Phase I, Open-Label, Dose-Escalation/Dose-Expansion Study of Lifirafenib (BGB-283), an RAF Family Kinase Inhibitor, in Patients With Solid Tumors

Jayesh Desai, Hui Gan, Catherine Barrow, Michael Jameson, Victoria Atkinson, Andrew Haydon, Michael Millward, Stephen Begbie, Michael Brown, Ben Markman, William Patterson, Andrew Hill, Lisa Horvath, Adnan Nagrial, Gary Richardson, Christopher Jackson, Michael Friedlander, Phillip Parente, Ben Tran, Lai WangYunxin Chen, Zhiyu Tang, Wendy Huang, John Wu, Dewan Zeng, Lusong Luo, Benjamin Solomon

Research output: Contribution to journalArticle

9 Citations (Scopus)


PURPOSE: Lifirafenib is an investigational, reversible inhibitor of B-RAFV600E, wild-type A-RAF, B-RAF, C-RAF, and EGFR. This first-in-human, phase I, dose-escalation/dose-expansion study evaluated the safety, tolerability, and efficacy of lifirafenib in patients with B-RAF- or K-RAS/N-RAS-mutated solid tumors.

METHODS: During dose escalation, adult patients with histologically/cytologically confirmed advanced solid tumors received escalating doses of lifirafenib. Primary end points were safety/tolerability during dose escalation and objective response rate in preselected patients with B-RAF and K-RAS/N-RAS mutations during dose expansion.

RESULTS: The maximum tolerated dose was established as 40 mg/d; dose-limiting toxicities included reversible thrombocytopenia and nonhematologic toxicity. Across the entire study, the most common grade ≥ 3 treatment-emergent adverse events were hypertension (n = 23; 17.6%) and fatigue (n = 13; 9.9%). One patient with B-RAF-mutated melanoma achieved complete response, and 8 patients with B-RAF mutations had confirmed objective responses: B-RAFV600E/K melanoma (n = 5, including 1 patient treated with prior B-RAF/MEK inhibitor therapy), B-RAFV600E thyroid cancer/papillary thyroid cancer (PTC; n = 2), and B-RAFV600E low-grade serous ovarian cancer (LGSOC; n = 1). One patient with B-RAF-mutated non-small-cell lung cancer (NSCLC) had unconfirmed partial response (PR). Patients with K-RAS-mutated endometrial cancer and K-RAS codon 12-mutated NSCLC had confirmed PR (n = 1 each). No responses were seen in patients with K-RAS/N-RAS-mutated colorectal cancer (n = 20).

CONCLUSION: Lifirafenib is a novel inhibitor of key RAF family kinases and EGFR, with an acceptable risk-benefit profile and antitumor activity in patients with B-RAFV600-mutated solid tumors, including melanoma, PTC, and LGSOC, as well as K-RAS-mutated NSCLC and endometrial carcinoma. Future comparisons with first-generation B-RAF inhibitors and exploration of lifirafenib alone or as combination therapy in patients with selected RAS mutations who are resistant/refractory to first-generation B-RAF inhibitors are warranted.

Original languageEnglish
Pages (from-to)2140-2150
JournalJournal of clinical oncology : official journal of the American Society of Clinical Oncology
Issue number19
Publication statusPublished - 1 Jul 2020
Externally publishedYes

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