain CDR H1 , CDR H2 and CDR H3 as follows:

[0071] (ai) CDR H1 : Arg His Gly He Thr (SEQ ID NO: 1 ) or

[0072] (a2) CDR H1 : Ser His Gly He Ser (SEQ ID NO: 2);

[0073] (bi) CDR H2: Trp He Asn Ala Tyr Asn Gly Asn Thr Asn Tyr Ala Gin Lys Vai Gin Gly (SEQ ID NO: 3) or (b2) CDR H2: Trp He Asn Ala Tyr Ser Gly Asn Thr Asn Tyr Ala Gin Lys Leu Gin Gly (SEQ ID NO: 4); and

[0074] (ci) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Leu Asp Tyr (SEQ ID NO: 5) or

[0075] (C2) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Cys Asp Tyr (SEQ ID NO: 6), and comprising a VL region having complementary determining regions (CDRs) of the light chain CDR L1 , CDR L2 and CDR L3 as follows:

[0076] (as) CDR L1 : Arg Ala Ser Gin Ser Vai Ser Ser Ser Tyr Leu Ala (SEQ ID NO: 7),

[0077] (bs) CDR L2: Gly Ala Ser Ser Arg Ala Thr (SEQ ID NO: 8), and

[0078] (cs) CDR L3: Gin Gin Tyr Gly Ser Ser Pro Trp Thr (SEQ ID NO: 9), or

[0079] (ii) an antibody or an antigen -binding fragment competing with the antibody or antigen-binding fragment of (i) in the binding to human soluble Fas ligand protein (sFasL); for use in the prevention and / ortreatment of a soluble FasL (sFasL)-mediated disorder in a subject, wherein the subject is characterized by a combination of the first and the second above aspects.

[0080] As described above, the disclosure also relates to a monoclonal antibody or an antigen-binding fragment which competes with the monoclonal antibodies or antigenbinding fragment disclosed above for the binding to human sFasL protein (sFasL). Preferably, the antibody competes with the monoclonal antibody having heavy chain CDR sequences H1 - H3 comprising the amino acid sequences of SEQ ID NOs: 1 -5 and light chain CDR sequences L1 -L3 comprising the amino acid sequences of SEQ ID NOs: 7-9 as described above. In a very preferred embodiment, the antibody competes with the monoclonal antibody having heavy chain CDR sequences H1 -H3 of SEQ ID NOs: 1 , 3 and 5 and light chain CDR L1 -L3 of SEQ ID NOs: 7-9 as described above.

[0081] In certain embodiments, a competing antibody as disclosed herein binds the same or an overlapping epitope on the human sFasL as the monoclonal antibody having CDRs as defined in SEQ ID NOs: 1 -9. Competition may be determined by standard assays in the art that can quantify binding affinity, relative and absolute, of the binding proteins, particularly antibody to human sFasL with respect to the given reference antibody.

[0082] A determination of quantitative binding of sFasL antibody to sFasL protein can be conducted by one of various surface plasmon resonance (SPR) measuring platforms. Examples include Biacore and Forte Octet. The recombinant target protein sFasL (e.g the His-tagged FasL protein Aero Bio FAL-H5241 ) is tethered to a capture chip and the sFasL antibody is flowed over the chip while changes in molecular interactions are recorded in real time. In certain embodiments the measurement is performed as described in Yakes BJ at al., Taianta, 2016 Aug 15; 156-157:55-63. On-rates (Ka; M’1s’1), off-rates (Kd; s’1) can be calculated by adding and removing sFasL from the flow. A measure of binding affinity (KD, pM) can be determined by dividing the off-rate by the on-rate. KD values less than 10 pM are typically required for therapeutic use. KD values of 10 nM to 1 pM are optimally used.

[0083] According to the first aspect, the disclosure particularly relates to a monoclonal antibody or an antigen-binding fragment thereof specific for human sFas ligand protein (sFasL) comprising at least one heavy chain variable (VH) region and at least one light chain variable (VL) region, wherein the amino acid sequences of the complementary determining regions (CDRs) of the heavy chain CDR H1 , CDR H2 and CDR H3 are as follows:

[0084] (ai) CDR H1 : Arg His Gly He Thr (SEQ ID NO: 1 ),

[0085] (bi) CDR H2: Trp lie Asn Ala Tyr Asn Gly Asn Thr Asn Tyr Ala Gin Lys Vai Gin Gly (SEQ ID NO: 3), and

[0086] (ci) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Leu Asp Tyr (SEQ ID NO: 5), and wherein the amino acid sequences of the complementary determining regions (CDRs) of the light chain CDR L1 , CDR L2 and CDR L3 are as follows:

[0087] (as) CDR L1 : Arg Ala Ser Gin Ser Vai Ser Ser Ser Tyr Leu Ala (SEQ ID NO: 7),

[0088] (bs) CDR L2: Gly Ala Ser Ser Arg Ala Thr (SEQ ID NO: 8), and

[0089] (cs) CDR L3: Gin Gin Tyr Gly Ser Ser Pro Trp Thr (SEQ ID NO: 9), for use in the prevention and / ortreatment of a soluble FasL (sFasL)-mediated disorder in a subject, wherein the subject additionally suffers from a dysfunction of immunological homeostasis and / or has an increased risk of developing a dysfunction of immunological homeostasis, e.g. an immune system related disfunction, such as an immuno-inflammatory disorder, an autoimmune disorder and / or cancer, or for use in the prevention and / ortreatment of a soluble FasL (sFasL)-mediated disorder in a subject, wherein the subject additionally suffers and / or is at risk of developing a lymphoproliferative disorder, an autoimmune disorder and / or cancer, or for use in the prevention and / ortreatment of a soluble FasL (sFasL)-mediated disorder in a subject, wherein the subject additionally suffers from a dysfunction of immunological homeostasis and / or has an increased risk of developing a dysfunction of immunological homeostasis, e.g., an immuno-inflammatory disorder, an autoimmune disorder and / or cancer.

[0090] According to the second aspect, the disclosure particularly relates to a monoclonal antibody or an antigen-binding fragment thereof specific for human sFas ligand protein (sFasL) comprising at least one heavy chain variable (VH) region and at least one light chain variable (VL) region, wherein the amino acid sequences of the complementary determining regions (CDRs) of the heavy chain CDR H1 , CDR H2 and CDR H3 are as follows:

[0091] (ai) CDR H1 : Arg His Gly He Thr (SEQ ID NO: 1 ),

[0092] (bi) CDR H2: Trp lie Asn Ala Tyr Asn Gly Asn Thr Asn Tyr Ala Gin Lys Vai Gin Gly (SEQ ID NO: 3), and

[0093] (ci) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Leu Asp Tyr (SEQ ID NO: 5), and wherein the amino acid sequences of the complementary determining regions (CDRs) of the light chain CDR L1 , CDR L2 and CDR L3 are as follows:

[0094] (as) CDR L1 : Arg Ala Ser Gin Ser Vai Ser Ser Ser Tyr Leu Ala (SEQ ID NO: 7),

[0095] (bs) CDR L2: Gly Ala Ser Ser Arg Ala Thr (SEQ ID NO: 8), and (C3) CDR L3: Gin Gin Tyr Gly Ser Ser Pro Trp Thr (SEQ ID NO: 9), for use in the prevention and / ortreatment of a soluble FasL (sFasL)-mediated disorder in a subject, wherein the subject additionally suffers from a secondary co-morbidity.

