Phase I clinical and pharmacokinetic study of PM01183 (a tetrahydroisoquinoline, Lurbinectedin) in combination with gemcitabine in patients with advanced solid tumors.

Abstract

Background To determine the recommended dose (RD) of a combination of PM01183 and gemcitabine in patients with advanced solid tumors. Methods Forty-five patients received escalating doses of PM01183/gemcitabine on Days 1 and 8 every 3weeks (d1,8 q3wk) following a standard 3+3 design. Results PM01183 3.5mg flat dose (FD)/gemcitabine 1000mg/m2 was the highest dose level tested. Dose-limiting toxicities (DLTs) were mostly hematological and resulted in the expansion of a lower dose level (PM01183 3.5mg FD/gemcitabine 800mg/m2); 19 patients at this dose level were evaluable but >30% had DLT and >20% had febrile neutropenia. No DLT was observed in 11 patients treated at PM01183 3.0mg FD/gemcitabine 800mg/m2, which was defined as the RD. This regimen was feasible and tolerable with manageable toxicity; mainly grade 3/4 myelosuppression. Non-hematological toxicity comprised fatigue, nausea, vomiting, and transaminases increases. Fifteen (33%) patients received ≥6cycles with no cumulative hematological toxicity. Pharmacokinetic analysis showed no evidence of drug-drug interaction. Nine of 38 patients had response as per RECIST (complete [3%] and partial [21%]), for an overall response rate (ORR) of 24% (95% Confidence Interval [CI] 12-40%). Eleven patients (29%) had disease stabilization ≥4months. Responses were durable (median of 8.5months): overall median progression-free survival (PFS) was 4.2months (95% CI, 2.7-6.5months). Conclusions The RD for this combination is PM01183 3.0mg FD (or 1.6mg/m2)/gemcitabine 800mg/m2 d1,8 q3wk. This schedule is well tolerated and has antitumor activity in several advanced solid tumor types.