Real world treatment patterns of first-line combination therapies among BRAF+ metastatic melanoma patients.

197 Background: For patients (pts) with metastatic melanoma (MM) and BRAF V600 mutation (BRAF+), options for first-line (1L) systemic combination therapy include immunotherapy (IO) or targeted therapy (TT). This study describes real world treatment patterns among BRAF+ MM pts treated with 1L ipilimumab+nivolumab (I+N) or dabrafenib+trametinib (D+T). Methods: This retrospective observational analysis used Flatiron Health’s electronic health record-derived database from Oct 2015 - Jul 2016. Oct 2015 was chosen as the start date as both combo use of I+N and D+T had been approved by the FDA. Pts were aged ≥18 years with a MM diagnosis, tested BRAF+ prior to therapy, and treated with either I+N or D+T as 1L therapy. Baseline demographic and clinical characteristics, and treatment patterns were collected from structured data and unstructured data in physician notes, and were descriptively assessed. Kaplan-Meier (KM) analysis measured time to discontinuation. Statistical inferences were not planned in this study. Results: Among 76 BRAF+ pts, 62% (47) were treated with D+T as 1L, and 38% (29) were treated with I+N as 1L. Compared to D+T pts, lower proportion of I+N pts had a history of brain metastases (31% vs. 34%) and elevated ( > 333 IU/L) lactate dehydrogenase (10% vs. 19%), while a higher proportion of I+N pts reported ECOG performance status score of zero (38% vs. 23%). The two cohorts were similar in age, gender and baseline comorbidities. Discontinuation among D+T and I+N was 43% (20) and 48% (14) respectively. The primary reason for discontinuation was progression among D+T pts (10/20) vs. toxic effects of therapy among I+N pts (8/14). KM median time to discontinuation was 213 days for D+T pts vs. 196 days for I+N pts. 55% of I+N pts did not complete full induction of 4 doses of ipilimumab, citing toxic effects of therapy. Conclusions: 1L D+T patients had higher tumor burden, elevated LDH levels, and higher ECOG performance status score, but lower discontinuation rate and longer time to treatment discontinuation relative to BRAF+ 1L I+N pts.