An update on BREAK-3, a phase III, randomized trial: Dabrafenib (DAB) versus dacarbazine (DTIC) in patients with BRAF V600E-positive mutation metastatic melanoma (MM).

9013 Background: Dabrafenib is a selective BRAF inhibitor with demonstrated efficacy in BRAF V600E-positive mutation in MM. The primary analysis of BREAK-3 (NCT01227889) compared progression-free survival (PFS) in patients (pts) with BRAF V600E-positive mutation MM treated with dabrafenib or DTIC. Methods: Median PFS for dabrafenib of 5.1 months (mo) and study methods were previously described (Hauschild A, et al. Lancet. 2012,380:358?365). Independent review ended at the primary analysis. PFS was updated in Jun 2012 at median follow-up of 10.5 mo for dabrafenib (67% of PFS events), and 9.9 mo for DTIC. Median overall survival (OS) was not reached, so another analysis of OS and safety was performed with data as of Dec 2012, at which time the median follow-up was 15.2 (dabrafenib) and 12.7 (DTIC) mo. PFS of subjects who crossed over was also evaluated at that time. Results: PFS hazard ratio was 0.37 [95% CI; 0.23, 0.57]; median PFS was 6.9 mo dabrafenib and 2.7 mo DTIC. In Dec 2012, 36/63 DTIC pts crossed over; median PFS was 4.3 [95% CI; 4.1, 6.1] mos. OS is presented in the Table.The four most common adverse events (AE) on the dabrafenib arm were hyperkeratosis (39%), headache (35%), arthralgia (35%), and pyrexia (32%). Serious AEs ≥ 5% on the dabrafenib arm included cutaneous squamous cell carcinoma/keratoacanthoma (10%) and pyrexia (5%). Conclusions: Longer follow-up confirms the benefits of dabrafenib on PFS and response rate. Median OS in the dabrafenib arm was over 18 mo and over 15 mo in the DTIC arm. OS results are confounded by crossover of DTIC pts to dabrafenib and likely by subsequent therapy after progression. The effects of subsequent therapy results will be investigated. The safety profile had no significant changes. Clinical trial information: NCT01227889. 25 Jun 2012 18 Dec 2012 Dabrafenib DTIC Dabrafenib DTIC OS # Deaths 55/187(29%) 21/63(33%) 78/187(42%) 28/63(44%) Median[95% CI] NR[NR, NR] NR[11.3, NR] 18.2[16.6, NR] 15.6[12.7, NR] HR[95% CI] 0.75[0.44, 1.29] 0.76[0.48, 1.21] NR = not reached. DTIC patients were not censored at crossover.