Treatment method

Abstract

The present disclosure relates to combinations of inhibitors of phosphodiesterase 1 (PDE1) useful in the treatment of certain cancers or tumors, such as colon cancer. In another embodiment, the present disclosure relates to the use of inhibitors of PDE1 and, optionally, an anti-tumor agent for the treatment of certain cancers or tumors.

Description

[Technical field]

[0001] Field of Disclosure The present invention relates to inhibitors of phosphodiesterase 1 (PDE1) useful in the treatment of certain cancers and tumors, such as colon cancer. The present invention also relates to the administration of inhibitors of phosphodiesterase 1 (PDE1) for the treatment of certain cancers and tumors, such as colon cancer. [Background technology]

[0002] Background of the disclosure Colorectal cancer is the third most commonly diagnosed cancer in men and the second most commonly diagnosed in women worldwide, accounting for an estimated 50,000 deaths annually. In contrast to incidence trends, a decline in colorectal cancer mortality has been observed in many countries, most likely attributable to colorectal cancer screening, reduced risk factor prevalence, and / or improved treatment. However, when widespread malignancies are encountered, these cases do not respond to curative treatment.

[0003] Moreover, metastasis is estimated to cause 90% of cancer-related deaths worldwide. In most cases, metastatic tumor cells develop ways to evade the immune response and become resistant to treatment. Resistance to cancer treatment can be intrinsic to tumor cells, but is often conferred or enhanced by non-malignant cells that compose the tumor microenvironment (TME). The TME is composed of tissue-resident cells, stromal cells, and other cells recruited by the tumor, and therefore may include endothelial cells, pericytes, fibroblasts, mesenchymal stem cells, and a variety of immune cells, including regulatory T (Treg) cells, mast cells, neutrophils, myeloid-derived suppressor cells, and tumor-associated macrophages. These cells promote tumor angiogenesis, cancer cell invasion, and / or interfere with immune surveillance. Macrophages are one of the most common types of tumor-associated cells. Although researchers initially assumed that these immune cells were part of the body's response to reject tumors, in fact, a major check on the development of cancer is the surveillance of the immune system and its reaction to the presence of cancer by cells of the innate immune system (e.g., macrophages, neutrophils) and cells associated with the adaptive immune response (e.g., T cells and B cells).

[0004] However, in some cases, cancers are able to evade and exploit the immune system, so that these immune system cells become part of the tumor's support and defense system rather than attacking it. The immune TME can be modified to support the tumor and promote its progression while suppressing immune cell-mediated cytotoxicity. Substantial clinical and experimental evidence indicates that macrophages, abundant in most tumor types, play a major regulatory role in promoting tumor progression to malignancy. Both macrophages in primary tumors (tumor-associated macrophages or TAMs) and macrophages in metastatic tumors (metastasis-associated macrophages or MAMs) are abundant in most solid tumors and may be associated with tumor metastasis. The accumulation of TAMs, MAMs, and their progenitors appears to be driven by chemokine ligands released by tumor and stromal cells. For example, there is evidence that TAMs and MAMs are derived, at least in part, from CCR2-expressing monocytes recruited by CCL2-expressing tumor cells and / or CCL2-expressing stromal cells. Although the exact mechanisms are not fully defined, other CCR2 ligands such as CCL12, cytokines such as VEGF and CSF1, and other chemotactic signals such as CCL5-CCR5, CCL20-CCR6, CXCL12-CXCR4 may provide alternative or additional chemotactic pathways for the recruitment of TAMs. Thus, efforts to target specific chemotactic receptors or ligands, for example by specifically blocking CCR2-CCL2 interactions, have not been completely effective, presumably because cancers can utilize alternative pathways.

[0005] Although 11 families of phosphodiesterases (PDEs) have been identified, only family I PDEs, the Ca2+ / calmodulin-dependent phosphodiesterases (CaM-PDEs), have been shown to be activated by Ca2+ / calmodulin and mediate calcium and cyclic nucleotide (e.g., cGMP and cAMP) signaling pathways. The three known CaM-PDE genes, PDE1A, PDE1B and PDE1C, are all expressed in central nervous system tissues. PDE1A is expressed in the brain, lung and heart. PDE1B is expressed primarily in the central nervous system, but has also been detected in monocytes and neutrophils and has been shown to be involved in the inflammatory response of these cells. PDE1C is expressed in the olfactory epithelium, cerebellar granule cells, striatum, heart and vascular smooth muscle. PDE1C has been demonstrated to be a major regulator of smooth muscle proliferation in human smooth muscle.

[0006] Cyclic nucleotide phosphodiesterases downregulate intracellular cAMP and cGMP signaling by hydrolyzing these cyclic nucleotides to their respective 5'-monophosphates (5'AMP and 5'GMP), which are inactive from the point of view of intracellular signaling pathways. Both cAMP and cGMP are central intracellular second messengers and play a role in regulating many cellular functions. PDE1A and PDE1B preferentially hydrolyze cGMP over cAMP, whereas PDE1C shows roughly equal hydrolysis of cGMP and cAMP.

[0007] With regard to PDE1C specifically, recent evidence indicates that PDE1C is a proliferation-related gene as it is expressed only in proliferating vascular smooth muscle cells (Rybalkin SD, et al., Calmodulin-stimulated cyclic nucleotide phosphodiesterase (PDE1C) is induced in human arterial smooth muscle cells of the synthetic, proliferative phenotype. J Clin Invest 1997;100:2611-2621). There have also been sporadic reports of PDE1C expression along with other PDE subtypes in experimental tumor models such as melanoma (Watanabe Y, et al., Phosphodiesterase 4 regulates the migration of B16-F10 melanoma cells. Exp Ther Med 2012;4:205-210), neuroblastoma (Jang IS, Juhnn YS. Adaptation of cAMP signaling system in SH-SY5Y neuroblastoma cells following expression of a constitutively active stimulatory G protein alpha, Q227L Gsalpha. Exp Mol Med 2001;33:37-45), and osteosarcoma (Ahlstroem M, et al., Cyclic nucleotide phosphodiesterases (PDEs) in human osteoblastic cells; the effect of PDE inhibition on cAMP accumulation. Cell Mol Biol Lett 2005;10:305-319).

[0008] Tumor-promoting cell proliferation, migration, tissue invasion and inflammation are considered enabling features of cancer development. Each of these processes is time-dependent, variable and complex, involving multiple signaling pathways. Multi-targeted agents are likely to produce greater benefits than those observed with single-targeted therapy, have acceptable tolerability profiles and be active against a broader range of tumor types. Regulation of cyclic nucleotide signaling is appropriately viewed as a complex of multiple component pathways involved in diverse aspects of tumor cell function. Impairment of cAMP production has been described in a variety of cancer pathologies. Attempts to directly modulate cyclic nucleotides in cancer cells, while having antiproliferative effects, have been unproductive due to high cytotoxicity. New, safer and more selective strategies to modulate cAMP in cancer cells are needed. Summary of the Invention

[0009] Disclosure Summary We have previously shown that inhibition of PDE1 activity with the disclosed compounds can safely restore cAMP function in a wide range of pathologies, including models of neurodegeneration and neuroinflammation, heart failure, pulmonary hypertension and peripheral inflammation, as well as in humans with certain diseases. More recently, we have shown that PDE1 inhibitors disrupt cell migration in microglia and monocytes. Recent evidence indicates that PDE1, particularly the PDE1C isoform, is overexpressed in experimental tumor models such as melanoma, neuroblastoma and osteosarcoma. Furthermore, local genomic over-representation of PDE1C in glioblastoma multiforme (GBM) cells has been demonstrated. Genomic gain of PDE1C is associated with increased expression in GBM-derived cell cultures and is essential for driving cell proliferation, migration and invasion in cancer cells.

[0010] Many types of cancer cells overexpress PDE1 activity, which is identified through various biomarkers such as increased RNA expression, DNA copy number, PDE1 binding (PET or radioisotope retention of PDE1 inhibitor molecules) or enzyme activity. These cancer cells also exhibit low levels of cAMP, which can be increased by PDE1 inhibitors. Such properties can be treated with PDE1 inhibitors alone or in combination with chemotherapeutic agents, gene therapy agents and / or immunological approaches. Inhibiting PDE1 induces apoptotic cell death, prevents migration, limits metastasis, and reduces inflammation. Thus, PDE1 inhibitors synergize with chemotherapy and immunological approaches.

[0011] Without being bound by theory, it is believed that selective inhibition of PDE1 isoforms, which increases the level of intracellular cAMP (and / or cGMP), induces apoptosis and cell cycle arrest in a wide range of tumor cells, and regulates the tumor microenvironment to prevent cell migration, inflammation and tissue invasion. Therefore, the development and clinical application of inhibitors specific to individual PDE1 and its isoforms, especially PDE1C, may selectively restore normal intracellular signaling to provide antitumor therapy with reduced side effects. Without being bound by theory, it is further believed that the PDE1 inhibitors of the present disclosure inhibit the recruitment of immune system cells, including macrophages, and other cells to cancer, and inhibit metastasis, tumor angiogenesis, cancer cell invasion and immune surveillance destruction brought about by the recruited cells. Since PDE1 inhibits not only CCL2 but also other cytokines and chemokines that are thought to be involved in this recruitment, it is expected to be more effective than treatments such as monoclonal antibodies or other specific inhibitors of CCR2-CCL2 interaction.

[0012] The present disclosure also provides the use of PDE1 inhibitors for the treatment of cancer or tumor, including, for example, carcinoma, melanoma and astrocytoma.In addition, impaired cAMP (or cGMP) levels can result from overexpression of PDE1 isoforms in various cancer pathologies.Selective inhibition of PDE1 isoforms, which increases intracellular cAMP (and / or cGMP) levels, induces apoptosis and cell cycle arrest in a wide range of tumor cells, and regulates tumor microenvironment to prevent cell migration, inflammation and tissue invasion.Therefore, the development and clinical application of inhibitors specific to individual PDE1 can selectively restore normal intracellular signaling to provide antitumor therapy with reduced side effects.

