Seliciclib (CYC202, R-roscovitine) is a second-generation orally available cyclin-dependent kinases (CDKs) inhibitor that competes for ATP binding sites on these kinases. It is a direct inhibitor of cyclin CDK2/E, CDK2/A and it has inhibitory effects on cyclin H/CDK7, CDK5, and CDK9. CDKs are enzymes that are central to the process of cell division and cell cycle control and play pivotal roles in cancer cell growth and DNA damage repair. Seliciclib exerts an anti-proliferative effect via several key mechanisms: selective downregulation of proliferative and survival proteins and upregulation of p53, leading to growth arrest or apoptosis. The second one is decreasing phosphorylation of Rb and modulating E2F transcriptional activity leading to growth arrest or apoptosis. Seliciclib is currently in phase II clinical trial as a drug candidate for the treatment of Cushing's disease and as a potential therapeutic agent for the treatment of cystic fibrosis (CF). In addition, it is in Phase II trials for non-small cell lung cancer and nasopharyngeal carcinoma.

RGB-286638 is a multi-targeted protein kinase inhibitor currently in Phase 1 clinical testing. In vitro cell-free kinase assays indicated that RGB-286638 inhibits CDK1, 2, 3, 4, 5, and 9 and is less active against CDK6 and 7. The RGB-286638 compound has been shown to inhibit the processes controlling cell division in cancer cells by targeting multiple cyclin-dependent kinase proteins involved in regulating the cell cycle. RGB-286638 has also been shown to induce apoptosis (programmed cell death) and to inhibit other important protein kinases involved in the proliferation of cancer cells. RGB-286638 treatment results in tumor regression and increased survival in a number of pre-clinical models of solid and hematological tumors.

Dinaciclib (SCH 727965) is a small molecule inhibitor of cyclin-dependent kinases. Dinaciclib demostrates potent and selective inhibition of CDK2, CDK5, CDK1, and CDK9 activity. Dinaciclib inhibits cell cycle progression and proliferation in various tumor cell lines in vitro. Dinaciclib is a product of a drug discovery collaboration between Pharmacopeia (later Ligand Pharmaceuticals) and Schering-Plough (later Merck & Co.) that began in 1998. Dinaciclib showed promising effect in treating haematological malignancies and solid tumors.

PHA-690509 is an ATP-competitive CDK inhibitor developed at Nerviano Medical Sciences. PHA-690509 demonstrates antiviral activity against ZIKV.

(S)-Seliciclib is enantiomer of the potent cyclin-dependent kinase (CDK) inhibitor Roscovitine. Roscovitine (racemic mixture) is an inhibitor of cell cyclin-dependent kinase (CDK)-2, CDK-4 and CDK-5, which are upregulated in stress conditions inducing apoptosis. (S)-Seliciclib potently inhibits Cyclin-dependent kinase 1. In vivo studies in rabbits demonstrated that both isomers (R- and S-) significantly reduce intraocular pressure (IOP). However, S- isomer was superior to R- isomer in lowering IOP and providing protection to retinal ganglionic cells.

RGB-286638 is a multi-targeted protein kinase inhibitor currently in Phase 1 clinical testing. In vitro cell-free kinase assays indicated that RGB-286638 inhibits CDK1, 2, 3, 4, 5, and 9 and is less active against CDK6 and 7. The RGB-286638 compound has been shown to inhibit the processes controlling cell division in cancer cells by targeting multiple cyclin-dependent kinase proteins involved in regulating the cell cycle. RGB-286638 has also been shown to induce apoptosis (programmed cell death) and to inhibit other important protein kinases involved in the proliferation of cancer cells. RGB-286638 treatment results in tumor regression and increased survival in a number of pre-clinical models of solid and hematological tumors.