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.

Lersivirine (UK-453,061) is a novel second-generation non-nucleoside reverse transcriptase inhibitor (NNRTI). It binds reverse transcriptase in a distinct way leading to a unique resistance profile. Lersivirine is a second-line NNRTI, which was investigated in a Phase IIb clinical trial. Lersivirine has shown encouraging virologic efficacy in a Phase IIa monotherapy study in NNRTI-naive patients. In a Phase IIb clinical trial in ART naive patients, clinical efficacy of lersivirine was compared with efavirenz, each administered together with tenofovir disoproxil fumarate/emtricitabine. After 48 weeks, lersivirine exhibited a slightly lower virologic response but similar immunologic efficacy. However, the trial was not powered for formal hypothesis testing of noninferiority of lersivirine. The development of lersivirine was recently stopped because the developing company determined that the compound would not provide an improvement over existing NNRTIs.

Fluorocyclopentenylcytosine (RX-3117) is a novel small molecule nucleoside compound that is incorporated into DNA or RNA of cancer cells and inhibits both DNA and RNA synthesis which induces apoptotic cell death of tumor cells. Fluorocyclopentenylcytosine also mediates the down-regulation of DNA methyltransferase 1 (DNMT1), an enzyme responsible for the methylation of cytosine residues on newly synthesized DNA and also a target for anticancer therapies. Preclinical studies have shown Fluorocyclopentenylcytosine to be effective in both inhibiting the growth of various human cancer xenograft models, including colon, lung, renal and pancreas, as well as overcoming chemotherapeutic drug resistance. Fluorocyclopentenylcytosine has demonstrated a broad spectrum anti-tumor activity against 50 different human cancer cell lines and efficacy in 12 different mouse xenograft models. The efficacy in the mouse xenograft models was superior to that of gemcitabine. In addition, in human cancer cell lines made resistant to the anti-tumor effects of gemcitabine, Fluorocyclopentenylcytosine still retains its full anti-tumor activity. In August 2012, Rexahn reported the completion of an exploratory Phase I clinical trial of Fluorocyclopentenylcytosine in cancer patients conducted in Europe, to investigate the oral bioavailability, safety and tolerability of the compound. In this study, oral administration of Fluorocyclopentenylcytosine demonstrated an oral bioavailability of 34-58% and a plasma half-life (T1/2) of 14 hours. In addition, Fluorocyclopentenylcytosine was safe and well tolerated in all subjects throughout the dose range tested. Fluorocyclopentenylcytosine is in phase I/II clinical trials by Rexahn for the treatment of bladder cancer and pancreatic cancer. This compound was granted Orphan Drug Designation by the U.S. Food and Drug Administration (FDA) for the treatment of patients with pancreatic cancer in September 2014.

Fevipiprant is a selective reversible antagonist of the prostaglandin D2 receptor (also known as CRTH2). It is currently in development for the treatment of allergic diseases.

Verinurad (RDEA3170) is a selective uric acid reabsorption inhibitor in clinical development for the treatment of gout and asymptomatic hyperuricemia. Verinurad specifically inhibits URAT1 with a potency of 25 nM. High affinity inhibition of uric acid transport requires URAT1 residues Cys-32, Ser-35, Phe-365 and Ile-481. Unlike other available uricosuric agents, the requirement for Cys-32 is unique to verinurad. Verinurad doses as low as 2.5 mg produce significant sUA lowering in humans, and this greater reduction in sUA may lead to improved outcomes and medical benefits for patients with gout. Verinurad in monotherapy studies has been associated with increased urinary uric acid concentrations and low rates of serum creatinine (sCr) elevation. Verinurad combined with febuxostat decreased sUA dose-dependently while maintaining uric acid excretion similar to baseline. All dose combinations of verinurad and febuxostat were generally well tolerated.