[0013] Previous studies have shown that PDE1 (i.e., PDE1C) is significantly overexpressed in the tumor environment of glioblastoma patients compared to healthy patients (i.e., patients without glioblastoma). siRNA-mediated silencing of PDE1C has been shown to inhibit proliferation and invasion in glioblastoma patient-derived cell cultures. Without being bound by theory, inhibition of PDE1 may be effective in therapeutic intervention of certain cancers or tumors, such as glioblastoma.

[0014] In various embodiments, the present application provides a method for treating colon cancer (e.g., colorectal cancer), comprising administering a pharmacologic acceptable amount of PDE1 inhibitor to a subject in need of such treatment.In some embodiments, the PDE1 inhibitor is administered in combination with an antitumor agent.

[0015] In various embodiments, the present disclosure also provides pharmaceutical compositions comprising the compounds of the present disclosure, which are prepared using conventional diluents or excipients and techniques known in the art.Accordingly, oral dosage forms can include tablets, capsules, liquids, suspensions, etc.

[0016] In various embodiments, the present disclosure also provides PDE1 inhibitors according to formula I, Ia, II, III, IV, V, VI and / or VII as set forth below, in free or salt form, for use in treating a condition selected from cancer or tumor, inhibiting tumor cell proliferation, migration and / or invasion, or treating colon cancer, e.g., colorectal cancer. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 shows the effect of PDE1 inhibition on CT26 mouse cancer cells in samples treated with Compound 1 and untreated controls.

[0018] [Diagram 2] FIG. 2 shows the change in relative proportions of immune cells in CT26 mouse cancer cells in samples treated with Compound 1 and untreated controls. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Detailed Description of the Disclosure Compounds for use in the disclosed methods In one embodiment, the PDE1 inhibitors for use in the methods of treatment and prevention described herein are selective PDE1 inhibitors.

[0020] PDE1 Inhibitors In one embodiment, the present invention provides a PDE1 inhibitor for use in the methods of treatment and prevention described herein, comprising a compound of formula I: [ka] [In the formula, (i) R1 is H or C 1-4 alkyl (e.g., methyl); (ii) R4 is H or C 1-4 alkyl, and R and R are independently H or C 1-4alkyl (e.g., R2 and R3 are both methyl, or R2 is H and R3 is isopropyl), aryl, heteroaryl, (optionally hetero)arylalkoxy, or (optionally hetero)arylalkyl; or R2 is H, and R3 and R4 together form a dimethylene, trimethylene or tetramethylene bridge (preferably, R3 and R4 together have a cis configuration, e.g., the carbons carrying R3 and R4 have the R and S configurations, respectively); (iii) R5 is a substituted heteroarylalkyl, e.g., substituted with haloalkyl; or R5 is attached to one of the nitrogens of the pyrazolo moiety of formula I and has formula A: [ka] (Wherein, X, Y and Z are independently N or C; R8, R9, R 11 and R 12 are independently H or halogen (e.g., Cl or F), and R 10 is halogen, alkyl, cycloalkyl, haloalkyl (e.g., trifluoromethyl), aryl (e.g., phenyl), heteroaryl (e.g., pyridyl (e.g., pyrid-2-yl), or thiadiazolyl (e.g., 1,2,3-thiadiazol-4-yl) optionally substituted with halogen), diazolyl, triazolyl, tetrazolyl, arylcarbonyl (e.g., benzoyl), alkylsulfonyl (e.g., methylsulfonyl), heteroarylcarbonyl, or alkoxycarbonyl; provided that when X, Y, or Z is nitrogen, then R, R, or R 10 do not exist) The part indicated by; (iv) R6 is H, alkyl, aryl, heteroaryl, arylalkyl (e.g., benzyl), arylamino (e.g., phenylamino), heteroarylamino, N,N-dialkylamino, N,N-diarylamino, or N-aryl-N-(arylalkyl)amino (e.g., N-phenyl-N-(1,1'-biphen-4-ylmethyl)amino); (v) n is 0 or 1; (vi) When n is 1, A is -C(R 13 R 14 )-(where R 13 and R 14 are independently H or C 1-4 alkyl, aryl, heteroaryl, (optionally hetero)arylalkoxy or (optionally hetero)arylalkyl)]. The compound is represented by the formula:

[0021] In another embodiment, the present invention provides a PDE1 inhibitor for use in the methods described herein, comprising a compound of formula 1a: [ka] [In the formula, (i) R2 and R5 are independently H or hydroxy and R3 and R4 together form a trimethylene or tetramethylene bridge [preferably the carbons bearing R3 and R4 have the R and S configurations, respectively]; or R2 and R3 are each methyl and R4 and R5 are each H; or R2, R4 and R5 are H and R3 is isopropyl [preferably the carbon bearing R3 has the R configuration]; (ii) R6 is phenylamino (optionally halo-substituted), benzylamino (optionally halo-substituted), C 1-4 Alkyl, or C 1-4alkylsulfide; for example, phenylamino or 4-fluorophenylamino; (iii) R 10 is C 1-4 alkyl, methylcarbonyl, hydroxyethyl, carboxylic acid, sulfonamide, (optionally halo- or hydroxy-substituted) phenyl, (optionally halo- or hydroxy-substituted) pyridyl (e.g., 6-fluoropyrid-2-yl), or thiadiazolyl (e.g., 1,2,3-thiadiazol-4-yl); X and Y are independently C or N. Provide that.

[0022] In another embodiment, the present invention provides a PDE1 inhibitor for use in the methods of treatment and prevention described herein, comprising a compound of formula II: [ka] [In the formula, (i) X is C 1-6 alkylene (e.g., methylene, ethylene or prop-2-yn-1-ylene); (ii) Y is a single bond, alkynylene (e.g., -C≡C-), arylene (e.g., phenylene) or heteroarylene (e.g., pyridylene); (iii) Z is H, aryl (e.g., phenyl), heteroaryl (e.g., pyridyl, e.g., pyrid-2-yl), halo (e.g., F, Br, Cl), haloC 1-6 alkyl (e.g., trifluoromethyl), -C(O)-R1, -N(R2)(R3), or C(O)-R1, which may contain at least one atom selected from the group consisting of N or O; 3-7 cycloalkyl (e.g., cyclopentyl, cyclohexyl, tetrahydro-2H-pyran-4-yl, or morpholinyl); (iv) R1 is C 1-6 Alkyl, haloC 1-6 Alkyl, -OH or -OC 1-6alkyl (e.g., -OCH3); (v) R2 and R3 are independently H or C 1-6 is alkyl; (vi) R4 and R5 are independently H, C 1-6 Alkyl, or one or more halo (e.g., fluorophenyl, e.g., 4-fluorophenyl), hydroxy (e.g., hydroxyphenyl, e.g., 4-hydroxyphenyl or 2-hydroxyphenyl) or C 1-6 aryl (e.g., phenyl) optionally substituted with alkoxy; (vii) where X, Y and Z are independently one or more halo (e.g., F, Cl or Br), C 1-6 Alkyl (e.g., methyl), haloC 1-6 For example, Z may be substituted with one or more halo (e.g., 6-fluoropyrid-2-yl, 5-fluoropyrid-2-yl, 6-fluoropyrid-2-yl, 3-fluoropyrid-2-yl, 4-fluoropyrid-2-yl, 4,6-dichloropyrid-2-yl), haloC 1-6 Alkyl (e.g., 5-trifluoromethylpyrid-2-yl) or C 1-6 Z is heteroaryl, e.g., pyridyl, substituted with alkyl (e.g., 5-methylpyrid-2-yl); or Z is aryl, e.g., phenyl, substituted with one or more halo (e.g., 4-fluorophenyl). The compound is

[0023] In yet another embodiment, the present invention provides a PDE1 inhibitor for use in the methods of treatment and prevention described herein, comprising a compound of formula III: [ka] [In the formula, (i) R1 is H or C 1-4 alkyl (e.g., methyl or ethyl); (ii) R2 and R3 are independently H or C1-6 alkyl (e.g., methyl or ethyl); (iii) R4 is H or C 1-4 alkyl (e.g., methyl or ethyl); (iv) R5 is independently -C(=O)-C 1-6 Alkyl (e.g., -C(=O)-CH3) and C 1-6 aryl (e.g., phenyl) optionally substituted with one or more groups selected from hydroxyalkyl (e.g., 1-hydroxyethyl); (v) R6 and R7 are independently H or independently C 1-6 Aryl (e.g., phenyl) optionally substituted with one or more groups selected from alkyl (e.g., methyl or ethyl) and halogen (e.g., F or Cl), e.g., unsubstituted phenyl, or phenyl substituted with one or more halogen (e.g., F), or one or more C 1-6 Phenyl substituted with alkyl and one or more halogens, or one C 1-6 phenyl substituted with alkyl and one halogen, such as 4-fluorophenyl or 3,4-difluorophenyl or 4-fluoro-3-methylphenyl; (vi) n is 1, 2, 3 or 4. Provide that.

[0024] In yet another embodiment, the present invention provides a PDE1 inhibitor for use in the methods of treatment and prevention described herein, comprising a compound of formula IV, in free or salt form: [ka] [In the formula, (i) R1 is C 1-4 alkyl (e.g., methyl or ethyl), or -NH(R2) (wherein R2 is phenyl optionally substituted with halo (e.g., fluoro), e.g., 4-fluorophenyl; (ii) X, Y and Z are independently N or C; (iii) R3, R4 and R5 are independently H or C 1-4 alkyl (e.g., methyl); or R3 is H and R4 and R5 together form a trimethylene bridge (preferably, R4 and R5 together have a cis configuration, e.g., the carbons bearing R4 and R5 have the R and S configurations, respectively); (iv) R6, R7 and R8 are independently H, C 1-4 Alkyl (e.g., methyl), hydroxy-substituted pyrid-2-yl; or -S(O)2-NH2 and; (v) with the proviso that when X, Y and / or Z are N, then R6, R7 and / or R8 are absent, respectively; when X, Y and Z are all C, then at least one of R6, R7 or R8 is -S(O)2-NH2, or pyrid-2-yl substituted with hydroxy. Provide that.

