Tazemetostat (EPZ-6438) is a selective inhibitor of histone-lysine N-methyltransferase EZH2. The drug is under clinical development (phase II) for the treatment of Diffuse Large B Cell Lymphoma, Malignant Mesothelioma and Synovial Sarcoma.

Zanubrutinib (formerly known as BGB-3111) was developed by BeiGene as a small-molecule inhibitor of Bruton's tyrosine kinase (BTK). The drug forms a covalent bond with a cysteine residue in the BTK active site, leading to inhibition of BTK activity. BTK signaling results in activation of pathways necessary for B-cell proliferation, trafficking, chemotaxis, and adhesion, thus Zanubrutinib inhibits malignant B-cell proliferation and reduces tumor growth. Zanubrutinib was granted accelerated approval by the FDA in November 2019 based on clinical trial results that demonstrated an 84% overall response rate from zanubrutinib therapy in patients with mantle cell lymphoma (MCL). On August 31, 2021, the Food and Drug Administration approved zanubrutinib for adult patients with Waldenström’s macroglobulinemia (WM).

GSK126, a potent, highly selective, S-adenosyl-methionine-competitive, small-molecule inhibitor of EZH2 methyltransferase activity, decreases global H3K27me3 levels and reactivates silenced PRC2 target genes. GSK126 effectively inhibits the proliferation of EZH2 mutant DLBCL cell lines and markedly inhibits the growth of EZH2 mutant DLBCL xenografts in mice. Pharmacological inhibition of EZH2 activity may provide a promising treatment for EZH2 mutant lymphoma. EZH2 inactivation by GSK126 is also effective in killing MM cells and CSCs as a single agent or in combination with bortezomib. Clinical trial of GSK126 in patients with MM may be warranted. GSK126 is undergoing phase I trials for hypermethylation-related cancers. GSK126 is in phase I diffuse large B cell lymphoma and follicular lymphoma. GSK126 inhibits cell migration and angiogenesis in solid tumor cell lines through down-regulation of VEGF-A expression. Thus, it may be considered as a novel anticancer drug candidate for solid tumor.

CUDC-907 is a small molecule inhibitor of histone deacetylase and PI3 kinase developed by Curis. It is investigated in clinical trials for the treatment of relapsed or refractory lymphomas, thyroid cancer, multiple myeloma, breast cancer and other malignancies.

Vistusertib (AZ-2014) is a dual inhibitor of mTORC1/mTORC2 which was developed by AstraZeneca for the treatment of cancer. The drug is under clinical development (phase II) in patients with Renal Carcinoma, Squamous Non Small Cell Lung Cancer, Diffuse Large B-Cell Lymphoma, Meningioma, Breast cancer and Gastric cancer, either alone or in combination therapy. Vistusertib penetrates blood-brain barrier.

ABC-294640 is an orally bioavailable and selective sphingosine kinase-2 (SphK2) inhibitor with IC50 of approximately 60 uM. ABC-294640 inhibits SK2, a lipid kinase that catalyzes formation of the lipid signaling molecule sphingosine 1-phosphate (S1P). S1P promotes cancer growth, and proliferation and pathological inflammation, including TNFα signaling and other inflammatory cytokine production. Specifically, by inhibiting the SK2 enzyme, ABC-294640 blocks the synthesis of S1P which regulates fundamental biological processes such as cell proliferation, migration, immune cell trafficking and angiogenesis, and are also involved in immune-modulation and suppression of innate immune responses from T cells. Preliminary evidence suggests that because of its specificity for targeting SK2, rather than SK1, ABC-294640 may have a better therapeutic ratio than nonspecific sphingosine kinase inhibitors or those targeting only SK1. Oral administration of ABC-294640 to mice bearing mammary adenocarcinoma xenografts results in dose-dependent antitumor activity associated with depletion of S1P levels in the tumors and progressive tumor cell apoptosis. Therefore, this newly developed SK2 inhibitor provides an orally available drug candidate for the treatment of cancer and other diseases. ABC-294640 has completed multiple successful pre-clinical studies in inflammatory, GI, radioprotection and oncology models, as well as a Phase I clinical study in cancer patients with advanced solid tumors.

