Preliminary results from a phase Ib/II, open-label, dose-escalation study of the oral BRAF inhibitor LGX818 in combination with the oral MEK1/2 inhibitor MEK162 in BRAF V600-dependent advanced solid tumors

Richard Kefford, Wilson H. Miller, Daniel Shao-Weng Tan, Ryan J. Sullivan, Georgina Long, Rodrigo Dienstmann, Wai Meng David Tai, Keith Flaherty, Simone Stutvoet, Karl Maria Schumacher, Simon Wandel, Laure A. De Parseval, Josep Tabernero

Research output: Contribution to journalMeeting abstract

Abstract

Background: Clinical data indicate that combining a BRAF and a MEK inhibitor (BRAFi, MEKi) may be more effective than BRAFi monotherapy in BRAF-mutant metastatic melanoma and that a MEKi may overcome or delay resistance to a BRAFi.

Methods: This ongoing phase 1b/2 study is evaluating the combination of LGX818, a potent, selective BRAF inhibitor, and MEK162, a selective MEK1/2 inhibitor, in BRAFi-naive and -pretreated patients with BRAF-mutant tumors. The objective of the phase 1b part is to determine the maximum tolerated dose and/or recommended phase 2 dose (RP2D) for oral, daily LGX818 + MEK162 in BRAF V600–mutant advanced solid tumors. A Bayesian logistic regression model with overdose control guides the treatment dose escalation.

Results: As of January 8, 2013, 20 patients (7 BRAFi-naive melanoma; 9 BRAFi-pretreated melanoma; 2 BRAFi-naive thyroid cancer; 1 BRAFi-naive metastatic colorectal cancer; 1 BRAFi-pretreated colorectal cancer) were treated with LGX818 qd + MEK162 bid at the following dose levels (DLs): 50 mg + 45 mg, 100 mg + 45 mg, 200 mg + 45 mg, and 400 mg + 45 mg. No dose-limiting toxicity has been observed at these DLs. The next DL of 600 mg + 45 mg is under investigation. The single agent RP2Ds for LGX818 and MEK162 are 450 mg and 45 mg, respectively. The most common adverse events (≥ 20%, all grades) suspected to be treatment related were nausea, abdominal pain, and headache. No events of fever, hand-foot-skin reactions, hyperkeratosis, or squamous cell carcinoma were observed. In patients with at least 1 post-baseline CT scan available for investigator-determined response, a complete response was observed in 1/7 (14%) BRAFi-naïve melanoma patients and partial responses were observed in 5/7 (71%) BRAFi-naive melanoma patients, 2/9 (22%) BRAFi-pretreated melanoma patients (starting at 50 mg + 45 mg DL), and 1/2 thyroid cancer patients.

Conclusions: Preliminary data from this study indicate that LGX818 + MEK162 can be safely combined with promising clinical benefit. No febrile events or photosensitivity were reported suggesting a distinct safety profile for this BRAFi/MEKi combination vs others. Clinical trial information: NCT01543698.
Original languageEnglish
Pages (from-to)9029-9029
Number of pages1
JournalJournal of Clinical Oncology
Volume31
Issue numberSupplement 15
Publication statusPublished - 20 May 2013
Externally publishedYes
EventAnnual Meeting of the American Society of Clinical Oncology (ASCO) - Chicago, United States
Duration: 31 May 20134 Jun 2013

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