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Belzutifan (Welireg, Merck & Co., Inc., Rahway, NJ, USA) is an oral, potent hypoxia‐inducible factor‐2α inhibitor, recently approved in the United States for the treatment of von Hippel–Lindau (VHL) disease‐associated renal cell carcinoma (RCC) and other VHL disease‐associated neoplasms. Safety and efficacy were investigated in two clinical studies: a Phase 1 dose escalation/expansion study in solid tumors and RCC and a Phase 2 study in VHL‐RCC. A population pharmacokinetic model was used to estimate belzutifan exposures to facilitate exposure–response (E‐R) analyses for efficacy and safety endpoints. Relationships between exposure and efficacy (overall response rate, disease control rate, progression‐free survival, best overall tumor size response, and other endpoints), safety outcomes (Grade ≥3 anemia, Grade ≥3 hypoxia, and time to first dose reduction/dose interruption), and pharmacodynamic biomarkers (erythropoietin [EPO] and hemoglobin [Hgb]) were evaluated using various regression techniques and time‐to‐event analyses. Efficacy E‐R was generally flat with non‐significant positive trends with exposure. The safety E‐R analyses demonstrated a lack of relationship for Grade ≥3 hypoxia and a positive relationship for Grade ≥3 anemia, with incidences also significantly dependent on baseline Hgb. Exposure‐dependent reductions in EPO and Hgb were observed. Based on the cumulative benefit–risk assessment in VHL disease‐associated neoplasms using E‐R, no a priori dose adjustment is recommended for any subpopulation. These analyses supported the benefit–risk profile of belzutifan 120 mg once daily dosing in patients with VHL‐RCC for labeling and the overall development program. [ABSTRACT FROM AUTHOR]

Camptothecin, a potent antineoplastic agent reversibly stabilizes a covalent enzyme-DNA intermediate formed by DNA topoisomerase I, and leads to G(sub 2) arrest and cell mortality. When ethyl methanesulfonate mutagenesis was carried out on yeast cells expressing plasmid borne wild-type DNA topoisomerase I, six dominant suppressors of camptothecin toxicity were shown to comprise a single genetic locus, SCT1. SCT1 cell sensitivity to other DNA-damaging agents suggests that changes in SCT1 function inhibit camptothecin-induced DNA damage caused in the vicinity of yeast DNA topoisomerase I.

1. Omarigliptin (MARIZEV®) is a once-weekly DPP-4 inhibitor approved in Japan for the treatment of type 2 diabetes. The objective of this study was to investigate the absorption, metabolism and excretion of omarigliptin in humans. 2. Six healthy subjects received a single oral dose of 25 mg (2.1 μCi) [14 C]omarigliptin. Blood, plasma, urine and fecal samples were collected at various intervals for up to 20 days post-dose. Radioactivity levels in excreta and plasma/blood samples were determined by accelerator mass spectrometry (AMS). 3. [14 C]Omarigliptin was rapidly absorbed, with peak plasma concentrations observed at 0.5-2 h post-dose. The majority of the radioactivity was recovered in urine (∼74.4% of the dose), with less recovered in feces (∼3.4%), suggesting the compound was well absorbed. 4. Omarigliptin was the major component in urine (∼89% of the urinary radioactivity), indicating renal excretion of the unchanged drug as the primary clearance mechanism. Omarigliptin accounted for almost all the circulating radioactivity in plasma, with no major metabolites detected. 5. The predominantly renal elimination pathway, combined with the fact that omarigliptin is not a substrate of key drug transporters, suggest omarigliptin is unlikely to be subject to pharmacokinetic drug-drug interactions with other commonly prescribed agents. [ABSTRACT FROM AUTHOR]

Aims/Introduction Omarigliptin is a novel, potent, long-acting oral dipeptidyl peptidase-4 inhibitor being developed as a once-weekly (q.w.) treatment for type 2 diabetes mellitus patients, with 25 mg and 12.5 mg tablets recently being approved as market formulations in Japan. Materials and Methods This was a two-part, double-blind, randomized, placebo-controlled study in healthy Japanese men to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of omarigliptin after single dose (5-100 mg) and multiple dose (1-50 mg q.w. for 3 weeks) administration. Results Omarigliptin was rapidly absorbed with a time to maximum concentration of 0.5-4 h. The pharmacokinetic profile was biphasic with a long terminal half-life >100 h. The area under the concentration-time curve from 0 to 168 h, maximum concentration and the concentration at 168 h post-dose increased dose-dependently after 3 weeks of once-weekly dosing for doses ranging 1-50 mg, with accumulation ratios ranging 1.03-1.35 and 0.87-1.36 for the area under the concentration-time curve from 0 to 168 h and maximum concentration, respectively. Plasma dipeptidyl peptidase-4 inhibition levels 1 week post-dose increased with dose, ranging 79.2-94.0% after 5-100 mg single dose administration and 51.3-90.2% after 1-50 mg multiple once-weekly dose administration. Administration with food did not meaningfully alter the pharmacokinetics of omarigliptin. Omarigliptin was generally well tolerated, with no hypoglycemia being reported. Conclusion The results of the present study in healthy Japanese men showed that omarigliptin was well tolerated and had a pharmacokinetic and dipeptidyl peptidase-4 inhibition profile that supports once-weekly dosing in Japanese patients with type 2 diabetes mellitus. [ABSTRACT FROM AUTHOR]