Real-world outcomes of advanced melanoma patients treated with pembrolizumab who have failed prior lines of therapy.

Abstract

e21031 Background: Pembrolizumab (PEM), a humanized antibody targeting programmed death-1 receptor, has been approved by FDA for the treatment of patients (pts) with advanced melanoma (AM) in the US since 2014. Real-world (RW) data supports the clinical effectiveness of 1L use of PEM, but there is limited information of PEM later line use. The study examined the RW outcomes of pts treated with PEM who have failed prior lines of therapy in US oncology clinical practices. Methods: Flatiron Health longitudinal database was used to identify adult pts with AM who received ≥1 dose of PEM in second line (2L) or later (3L+) between September 4, 2014 and May 31, 2017. Pts were followed up to May 31, 2018. Pts in clinical trials were excluded. Pt demographic, treatment, and clinical characteristics were described. Time on treatment (ToT) and overall survival (OS) were analyzed using the Kaplan Meier (KM) method, with the first dose of PEM as the starting point. Results: Two hundred thirty-six pts were included in the analysis, of which there were 171 2L and 65 3L+. Overall, median age at PEM initiation was 66 years; most were male (66.1%) and Caucasian (95.4%). 41.1% of pts’ tumors were confirmed BRAF mutant; 49.6% of pts’ tumors were confirmed BRAF wildtype; the rest was not tested or indeterminate. When data were available, 26.2% had an elevated lactate dehydrogenase (> ULN), 24.6% had brain metastases, and 25.5% had an ECOG performance status of > 1. At the time of analysis, pts were followed for a median of 12.5 months (mo, range, 0.1-44.6). Overall median ToT was 4.4 mo (95% CI, 3.5-5.3), with 4.7 and 4.4 mo in 2L and 3L+, respectively. Overall median OS was 16.8 mo (95% CI, 12.2-25.9), with 16.8 and 18.9 mo for 2L and 3L+ respectively. 1-year and 2-year survival, using the KM method, was 58.0% (95% CI, 51.2-64.1; 2L, 57.4%; 3L+, 59.6%) and 44.7% (95% CI, 37.9-51.3; 2L, 44.3%; 3L+, 46.1%) respectively. Conclusions: The study reports RW use of PEM in a large cohort of pts with AM who have failed initial therapy in US oncology clinical practices, with a heterogeneous study population compared to clinical trials. The findings of OS based on RW use suggest PEM is an effective treatment option for patients in later lines of therapy.