Overall survival and efficacy subgroup analysis of tunlametinib in patients with advanced NRAS-mutant melanoma: A multicenter, open-label, single-arm, phase 2 study.

Abstract

9545 Background: NRAS-mutant melanoma is an aggressive subtype with worse prognosis. However, no targeted therapy has been approved to date worldwide. Tunlametinib (HL-085) has showed an encouraging efficacy (confirmed ORR:34.8%, mPFS:4.2 months) with a manageable safety profile in phase II pivotal registrational study, which was published in ASCO 2023 annal meeting (NO.:9510). Here, we report the updated efficacy results. Methods: This is a multicenter, single-arm, phase II, pivotal registrational study. Patients (pts) with NRAS-mutant unresectable stage III or IV melanoma were enrolled and received tunlametinib 12 mg orally twice daily. The primary endpoint was confirmed objective response rate (ORR) per Response Evaluation Criteria In Solid Tumors, version 1.1 assessed by independent radiology review committee (IRRC). Results: A total of 100 pts were enrolled and 95 pts were included in the full analysis set (FAS) for efficacy analysis. At cut-off date (October 31, 2023), median follow-up was 24.4 months (95% CI: 21.9, 27.9). The confirmed ORR was 35.8% (95%CI: 26.3%, 46.3%). Median progression-free survival (mPFS) was 4.2 months (95%CI: 3.5, 5.6). The median overall survival (mOS) was immature during last year's ASCO annual meeting, and the present mOS was 13.7 months (95% CI of 10.3–18.0). The IRRC-assessed ORRs by melanoma subtype were 42.9% (95% CI of 29.7–56.8) in acral melanoma, 25.0% (95% CI of 7.3–52.4) in mucosal melanoma. ORRs by NRASmutation site were 41.3% (95% CI of 30.1–53.3), 13.3% (95% CI of 1.7–40.5) and 20.0% (95% CI of 0.5–71.6) for Q61, G12, and G13, respectively. ORR in patients who had been treated with immunotherapy was 40.6% (95% CI of 28.5–53.6), while in those without immunotherapy, ORR was 25.8% (95% CI of 11.9–44.6). The difference in PFS was not statistically significant across subgroups, regardless of melanoma type, NRAS mutation site, line of previous treatment, type of previous treatment and previous treatment with immunotherapy. The safety profile is similar with last year's ASCO annual meeting. The most frequent treatment related adverse events (TRAEs) were increased blood creatine phosphokinase (CK), diarrhea, facial oedema, peripheral oedema, and increased aspartate aminotransferase. No treatment-related death was reported. Conclusions: Tunlametinib demonstrated an encouraging treatment response rate in patients with advanced NRAS-mutant melanoma with a manageable safety profile. These results suggest that tunlametinib could be a promising treatment option for NRAS-mutant melanoma, even for those who had previously received immunotherapy. Clinical trial information: NCT05217303 .