Encorafenib plus binimetinib maintains quality of life in BRAF V600E-mutated thyroid cancer

BACKGROUND: A Japanese phase 2 trial of encorafenib plus binimetinib met the primary endpoint of the centrally assessed objective response rate in patients with unresectable BRAF V600E-mutated thyroid cancer. Consequently, encorafenib plus binimetinib has been approved in Japan. We present the health-related quality of life (HR-QoL) outcomes from the trial. METHODS: The multicenter, open-label, uncontrolled phase 2 trial enrolled patients with unresectable locally advanced or metastatic BRAF V600E-mutated thyroid cancer. HR-QoL score, one of the secondary endpoints, was assessed using the EORTC QLQ-C30 and QLQ-THY34 at baseline and during follow-up. The minimal important change (MIC) threshold was set at 10 points. RESULTS: We enrolled 22 patients with BRAF V600E-mutated thyroid cancer. The median follow-up was 11.5 months. Completion rates for the questionnaires were 100% (22 of 22 patients) at baseline and 68% (15 of 22) at week 20. Until week 20, changes from baseline were below MIC at most time points in 29 of all 32 domains in QLQ-C30 and QLQ-THY34. In the other 3 domains, patients showed tendencies toward improvement (social support and appetite loss) or deterioration (joint pain) for consecutive time points. Patients with anaplastic thyroid cancer showed tendencies toward improvement for swallowing, restlessness, body image, and discomfort in the head and neck, from the first assessment after the initial treatment. CONCLUSION: The combination therapy of encorafenib plus binimetinib for unresectable BRAF V600E-mutated thyroid cancer was associated with generally maintained HR-QoL. Considering the efficacy and safety data from the trial, the regimen may provide clinical benefits while maintaining HR-QoL.