[0025] In another embodiment, the disclosure provides that a PDE1 inhibitor for use in the methods described herein is a compound represented by formula V: [ka] [In the formula, (i) R1 is -NH(R4), where R4 is phenyl optionally substituted with halo (e.g., fluoro), such as 4-fluorophenyl; (ii) R2 is H or C 1-6 alkyl (e.g., methyl, isobutyl, or neopentyl); (iii) R3 is -SO2NH2 or -COOH. Provide that.

[0026] In another embodiment, the disclosure provides that a PDE1 inhibitor for use in the methods described herein is a compound represented by formula VI: [ka] [In the formula, (i) R1 is -NH(R4), where R4 is phenyl optionally substituted with halo (e.g., fluoro), such as 4-fluorophenyl; (ii) R2 is H or C 1-6 alkyl (e.g., methyl or ethyl); (iii) R3 is H, halogen (e.g., bromo), C 1-6 alkyl (e.g., methyl), aryl optionally substituted with halogen (e.g., 4-fluorophenyl), heteroaryl optionally substituted with halogen (e.g., 6-fluoropyrid-2-yl or pyrid-2-yl), or acyl (e.g., acetyl). Provide that.

[0027] In another embodiment, the disclosure provides that a PDE1 inhibitor for use in the methods described herein is a compound of formula VII: [ka] [In the formula, (i) R1 is -NH(R5), where R5 is phenyl optionally substituted with halo (e.g., fluoro), for example, 4-fluorophenyl; (ii) R2 and R3 are each independently H or C 1-6 alkyl (e.g., methyl or ethyl); (iii) R4 is aryl optionally substituted with halogen (e.g., 4-fluorophenyl) or heteroaryl optionally substituted with halogen (e.g., 6-fluoropyrid-2-yl). Provide that.

[0028] In one embodiment, the disclosure relates to the administration of a PDE1 inhibitor (e.g., a compound according to Formula I, Ia, II, III, IV, V, VI and / or VII) for use in the methods described herein, wherein the inhibitor is [ka] [ka] [ka] [ka] or [ka] The present invention provides a compound represented by the formula:

[0029] In one embodiment, the present invention provides the administration of a PDE1 inhibitor for the treatment or prevention of inflammation or an inflammation-related disease or disorder, wherein the inhibitor is one of the following, in free form or in pharma- ceutical acceptable salt form: [ka] The present invention provides a compound represented by the formula:

[0030] In yet another embodiment, the present invention provides the administration of a PDE1 inhibitor for the treatment or prevention of inflammation or an inflammation-related disease or disorder, wherein the inhibitor is selected from the group consisting of the following, in free form or in pharma- ceutically acceptable salt form: [ka] The present invention provides a compound represented by the formula:

[0031] In yet another embodiment, the present invention provides the administration of a PDE1 inhibitor for the treatment or prevention of inflammation or an inflammation-related disease or disorder, wherein the inhibitor is selected from the group consisting of the following, in free form or in pharma- ceutically acceptable salt form: [ka] The present invention provides a compound represented by the formula:

[0032] In yet another embodiment, the present invention provides the administration of a PDE1 inhibitor for the treatment or prevention of inflammation or an inflammation-related disease or disorder, wherein the inhibitor is selected from the group consisting of the following, in free form or in pharma- ceutically acceptable salt form: [ka] The present invention provides a compound represented by the formula:

[0033] In yet another embodiment, the present invention provides the administration of a PDE1 inhibitor for the treatment or prevention of inflammation or an inflammation-related disease or disorder, wherein the inhibitor is selected from the group consisting of the following, in free form or in pharma- ceutically acceptable salt form: [ka] The present invention provides a compound represented by the formula:

[0034] In one embodiment, a selective PDE1 inhibitor according to any of the above formulas (e.g., Formula I, Ia, II, III, IV, V, VI and / or VII) is a compound that inhibits phosphodiesterase-mediated (e.g., PDE1-mediated, particularly PDE1B-mediated) hydrolysis of cGMP, e.g., preferred compounds have an IC of less than 1 μM, preferably less than 500 nM, preferably less than 50 nM, preferably less than 5 nM, in the immobilized metal affinity particle reagent PDE assay, in free or salt form. 50 has.

[0035] In another embodiment, the present invention provides the administration of a PDE1 inhibitor for the treatment of a condition selected from cancer or tumor, inhibiting tumor cell proliferation, migration and / or invasion; and / or treating glioma, wherein the inhibitor is selected from the group consisting of: [ka] The present invention provides a compound represented by the formula:

[0036] Further examples of PDE1 inhibitors suitable for use in the methods and treatments described herein are described in WO 2006133261 (A2); U.S. Patent No. 8,273,750; U.S. Patent No. 9,000,001; U.S. Patent No. 9,624,230; WO 2009075784 (A1); U.S. Patent No. 8,273,751; U.S. Patent No. 8,829,008; U.S. Patent No. 9,403,836; No. 2014151409 (A1), U.S. Pat. No. 9,073,936; U.S. Pat. No. 9,598,426; U.S. Pat. No. 9,556,186; U.S. Patent Application Publication No. 2017 / 0231994 (A1), WO 2016022893 (A1), and U.S. Patent Application Publication No. 2017 / 0226117 (A1), each of which is incorporated herein by reference in its entirety.

[0037] Still further examples of PDE1 inhibitors suitable for use in the methods and treatments described herein include those described in WO 2018007249 (A1); U.S. Patent Application Publication No. 2018 / 0000786; WO 2015118097 (A1); U.S. Patent No. 9,718,832; WO 2015091805 (A1); U.S. Patent No. 9,701,665; U.S. Patent Application Publication No. 2015 / 0175584 (A1); U.S. Patent Application Publication No. 2017 / 0267664 (A1); WO No. 2016055618 (A1); U.S. Patent Application Publication No. 2017 / 0298072 (A1); International Publication No. 2016170064 (A1); U.S. Patent Application Publication No. 2016 / 0311831 (A1); International Publication No. 2015150254 (A1); U.S. Patent Application Publication No. 2017 / 0022186 (A1); International Publication No. 2016174188 (A1); U.S. Patent Application Publication No. 2016 / 0318939 (A1); U.S. Patent Application Publication No. 2017 / 0291903 (A1); International Publication No. 20180 73251 (A1); WO 2017178350 (A1); U.S. Patent Application Publication No. 2017 / 0291901 (A1); WO 2018 / 115067; U.S. Patent Application Publication No. 2018 / 0179200 (A); U.S. Patent Application Publication No. 20160318910 (A1); U.S. Patent No. 9,868,741; WO 2017 / 139186 (A1); WO 2016 / 040083; U.S. Patent Application Publication No. 2017 / 0240532; WO 2016033776 ( A1); U.S. Patent Application Publication No. 2017 / 0233373; International Publication No. 2015130568; International Publication No. 2014159012; U.S. Patent No. 9,034,864; U.S. Patent No. 9,266,859; International Publication No. 2009085917; U.S. Patent No. 8,084,261; International Publication No. 2018039052; U.S. Patent Application Publication No. 20180062729; and International Publication No. 2019027783 (each of which is incorporated herein by reference in its entirety). In the event that the statements in a document incorporated herein by reference conflict or are incompatible with the statements in this disclosure, the statements in this disclosure shall be understood to control.

[0038] Further examples of PDE1 inhibitors and suitable methods of use are disclosed in International Application No. PCT / US2019 / 033941 and U.S. Provisional Application No. 62 / 789,499, both of which are incorporated herein by reference.

[0039] Unless otherwise specified or clear from context, the following terms used herein have the following meanings:

[0040] (a) "Selective PDE1 inhibitor," as used herein, refers to a PDE1 inhibitor whose inhibition of PDE1 is at least 100-fold more selective than inhibition of any other PDE isoform.

[0041] (b) "Alkyl," as used herein, means a saturated or unsaturated hydrocarbon moiety, preferably saturated, preferably having 1 to 6 carbon atoms, which may be straight or branched, and which may be mono-, di-, or tri-substituted, for example, by halogen (e.g., chloro or fluoro), hydroxy, or carboxy.

[0042] (c) "Cycloalkyl" as used herein means a saturated or unsaturated non-aromatic hydrocarbon moiety, preferably saturated, containing preferably 3 to 9 carbon atoms, at least some of which form a non-aromatic monocyclic or bicyclic or bridged ring structure, optionally substituted, for example, with halogen (e.g., chloro or fluoro), hydroxy or carboxy. When the cycloalkyl optionally contains one or more atoms selected from N and O and / or S, the cycloalkyl may be a heterocycloalkyl.

[0043] (d) "Heterocycloalkyl" means, unless otherwise specified, a saturated or unsaturated non-aromatic hydrocarbon moiety, preferably saturated, containing preferably from 3 to 9 carbon atoms, at least some of which are formed into a non-aromatic monocyclic or bicyclic or bridged ring structure, in which at least one carbon atom is replaced by N, O or S, and the heterocycloalkyl may be optionally substituted, for example, by halogen (e.g., chloro or fluoro), hydroxy or carboxy.

[0044] (e) "Aryl," as used herein, refers to a monocyclic or bicyclic aromatic hydrocarbon, preferably phenyl, optionally substituted, for example, with alkyl (e.g., methyl), halogen (e.g., chloro or fluoro), haloalkyl (e.g., trifluoromethyl), hydroxy, carboxy, or further aryl or heteroaryl (e.g., biphenyl or pyridylphenyl).

