Population pharmacokinetic analyses for belzutifan to inform dosing considerations and labeling.

Belzutifan (Welireg, Merck & Co., Inc., Rahway, NJ, USA) is an oral, potent inhibitor of hypoxia-inducible factor 2α, approved for the treatment of certain patients with von Hippel-Lindau (VHL) disease-associated renal cell carcinoma (RCC), central nervous system hemangioblastomas, and pancreatic neuroendocrine tumors. It is primarily metabolized by the polymorphic uridine 5'-diphospho-glucuronosyltransferase (UGT) 2B17 and cytochrome (CYP) 2C19. A population pharmacokinetic (PK) model was built, using NONMEM version 7.3, based on demographics/PK data from three clinical pharmacology (food effect, formulation bridging, and genotype/race effect) and two clinical studies (phase I dose escalation/expansion in patients with RCC and other solid tumors; phase II in patients with VHL). Median (range) age for the combined studies was 55 years (19-84) and body weight was 73.6 kg (42.1-165.8). Belzutifan plasma PK was well-characterized by a linear two-compartment model with first-order absorption and elimination. For patients with VHL, the predicted geometric mean (% coefficient of variation) apparent clearance was 7.3 L/h (51%), apparent total volume of distribution was 130 L (35%), and half-life was 12.39 h (42%). There were no clinically relevant differences in belzutifan PK based on the individual covariates of age, sex, ethnicity, race, body weight, mild/moderate renal impairment, or mild hepatic impairment. In this model, dual UGT2B17 and CYP2C19 poor metabolizers (PMs) were estimated to have a 3.2-fold higher area under the plasma concentration-time curve compared to UGT2B17 extensive metabolizer and CYP2C19 non-PM patients. This population PK analysis enabled an integrated assessment of PK characteristics with covariate effects in the overall population and subpopulations for belzutifan labeling.

Orally Bioavailable Macrocyclic Peptide That Inhibits Binding of PCSK9 to the Low Density Lipoprotein Receptor.

BACKGROUND: Inhibition of PCSK9 (proprotein convertase subtilisin/kexin type 9)-low density lipoprotein receptor interaction with injectable monoclonal antibodies or small interfering RNA lowers plasma low density lipoprotein-cholesterol, but despite nearly 2 decades of effort, an oral inhibitor of PCSK9 is not available. Macrocyclic peptides represent a novel approach to target proteins traditionally considered intractable to small-molecule drug design. METHODS: Novel mRNA display screening technology was used to identify lead chemical matter, which was then optimized by applying structure-based drug design enabled by novel synthetic chemistry to identify macrocyclic peptide (MK-0616) with exquisite potency and selectivity for PCSK9. Following completion of nonclinical safety studies, MK-0616 was administered to healthy adult participants in a single rising-dose Phase 1 clinical trial designed to evaluate its safety, pharmacokinetics, and pharmacodynamics. In a multiple-dose trial in participants taking statins, MK-0616 was administered once daily for 14 days to characterize the safety, pharmacokinetics, and pharmacodynamics (change in low density lipoprotein cholesterol). RESULTS: MK-0616 displayed high affinity (Ki = 5pM) for PCSK9 in vitro and sufficient safety and oral bioavailability preclinically to enable advancement into the clinic. In Phase 1 clinical studies in healthy adults, single oral doses of MK-0616 were associated with >93% geometric mean reduction (95% CI, 84-103) of free, unbound plasma PCSK9; in participants on statin therapy, multiple-oral-dose regimens provided a maximum 61% geometric mean reduction (95% CI, 43-85) in low density lipoprotein cholesterol from baseline after 14 days of once-daily dosing of 20 mg MK-0616. CONCLUSIONS: This work validates the use of mRNA display technology for identification of novel oral therapeutic agents, exemplified by the identification of an oral PCSK9 inhibitor, which has the potential to be a highly effective cholesterol lowering therapy for patients in need.

Pharmacokinetic-pharmacodynamic (dipeptidyl peptidase-4 inhibition) model to support dose rationale in diabetes patients, including those with renal impairment, for once-weekly administered omarigliptin.

