Abstract 1479: Pan-cancer efficacy of BRAF and/or MEK inhibitors in BRAF V600-mutant multiple non-melanoma cancers: A clinico-genomic study

Abstract

Abstract Background: BRAF and MEK inhibitors are currently FDA approved for melanoma, non-small cell lung cancer, and anaplastic thyroid cancer. The lack of clinical benefit with BRAF inhibition in BRAF V600+ colorectal cancer (CRC) has prevented its tissue-agnostic drug development. However, updated results from Vemurafenib-Basket study (Cancer Discov. 2020 May;10(5):657-663 ) and the NCI-match trial ( J Clin Oncol. 2020 Nov 20;38(33):3895-3904) reveal that BRAF pathway inhibition is active in > 20 unique cancer types. Objective: We aimed to describe the characteristics of BRAF V600 and study real-world outcomes using a clinico-genomic analysis using the AACR Genie database and the current medical literature. Methods: We reviewed the AACR GENIE database for the prevalence of BRAF V600 mutations across tumor types. We conducted a literature search (using PubMed from 2012-2019) for case reports of clinical response and outcomes in patients with BRAF V600 mutation-positive non-melanoma cancers who received BRAF inhibitor therapy. Results: Among 96,324 samples, BRAF V600 mutations were seen in 43 different tumor types across 2,963 samples (3.07 %) in the AACR GENIE database. BRAF V600 was most commonly present in thyroid cancer (40.9%), parathyroid cancer (31.8%), melanoma (26.1%), histiocytosis (25.7%), and head and neck NOS (14.3%). Literature review revealed total of 178 cases across 69 tumor types. The most common cases included Erdheim-Chester disease (n = 30, 16.9%), papillary thyroid carcinoma (n=16, 8.9%), anaplastic thyroid carcinoma (n = 13, 7.3%), and hairy cell leukemia (n = 13, 7.3%). Furthermore, dabrafenib (BRAF), dabrafenib/trametinib (BRAF+MEK), trametinib(MEK), vemurafenib (BRAF), vemurafenib/trametinib (BRAF+MEK), vemurafenib/cobimetinib (BRAF+MEK) were used in 34% (n =56), 16% (n = 27), 4% (n = 6), 44% (n = 72), 1% (n = 1), 2% (n =3), respectively. Overall, median PFS was 6.5 months, and median OS was 28.5 months with a median duration of response (DOR) of 8 months. Conclusion: BRAF V600 mutations are prevalent across multiple non-melanoma cancers, lead to oncogene addiction and are clinically actionable in a broad range of non-melanoma cancers. Continued drug development is warranted beyond the current BRAF+/- MEK approved cancers. Citation Format: Jacob J. Adashek, Aakash P. Desai, Arjun K. Menta, Jason Roszik, Vivek Subbiah. Pan-cancer efficacy of BRAF and/or MEK inhibitors in BRAF V600-mutant multiple non-melanoma cancers: A clinico-genomic study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1479.