[0096] According to the third aspect, the disclosure particularly relates to a monoclonal antibody or an antigen-binding fragment thereof specific for human sFas ligand protein (sFasL) comprising at least one heavy chain variable (VH) region and at least one light chain variable (VL) region, wherein the amino acid sequences of the complementary determining regions (CDRs) of the heavy chain CDR H1 , CDR H2 and CDR H3 are as follows:

[0097] (ai) CDR H1 : Arg His Gly He Thr (SEQ ID NO: 1 ),

[0098] (bi) CDR H2: Trp He Asn Ala Tyr Asn Gly Asn Thr Asn Tyr Ala Gin Lys Vai Gin Gly (SEQ ID NO: 3), and

[0099] (ci) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Leu Asp Tyr (SEQ ID NO: 5), and wherein the amino acid sequences of the complementary determining regions (CDRs) of the light chain CDR L1 , CDR L2 and CDR L3 are as follows:

[0100] (as) CDR L1 : Arg Ala Ser Gin Ser Vai Ser Ser Ser Tyr Leu Ala (SEQ ID NO: 7),

[0101] (bs) CDR L2: Gly Ala Ser Ser Arg Ala Thr (SEQ ID NO: 8), and

[0102] (cs) CDR L3: Gin Gin Tyr Gly Ser Ser Pro Trp Thr (SEQ ID NO: 9), for use in the prevention and / ortreatment of a soluble FasL (sFasL)-mediated disorder in a subject, wherein the subject is characterized by a combination of the first and the second above aspects.

[0103] In a particular embodiment of the present disclosure, at least one amino acid of the above CDR1 , CDR2 or CDR3 amino acid sequence of the VH and / or VL chain as defined in SEQ ID Nos: 1 -9 is replaced by another amino acid, while preserving structural integrity and epitope-binding of the antibody. These exchanges can be conservative (i.e., by a similar amino acid) or non-conservative. In particular, at least one amino acid of the VH and VL CDR1 , CDR2 or CDR3 sequences as defined in SEQ ID NOs: 1 -9, may be replaced by a conservative amino acid substitution, i.e., a substitution of an amino acid by another amino acid with similar biochemical properties, for example a substitution of an aliphatic amino acid, e.g., Gly, Ala, Vai, Leu, or He, for another aliphatic amino acid; a substitution of a basic amino acid, e.g. His, Lys or Arg, against another basic amino acid or against Met; a substitution of an acidic amino acid or an amide thereof, e.g., Asp, Glu, Asn or Gin, against another acidic amino acid or an amide thereof; a substitution of an aromatic amino acid, e.g., Phe, Tyr or Trp, against another aromatic amino acid. In certain preferred embodiments, 1 , 2, 3, 4, or 5 amino acids of SEQ. ID NOs: 1 -9 are replaced by another conservative or non-conservative amino acid.

[0104] A preferred embodiment, the present disclosure is directed to the use of anti-FasL human antibodies, or antigen -binding portions thereof, comprising a lightchain variable region and / or a heavy chain variable region as described in US 7,262,277 (SEQ ID NO: 2 and SEQ ID NO: 10 or 18, respectively), the content of which is herein incorporated by reference.

[0105] Accordingly, in a still fu rth er pref erred embodiment, the present disclosure relates to an anti-sFasL antibody or antibody-binding fragmentthereof, wherein the light chain variable region of the antibody or antibody-binding fragment thereof comprising a polypeptide with the amino acid sequence as follows:

[0106] E IVLTQS PGTLS LS P GE RATLSCRASQSVSSSYLAWYQQKPGQAPRLLIYGASSRAT GlPDRFSGSGSGTDFTLTISRLEPEDFAVYYCQQYGSSPWTFGQGTKVEIK tSEQ ID NO: 10), and a heavy chain variable region of the antibody or antibody-binding fragment thereof comprising a polypeptide with the amino acid sequence as follows:

[0107] QVQLVQSGAEVKKPGASVKVSCKASGYIFIRHGITWVRQAPGQGLEWMGWINAYN GNTNYAQKVQGRVTMTTD KSTSTAYMELRSLRSDDAAVYYCARETMVRGVPLDY WGQGTLVTVSS (SEQ ID NO: 1 1 ) or QVQLVQSGAEVKKPGASVKVSCKASGYIFISHGISWVRQAPGQGLEWMGWINAYS GNTNYAQKLQGRVTMTTDRSTSTAYMELRSLRSDDTAVYYCARETMVRGVPCDY WGQGTLVTVSS (SEQ ID NO: 12). for use in the prevention and / ortreatment of a soluble FasL (sFasL)-mediated disorder in a subject, wherein the subject additionally suffers from a dysfunction of immunological homeostasis and / or has an increased risk of developing a dysfunction of immunological homeostasis, e.g. an immune system related disfunction, such as an immuno-inflammatory disorder, an autoimmune disorder and / or cancer, or for use in the prevention and / or treatment of a soluble FasL (sFasL)-mediated disorder in a subject, wherein the subject additionally suffers and / or is at risk of developing a lymphoproliferative disorder, an autoimmune disorder and / or cancer or for use in the prevention and / ortreatment of a soluble FasL (sFasL)-mediated disorder in a subject, wherein the subject additionally suffers from a secondary co-morbidity or for use in the prevention and / ortreatment of a soluble FasL (sFasL)-mediated disorder in a subject, wherein the subject additionally suffers from a dysfunction of immunological homeostasis and / or has an increased risk of developing a dysfunction of immunological homeostasis, e.g. an immune system related disfunction, such as an immuno-inflammatory disorder, an autoimmune disorder and / or cancer, and further additionally suffers from a secondary co-morbidity.

[0108] The monoclonal sFasL antibody or an antigen-binding fragment thereof can comprise an VL amino acid sequence having an identity to the SEQ ID NO: 10 of at least 85%, at least 90%, at least 95% or at least 99% and an VH amino acid sequence having an identity to the SEQ ID NO: 11 or 12 of at least 85%, at least 90%, at least 95% or at least 99% over the whole length of the protein.

[0109] "Percent (%) amino acid sequence identity" with respect to a peptide or polypeptide sequence is defined as the percentage of amino acid residues in a candidate sequence that are identical with the amino acid residues in the specific peptide or polypeptide sequence, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity. Alignment for purposes of determining percent amino acid sequence identity can be achieved in various ways that are within the skill in the art, for instance, using publicly available computer software such as BLAST.

[0110] The antibody for the use in the prevention and / or treatment of a soluble FasL (sFasL)- mediated disorder in a subject as disclosed above may be selected from a partially or fully human antibody, a chimeric antibody and / or a humanized antibody. Preferably, the antibody is a human antibody. Further, the antibody according to the present disclosure may be monospecific and / or bispecific. Alternatively, the antibody may be multivalent and multispecific. Further, the antigen-binding fragment of the antibody according to the present disclosure may be selected from a Fab, Fab' and / or F(ab')2 and / or a single chain Fv fragment.

