Part 1 is the open label, dose-escalation phase Ib portion of the study to establish the maximum tolerated dose (MTD)/RP2D of APG-115 in combination with pembrolizumab. APG-115 will be administered orally every other day (QOD) for consecutive 2 weeks and 1 week off dosing as a cycle of 21 days (3 weeks), pembrolizumab will administrated with label dose.~Part 2 is a phase II study design. The patients will be treated with APG-115 at 150 mg QOD (RP2D) in combination with pembrolizumab until disease progression, unacceptable toxicity, or another discontinuation criterion is met. Part 2 includes patients with programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) refractory/relapsed melanoma and MPNST.
Part 1 is the dose escalation of APG-115 in combination with label dose of pembrolizumab.~Part 2 is phase II design of APG-115 at recommended phase 2 dose (RP2D) in combination with pembrolizumab.