Pharmacokinetic characteristics of vactosertib, a new activin receptor-like kinase 5 inhibitor, in patients with advanced solid tumors in a first-in-human phase 1 study.

Purposes Vactosertib is a new investigational inhibitor of activin receptor-like kinase 5. The objective of this study was to characterize vactosertib pharmacokinetics that are to be applied for subsequent clinical studies. Methods Vactosertib plasma concentration-time data were obtained from a multicenter, dose-escalation, first-in-human phase 1 study conducted in patients with advanced solid tumors. Each patient orally received a fixed dose of vactosertib with the range of 30 mg to 340 mg once daily under fasted condition. Pharmacokinetic analysis was performed using a non-compartmental method. Results Pharmacokinetic data were evaluable in 29 patients. Vactosertib was rapidly absorbed after the first dose with a median time to maximum concentration (tmax) of 1.2 h (interquartile range, 0.8-1.8 h) and quickly eliminated with a median terminal half-life (t1/2) of 3.2 h (2.2-4.2 h) over the dose range studied. Such trend was also observed after repeated doses for five days (median tmax, 1.5 h; median t1/2, 3.0 h). The area under the concentration-time curve within a dosing interval increased in proportion to dose. The median values of apparent clearance and volume of distribution were 29 L/h (21-44 L/h) and 133 L (77-222 L), respectively. The median accumulation ratio after repeated once-daily doses for five days was 0.87 (0.69-1.07). Conclusions Vactosertib pharmacokinetics were dose-proportional within tested dose range with negligible accumulation when administered once daily for five days. Considering the short half-life, it seems necessary to administer vactosertib twice- or thrice-daily to maintain its concentrations above minimum effective level over a dosing interval.

First-in-human phase I trial of anti-hepatocyte growth factor antibody (YYB101) in refractory solid tumor patients.

BACKGROUND: YYB101, a humanized monoclonal antibody against hepatocyte growth factor (HGF), has shown safety and efficacy in vitro and in vivo. This is a first-in-human trial of this antibody. MATERIALS AND METHODS: YYB101 was administered intravenously to refractory cancer patients once every 4 weeks for 1 month, and then once every 2 weeks until disease progression or intolerable toxicity, at doses of 0.3, 1, 3, 5, 10, 20, 30 mg/kg, according to a 3+3 dose escalation design. Maximum tolerated dose, safety, pharmacokinetics, and pharmacodynamics were studied. HGF, MET, PD-L1, and ERK expression was evaluated for 9 of 17 patients of the expansion cohort (20 mg/kg). RESULTS: In 39 patients enrolled, no dose-limiting toxicity was observed at 0.3 mg/kg, and the most commonly detected toxicity was generalized edema (n = 7, 18.9%) followed by pruritis and nausea (n = 5, 13.5%, each), fatigue, anemia, and decreased appetite (n = 4, 10.8%, each). No patient discontinued treatment because of adverse events. YYB101 showed dose-proportional pharmacokinetics up to 30 mg/kg. Partial response in 1 (2.5%) and stable disease in 17 (43.5%) were observed. HGF, MET, PD-L1, and ERK proteins were not significant predictors for treatment response. However, serum HGF level was significantly lowered in responders upon drug administration. RNA sequencing revealed a mesenchymal signature in two long-term responders. CONCLUSION: YYB101 showed favorable safety and efficacy in patients with refractory solid tumors. Based on this phase I trial, a phase II study on the YYB101 + irinotecan combination in refractory metastatic colorectal cancer patients is planned. CONCLUSION: ClinicalTrials.gov Identifier: NCT02499224.