[0111] The antibody may be of any suitable class. The term “class” refers to the type of constant domain or constant region possessed by its heavy chain. As used herein, “constant domain” or “constant region” denotes the sum of the domains of an antibody other than the variable region. The constant region is not directly involved in binding of an antigen but exhibits various effector functions. The antibody of the present disclosure may be of any of the five major classes of antibodies: IgA, IgD, IgE, IgG, and IgM, or any subclass thereof (isotype), e.g., lgG1 , lgG2, lgG3, lgG-4, lgA1 , and lgA2. The heavy chain constant domains that correspond to the different classes of immunoglobulins are called a, 5, E, y and p, respectively. According to the present disclosure, an antibody of the class IgG, IgA or IgM or a fragment thereof is particularly suitable.

[0112] According to a very preferred embodiment, the antibody is selected from class IgG, e.g. of subclass lgG1 , lgG2, lgG3 of lgG-4, or of class IgM or of class IgA or an antigenbinding fragment thereof. In the most preferred embodiment of the disclosure, the antibody has an IgG heavy chain constant region, preferably of subclass lgG1 or lgG4. In a most preferred embodiment of the invention, the antibody has an lgG4 heavy chain constant region. In a further most preferred embodiment, the antibody has a kappa (K) light chain.

[0113] Thus, the most preferred antibody of the invention is a monoclonal lgG4 anti-sFasL antibody or an antigen-binding fragment thereof comprising a VH region having complementary determining regions CDR H1 , CDR H2 and CDR H3 as assigned in SEQ ID NOs: 1 , 3 and 5 described above and a VL region having complementary determining regions CDR L1 , CDR L2 and CDR L3 as assigned in SEQ ID N Os: 7-9 described herein. In a more preferred embodiment of the invention the antibody comprises a light chain variable region (VL) comprising a polypeptide with the sequence as assigned in SEQ ID NO: 10 described herein and a heavy chain variable region (VH) comprising a polypeptide with the sequence as assigned in SEQ ID NO: 11 or 12 described above.

[0114] In a more preferred embodiment of the invention the anti-sFasL antibody described above comprises a light chain constant region (LC) having a polypeptide with the amino acid sequence as follows:

[0115] RTVAAPSVFI FPPSDEQLKS GTASVVCLLN NFYPREAKVQ WKVDNALQSG NSQESVTEQD SKDSTYSLSS TLTLSKADYE KHKVYACEVT HQGLSSPVTK SFNRGEC (SEQ ID NO: 13) and a heavy chain constant region (HC) comprising a polypeptide with the amino acid sequence as follows:

[0116] ASTKGPSVFP LAPCSRSTSE STAALGCLVK DYFPEPVTVS WNSGALTSGV HTFPAVLQSS GLYSLSSVVT VPSSSLGTKT YTCNVDHKPS NTKVDKRVES KYGPPCPPCP APEFLGGPSV FLFPPKPKDT LMISRTPEVT CVVVDVSQED PEVQFNWYVD GVEVHNAKTK PREEQFNSTY RVVSVLTVLH QDWLNGKEYK CKVSNKGLPS SIEKTISKAK GQPREPQVYT LPPSQEEMTK NQVSLTCLVK GFYPSDIAVE WESNGQPENN YKTTPPVLDS DGSFFLYSRL TVDKSRWQEG NVFSCSVMHE ALHNHYTQKS LSLSLGK (SEQ ID NO: 14). In a still further embodiment, the present disclosure relates to the use of the anti-hFas Ligand human antibody, or an antigen binding fragment thereof, produced by the hybridoma cell with accession number ATCC PTA-4017 and / or to the use of the anti- hFas Ligand human antibody, or an antigen binding fragment thereof, produced by the hybridoma cell with accession number ATCC PTA-4018 as described in US 7,262,277 as antibodies 3E1 and 4G11 , respectively for the prevention and / or treatment of an above-described subject suffering of a sFasL-mediated disorder. In the most preferred embodiment of the disclosure is directed to the use of the anti-hFas Ligand human antibody 3E1 (produced by the hybridoma cell with accession number ATCC PTA- 4017), or an antigen binding fragment thereof for the prevention and / or treatment of the above-described subject suffering of a sFasL-mediated disorder.

[0117] In a finally further preferred aspect, the present disclosure refers to the use of a monoclonal antibody or an antigen-binding fragment thereof recognizing the same epitope of human sFasL as the antibodies described above.

[0118] The antibody or the antigen-binding fragment thereof of the present disclosure specifically binds with high affinity to the soluble form of human FasL (sFasL). Further, the antibody or the antigen-binding fragment does not effectively bind to the membrane-bound form of FasL. The binding characteristics of the antibody allow selective targeting of sFasL without undesired side-effects resulting from binding to mFasL. In particular, administration of an antibody of the present disclosure may lead to a reduced risk of triggering physiological and / or pathological processes mediated and / or triggered by inhibition of the mFasL pathway.

[0119] As used herein, the terms “binding” and “specific binding” refer to the binding of the antibody or fragment thereof to human sFasL. The measure of the binding strength of an antibody is referred to as affinity. Methods for determining such a binding and / or affinity using in vitro assays are known to the person skilled in the art. According to the present disclosure, detection with flow cytometry, immuno-histochemistry and / or fluorescence are described and in particular preferred herein. The affinity of the binding of an antibody to an antigen is defined by the terms ka (rate constant for the association of the antibody to the antigen), kd (dissociation rate constant) and KD (equilibrium dissociation constant).

[0120] Antibodies according to the present disclosure and antigen-binding fragments thereof preferably show a dissociation constant KD with human soluble FasL of about 1000 pM or less, preferably of about 750 or less, about 500 pM or less or about 400 pM or less, and most preferably of about 350 pM or less, or about 200 pM or less when measured by surface plasmon resonance (SPR). In a very preferred embodiment, the antibodies and antigen-binding fragments thereof show a dissociation constant KD with the human soluble FasL in the range of about 100-500 pM, preferably in the range of about 200-400 pM, more preferably in the range of about 200-300 pM when measured by SPR. In a very preferred embodiment, the dissociation constant KD with the human soluble FasL is about 250 pM when measured by SPR. In an alternative preferred embodiment, the dissociation constant KD with the human soluble FasL is about 340 pM when measured by Flow-Induced Dispersion Analysis FIDA.

[0121] Moreover, the antibodies according to the disclosure and the antigen-binding fragments thereof have no effective binding affinity to the membrane-bound form of human FasL (mFasL). In certain embodiments, the antibody or the antigen-binding fragment thereof has an at least about 100-fold or at least about 1000-fold lower binding affinity to mFasL compared with the binding affinity to sFasL when measured under comparable conditions. In particular, the antibodies according to the disclosure and the antigen-binding fragments thereof show a dissociation constant KD with the human membrane-bound form of FasL (mFasL) of at least about 500 nM, preferably at least about 1000 nM.

[0122] In the context of the present disclosure the term “soluble FasL (sFasL)-mediated disorder” refers to a disorder wherein the level of soluble FasL in the body and particularly the level of soluble FasL measurable in blood circulation of the patient needs to be lowered for ameliorating and / or curing the disorder. In certain embodiments, the level of soluble FasL is upregulated compared to a healthy subject. In sera of healthy subjects, the level of sFasL is in a mean concentration of about 120- 125 pg / mL or less (Puviani et aL, The Journal of Investigative Dermatology, Vol. 120, No.1 , Jan 2003, 164-167). In an embodiment, the level of sFasL in the sera of the patient affected by a soluble FasL (sFasL)-mediated disorder is significantly elevated compared to a healthy subject. According to a preferred embodiment, the level of soluble FasL in the sera of the patient affected by a soluble FasL (sFasL)-mediated disorder according to the present invention isatleast 2-times higher, preferably 3-times higher, more preferably 4- or 5-times higher and even still higher than in a healthy subject. Even more preferably the amount of sFasL in the blood of the patient according to the present disclosure has a mean concentration of more than 124 pg / ml or significantly more than 124 pg / mL According to a further preferred embodiment of the disclosure, the level of sFasL in the sera of the patients correlates with the severity and / or progression of the sFasL-mediated disorder.

