Phase II study of docetaxel and trametinib in patients with KRAS mutation positive recurrent non-small cell lung cancer (NSCLC) (SWOG S1507, NCT-02642042)

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Clinical cancer research


PURPOSE: Efficacy of MEK inhibitors in KRAS+ NSCLC may differ based on specific KRAS mutations and co-mutations. Our hypothesis was that docetaxel and trametinib would improve activity in KRAS+ NSCLC and specifically in KRAS G12C NSCLC.

PATIENTS AND METHODS: S1507 is a single arm phase II assessing the response rate (RR) with docetaxel plus trametinib in recurrent KRAS+ NSCLC and secondarily in the G12C subset. The accrual goal was 45 eligible patients with at least 25 with G12C mutation. The design was 2-stage design to rule out a 17% RR, within the overall population at the 1-sided 3% level and within the G12C subset at the 5% level.

RESULTS: Between July 18, 2016 and March 15, 2018, 60 patients were enrolled with 53 eligible and 18 eligible in the G12C cohort. The RR was 34% (95%CI- 22-48) overall and 28% (95%CI- 10-53) in G12C. Median PFS and OS were 4.1 and 3.3 months and 10.9 and 8.8 months, overall and in the subset, respectively. Common toxicities were fatigue, diarrhea, nausea, rash, anemia, mucositis, neutropenia. Among 26 patients with known status for TP53 (10+ve) and STK11 (5+ve), OS (HR:2.85, 95%CI 1.16-7.01) and RR (0% vs. 56%, p = 0.004) were worse in patients with TP53 mutated versus wild type cancers.

CONCLUSIONS: RRs were significantly improved in the overall population. Contrary to pre-clinical studies, the combination showed no improvement in efficacy in G12C patients. Co-mutations may influence therapeutic efficacy of KRAS directed therapies and are worthy of further evaluation.

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ePub ahead of print