A retrospective observational study of patients with melanoma prescribed combined BRAF and MEK inhibitors in a real‐world treatment setting in Japan

Abstract Objective This study aimed to describe patients with melanoma initiating treatments with dabrafenib plus trametinib (Dab + Tram) or encorafenib plus binimetinib (Enco + Bini) in a real‐world setting in Japan. Methods Data were extracted from the Japanese Medical Data Vision (MDV) insurance claims database. Patients diagnosed with melanoma between 2012 and 2021 and prescribed with Dab + Tram or Enco + Bini were included in three cohorts: non‐adjuvant Dab + Tram, adjuvant Dab + Tram, and Enco + Bini. Data were extracted on patient characteristics at treatment initiation. During follow‐up, all changes in melanoma treatments were documented. Treatment adherence was determined as the proportion of prescription days covered (PDC) and treatment dose intensity as the relative dose intensity (RDI). Results Sixty‐seven patients were included in the non‐adjuvant Dab + Tram cohort (55 first‐line treatments), seven in the adjuvant Dab + Tram cohort (six first‐line treatments), and 16 in the Enco + Bini cohort (four first‐line treatments). The mean age was 61.3 ± 13.5 years and 56.1% were men. Twenty‐seven patients with non‐adjuvant Dab + Tram or Enco + Bini in first line (45.8%) switched to a second line. The median treatment duration was 11.8 months for Dab + Tram and 8.1 months for Enco + Bini. A PDC ≥ 80% was observed for 85.7% of patients with adjuvant Dab + Tram, 68.7% for non‐adjuvant Dab + Tram, and 75.0% for Enco + Bini. Median RDI was 1.0 for adjuvant Dab + Tram, 0.9 for non‐adjuvant Dab + Tram, and 0.6 for Enco + Bini. Conclusion Dab + Tram is used consistently with clinical practice guidelines in the adjuvant setting, but adherence in the non‐adjuvant setting is suboptimal, as is the prescribed dose of Enco + Bini. Prescribers should ensure that these therapies are used in an optimal way to improve outcomes in melanoma.