[0123] In a preferred embodiment, the sFasL-mediated disorder is selected from an immune- inflammatory and / or infectious disorder and / or a skin disorder associated with keratinocyte acantholysis,apoptosisand / or necrosis. In a more preferred embodiment, the skin disorder is selected from a bullous and / or a skin-blistering disorder, most preferably selected from pemphigus, toxic epidermal necrolysis (TEN) and / or Stevens- Johnson-Syndrome (SJS). According to an especially preferred embodiment the sFasL-mediated disorder is pemphigus. Further examples of sFasL-mediated disorder skin blistering disorders showing elevated sFasL in plasma according to the present disclosure are selected from drug-induced hypersensitivity syndrome (DIHS), drug reaction with eosinophilia and systemic symptoms (DRESS), systemic lupus erythematosus and erosive oral and genital lichen planus. Further preferred sFasL- mediated non-dermatological disorders are selected form acute respiratory distress syndrome and rheumatoid arthritis.

[0124] According to the first aspect, the subject to be treated in accordance with the present disclosure suffers from a dysfunction of immunological homeostasis and / or has an increased risk of developing a dysfunction of immunological homeostasis wherein dysfunction of immunological homeostasis is particularly a mFasL-mediated disorder. In the context of the present disclosure a mFasL-mediated disorder is a disorder which is triggered by a defect and / or unregulated homeostasis of the immune system due the blockage of the membrane-bound FasL activity. The Fas / mFasL pathway is involved in the pathomechanisms of several immune-inflammatory disorders, autoimmune disorders, and cancer.

[0125] Thus, in the present disclosure the membrane-bound FasL (mFasL)-mediated disorders are preferably selected from a lymphoproliferative disorder, an autoimmune disorder and / or cancer. A preferred example of a lymphoproliferative disorder caused by blocking the mFasL pathway is selected from autoimmune lymphoproliferative syndrome (ALPS). An example of an autoimmune disorder caused by dysfunction of the mFasL pathway is selected from Hashimoto’s thyroiditis. Further, an example of cancer caused by and / or associated with dysfunction of the mFasL pathway is from lymphoma.

[0126] The present disclosure is therefore directed to the use of the above antibodies and antigen-binding fragments thereof for use in the treatment of a subject, wherein the subject suffers of a sFasL-mediated disorder and is at risk of developing and / or suffering from a mFasL-mediated disorder, particularly selected from an immune- inflammatory disorder, an autoimmune disorder, and cancer as described above.

[0127] According to a preferred embodiment of the present disclosure, a subject suffering of a sFasL-mediated disorder has undergone cancer treatment within the last 10 years, within the last 5 years, within the last 3 years or within the last 1 year and which is therefore at an increased risk of cancer recurrence.

[0128] Moreover, the present disclosure is directed to the use of the above antibodies and antigen-binding fragments thereof for use in the treatment of a subject, wherein the subject suffers of a primary sFasL-mediated disorder and additionally suffers from a secondary co-morbidity disorder.

[0129] Preferably, the sFasL-mediated disorder is selected from pemphigus, toxic epidermal necrolysis (TEN) and / or Stevens-Johnson-Syndrome (SJS), most preferably from pemphigus. In a preferred aspect the secondary co-morbidity disorder is triggered by the primary sFasL-mediated disorder, particularly by pemphigus, toxic epidermal necrolysis (TEN) and / or Stevens-Johnson-Syndrome (SJS), most preferably by pemphigus.

[0130] Preferred examples of secondary co-morbidity disorders according to the present invention, which are preferably related to or triggered by pemphigus, are selected from Cushing syndrome, adrenal insufficiency, myasthenia gravis, mucositis, herpes infection, fungal infections, insomnia, hidradenitis, type 2 diabetes mellitus, hypertension, cataract, benign prostatic hyperplasia and bone disorders, such as osteoporosis, osteopenia and pathological or fragility fractures due to decreased bone mineral density. Most preferred secondary co-morbidity disorders are selected from type-2 diabetes mellitus, hypertension, benign prostatic hypertrophy, cataract, myasthenia gravis and bone disorders, such as osteoporosis, osteopenia and pathological or fragility fractures due to decreased bone mineral density

[0131] In a further preferred aspect, the secondary co-morbidity disorder is an iatrogenic- induced co-morbidity caused and / or induced by a treatment of the primary sFasL- mediated disorder, particularly by a treatment of pemphigus, toxic epidermal necrolysis (TEN) and / or Stevens-Johnson-Syndrome (SJS), most preferably by a treatment of pemphigus. The treatment may be a previous or a concomitant treatment of the sFasL- mediated disorder. The previous or a concomitant treatment of the sFasL therapy is preferably selected from an immunosuppressive treatment such as a treatment with corticosteroids, rituximab, azathioprine, mycophenolate mofetil, cyclophosphamide and Intravenous immunoglobulins (IVIg).

[0132] The iatrogenic-induced co-morbidities according to the present disclosure may be selected from hypertension, dyslipidemia, heart diseases, diabetes, pulmonary infection and bone disorders, such as osteoporosis, osteopenia and pathological or fragility fractures due to decreased bone mineral density. In particular aspects, the present invention is directed to the use of the above antibodies and antigen-bindingfragments thereof in the treatment of a subject, wherein the subject suffers from a sFasL-mediated disorder, particularly pemphigus, and

[0133] (i) additionally suffers from a co-morbidity disorder as described above;

[0134] (ii) additionally suffers from a lymphoproliferative disorder, an immune- inflammatory disorder, an immunological and / or autoimmune disorder as described above;

[0135] (iii) additionally suffers from cancer;

[0136] (iv) additionally suffers from a co-morbidity disorder before the start of any sFasL-mediated disorder treatment, particularly before the start of pemphigus treatment (treatment-naive patients);

[0137] (v) additionally suffers from a co-morbidity disorder acquired during previous or concomitant sFasL-mediated disorder treatment, particularly during previous or concomitant immunosuppressive pemphigus treatment, e.g., with rituximab, steroids, azathioprine, mycophenolate mofetil cyclophosphamide and Intravenous immunoglobulins (IVIg). ; and

[0138] (vi) additionally suffering from a co-morbidity disorder as described above with or without immunosuppressive co-treatment.

[0139] A still further aspect refers to a nucleic acid molecule, e.g., a DNA molecule, encoding an antibody VH region, or an antibody VL region, or encoding a complete monoclonal antibody or an antibody fragment thereof as disclosed above for the use in the prevention and / or treatment of a soluble FasL (sFasL)-mediated disorder in a subject as described above.