[0045] (f) "Heteroaryl," as used herein, means an aromatic moiety in which one or more of the atoms in the aromatic ring is sulfur or nitrogen rather than carbon, e.g., pyridyl or thiadiazolyl, which may be optionally substituted, e.g., with alkyl, halogen, haloalkyl, hydroxy or carboxy.

[0046] The disclosed compounds, for example, PDE1 inhibitors as described herein, can be in free form or salt form, for example, as acid addition salt.In this specification, unless otherwise specified, the phrase "disclosed compounds" and the like should be understood to include the compounds in any form, for example, in free form or acid addition salt form, or in base addition salt form if the compounds contain acidic substituents.Since the disclosed compounds are intended to be used as pharmaceuticals, pharma-ceutically acceptable salts are preferred.Salts that are not suitable for pharmaceutical use may be useful, for example, for the isolation or purification of the disclosed compounds in free form or their pharma-ceutically acceptable salts, and therefore also include such salts.

[0047] The disclosed compounds may also exist in prodrug form in some cases. Prodrug form is a compound that is converted to the disclosed compounds in the body. For example, when the disclosed compounds contain hydroxy or carboxy substituents, these substituents may form physiologically hydrolyzable and acceptable esters. As used herein, "physiologically hydrolyzable and acceptable esters" refers to esters of the disclosed compounds that are hydrolyzable under physiological conditions and produce physiologically acceptable acids (in the case of the disclosed compounds with hydroxy substituents) or alcohols (in the case of the disclosed compounds with carboxy substituents) at the doses to be administered. Thus, when the disclosed compounds contain hydroxy groups, for example the compound -OH, the acyl ester prodrugs of the compounds, i.e., the compound -OC(O)-C 1-4 Alkyl groups can be hydrolyzed in the body to form physiologically hydrolyzable alcohols (compounds -OH) on the one hand, and acids (e.g., HOC(O)-C 1-4 Alternatively, when a compound of the present disclosure contains a carboxylic acid, for example Compound -C(O)OH, an acid ester prodrug of the compound, Compound -C(O)OC 1-4 The alkyl group is hydrolyzed to give the compounds -C(O)OH and HO-C 1-4 Alkyl can be formed. Thus, as will be understood, this term encompasses conventional pharmaceutical prodrug forms.

[0048] In another embodiment, the present disclosure further provides a pharmaceutical composition comprising a PDE1 inhibitor in combination with an antitumor agent, each in free form or in pharma- ceutically acceptable salt form, mixed with a pharma- ceutically acceptable carrier.The term "combination" as used herein includes simultaneous, sequential or contemporaneous administration of a PDE1 inhibitor and an antitumor agent.In another embodiment, the present disclosure provides a pharmaceutical composition containing such a compound.In some embodiments, the combination of a PDE1 inhibitor and an antitumor agent can be administered at a lower dose than is effective when the antitumor agent is administered as a single monotherapy.

[0049] Methods of Using the Disclosed Compounds In another embodiment, the present application provides a method for treating colon cancer (Method 1), comprising administering to a subject in need of such treatment a pharma- ceutically acceptable amount of a PDE1 inhibitor (i.e., a PDE1 inhibitor according to Formula I, Ia, II, III, IV, V, VI and / or VII).

[0050] 1.1 Method 1, wherein the colon cancer is colorectal cancer.

[0051] 1.2 Any of the above methods further comprising the step of administering to said patient an anti-tumor agent.

[0052] 1.3 Method 1.2, wherein the anti-tumor agent is administered concurrently with the PDE1 inhibitor.

[0053] 1.4 Method 1.2, wherein the anti-tumor agent is administered prior to administration of the PDE1 inhibitor.

[0054] 1.5 Method 1.2, wherein the anti-tumor agent is administered after administration of the PDE1 inhibitor.

[0055] 1.6 Any of the above methods wherein the PDE1 inhibitor, and optionally the anti-tumor agent, are administered in conjunction with radiation therapy or chemotherapy.

[0056] 1.7 Any of the above methods wherein the PDE1 inhibitor, and optionally the anti-tumor agent, are administered simultaneously with radiation therapy or chemotherapy.

[0057] 1.8 Any of the above methods, wherein the PDE1 inhibitor, and optionally the anti-tumor agent, are administered prior to radiation therapy or chemotherapy.

[0058] 1.9 Any of the above methods, wherein the PDE1 inhibitor, and optionally the anti-tumor agent, are administered after radiation therapy or chemotherapy.

[0059] 1.10 Any of the above methods wherein the PDE1 inhibitor is administered in combination with an anti-tumor agent, a chemotherapeutic agent, a gene therapy agent and / or an immunological therapy.

[0060] 1.11 Any of the above methods, wherein administration of a PDE1 inhibitor is effective to induce one or more of apoptotic cell death, inhibition of migration, inhibition of metastasis, and / or reduction of inflammation in colon cancer.

[0061] 1.12 Any of the above methods wherein the PDE1 inhibitor is administered in combination with an anti-tumor agent, a chemotherapeutic agent, a gene therapy agent, an immunological therapy, a corticosteroid, and / or an antihistamine.

[0062] 1.13 Any of the above methods, wherein the colon cancer is mediated by a PDE.

[0063] 1.14 Any of the above methods, wherein the colon cancer is mediated by PDE1.

[0064] 1.15 Any of the above methods, wherein the colon cancer is mediated by PDE1C.

[0065] 1.16 Any of the above methods, wherein the colon cancer is characterized by a loss of calcium / calmodulin regulation.

[0066] 1.17 Any of the above methods, wherein the subject is a human.

[0067] The disclosure further provides PDE1 inhibitors for use in methods of treating colon cancer, such as for use in any of Methods 1 et seq..

[0068] The disclosure further provides the use of a PDE1 inhibitor in the manufacture of a medicament for use in a method of treating colon cancer, such as a medicament for use in any of Methods 1 et seq.

[0069] The invention further provides pharmaceutical compositions for use in any of Methods 1 and following, comprising a PDE1 inhibitor, e.g., any of the compounds of Formula I, Ia, II, III, IV, V, VI and / or VII.

[0070] In another embodiment, the present application provides a method (Method 2) for inhibiting the proliferation, migration and / or invasion of cancerous or neoplastic cells in the colon, comprising administering to a subject in need of such inhibition a pharma- ceutically acceptable amount of a PDE1 inhibitor (i.e., a PDE1 inhibitor according to Formula I, Ia, II, III, IV, V, VI and / or VII).

[0071] 2.1 Method 2, wherein the method is for inhibiting the proliferation of cancerous or neoplastic cells.

[0072] 2.2 Any of the above methods, wherein the subject is afflicted with colon cancer.

[0073] 2.3 Any of the above methods, wherein the subject is afflicted with colorectal cancer.

[0074] 2.4 Any of the above methods further comprising the step of administering to said patient an anti-tumor agent.

[0075] 2.5 Method 2.4, wherein the anti-tumor agent is administered concurrently with the PDE1 inhibitor.

[0076] 2.6 Method 2.4, wherein the anti-tumor agent is administered prior to administration of the PDE1 inhibitor.

[0077] 2.7 Method 2.4, wherein the anti-tumor agent is administered subsequent to administration of the PDE1 inhibitor.

[0078] 2.8 Any of the above methods, wherein the PDE1 inhibitor, and optionally the anti-tumor agent, are administered in conjunction with radiation therapy or chemotherapy.

[0079] 2.9 Any of the above methods wherein the PDE1 inhibitor, and optionally the anti-tumor agent, are administered simultaneously with radiation therapy or chemotherapy.

[0080] 2.10 Any of the above methods, wherein the PDE1 inhibitor, and optionally the anti-tumor agent, are administered prior to radiation therapy or chemotherapy.

[0081] 2.11 Any of the above methods, wherein the PDE1 inhibitor, and optionally the anti-tumor agent, are administered after radiation therapy or chemotherapy.

[0082] 2.12 Any of the above methods wherein the PDE1 inhibitor is administered in combination with an anti-tumor agent, a chemotherapeutic agent, a gene therapy agent and / or an immunological therapy.

[0083] 2.13 Any of the above methods wherein the PDE1 inhibitor is administered in combination with an anti-tumor agent, a chemotherapeutic agent, a gene therapy agent, an immunological therapy, a corticosteroid, and / or an antihistamine.

[0084] 2.14 Any of the above methods, wherein the expression of cancerous or neoplastic cells in the colon is mediated by a PDE.

[0085] 2.15 Any of the above methods, wherein the cancerous or neoplastic cells in the colon are mediated by PDE1.

[0086] 2.16 Any of the above methods, wherein the cancerous or neoplastic cells in the colon are mediated by PDE1C.

[0087] 2.17 Any of the above methods further comprising the step of assessing the subject's degree of calcium / calmodulin sensitivity in expressed PDE1, restoration of cyclic nucleotide levels, RNA expression of PDE1, or mutations in the PDE1 gene.

[0088] 2.18 Any of the above methods, wherein the subject is a human.

[0089] The disclosure further provides PDE1 inhibitors for use in methods for inhibiting the proliferation, migration and / or invasion of cancerous or neoplastic cells, eg, for use in any of methods 2 et seq.

[0090] The disclosure further provides the use of a PDE1 inhibitor in the manufacture of a medicament for use in a method of inhibiting cancerous or neoplastic cell proliferation, migration and / or invasion, such as a medicament for use in any of methods 2 et seq.

[0091] The present invention further provides pharmaceutical compositions for use in any of Methods 2 and subsequent methods, comprising a PDE1 inhibitor, e.g., any of the compounds represented by Formulas I, Ia, II, III, IV, V, VI and / or VII.