Sotrastaurin, an orally-active, first-in-class immunomodulator, is under development by Novartis for the treatment of uveal melanoma and diffuse-large B-cell lymphoma. Sotrastaurin is a low molecular mass synthetic compound that potently inhibits the PKC α, β and the θ isoforms resulting in selective NF-κB inactivation. Sotrastaurin is a potent and selective pan-PKC inhibitor, mostly for PKCθ with Ki of 0.22 nM in a cell-free assay. Inhibition of PKC beta in B-cells results in prevention of NF-kB-mediated signaling and down regulation of NF-kB target genes. This may eventually lead to an induction of G1 cell cycle arrest and tumor cell apoptosis in susceptible tumor cells. This agent may act synergistically with other chemotherapeutic agents. PKC, a family of serine/threonine protein kinases overexpressed in certain types of cancer cells, is involved in cell differentiation, mitogenesis, inflammation, and the activation and survival of lymphocytes. Sotrastaurin is currently in phase II trials by Novartis for the treatment of large B-cell lymphoma and uveal melanoma. Sotrastaurin was in Phase II of clinical development for the prevention of acute rejection after solid organ transplantation and psoriasis, but this reseach had being discontinued.

Enzastaurin is a serine/threonine kinase inhibitor that showed antiangiogenic, antiproliferative, and proapoptotic properties in vitro and antitumor activity in vivo in a xenograft Waldenström macroglobulinemia (WM) model. Enzastaurin (LY317615) is a potent PKCβ selective inhibitor. Enzastaurin suppresses angiogenesis and was advanced for clinical development based upon this antiangiogenic activity. Enzastaurin suppresses tumor growth through multiple mechanisms: direct suppression of tumor cell proliferation and the induction of tumor cell death coupled to the indirect effect of suppressing tumor-induced angiogenesis. Enzastaurin is an orally administered drug that was intended for the treatment of solid and haematological cancers. Enzastaurin had shown encouraging preclinical results for the prevention of angiogenesis, inhibition of proliferation and induction of apoptosis as well as showing limited cytotoxicity within phase I clinical trials. However, during its assessment in phase II and III clinical trials the efficacy of enzastaurin was poor both in combination with other drugs and as a single agent. Eli Lilly discontinued development of enzastaurin after top-line data from the double-blind, international Phase III PRELUDE trial in 758 DLBCL patients showed that enzastaurin missed the primary endpoint of improving DFS vs. placebo.

Threo-sphingosine, (-)- is a stereoisomer of naturally occurring D-erythro-sphingosine. It is a Protein kinase C inhibitor. Threo-sphingosine, (-)- is partly active in induction of apoptosis and inhibition of MAPK activity in different kinds of solid tumor cell lines. It can be phosphorylated by cells, but the resulting L-Threo-sphingosine 1-phosphate does not bind and activate sphingosine 1-phosphate receptors, excluding their role in Threo-sphingosine, (-)-induced growth inhibition. Cell culture experiments with Diffuse large B cell lymphoma cell lines that were incubated with Threo-sphingosine, (-)- manifested significant inhibition of cell growth, while incubation of cells with similar concentrations of sphingosine 1-phosphate was ineffective. These results suggest that Threo-sphingosine, (-)- accumulation could be an alternative treatment option for Diffuse large B cell lymphoma.

Pixantrone is a novel anthracenedione. It is a weak inhibitor of topoisomerase II. Pixantrone directly alkylates DNA forming stable DNA adducts and cross-strand breaks. Pixuvri is approved for the treatment of adult patients with multiply relapsed or refractory aggressive Non-Hodgkin lymphomas. It is used for patients whose cancer does not respond or has returned after they have received other chemotherapy treatments. The most frequent AE were seen in the blood (mainly neutropaenia), gastrointestinal (nausea, abdominal pain, constipation) and respiratory systems (cough, dyspnea). No drug-drug interaction studies have been submitted and no drug interactions have been reported in human subjects