[0140] The nucleic acid molecule may be a DNA vector, or an RNA molecule typically formulated as a lipid nanoparticle encapsulation. The nucleic acid molecule encoding the antibody of the present disclosure when injected into a patient is incorporated into the cells, which express the antibody into circulation. The use of DNAand RNAdelivery technology in antibody therapy and, in particular, the use of mRNA encoded therapeutic antibodies, is a well-known therapeutic approach in the art (e.g., Van Hoecke and Roose, J Trans Med (2019) 17:54 and Deal at al., Vaccines (2021 ), 9, 2018). In therapeutic applications, the anti-sFasL antibodies fragments thereof are administered in an effective amount to a subject in need thereof, particularly to a human subject. The dose will depend on the specific type of antibody, the seventy and stage of disease, and the route of administration.

[0141] In a preferred embodiment of the disclosure, the subjects affected by soluble FasL (sFasL)-mediated disorder in need of the anti-sFasL antibodies of the disclosure are subjects which have a sFasL concentration value in the serum elevated compared to a healthy subject.

[0142] Typically, the anti-sFasL antibodies or the antigen-binding fragments thereof are administered as a pharmaceutical composition comprising the active agent and a pharmaceutically acceptable carrier or excipient. Examples of suitable carriers and excipients for formulating antibodies or antibody fragments are well-known in the art. An effective dose of a medicament of the present disclosure may be in the range of 0.1 pg to 100 mg, up to a total dose of about 1 g depending upon the route of administration.

[0143] Examples of suitable carriers and excipients for formulating antibodies or antibody fragments include saline and aqueous buffer solutions and are well known in the art. An effective dose of a medicament of the present disclosure may be in the range of 0.1 pg to 100 mg, up to a total dose of about 1 g depending upon the route of administration.

[0144] Thus, a further aspect of the present disclosure is a pharmaceutical composition comprising an anti-sFasL antibody or antigen-binding fragment thereof as described above or a nucleic acid molecule as described above together with one or more pharmaceutical acceptable carriers or excipients for use in human medicine, preferably in a method for the prevention and / or treatment of a soluble FasL (sFasL)-mediated disorder in subjects as disclosed above. Depending on the stage and the severity of the disorder, the pharmaceutical composition may be administered once or several times during the course of the disorder. Forexample, it may be administered once or several times daily, each second day, two times weekly or weekly for a suitable period of time. The pharmaceutical composition may be administered in a single treatment cycle consisting of one or several administrations or in several treatment cycles each consisting of one or several administrations. Each treatment cycle may have a duration of one day up to several weeks, months, or even years.

[0145] In certain embodiments, the pharmaceutical composition is administered parenterally, e.g., by subcutaneous, intramuscular, or intravenous injection or by infusion. In further embodiments, the pharmaceutical composition is administered locally, e.g., topically, orally, nasally, or intrapulmonary, for example by inhalation as an aerosol. Preferably, the composition is administered systemically.

[0146] The anti-sFasL antibodies or antibody fragments thereof may be used in a monotherapy or in a combination therapy. Thus, the anti-sFasL antibodies or antibody fragments thereof may be administered alone or together with at least one further active agent effective in the treatment of soluble FasL (sFasL)-mediated disorders, preferably effective against a skin disorder selected from a bullous and / or a skin blistering disorder, most preferably effective against pemphigus, toxic epidermal necrosis (TEN) and / or Steven s-Johnson-Syndrome (SJS). In particular, the anti-sFasL antibodies of the present disclosure may be used in combination with other active ingredients particularly selected from steroids, cyclosporine, IVIg, TNF-inhibitors an IL17 or lL23 inhibitor, rituximab, anti-CD20 antibodies and / or plasmapheresis.

[0147] Further, the present disclosure is explained in more detail by the following Figures and Examples.

[0148] Figure 1 : Binding curve of FasL (sFasL) titrated against a constant concentration of PC111 at 15nM (A), the data points involved in higher-order oligomers are marked in orange. Binding isotherm of the curve in panel A with the 3 points marked in orange are removed to allow the fitting (B).

[0149] Figure 2: Membrane Proteome Array overview.

[0150] Figure 3: Membrane Proteome Array (MPA): Optimization of ligand concentrations for screening. Serial dilutions of each test ligand were assayed by incubation with known targets, and target binding was measured by flow cytometry. The optimal ligand concentration for screening was chosen based on a joint assessment of binding strength and background signal (left) and rate of high background events (right).

[0151] Figure 4: MPA screen results. Each ligand was tested for binding by flow cytometry against the MPA at the previously determined optimal concentration. Binding interactions confirmed in downstream validation studies are displayed and any proteins that did not pass validation were removed.

[0152] Figure 5: Levels of PC111 in mouse plasma at 2 hours in a Concanavalin-A (Con A) liver injury model.

[0153] Figure 6: Levels of sFasL in mouse plasma at 2 hours in a Concanavalin-A (Con A) liver injury model. Examples

[0154] An anti-FasL human lgG-4, kappa, monospecific bivalent antibody comprising a heavy chain variable (VH) region of SEQ ID NO: 11 with complementary determining regions CDR H1 , CDR H2 and CDR H3 according to SEQ ID NOs: 1 , 3 and 5 and a light chain variable (VL) region of SEQ ID NO: 10 with complementary determining regions CDR L1 , CDR L2 and CDR L3 according to SEQ ID NOs: 7-9 was used. This antibody is internally and hereafter named “antibody PC111".

[0155] Example 1 - Surface Plasmon Resonance (SPR) Analysis of PC111 Biding Affinity to sFasL

[0156] The binding affinity of PC 111 to sFasLwas determined for 3 different batches of PC111 using different source sFasL and different SPR instrumentation. The average binding affinity (equilibrium dissociation constant; KD) of the 6 measurements shown in Table 1 was 238 pM with a range from 650 pM to 93 pM.

[0157] Table 1

[0158] Example 2 - Flow-Induced Dispersion Analysis In the following experiments the antibody PC 111 was tested against FasL protein for binding studies. In these studies, a flow-induced Dispersion Analysis (FIDA) was used which takes advantage of a dispersion phenomenon in a pressure driven flow which, following signal analysis, gives rise to an accurate assessment of molecular diffusivity and hydrodynamic radius (Rh). The change in the hydrodynamic radius of a binder reflects the strength of the interaction.

[0159] 2.1 Methods and Materials

[0160] Capillary. Coated capillary

[0161] Detector. 480 nm fluorescence detection of riboflavin

[0162] Indicator (labelled molecule) consumption per measurement: 39 nL

[0163] Analyte consumption per measurement: 12 pL

[0164] Analysis time: 5.5 min per measurement

[0165] PC1 11 -Alexa cone.: 100 nM

[0166] FasL cone.: 0.01 - 320 nM

[0167] Assay buffer. PBS pH 7.45, BSA 0.1 % (1 mg / ml)

[0168] Mixing principle: Pre-Mix (> 10 min)

[0169] Temperature: 25 °C

[0170] 2.2 Results

[0171] PC111 was used as indicator at 15nM constant concentration and titrated FasL from 0.01 to 320 nM. The Rh of PC111 alone was measured 4.8nm and 6.8nm when in complex FasL. Since FasL is a homotrimer, PC 111 might theoretically bind to FasL in a 1 FasL:3PC111 stoichiometry depending on the steric hindrance. Multiple stoichiometry combinations are possible.

