Real World Treatment Patterns Of First-Line Combination Therapies Among Patients With Metastatic Melanoma And Braf Mutation.

e21011 Background: First line (1L) systemic combination (combo) therapies for treatment of metastatic melanoma (MM) include targeted combo therapies such as dabrafenib+trametinib (D+T) or vemurafenib+cobimetinib for patients (pts) with BRAF mutation (BRAF+), or immunotherapy combo ipilimumab+nivolumab (I+N) for pts irrespective of BRAF status. The objective of this study was to describe real world characteristics and treatment patterns among BRAF+ mm pts who were treated with either D+T or I+N as 1L therapy. Methods: This retrospective observational study utilized Flatiron Health’s electronic health record (EHR) data from Jan 2013 to Jul 2016. Pts were aged ≥18 years with a mm diagnosis, and treated with either D+T (N = 86) or I+N (N = 61) as 1L therapy. Prior to therapy initiation, 86/86 of D+T pts were tested BRAF+. 55/61 of I+N pts completed BRAF testing and 19/61 were BRAF+. All analyses focused on BRAF+ pts who were treated with either D+T or I+N as 1L therapy. Baseline characteristics, treatment patterns and data on therapy discontinuation were collected from structured data in patient records and unstructured data in physician notes, and were descriptively assessed. Statistical inferences were not drawn due to sample size limitations. Results: At baseline, 35% of D+T pts vs 32% of I+N pts had brain metastasis, 29% of D+T pts vs 11% of I+N pts had high LDH levels, and 20% of D+T pts vs 42% of I+N pts reported ECOG = 0 status. The median follow-up time was 219 days for the D+T pts vs 150 days for the I+N pts. The 3 and 6 month discontinuation rates were 9% and 24% for the D+T pts vs 21% and 47% for the I+N pts. 13% of D+T pts vs 26% of I+N pts discontinued treatment citing toxicity in physician notes. Among pts with brain metastasis, the 3 and 6 month discontinuation rates were 3% and 20% for D+T pts vs 33% and 50% for I+N pts. Conclusions: Among BRAF+ mm pts who were treated with either D+T or I+N as 1L therapy, D+T pts were more likely to have advanced disease such as brain metastasis and high LDH levels than I+N pts. Compared with 1L D+T pts, 1L I+N pts had higher discontinuation rates due to toxicity, even with a shorter median follow-up time. 1L I+N pts with brain metastasis also had higher discontinuation rates.