AIMS: To characterize the population pharmacokinetics (PK) and pharmacodynamics (PD) of the once-weekly dipeptidyl peptidase-4 (DPP-4) inhibitor omarigliptin in healthy subjects and patients with type 2 diabetes mellitus, and use these models to support the dosing recommendation for patient labelling including patients with renal impairment. METHODS: PK and PD were assessed from a total of 9827 omarigliptin concentrations collected from 1387 healthy subjects and patients participating in Phase 1, 2 and 3 studies examining single- or multiple-dose weekly administration of omarigliptin at doses ranging from 0.25 to 400 mg. Population PK and PD analyses were performed using nonlinear mixed effect modelling. RESULTS: A semi-mechanistic 2-compartment model with linear unbound clearance and concentration-dependent binding of omarigliptin to the DPP-4 enzyme in both the central and peripheral compartments adequately described omarigliptin PK. Key covariates on omarigliptin PK included reduced unbound clearance with renal impairment. A direct effect sigmoid maximum inhibitory efficacy model adequately described the relationship between omarigliptin plasma concentrations and DPP-4 inhibition. These models supported the current Japan label instructions that the approved omarigliptin 25-mg once-weekly dose be halved in patients with severe renal impairment and in those with end-stage renal disease. Also, if patients missed a dose, the next dose of omarigliptin should be taken as soon as remembered up to and including the day before the next scheduled dose. No other clinically important covariates were identified. CONCLUSION: The models in the present analysis adequately described PK and PD characteristics of omarigliptin and supported the dosing and administration section of the omarigliptin label.

Effects of Age, Sex, and Obesity on the Single-Dose Pharmacokinetics of Omarigliptin in Healthy Subjects.

Omarigliptin is being developed as a potent, once-weekly, oral dipeptidyl peptidase-4 inhibitor for the treatment of type 2 diabetes. This double-blind, randomized, placebo-controlled study evaluated the effects of age, sex, and obesity on the pharmacokinetics of omarigliptin in healthy subjects. A single oral dose of omarigliptin 10 mg (n = 6/panel) or placebo (n = 2/panel) was administered in the fasted state to elderly nonobese men and women, young obese (30 ≤ body mass index [BMI] ≤ 35 kg/m(2) ) men and women, and young nonobese women of nonchildbearing potential. Plasma was collected at selected postdose times for evaluation of omarigliptin concentrations. Pharmacokinetic parameters were compared with historical data from a previously-conducted single-dose study in young, healthy, nonobese men. There were no clinically significant differences in omarigliptin AUC0-∞ , the primary pharmacokinetic parameter for assessing efficacy and safety, based on age, sex, or BMI (pooled nonobese elderly versus pooled nonobese young, young nonobese female versus young nonobese male, and pooled young obese versus pooled young nonobese). There were no serious adverse events or hypoglycemic events attributable to omarigliptin administration. Demographic factors and BMI had no meaningful effect on omarigliptin pharmacokinetics, suggesting that dose adjustment based on age, sex, or obesity is not required.

Dipeptidyl peptidase-4 inhibition in patients with type 2 diabetes treated with saxagliptin, sitagliptin, or vildagliptin.

INTRODUCTION: Saxagliptin, sitagliptin, and vildagliptin are dipeptidyl peptidase-4 (DPP-4) inhibitors widely approved for use in patients with type 2 diabetes. Using a crossover design, the present study compared trough levels of DPP-4 inhibition provided by these agents in a single cohort of patients with type 2 diabetes. METHODS: This was a randomized, placebo-controlled, open-label, five-period crossover study. Eligible patients were 18-65 years of age, either treatment-naïve or off prior antihyperglycemic agent therapy for at least 6 or 12 weeks (depending on the prior therapy), and had glycated hemoglobin (HbA1C) ≥6.5% and ≤10.0%. In separate study periods, patients received 5 mg saxagliptin q.d. (saxa-5), 100 mg sitagliptin q.d. (sita-100), 50 mg vildagliptin q.d. (vilda-50-q.d.), 50 mg vildagliptin b.i.d. (vilda-50-b.i.d.), or placebo for 5 days. The primary endpoint was trough %DPP-4 inhibition, derived by comparing DPP-4 activity 24 h after the Day-5 morning dose with predose activity in the same period and analyzed using a linear mixed-effects model with fixed-effects terms for treatment and period. RESULTS: Mean (range) baseline HbA1C was 7.4% (6.4-9.0%; N = 22). Least-squares (LS) mean trough %DPP-4 inhibition was 73.5%, 91.7%, 28.9%, 90.6%, and 3.5% after saxa-5, sita-100, vilda-50-q.d., vilda-50-b.i.d., and placebo, respectively. In patients treated with sita-100, the LS-mean difference in trough %DPP-4 inhibition was 18.2% greater than with saxa-5 (p < 0.001), 62.9% greater than with vilda-50-q.d. (p < 0.001), 1.1% greater than with vilda-50-b.i.d. (p = 0.128), and 87.8% greater than with placebo (p < 0.001). Mean %DPP-4 inhibition was nearly maximal at 12 h postdose regardless of active treatment. Thus, these between-group comparisons at trough primarily reflected differences in duration of action. Adverse events reported during the study were transient and mild or moderate in intensity. CONCLUSION: Once daily treatment with sitagliptin provided trough DPP-4 inhibition significantly greater than saxagliptin or vildagliptin administered once daily, and similar to that provided by vildagliptin administered twice daily.