[0172] PC111 was labelled and an increase in its Rh was detected upon sFasL addition (Figure 1A). When sFasL concentration reached the range of 10-80 nM a higher Rh is detected. The orange squared points in Figure 1 A strongly suggest the presence of higher-order oligomers. When sFasL was >1 OOnM the Rh of PC11 was back to 6.8nm suggesting a 1 :1 stoichiometry. A fitting model that includes also the higher-order oligomers is not yet developed as it might be different for each system, therefore by removing the 3 points marked in orange in Figure 1A a standard 1 :1 Excess Indicator fitting model was applied (Figure 1 B). The dissociation constant between PC111 and sFasL in solution KD was 340 pM.

[0173] Example 3 - Membrane Proteome Array

[0174] A Membrane Proteome Array (MPA) technology was used to screen PC 111 for binding targets against the human membrane proteome in order to determine antibody target specificity and potential off-target biding. The technology uses flow cytometry to directly detect antibody binding to membrane proteins expressed in unfixed cells (Figure 2). All target proteins have native conformations and appropriate post-translational modifications.

[0175] 3.1 Determination of assay screening conditions

[0176] To optimize ligand concentrations and cell lines for screening, HEK-293T cells (ATCC CRL-3216) and QT6 cells (ATCC CRL-1708) were transfected with plasmids encoding known ligand targets, Protein A (binds antibody Fc; positive control), or vector alone (pUC; negative control) in 384-well cell-culture plates at a density of 18,000 cells / well. The transfected cells were then incubated in media composed of Corning DMEM, 10% FBS, 2 mM L-alanyl-L-glutamine, Pen Strep, MEM NEAA, and 10 mM HEPES for 36 hours at 37°C and 5% CO2. After incubation, four four-fold dilutions of each ligand starting at 20 pg / ml were added in quadruplicate to transfected cells, and bound ligand was detected using a single dilution of a fluorescently labelled secondary antibody in a high-throughput immunofluorescence flow cytometry assay. Average mean fluorescence intensity (MFI) values were determined for each test ligand dilution in each cell line using ForeCyt Software (Intellicyt) and plotted using Excel (Microsoft). The high background rate for each assayed condition was calculated as the percentage of positive events above a defined fluorescence threshold in cells transfected with negative control. Optimal screening concentrations and cell line for each test ligand (Table 2, below) were determined by the background signal (MFI), and high background rate in the vector control (Figure 3). Molecules are preferentially screened on HEK-293T cells at the highest concentration yielding an acceptably low background (< 50,000 MFI) and minimal high background rate (<1 %). If no acceptable screening conditions are identified on HEK-293T cells, molecules are screened at the highest acceptable concentration on QT6 cells.

[0177] Table 2

[0178] 3.2. Membrane Proteome Array Screen Plasmids containing cDNA clones of ~6,000 membrane proteins (representing over 94% of the human membrane proteome) were each transfected into HEK-293T cells (18,000 cells / well) in 384-well cell-culture plates (one unique cDNA-containing plasmid per well) and incubated at 37°C and 5% CO2 in media composed of Corning DMEM, 10% FBS, 2 mM L-alanyl-L-glutamine, Penn / strep, MEM NEAA, and 10 mM HEPES. Each 384-well plate contained wells independentlytransfected with plasmids encoding GFP or a membrane-bound protein-A construct as controls for transfection efficiency and fluorescently labelled detection antibody binding respectively. After incubation for 36 hours, the cells were lifted using CellStripper and re-formatted into a two- dimensional matrix in a new 384-well plate by rows and columns using a JANUS Automated Workstation. Each well on the matrix plate contains 48 different overexpressed protein constituents, and each protein is represented in a unique combination of two different wells of the matrix plate, as it is contained within a “row” pool and a “column” pool. Thus, every protein in the MPA is tested twice for reactivity. Test ligandswere added to Membrane Proteome Array matrix plates at pre-determined concentrations (Table 2, above), washed in 1 x PBS and detected by flow cytometry using a fluorescently labelled antibody. All flow cytometry data was captured using ForeCyt Software (Intell icyt).

[0179] Test ligand targets were then identified by detecting binding to overlapping pooled matrix wells emanating from the same transfection plate, thereby allowing specific deconvolution. Individual targets displaying binding of greater than 3 standard deviations above background in both wells were selected for downstream validation experiments.

[0180] In order to present a single value for test ligand binding to each protein in the Membrane Proteome Array, the two-dimensional binding data was transformed using standard matrix deconvolution methods. Briefly, each point (representing an individual over-expressed protein) was converted to radians, followed by transformation using the formula r.sin(20) and plotted as Target Binding (Figure 4). Non-specific fluorescence was determined to be any value below the transformed value of 3 standard deviations of the calculated background fluorescence. All data and analyses were conducted in Excel (Microsoft). 3.3 Target Validation

[0181] To validate any off-target interaction identified, cells were transfected with plasmids encoding the identified targets, protein A, or vector alone in 384-well format. After incubation for 36 hours at 37°C and 5% CO2, four four-fold dilutions of each test ligand, starting at 20 pg / ml, were added to transfected cells followed by detection of ligand binding using a high-throughput immunofluorescence flow cytometry assay (same conditions as described in Table 2, above).

[0182] No validation is shown if a molecule’s known target was the only protein validated in the MPA screen, as the Assay Setup results already demonstrate specific reactivity in a screen equivalent to the validation screen.

[0183] 3.4 Results

[0184] During the MPA study, binding of PC111 to Fc-binding control, Protein A, was identified in addition to Fc-receptors FCGRIA and FCGR2B. No binding of PC111 was detected against membrane-bound FASLG. No off-target binding was identified for PC111 .

[0185] 4 - PC111 and sFasL ic relationship in humanized FasL mice

[0186] The study was performed to obtain data on the concentration of PC111 required to neutralize plasma sFasL. The Concanavalin-A(Con A) liver injury model was used as a model able to induce an acute sFasL release into the blood (Heymann et al., 2015). Based on a pilot study, it was demonstrated that a 12 mg / kg dose of Con A is able to induce a significant release of the highest levels of sFasL after 2 hrs from injection, as compared to saline control, in WT. In a follow-on treatment study, humanized FasL mice were dosed with different doses of i.v. PC111 orthe vehicle(PBS), and 15 minutes later they received Con A (12 mg / kg; i.v.). The study design is shown in the Table 3, below (n=2 animals per group).

[0187] Table 3

[0188] Mice were anesthetized and terminally bled 2 hours after the Con A dose. Total human IgG (representing PC111 ) and human sFasL were quantified by ELISA. Each sample was measured three times for IgG and sFasL. A near linear increase in human IgG from 0.33 mg / kg (0.6 pg / mL) to 10 mg / kg (17 pg / mL) of PC 111 was observed (Figure 5).

[0189] The same plasma samples were analyzed for sFasL. Con A administration elicited a significant 7-fold induction of sFasL to >200 pg / mL. Administration of PC111 showed a near linear dose dependent decrease in human sFasL, from 0.33 mg / kg (200 pg / mL) to 10 mg / kg (50 pg / mL) of PC111 (Figure 6).

[0190] The dose of PC 111 that gave a 50% decrease in sFasL (ED50) was determined to be 1.25 mg / kg giving a plasma exposure of 5 pg / mL at 2 hours. In conclusion, a directly proportional relationship of increasing PC111 administered doses and blood levels was observed resulting in a lowering of circulating sFasL levels. Notably, it confirms that PC111 can neutralize human sFasL in an in vivo setting.

