Abstract
Recurrent small cell lung cancer (SCLC) has few effective treatments. The EZH2-SLFN11 pathway is a driver of acquired chemoresistance that may be targeted. This phase I/II trial investigated valemetostat, an EZH1/2 inhibitor, with fixed-dose irinotecan in patients with recurrent SCLC. Phase I primary objectives were to assess safety and a recommended phase II dose (RP2D). The phase II primary objective was to determine overall response rate (ORR), with secondary objectives of duration of response (DoR), progression-free survival (PFS) and overall survival (OS). Immunohistochemistry of pre- and on-treatment tumor biopsies and pharmacokinetics analysis were performed. Twenty-two patients enrolled (phase I, n=12; phase II n=10); one withdrew consent prior to treatment. Three dose-limiting toxicities (DLTs) in dose-escalation resulted in valemetostat 100 mg orally daily selected as RP2D. Among 21 toxicity-evaluable patients, the most frequent (≥20%) treatment-related adverse events were diarrhea, fatigue, nausea, and rash; 3 patients discontinued treatment for toxicity. In phase II, 3/10 patients experienced DLTs triggering a stopping rule. The ORR was 4/19 (21%, 95% CI 6 to 46%). The median DoR, PFS and OS were 4.6 mo, 2.2 mo (95% CI 1.3 to 7.6 mo) and 6.6 mo (95% CI 4.3 to not reached). SLFN11, EZH2 and SCLC subtyping markers did not correlate with response. MHC-I protein expression increased in 4/4 patients with paired biopsies, including 3/3 responders; two responders demonstrated subtype switching on treatment. Valemetostat and irinotecan was not tolerated but demonstrated efficacy in recurrent SCLC. Valemetostat may warrant further investigation in SCLC.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Clinical cancer research : an official journal of the American Association for Cancer Research
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.