SELECT-3: a phase I study of selumetinib in combination with platinum-doublet chemotherapy for advanced NSCLC in the first-line setting

Background: We investigated selumetinib (AZD6244, ARRY-142886), an oral, potent, and highly selective, allosteric MEK1/2 inhibitor, plus platinum-doublet chemotherapy for patients with advanced/metastatic non-small cell lung cancer. Methods: In this Phase I, open-label study (NCT01809210), treatment-naïve patients received selumetinib (50, 75, 100 mg BID PO) plus standard doses of gemcitabine or pemetrexed plus cisplatin or carboplatin. Primary objectives were safety, tolerability, and determination of recommended Phase II doses. Results: Fifty-five patients received treatment: selumetinib 50 or 75 mg plus gemcitabine/cisplatin ( n =10); selumetinib 50 mg plus gemcitabine/carboplatin ( n =9); selumetinib 50, 75 or 100 mg plus pemetrexed/carboplatin ( n =21); selumetinib 75 mg plus pemetrexed/cisplatin ( n =15). Most frequent adverse events (AEs) were fatigue, nausea, diarrhoea and vomiting. Grade ⩾3 selumetinib-related AEs were reported in 30 (55%) patients. Dose-limiting toxicities (all n =1) were Grade 4 anaemia (selumetinib 75 mg plus gemcitabine/cisplatin), Grade 4 thrombocytopenia/epistaxis and Grade 4 thrombocytopenia (selumetinib 50 mg plus gemcitabine/carboplatin), Grade 4 febrile neutropenia (selumetinib 100 mg plus pemetrexed/carboplatin), and Grade 3 lethargy (selumetinib 75 mg plus pemetrexed/cisplatin). Partial responses were confirmed in 11 (20%) and unconfirmed in 9 (16%) patients. Conclusions: Standard doses of pemetrexed/carboplatin or pemetrexed/cisplatin were tolerated with selumetinib 75 mg BID. The selumetinib plus gemcitabine-containing regimens were not tolerated.