Claims

CLAIMS1. A monoclonal antibody or an antigen-binding fragment thereof specific for human soluble Fas ligand protein (sFasL) comprising at least one heavy chain variable (VH) region and at least one light chain variable (VL) region, wherein said antibody or an antigen -binding fragment is selected from:(i) an antibody or an antigen -binding fragment comprising a VH region having complementary determining regions (CDRs) of the heavy chain CDR H1 , CDR H2 and CDR H3 as follows:(ai) CDR H1 : Arg His Gly He Thr (SEQ ID NO: 1 ) or(a2) CDR H1 : Ser His Gly He Ser (SEQ ID NO: 2);(bi) CDR H2: Trp He Asn Ala Tyr Asn Gly Asn Thr Asn Tyr Ala Gin Lys Vai Gin Gly (SEQ ID NO: 3) or(b2) CDR H2: Trp He Asn Ala Tyr Ser Gly Asn Thr Asn Tyr Ala Gin Lys Leu Gin Gly (SEQ ID NO: 4); and(m) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Leu Asp Tyr (SEQ ID NO: 5) or(C2) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Cys Asp Tyr (SEQ ID NO: 6), and comprisinga VL region having complementary determining regions (CDRs) of the light chain CDR L1 , CDR L2 and CDR L3 as follows:(as) CDR L1 : Arg Ala Ser Gin Ser Vai Ser Ser Ser Tyr Leu Ala (SEQ ID NO: 7),(bs) CDR L2: Gly Ala Ser Ser Arg Ala Thr (SEQ ID NO: 8), and(cs) CDR L3: Gin Gin Tyr Gly Ser Ser Pro Trp Thr (SEQ ID NO: 9), or(ii) an antibody or an antigen -binding fragment competing with the antibody or antigen-binding fragment of (i) in the binding to human Fas ligand protein (FasL); for use in the prevention and / or treatment of a soluble FasL (sFasL)-mediated disorder in a subject, wherein the subject additionally suffers from a dysfunction of immunological homeostasis and / or has an increased risk of developing a dysfunction of immunological homeostasis.

2. A monoclonal antibody or an antigen -binding fragment thereof specific for human soluble Fas ligand protein (sFasL) comprising at least one heavy chain variable (VH) region and at least one light chain variable (VL) region, wherein said antibody or an antigen -binding fragment is selected from:(i) an antibody or an antigen -binding fragment comprising a VH region having complementary determining regions (CDRs) of the heavy chain CDR H1 , CDR H2 and CDR H3 as follows:(ai) CDR H1 : Arg His Gly He Thr (SEQ ID NO: 1 ) or(a2) CDR H1 : Ser His Gly He Ser (SEQ ID NO: 2);(bi) CDR H2: Trp He Asn Ala Tyr Asn Gly Asn Thr Asn Tyr Ala Gin Lys Vai Gin Gly (SEQ ID NO: 3) or(b2) CDR H2: Trp He Asn Ala Tyr Ser Gly Asn Thr Asn Tyr Ala Gin Lys Leu Gin Gly (SEQ ID NO: 4); and(m) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Leu Asp Tyr (SEQ ID NO: 5) or(C2) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Cys Asp Tyr (SEQ ID NO: 6), and comprisin g a VL region having complementary determining regions (CDRs) of the light chain CDR L1 , CDR L2 and CDR L3 as follows:(as) CDR L1 : Arg Ala Ser Gin Ser Vai Ser Ser Ser Tyr Leu Ala(SEQ ID NO: 7),(b3) CDR L2: Gly Ala Ser Ser Arg Ala Thr (SEQ ID NO: 8), and(C3) CDR L3: Gin Gin Tyr Gly Ser Ser Pro Trp Thr (SEQ ID NO: 9), or(ii) an antibody or an antigen-binding fragment competing with the antibody or antigen-binding fragment of (i) in the binding to human Fas ligand protein (FasL); for use in the prevention and / or treatment of a soluble FasL (sFasL)-mediated disorder in a subject, wherein the subject additionally suffers and / or is at risk of developing a lymphoproliferative disorder, an autoimmune disorder and / or cancer.

3. A monoclonal antibody or an antigen -binding fragment thereof specific for human soluble Fas ligand protein (sFasL) comprising at least one heavy chain variable (VH) region and at least one light chain variable (VL) region, wherein said antibody or an antigen -binding fragment is selected from:(i) an antibody or an antigen -binding fragment comprising a VH region having complementary determining regions (CDRs) of the heavy chain CDR H1 , CDR H2 and CDR H3 as follows:(ai) CDR H1 : Arg His Gly He Thr (SEQ ID NO: 1 ) or(a2) CDR H1 : Ser His Gly He Ser (SEQ ID NO: 2);(bi) CDR H2: Trp He Asn Ala Tyr Asn Gly Asn Thr Asn Tyr Ala Gin LysVai Gin Gly (SEQ ID NO: 3) or(b2) CDR H2: Trp He Asn Ala Tyr Ser Gly Asn Thr Asn Tyr Ala Gin LysLeu Gin Gly (SEQ ID NO: 4); and(m) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Leu Asp Tyr (SEQ ID NO: 5) or(C2) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Cys Asp Tyr(SEQ ID NO: 6),and comprisin g a VL region having complementary determining regions (CD Rs) of the light chain CDR L1 , CDR L2 and CDR L3 as follows:(as) CDR L1 : Arg Ala Ser Gin Ser Vai Ser Ser Ser Tyr Leu Ala (SEQ ID NO: 7),(bs) CDR L2: Gly Ala Ser Ser Arg Ala Thr (SEQ ID NO: 8), and(cs) CDR L3: Gin Gin Tyr Gly Ser Ser Pro Trp Thr (SEQ ID NO: 9), or(ii) an antibody or an antigen -binding fragment competing with the antibody or antigen-binding fragment of (i) in the binding to human Fas ligand protein (FasL); for use in the prevention and / or treatment of a soluble FasL (sFasL)-mediated disorder in a subject, wherein the subject additionally suffers from a secondary co-morbidity disorder.

4. The monoclonal antibody or an antigen -binding fragmentthereof of any one of claims 1 -3 for the use of any one of claims 1 -3 comprising at least one heavy chain variable (VH) region and at least one light chain variable (VL) region, wherein the amino acid sequence of the complementary determining regions (CDRs) of the heavy chain CDR H1 , CDR H2 and CDR H3 are as follows:(ai) CDR H1 : Arg His Gly He Thr (SEQ ID NO: 1 ),(bi) CDR H2: Trp lie Asn Ala Tyr Asn Gly Asn Thr Asn Tyr Ala Gin Lys Vai Gin Gly (SEQ ID NO: 3), and(m) CDR H3: Glu Thr Met Vai Arg Gly Vai Pro Leu Asp Tyr (SEQ ID NO: 5), and wherein the amino acid sequence of the complementary determining regions (CDRs) of the lightchain CDR L1 , CDR L2 and CDR L3 are as follows:(as) CDR L1 : Arg Ala Ser Gin Ser Vai Ser Ser Ser Tyr Leu Ala(SEQ ID NO: 7),(bs) CDR L2: Gly Ala Ser Ser Arg Ala Thr (SEQ ID NO: 8), and(cs) CDR L3: Gin Gin Tyr Gly Ser Ser Pro Trp Thr (SEQ ID NO: 9).