[0092] In another embodiment, the present application provides a method for treating a condition selected from cancer or tumor cancer, the method comprising administering to a subject in need of such treatment a pharma- ceutically acceptable amount of a PDE1 inhibitor (i.e., a PDE1 inhibitor according to Formula I, Ia, II, III, IV, V, VI and / or VII) and a checkpoint inhibitor (Method 3).

[0093] 3.1 Method 3, wherein the cancer is colon cancer.

[0094] 3.2 Any of the above methods, wherein the cancer is colorectal cancer.

[0095] 3.3 Any of the above methods wherein the PDE1 inhibitor and checkpoint inhibitor are administered in conjunction with radiation therapy or chemotherapy.

[0096] 3.4 Any of the above methods wherein the PDE1 inhibitor and checkpoint inhibitor are administered concurrently with radiation therapy or chemotherapy.

[0097] 3.5 Any of the above methods, wherein the PDE1 inhibitor and checkpoint inhibitor are administered prior to radiation therapy or chemotherapy.

[0098] 3.6 Any of the above methods, wherein the PDE1 inhibitor and checkpoint inhibitor are administered following radiation therapy or chemotherapy.

[0099] 3.7 Any of the above methods wherein the PDE1 inhibitor and checkpoint inhibitor are administered in combination with an anti-tumor agent, a chemotherapeutic agent, a gene therapy agent and / or an immunological therapy.

[0100] 3.8 Any of the above methods, wherein administration of a PDE1 inhibitor is effective to induce one or more of apoptotic cell death, inhibition of migration, inhibition of metastasis, and / or reduction of inflammation in colon cancer.

[0101] 3.9 Any of the above methods wherein the PDE1 inhibitor is administered in combination with an anti-tumor agent, a chemotherapeutic agent, a gene therapy agent, an immunological therapy, a corticosteroid, and / or an antihistamine.

[0102] 3.10 Any of the above methods, wherein the colon cancer is mediated by a PDE.

[0103] 3.11 Any of the above methods, wherein the colon cancer is mediated by PDE1.

[0104] 3.12 Any of the above methods, wherein the colon cancer is mediated by PDE1C.

[0105] 3.13 Any of the above methods, wherein the checkpoint inhibitor is an inhibitor of CTLA-4, PD-1 and / or PD-L1.

[0106] 3.14 Any of the above methods wherein the checkpoint inhibitor is selected from nivolumab, pembrolizumab, cemiplimab, ipilimumab, avelumab, durvalumab, atezolizumab, spartalizumab, or combinations thereof.

[0107] 3.15 Any of the above methods, wherein the colon cancer is characterized by a loss of calcium / calmodulin regulation.

[0108] 3.16 Any of the above methods, wherein the subject is a human.

[0109] 3.17 Any of the above methods, wherein the PDE1 inhibitor is administered in an amount sufficient to reduce infiltration of monocytes and / or macrophages into the tumor-associated microenvironment.

[0110] 3.18 PDE1 inhibitors and checkpoint inhibitors may be used to reduce the infiltration of monocytes and / or macrophages into the tumor-associated microenvironment and / or to inhibit the infiltration of natural killer cells and CD4+ 4+ T cells (i.e., TNFα-producing CD4 4+ Any of the above methods, wherein the antibody or antibody fragment is administered together in an amount sufficient to increase infiltration of the antibody or antibody fragment (e.g., T cells) into a tumor-associated microenvironment.

[0111] 3.19 Any of the above methods, wherein the PDE1 inhibitor is administered in an amount of about 1-1000 mg / kg, such as about 250-750 mg / kg, such as about 400-600 mg / kg, for example about 500 mg / kg.

[0112] The disclosure further provides PDE1 inhibitors for use in methods for inhibiting the proliferation, migration and / or invasion of cancerous or neoplastic cells, such as for use in any of methods 3 et seq.

[0113] The disclosure further provides the use of a PDE1 inhibitor in the manufacture of a medicament for use in a method of inhibiting cancerous or neoplastic cell proliferation, migration and / or invasion, such as a medicament for use in any of methods 3 or later.

[0114] The present invention further provides pharmaceutical compositions for use in any of Methods 3 and subsequent thereto, comprising a PDE1 inhibitor, e.g., any of the compounds represented by Formulas I, Ia, II, III, IV, V, VI and / or VII.