5. The antibody or antigen-binding fragment thereof of any one of claims 1 -4 for the use of any one of claims 1 -3, wherein the VL region of the antibody or of the antigen-binding fragment thereof comprises the amino acid sequence:E IVLTQS PGTLSLSPGERATLSCRASQSVSSSYLAWYQQKPGQAPRLLIYGA SSRATG I P D R FSGSGSGTD FTLTIS R LE P E D FAVYYCQQYGSSPWTFGQGT KVEIK (SEQ ID NO: 10) and the VH region of the antibody or antigen -binding fragment thereof comprises the amino acid sequence:QVQLVQSGAEVKKPGASVKVSCKASGYIFIRHGITWVRQAPGQGLEWMGWI NAYNGNTNYAQKVQGRVTMTTDKSTSTAYMELRSLRSDDAAVYYCARETM VRGVPLDYWGQGTLVTVSS (SEQ ID NO: 1 1 ) orQVQLVQSGAEVKKPGASVKVSCKASGYIFISHGISWVRQAPGQGLEWMGWI NAYSGNTNYAQKLQGRVTMTTDRSTSTAYMELRSLRSD DTA VYYC A RETM VRGVPCDYWGQGTLVTVSS (SEQ ID NO: 12).

6. The antibody or antigen-binding fragment thereof of any one of claims 1 -5 for the use of any one of claims 1 -3 recognizing the same epitope on human soluble FasL as the antibody or antigen -binding fragment thereof of claim 1 (i), 2 (i) or 3.

7. The antibody or antigen-binding fragment thereof of any one of claims 1 -6 for the use of any one of claims 1 -3, wherein the antibody or antigen -binding fragment has a dissociation constant with the human soluble FasL of about about 1000 pM or less, preferably about 750 or less, about 500 pM or less or about 400 pM or less, more preferably of about 350 pM or less, or about 200 pM or less and most preferably of 250 pM when measured by SPR.

8. The antibody or antigen-binding fragment thereof of any one of claims 1 -7 for the use of any one of claims 1 -3, wherein the antibody or antigen-binding fragment has a dissociation constant with the membrane-bound FasL (mFasL) of at least about 500 n M, preferably at least about 1000 n M.

9. The antibody or antigen-binding fragment thereof of any one of claims 1 -8 for the useof anyoneof claims 1 -3, wherein theantibodyisselected from a partially or fully human antibody, a chimeric antibody and / or a humanized antibody, and wherein the antigen -binding fragment thereof is selected from a Fab, Fab' and / or F(ab')2 and / or a single chain Fv fragment.

10. The antibody or antigen-binding fragment thereof of any one of claims 1 -9 for the use of any one of claims 1 -3, wherein the antibody has an IgG heavy chain constant region, preferably an lgG1 or lgG4 heavy chain constant region.11 .The antibody or antigen -binding fragmentthereof of any one of claims 1 -10 for the use of any one of claims 1 -3, wherein the soluble FasL (sFasL)-mediated disorder is selected from an immune-inflammatory and / or infectious disorder and / or a skin disorder associated with keratinocyte acantholysis, apoptosis and / or necrosis.

12. The antibody or antigen -binding fragmentthereof of any one of claims 1 -10 for the use of any one of claims 1 -3 and 11 , wherein the skin disorder is selected from a bullous and / or a skin -blistering disorder, preferably selected from pemphigus, toxic epidermal necrosis (TEN) and / or Steven -John son-Syndrome (SJS), most preferably from pemphigus.

13. The antibody or antigen -binding fragmentthereof of any one of claims 1 -10 for the use of any one of claims 1 -3 and 1 1 -12, wherein the dysfunction of immunological homeostasis is a membrane-bound FasL (mFasL)-mediated disorder, preferably selected from a lymphoproliferative disorder, an autoimmune disorder and / or cancer.

14. The antibody or antigen -binding fragmentthereof of any one of claims 1 -10 for the use of any one of claims 1 -3 and 1 1 -13, wherein the lymphoproliferative disorder is selected from autoimmune lymphoproliferative syndrome (ALPS), the autoimmune disorder is selected from Hashimoto’s thyroiditis and the cancer is selected from lymphoma.

15. The antibody or antigen -binding fragmentthereof of any one of claims 1 -10 for the use of any one of claims 1 -3 and 1 1 -14, wherein the subject has undergone cancer treatment within the last 5- 10 years, preferably the last 3 years and more preferably within the last 1 year.

16. The antibody or antigen -binding fragmentthereof of any one of claims 1 -10 for the use of any one of claims 3 and 1 1 -13, wherein the co-morbidity disorder is selected from Cushing syndrome, adrenal insufficiency, myasthenia gravis, mucositis, herpes infection , fungal infections, insomnia, hidradenitis, type 2 diabetes mellitus, hypertension, cataract, benign prostatic hyperplasiaand bone disorders, such as osteoporosis, osteopenia and pathological or fragility fractu res.

17. The antibody or antigen -binding fragmentthereof of any one of claims 1 -10 for the use of any one of claims 3 and 1 1 -13, wherein the co-morbidity disorder is an iatrogenic-induced co-morbidities and is preferably selected from hypertension, dyslipidemia, heart diseases, diabetes, pulmonary infection, and bone disorders, such as osteoporosis, osteopenia and pathological or fragility fractu res.

18. A nucleic acid molecule encoding a monoclonal anti body oran antigen -fragment thereof of any one of claims 1 - 10for the use in any one of claims 1 -3 and 1 1 - 17.

19. A nucleic acid molecule of claim 18 for the use in any one of claims 1 -3 and 1 1 - 17, which is a DNA vector or an RNA molecule.

20. The antibody or antigen-binding fragment thereof of any one of any one of claims 1 -10 or the nucleic acid molecule of any one of claims 18-19 for the use in any one of claims 1 -3 and 1 1 -17 in a monotherapy.21 .The antibody or antigen -binding fragment thereof of any one of claims 1 -10 or the nucleic acid molecule of any one of claims 18-19 for the use in any one of claims 1 -3 and 1 1 -17 in combination with at least one further active ingredient effective against a soluble FasL (sFasL)-mediated disorder, preferably effective againsta skin disorder selected from a bullous and / ora skin -blistering disorder, most preferably effective against pemphigus, toxic epidermal necrolysis (TEN) and / or Steven s-John son -Syndrome (SJS).

22. The antibody or antigen -binding fragment thereof of any one of claims 1 -10 or the nucleic acid molecule of any one of claims 18-19 for the use of claim 21 , wherein the further active ingredient is selected from at least one of a steroid, cyclosporine, IVIg, a TNF inhibitor, an IL17 or IL23 inhibitor and / or plasmapheresis.

23. The antibody or antigen-binding fragment thereof of any one of claims 1 -10 or the nucleic acid molecule of any one of claims 18-19 for the use in any one of claims 1 -3 and 1 1 -17 in human therapy.

24. A pharmaceutical composition comprising the antibody or antigen -binding fragment of any one of claims 1 -10 or the nucleic acid molecule of any one ofclaims 18-19 together with one or more pharmaceutical acceptable carriers for the use in any one of claims 1 -3 and 11 -17.

25. The antibody or antigen-binding fragment thereof of any one of claims 1 -10 or the nucleic acid molecule of any one of claims 18-19 or the pharmaceutical composition of claim 24, which is administered systemically and / or locally.