[0115] In some embodiments, the pharmaceutical compositions are administered in combination with one or more anti-tumor agents, such as drugs known to be effective in treating or eliminating various types of cancers and / or tumors. Non-limiting examples of antineoplastic agents are: Abemaciclib, Abiraterone acetate, Abitrexate (methotrexate), Abraxane (paclitaxel albumin stabilized nanoparticle formulation), ABVD, ABVE, ABVE-PC, AC, acalabrutinib, AC-T, Adcetris (brentuximab vedotin), ADE, Ado-trastuzumab emtansine, Adriamycin (doxorubicin hydrochloride), afatinib dimaleate, Afinitor (everolimus), Akynzeo (netupitant / palonosetron hydrochloride), Aldara (imiquimod), aldesleukin, Alecensa (alectinib), alectinib, alemtuzumab. , Alimta (pemetrexed disodium), Aliqopa (copanlisib hydrochloride), Alkeran for injection (melphalan hydrochloride), Alkeran tablets (melphalan), Aloxi (palonosetron hydrochloride), Alumbrig (brigutinib), Ambochlorin (chlorambucil), Amifostine, Aminolevulinic acid, Anastrozole, Aprepitant, Aredia, Pamidronate disodium), Arimidex (anastrozole), Aromasin (exemestane), Alanongy (nelarabine), Arsenic trioxide, Arzerra (ofatumumab), Blackleg asparaginase Erwinia chrysanthemi), Atezolizumab, Avastin (bevacizumab), Avelumab, Axicabtagene ciloleucel, Axitinib, Azacitidine, Bavencio (avelumab), BEACOPP, Becenum (carmustine), Beleodak (belinostat), Belinostat, Bendamustine hydrochloride, BEP, Besponsa (inotuzumab ozogamicin), Bevacizumab, Bexarotene, Bicalutamide, BiCNU (carmustine), Bleomycin, Blincyto (blinatumomab), Bortezomib,Bosulif (bosutinib), bosutinib, brentuximab vedotin, brigutinib, BuMel, busulfan, Busulfex (busulfan), cabazitaxel, Cabometyx (cabozantinib S-malate), cabozantinib S-malate, CAF, Calquence (acalabrutinib), Campath (alemtuzumab), Camptosar (irinotecan hydrochloride), capecitabine, CAPOX, Carac (fluorouracil-topical), carboplatin, carboplatin-taxol, carfilzomib, Carmubris (carmustine), carmustine, carmustine implant, Casodex (bicalutamide), CEM, ceritinib, Cervizin (daunorubicin hydrochloride), Cervarix (recombinant HPV bivalent vaccine), cetuximab, CEV, chlorambucil, chlorambucil-prednisone, CHOP, cisplatin, cladribine, Clafen (cyclophosphamide), clofarabine, Clofarex (clofarabine), Clolar (clofarabine), CM F, cobimetinib, Cometriq (cabozantinib S-malate), copanlisib hydrochloride, COPDAC, COPP, COPP-ABV, Cosmegen (dactinomycin), Cotellic (cobimetinib), crizotinib, CVP, cyclophosphamide, Cyfos (ifosfamide), Cyramza (ramucirumab), cytarabine, cytarabine liposomal, Cytosar-U (cytarabine), Cytoxan (cyclophosphamide), dabrafenib, dacarbazine, Dacogen )(decitabine), dactinomycin, daratumumab, Darzalex (daratumumab), dasatinib, daunorubicin hydrochloride, daunorubicin hydrochloride-cytarabine liposome, decitabine, defibrotide sodium, Defitelio (defibrotide sodium), degarelix, denileukin diftitox, denosumab, Depocyto (cytarabine liposome), dexamethasone, dexrazoxane hydrochloride, dinutuximab, docetaxel, Doxil (doxorubicin hydrochloride liposome), doxorubicin hydrochloride, doxorubicin hydrochloride liposome,Dox-SL (doxorubicin hydrochloride liposomal), DTIC-Dome (dacarbazine), durvalumab, Efudex (fluorouracil-topical), Elitek (rasburicase), Ellence (epirubicin hydrochloride), elotuzumab, Eloxatin (oxaliplatin), eltrombopag olamine, Emend (aprepitant), Empliciti (elotuzumab), enasidenib mesylate, enzalutamide, epirubicin hydrochloride, EPOCH, Erbitux (cetuximab), eribulin mesylate, Erivedge (vismodegib), erlotinib hydrochloride, Erwinase (Asparaginase Erwinia chrysanthemi), Ethiol (amifostine), Etopophos (etoposide phosphate), etoposide, etoposide phosphate, Evacet (doxorubicin hydrochloride liposomal), everolimus, Evista (raloxifene hydrochloride), Evomela (melphalan hydrochloride), exemestane, 5-FU (fluorouracil injection), 5-FU (fluorouracil topical), Fairston (toremifene), Faridak (panobinostat), Faslodex (fulvestrant), FEC, Femara (letrozole), filgrastim, Fludara (fludarabine phosphate), fludarabine phosphate, Fluoroprex lex) (fluorouracil-topical), fluorouracil injection, fluorouracil-topical, flutamide, Folex (methotrexate), Folex PFS (methotrexate), Folfiri, Folfiri-bevacizumab, Folfiri-cetuximab, Folfirinox, Folotin (pralatrexate), FU-LV, fulvestrant, Gardasil (recombinant HPV quadrivalent vaccine), Gardasil 9 (recombinant HPV nonavalent vaccine), Gazyva (obinutuzumab), gefitinib, gemcitabine hydrochloride, gemcitabine-cisplatin, gemcitabine-oxaliplatin, gemtuzumab ozogamicin, Gemzar (gemcitabine hydrochloride),Gilotrif (afatinib dimaleate), Glivec (imatinib mesylate), Gliadel (carmustine implant), Gliadel wafer (carmustine implant), glucarpidase, goserelin acetate, Halaven (eribulin mesylate), Hemandiol (propranolol hydrochloride), Herceptin (trastuzumab), recombinant HPV bivalent vaccine, recombinant HPV nonavalent vaccine, recombinant HPV quadrivalent vaccine, Hycamtin (topotecan hydrochloride), Hydrea (hydroxyurea), hydroxyurea, Hyper-CVAD , Ibrance (palbociclib), ibritumomab tiuxetan, ibrutinib, ICE, Iclusig (ponatinib hydrochloride), Idamycin (idarubicin hydrochloride), idarubicin hydrochloride, idelalisib, Idhifa (enasidenib mesylate), Ifex (ifosfamide), ifosfamide, Ifosfamidum (ifosfamide), IL-2 (aldesleukin), imatinib mesylate, Imbruvica (ibrutinib), Imfinzi (durvalumab), imiquimod, Im Imlygic (talimogene laherparepvec), Inlyta (axitinib), inotuzumab ozogamicin, recombinant interferon alpha 2b, interleukin 2 (aldesleukin), Intron A (recombinant interferon alpha 2b), ipilimumab, Iressa (gefitinib), irinotecan hydrochloride, irinotecan hydrochloride liposomal, Istodax (romidepsin), ixabepilone, ixazomib citrate, Ixempra (ixabepilone), Jakafi (ruxolitinib), JEB, Jevtana (cabazitaxel), Kadcyla (Ado-trastuzumab emtansine), Keoxifene (raloxifene hydrochloride), Kepivance (palifermin), Keytruda (pembrolizumab), Kisqali (ribociclib), Kymriah (tisagenlecleucel), Kyprolis (carfilzomib), lanreotide acetate, lapatinib ditosylate, Lartruvo (olaratumab), lenalidomide, lenvatinib mesylate, Lenvima (lenvatinib mesylate), letrozole,Leucovorin calcium, Leukeran (chlorambucil), leuprolide acetate, Leystatin (cladribine), Levulan (aminolevulinic acid), Linfolizin (chlorambucil), LipoDox (liposomal doxorubicin hydrochloride), Lomustine, Lonsurf (trifluridine-tipiracil hydrochloride), Lupron (leuprolide acetate), Leupron Depot (leuprolide acetate), Leupron Depot Ped (leuprolide acetate), Lynparza (olaparib), Malki Marqibo (Vincristine Sulfate Liposomal), Matulane (Procarbazine Hydrochloride), Mechlorethamine Hydrochloride, Megestrol Acetate, Mekinist (Trametinib), Melphalan, Melphalan Hydrochloride, Mercaptopurine, Mesna, Mesnex (Mesna), Methazolastone (Temozolomide), Methotrexate, Methotrexate LPF (Methotrexate), Methylnaltrexone Bromide, Mexate (Methotrexate), Mexar Mexate-AQ (methotrexate), Midostaurin, Mitomycin C, Mitoxantrone hydrochloride, Mitozytrex (mitomycin C), MOPP, Mozovir (plelixafor), Mustargen (mechlorethamine hydrochloride), Mutamycin (mitomycin C), Myleran (busulfan), Mylosar (azacitidine), Mylotarg (gemtuzumab ozogamicin), Nanoparticle Paclitaxel (paclitaxel albumin stabilized nanoparticles) formulations), Navelbine (vinorelbine tartrate), necitumumab, nelarabine, Neosar (cyclophosphamide), neratinib maleate, Nerlynx (neratinib maleate), netupitant / palonosetron hydrochloride, Neulasta (pegfilgrastim), Neupogen (filgrastim), Nexavar (sorafenib tosylate), Nilandron (nilutamide), nilotinib, nilutamide, Ninlaro (ixazomib citrate), niraparibut tosylate monohydrate,Nivolumab, Nolvadex (tamoxifen citrate), Nplate (romiplostim), Obinutuzumab, Odomzo (sonidegib), OEPA, Ofatumumab, OFF, Olaparib, Olaratumab, Omacetaxine Mepesuccinate, Oncaspar (Pegaspagase), Ondansetron hydrochloride, Onivyde (Irinotecan hydrochloride liposomal), On Ontak (denileukin diftitox), Opdivo (nivolumab), OPPA, osimertinib, oxaliplatin, paclitaxel, paclitaxel albumin-stabilized nanoparticle formulation, PAD, palbociclib, palifermin, palonosetron hydrochloride, palonosetron hydrochloride-netupitant, pamidronate disodium, panitumumab, panobinostat, Paraplat (carboplatin), Paraplatin (carbo, Platin), pazopanib hydrochloride, PCV, PEB, pegaspargase, pegfilgrastim, peginterferon alpha 2b, PEG-Intron (peginterferon alpha 2b), pembrolizumab, pemetrexed disodium, Perjeta (pertuzumab), pertuzumab, Platinol (cisplatin), Platinol-AQ (cisplatin), plerixafor, pomalidomide, Pomalyst ( pomalidomide), ponatinib hydrochloride, Portrazza (necitumumab), pralatrexate, prednisone, procarbazine hydrochloride, Proleukin (aldesleukin), Prolia (denosumab), Promacta (eltrombopag olamine), propranolol hydrochloride, Provenzi (sipuleucel-T), Purinethol (mercaptopurine), Purixan (methacin), rucaptopurine), radium 223 chloride, raloxifene hydrochloride, ramucirumab, rasburicase, R-CHOP, R-CVP, recombinant human papillomavirus (HPV) bivalent vaccine, recombinant human papillomavirus (HPV) nonavalent vaccine, recombinant human papillomavirus (HPV) quadrivalent vaccine, recombinant interferon alpha 2b, regorafenib, relistol (methylnaltrexone bromide), R-EPOCH, revra rimidin (lenalidomide), rhumatrex (methotrexate), ribociclib, R-ICE, rituxan (rituximab), rituxan-hycera (rituximab-human hyaluronidase), rituximab, rituximab-human hyaluronidase, rolapitant hydrochloride, romidepsin, romiplostim, rubidomycin (daunorubicin hydrochloride), rubraca (rucaparib camsylate Camsylate), Rucaparib Camsylate, Ruxolitinib Phosphate, Rydapt (Midostaurin), Sclerosol Intrapleural Aerosol (Talc), Siltuximab, Sipuleucel-T, Somatuline Depot (Lanreotide Acetate), Sonidegib, Sorafenib Tosylate, Sprycel (Dasatinib), STANFORDV, Sterile Talc Powder (Talc), Steritalc (Talc), Stivarga (Regorafenib), Sunitinib Malate, Sutent (Sunitinib Malate), Sylatron (Peginterferon alpha 2b), Sylvant (Siltuximab), Synribo (Omacetaxine Mepesuccinate), Tabloid (Thioguanine), TAC, Tafinlar (Dabrafenib), Tagrisso (Osimertinib), Talc, Talimogene Laherparepvec, Tamoxifen Citrate, Tarabine PFS PFS) (cytarabine), Tarceva (erlotinib hydrochloride), Targretin (bexarotene), Tasigna (nilotinib), Taxol (paclitaxel), Taxotere (docetaxel), Tecentriq (atezolizumab), Temodar (temozolomide), temozolomide, temsirolimus, thalidomide, Thalomid (thalidomide), Thioguanine, thiotepa, tisagenlecleucel, Tolak (fluorouracil - topical), topotecan hydrochloride, toremifene, Torisel (temsirolimus), Totect (dexrazoxane hydrochloride), TPF, trabectedin, trametinib, trastuzumab, Treanda (bendamustine hydrochloride), trifluridine-tipiracil hydrochloride, Trisenoc (arsenic trioxide), Tykerb (lapatinib ditosylate), Unituxin (dinutuximab), Uridine triacetate, VAC, Valrubicin, Valstar (valrubicin), vandetanib, VAMP, Varubi (rolapitant hydrochloride), Vectibix (panitumumab), VeIP, Velban (vinblastine sulfate), Velcade (bortezomib), Velsar (vinblastine sulfate), Vemurafenib, Veneclexta (venetoclax), Venetoclax, Verzenio (abemaciclib), Viadur (leuprolide acetate), Vidaza (azacitidine), vinblastine sulfate, Vincasar PFSPFS) (vincristine sulfate), vincristine sulfate, vincristine sulfate liposomal, vinorelbine tartrate, VIP, vismodegib, Vistogard (uridine triacetate), Voraxaze (glucarpidase), vorinostat, Votrient (pazopanib hydrochloride), Vixeos (daunorubicin hydrochloride-cytarabine liposomal), Wellcovorin (leucovorin calcium), Xalkori (crizotinib), Xeloda (capecitabine), XELIRI, XELOX, Xgeva (denosumab), Xofigo (radium-223 chloride), Xtandi (enzalutamide), Yervoy ( Ipilimumab), Yescarta (Axicabtagene ciloleucel), Yondelis (Trabectedin), Zaltrap (Ziv-aflibercept), Zarxio (Filgrastim), Zejula (Niraparibut tosilate monohydrate), Zelboraf (Vemurafenib), Zevalin (Ibritumomab tiuxetan), Zinecard (Dexrazoxane hydrochloride), Ziv-aflibercept, Zofran (Ondansetron hydrochloride), Zoladex (Goserelin acetate), Zoledronic acid, Zolinza (Vorinostat), Zometa (Zoledronic acid), Zydelig (Idelalisib), Zykadia (Ceritinib), Zytiga (Abiraterone acetate).

[0116] As used herein, the term "anti-tumor agent" is understood to refer to a chemical agent or drug that is effective in preventing or inhibiting the formation or growth of cancer or tumors. Anti-tumor agents discussed herein may include alkylating agents, antimetabolites, natural products, hormones, and / or antibodies. Treating tumors or cancer may include limiting the proliferation, migration, and / or invasion of cancerous or neoplastic cells in the body, or limiting symptoms associated with said cancer or tumor. As used herein, anti-tumor agents are understood to include anti-cancer agents, or otherwise synonymous.

[0117] Methods for producing the disclosed compounds The disclosed PDE1 inhibitors and pharma- ceutically acceptable salts thereof are disclosed in U.S. Pat. No. 8,273,750, U.S. Patent Application Publication No. 2006 / 0173878, U.S. Pat. No. 8,273,751, U.S. Patent Application Publication No. 2010 / 0273753, U.S. Pat. No. 8,697,710, U.S. Pat. No. 8,664,207, U.S. Pat. No. 8,633,180, U.S. Pat. No. 8,536,159, U.S. Patent Application Publication No. 2012 / 0136013, U.S. Patent Application Publication No. 2011 US Patent Publication No. 2013 / 0281832, US Patent Publication No. 2013 / 0085123, US Patent Publication No. 2013 / 0324565, US Patent Publication No. 2013 / 0338124, US Patent Publication No. 2013 / 0331363, WO 2012 / 171016, and WO 2013 / 192556, or by methods known in the chemical arts. Such methods include, but are not limited to, the following methods. The starting materials for these processes, if not commercially available, can be prepared by procedures selected from chemical techniques using techniques similar or similar to those used for the synthesis of known compounds.

[0118] Various PDE1 inhibitors and starting materials therefor are disclosed in U.S. Patent Application Publication No. 2008-0188492 (A1), U.S. Patent Application Publication No. 2010-0173878 (A1), U.S. Patent Application Publication No. 2010-0273754 (A1), U.S. Patent Application Publication No. 2010-0273753 (A1), WO 2010 / 065153, WO 2010 / 065151, WO 2010 / 065152, WO 2010 / 065153, WO 2010 / 065154, WO 2010 / 065155, WO 2010 / 065156, WO 2010 / 065157, WO 2010 / 065158, WO 2010 / 065159 ... The compounds can be prepared using the methods described in WO 2010 / 065151, WO 2010 / 065149, WO 2010 / 065147, WO 2010 / 065152, WO 2011 / 153129, WO 2011 / 133224, WO 2011 / 153135, WO 2011 / 153136, WO 2011 / 153138. All references cited herein are incorporated by reference in their entirety.

[0119] Further PDE1 inhibitors and related methods are disclosed in U.S. Provisional Application No. 62 / 833,481, which is incorporated herein by reference in its entirety. Further related PDE1 inhibitors and related methods are disclosed in WO 2018 / 049417, which is incorporated herein by reference in its entirety.

[0120] The disclosed compounds include their enantiomers, diastereomers and racemates, as well as their polymorphs, hydrates, solvates and complexes.Some individual compounds within the scope of the disclosure may contain double bonds.The expression of double bonds in the disclosure is meant to include both the E and Z isomers of the double bond.In addition, some compounds within the scope of the disclosure may contain one or more asymmetric centers.The disclosure includes the use of any of the optically pure stereoisomers, and combinations of stereoisomers.

[0121] It is also intended that the disclosed compounds encompass their stable and unstable isotopes. Stable isotopes are non-radioactive isotopes that contain one additional neutron compared to the abundant nuclide of the same species (i.e., element). The activity of compounds containing such isotopes is retained, and such compounds are also believed to have utility for measuring the pharmacokinetics of non-isotopic analogs. For example, hydrogen atoms at certain positions of the disclosed compounds can be replaced with deuterium (a non-radioactive stable isotope). Examples of known stable isotopes include deuterium, 13 C. 15 N, 18 Alternatively, unstable isotopes, which are radioisotopes that contain additional neutrons compared to the abundant nuclide of the same species (i.e., element), e.g. 123 I, 131 I, 125 I, 11 C. 18 F may be replaced by the corresponding abundant species of I, C, and F. Another example of a useful isotope of the compounds of the present disclosure is: 11C isotope. These radioisotopes are useful for radioimaging and / or pharmacokinetic studies of the compounds of the present disclosure.

[0122] Melting points are uncorrected and (dec) indicates decomposition. Temperatures are given in degrees Celsius (°C); unless otherwise stated, operations are performed at room or ambient temperature, i.e., at temperatures in the range of 18-25°C. Chromatography means silica gel flash chromatography; thin layer chromatography (TLC) is performed on silica gel plates. NMR data are given in delta values ​​of major diagnostic protons expressed in parts per million (ppm) relative to tetramethylsilane (TMS) as internal standard. Conventional abbreviations for signal shapes are used. Coupling constants (J) are expressed in Hz. For mass spectra (MS), the major ion of smallest mass is reported for molecules where isotopic splitting gives rise to multiple mass spectral peaks. Compositions of solvent mixtures are given as volume percentages or volume ratios. In cases where the NMR spectra are complex, only characteristic signals are reported.

[0123] The terms "treatment" and "treating" should be understood to include treatment or amelioration of symptoms of disease as well as treatment of the cause of disease, as appropriate.

[0124] With respect to treatment methods, the term "effective amount" is intended to encompass a therapeutically effective amount for treating a particular disease or disorder.

[0125] The term "patient" includes a human patient or a non-human (i.e., animal) patient. In certain embodiments, the disclosure includes both humans and non-humans. In other embodiments, the disclosure includes non-humans. In other embodiments, the term includes humans.

[0126] The term "comprising" is used in this disclosure to be intended to be open-ended and does not exclude additional, unrecited elements or method steps.

[0127] Dosages used in practicing the present disclosure will of course vary depending, for example, on the particular disease or condition being treated, the particular disclosed compound being used, the mode of administration, and the desired therapy. The disclosed compounds may be administered by any suitable route, including orally, parenterally, transdermally, or by inhalation, but are preferably administered orally. In general, satisfactory results, for example for the treatment of diseases such as those mentioned above, have been shown to be obtained by oral administration at doses on the order of about 0.01 to 2.0 mg / kg. In larger mammals, such as humans, the doses will therefore range from about 0.50 to 300 mg, conveniently administered once a day or in divided doses two to four times a day, or in sustained release dosage form. Thus, a unit dosage form for oral administration may contain, for example, about 0.2 to 150 or 300 mg, for example about 0.2 or 2.0 to 10, 25, 50, 75, 100, 150 or 200 mg, of the disclosed compound together with a pharma- ceutically acceptable diluent or carrier.

[0128] In particular, the disclosed compounds for use or administration in any of the methods 1 and subsequent or 2 and subsequent may be administered in high doses as necessary to treat cancer or tumors, such as colorectal cancer. It is contemplated that the administration of PDE1 inhibitors for such methods may be in the range of about 50 mg to 1000 mg per day. For example, a patient being administered a PDE1 inhibitor for a condition according to any of Methods 1 et seq. through 6 et seq. may be administered a PDE1 inhibitor according to Formula I, Ia, II, III, IV, V, VI and / or VII in an amount of 50 mg to 1000 mg per day, 50 mg to 900 mg per day, 50 mg to 800 mg per day, 50 mg to 700 mg per day, 50 mg to 600 mg per day, 50 mg to 500 mg per day, 50 mg to 400 mg per day, 50 mg to 350 mg per day, 50 mg to 300 mg per day, 50 mg to 250 mg per day, 50 mg to 200 mg per day, 50 mg to 150 mg per day or 50 mg to 100 mg per day.

[0129] The disclosed compounds can be administered by any suitable route, including orally, parenterally (intravenously, intramuscularly or subcutaneously) or transdermally, but are preferably administered orally. In certain embodiments, the disclosed compounds, for example in depot formulations, are preferably administered parenterally, for example by injection.

[0130] The disclosed compounds and pharmaceutical compositions can be used in conjunction with one or more additional therapeutic agents, particularly at lower doses than when the individual agents are used as monotherapy, to enhance the therapeutic activity of the combined agents without causing the undesirable side effects that typically occur with conventional monotherapy. Thus, the disclosed compounds can be administered simultaneously, separately, sequentially, or contemporaneously with other agents useful for treating diseases. In another example, side effects can be reduced or minimized by administering the disclosed compounds in combination with one or more additional therapeutic agents in free or salt form, where (i) the dose of the second therapeutic agent or (ii) the dose of both the disclosed compounds and the second therapeutic agent is lower than when the agents / compounds are administered as monotherapy. Such additional therapeutic agents can include, by way of non-limiting example, ACE inhibitors, angiotensin II receptor antagonists, calcium channel blockers, and the like.

[0131] The term "concurrently" when referring to therapeutic use means that two or more active ingredients are administered at the same time or at about the same time and by the same route of administration.

[0132] The term "separately" when referring to therapeutic use means that two or more active ingredients are administered simultaneously or at about the same time by different routes of administration.

[0133] Pharmaceutical compositions containing the disclosed compounds can be prepared using conventional diluents or excipients and techniques known in the galenic art. Thus, oral dosage forms can include tablets, capsules, solutions, suspensions, etc. EXAMPLES

[0134] Example 1: Determination of the ability of PDE1 inhibitors to inhibit the growth of mouse colon carcinomas. An aliquot of cancerous cells is injected into the subscapular space of BALB / C mice to induce colon carcinoma. Tumors are allowed to grow for 7 days, at which time tumor volume is measured. Once tumors are formed, drug treatment is initiated (Compound 1 50 mg / kg, once daily ip in 0.5% methylcellulose vehicle) and tumor growth is observed and recorded daily. Compound 1 is shown below: [ka]

[0135] Mice are sacrificed 30 days after injection and tumors are isolated from the mice. As shown in Figure 1, compound 1 significantly delayed tumor growth in CT26 cell samples after 30 days.

[0136] Tumors are then enzymatically dissociated into single cell suspensions, stained with fluorophore-labeled antibodies, and analyzed by flow cytometry. Cells were sorted and analyzed for immune markers. As shown in Figure 2, treatment with compound 1 resulted in a significant increase in monocytes and CD8 T cells, while a significant decrease in the presence of macrophages in the tumor microenvironment was observed. Without being bound by theory, it is believed that PDE1 inhibitors have the ability to modulate immune function in the tumor microenvironment, one way of doing this is by reducing tumor infiltration by macrophages. This would then enable the innate immune system to target tumor cells more efficiently, which is consistent with the results observed here (i.e., increased activation of T cells in the tumor microenvironment).

[0137] Example 2: Analysis of co-administration of PDE1 inhibitors and checkpoint inhibitors to inhibit mouse cancer growth The effect of Compound 1 alone or in combination with a sub-effective dose of a checkpoint inhibitor, anti-PD-1, was evaluated on the growth of CT26 xenograft tumors in BALB / c mice. Treatment-naïve tumor-bearing mice (i.e., isotype groups) were compared to groups of mice receiving Compound 1 monotherapy as defined in Example 1, groups of mice receiving a sub-effective dose of a checkpoint inhibitor (anti-PD-1 antibody), and groups of mice receiving both Compound 1 and a sub-effective dose of an anti-PD-1 antibody.

[0138] BALB / c mice were injected subcutaneously with CT26 cells on day 0 and then divided into four groups on day 7: (1) compound 1 treatment (50 mg / kg, ip qd), 5 days / week; (2) isotype group, ip mlgG isotype on days 7, 10, and 14; (3) anti-PD-1 group, ip administration on days 7, 10, and 14; and (4) combination group, treated similarly to groups 1 and 3 with compound 1 and anti-PD-1. Tumor volumes were measured every 2 or 3 days. On days 17-18, tumors were excised, dissected, and used to make single cell suspensions. These tumor single cell suspensions were incubated with FACS blocker (eBioscience) and then stained with antibodies on ice in the dark. Samples were acquired on a FACSCalibur, LSRII or LSRII yellow (BD Biosciences) and analyzed with FlowJo (Tree Star).

[0139] In the isotype-treated group, 0 of 9 mice showed tumor clearance (i.e., tumors grew to 100 mm 3In the group treated with compound 1 and anti-PD-1, tumor volume was smaller than that in the control group, whereas 1 out of 5 mice in the group treated with compound 1 and 1 out of 10 mice in the group treated with anti-PD-1 showed tumor clearance. However, 7 out of 15 mice in the group treated with compound 1 and anti-PD-1 showed tumor clearance. At the end of the experiment, tumor weights were also measured. The results showed that tumor weights in mice treated with compound 1 and anti-PD-1 combination therapy were significantly less than those in the isotype-treated control group.

[0140] Fluorescence-activated cell sorting (FACS) of tumor-infiltrating immune cells revealed that tumors from compound 1 monotherapy-treated mice had significantly reduced numbers of CD45+ tumor-infiltrating macrophages and monocytes, and combination therapy of compound 1 and anti-PD-1 enhanced anti-tumor immunity by inducing increased numbers of CD45+ natural killer (NK) cells and TNFα-producing CD4 T cells. This result suggests that compound 1 alone can reduce tumor macrophages and enhance anti-PD-1 anti-tumor immunity.

[0141] Alternative combinations and variations of the examples provided will become apparent based on this disclosure, and while it is not possible to provide specific examples of all of the many possible variations of the described embodiments, such combinations and variations may ultimately fall within the scope of the claims at issue. The present application also includes the following aspects. [Aspect 1] A method for treating colon cancer, comprising administering to a subject in need of such treatment a pharma- ceutically acceptable amount of a PDE1 inhibitor. [Aspect 2] The method of embodiment 1, wherein the colon cancer is colorectal cancer. [Aspect 3] A method for inhibiting the proliferation, migration and / or invasion of cancerous or neoplastic cells in the colon, comprising administering to a subject in need of such inhibition a pharma- ceutically acceptable amount of a PDE1 inhibitor. [Aspect 4] The method of embodiment 3, wherein the subject is suffering from colon cancer. [Aspect 5] The method of embodiment 3 or 4, wherein the subject is suffering from colorectal cancer. [Aspect 6] PDE1 inhibitors (A) A compound of formula I, in free, salt or prodrug form, including enantiomers, diastereoisomers and racemates:

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Claims

1. A medicament for the treatment of colon cancer comprising a PDE1 inhibitor, the PDE1 inhibitor being (A) a compound of formula II, in free form or in pharma- ceutically acceptable salt form: 【Chemistry 1】 [In the formula, (i) X is methylene; (ii) Y is arylene; (iii) Z is aryl, pyridyl or -C(O)-R1; (iv) R 1 is C 1-6 alkyl or -OH; (v) R 4 is H and R 5 is aryl optionally substituted with halo; (vii) wherein Z is optionally substituted with halo; or (B) A compound of formula Ia, in free form or in pharma- ceutically acceptable salt form: 【Chemistry 2】 [In the formula, (i) R 2 and R 3 are each methyl, R 4 and R 5 are each H; (ii) R 6 is (optionally halo-substituted)phenylamino; (iii) R 10 is C 1-4 alkyl, methylcarbonyl, hydroxyethyl, carboxylic acid, (optionally halo-substituted)phenyl, (optionally halo-substituted)pyridyl; and (iv) X and Y are independently C or N. A pharmaceutical agent which is a compound selected from the group consisting of

2. The method of claim 1, wherein the colon cancer is colorectal cancer.

3. 1. A medicament for inhibiting the proliferation, migration and / or invasion of cancerous or neoplastic cells in the colon in a subject in need thereof comprising a PDE1 inhibitor, the PDE1 inhibitor being (A) a compound of formula II, in free form or in pharma- ceutically acceptable salt form: 【Chemistry 3】 [In the formula, (i) X is methylene; (ii) Y is arylene; (iii) Z is aryl, pyridyl or -C(O)-R1; (iv) R 1 is C 1-6 alkyl or -OH; (v) R 4 is H and R 5 is aryl optionally substituted with halo; (vii) wherein Z is optionally substituted with halo; or (B) A compound of formula Ia, in free form or in pharma- ceutically acceptable salt form: 【Chemistry 4】 [In the formula, (i) R 2 and R 3 are each methyl, R 4 and R 5 are each H; (ii) R 6 is (optionally halo-substituted)phenylamino; (iii) R 10 is C 1-4 alkyl, methylcarbonyl, hydroxyethyl, carboxylic acid, (optionally halo-substituted)phenyl, (optionally halo-substituted)pyridyl; and (iv) X and Y are independently C or N. A pharmaceutical agent which is a compound selected from the group consisting of

4. The pharmaceutical composition of claim 3, wherein the subject is suffering from colon cancer.

5. The pharmaceutical composition of claim 3 or 4, wherein the subject is suffering from colorectal cancer.

6. The PDE1 inhibitor is one of the following in free form or in pharma- ceutically acceptable salt form: 【Chemistry 5】 The pharmaceutical composition according to any one of claims 1 to 5, wherein the pharmaceutical composition is selected from any one of the following:

7. The method according to any one of claims 1 to 6, wherein the PDE1 inhibitor is administered in combination with an antitumor agent.

8. A pharmaceutical combination for the treatment of colon cancer comprising a PDE1 inhibitor and a checkpoint inhibitor, wherein the PDE1 inhibitor and the checkpoint inhibitor are administered simultaneously, separately, sequentially, or contemporaneously, and the PDE1 inhibitor is (A) a compound of formula II, in free form or in pharma- ceutically acceptable salt form: 【Chemistry 6】 [In the formula, (i) X is methylene; (ii) Y is arylene; (iii) Z is aryl, pyridyl or -C(O)-R1; (iv) R 1 is C 1-6 alkyl or -OH; (v) R 4 is H and R 5 is aryl optionally substituted with halo; (vii) wherein Z is optionally substituted with halo; or (B) A compound of formula Ia, in free form or in pharma- ceutically acceptable salt form: 【Chemistry 7】 [In the formula, (i) R 2 and R 3 are each methyl, R 4 and R 5 are each H; (ii) R 6 is (optionally halo-substituted)phenylamino; (iii) R 10 is C 1-4 alkyl, methylcarbonyl, hydroxyethyl, carboxylic acid, (optionally halo-substituted)phenyl, (optionally halo-substituted)pyridyl; and (iv) X and Y are independently C or N. A combination pharmaceutical, which is a compound selected from:

9. The combination pharmaceutical of claim 8, wherein the colon cancer is colorectal cancer.

10. The PDE1 inhibitor is one of the following in free form or in pharma- ceutically acceptable salt form: 【Chemistry 8】 The combination pharmaceutical according to claim 8 or 9, selected from any one of:

11. The pharmaceutical combination according to any one of claims 8 to 10, wherein the checkpoint inhibitor is an inhibitor of CTLA-4, PD-1 and / or PD-L1.

12. The combination pharmaceutical of any one of claims 8 to 11, wherein the checkpoint inhibitor is selected from nivolumab, pembrolizumab, cemiplimab, ipilimumab, avelumab, durvalumab, atezolizumab, spartalizumab, or a combination thereof.

13. The pharmaceutical combination according to any one of claims 8 to 12, wherein the PDE1 inhibitor is administered in an amount sufficient to reduce the infiltration of monocytes and / or macrophages into the tumor-associated microenvironment.

14. PDE1 inhibitors and checkpoint inhibitors may be used to reduce the infiltration of monocytes and / or macrophages into the tumor-associated microenvironment and / or to inhibit the infiltration of natural killer cells and CD4+ cells into the tumor-associated microenvironment. 4+ The pharmaceutical combination according to any one of claims 8 to 13, administered together in amounts sufficient to increase infiltration of T cells into the tumor-associated microenvironment.

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