Adjuvant targeted therapy in patients with skin melanoma: evidence from Russian real-world clinical practice (RATIONALE study)

Background. Adjuvant targeted therapy (ATT) with a combination of dabrafenib and trametinib after radical surgical treatment in patients with stage III skin melanoma (SM) with a BRAF V600 mutation reduces the risk of disease recurrence. The effectiveness of this approach has been demonstrated in randomized clinical trials, and also confirmed in several large non-Russian real-world (RW) studies. Aim. To evaluate, in RW settings, the effectiveness of ATT with a combination of dabrafenib and trametinib after definitive surgical treatment in patients with BRAF V600-positive SM in Russia. Materials and methods. The RATIONALE study is a prospective, non-interventional, multicenter RW study. The follow-up duration for the study was 1 year. Patients with SM older than 18 years who had previously started dabrafenib and trametinib therapy no more than 8 weeks prior to Visit 1 were included in the study. The paper presents results from the analysis of Cohort 1 only (patients who received dabrafenib and trametinib in the adjuvant setting). Results. The cohort included 214 patients with BRAF V600-mutated SM of stages IIIA–D and IV resectable. At the time of therapy initiation, the majority of patients were stage IIIc (54.7%) or IIIb (22.0%). The most common mutation – BRAF V600E – occurred in 66.3% of cases, while the second most common variant – BRAF V600 not otherwise specified – was detected in 31.3%. One-year overall survival for all included patients was 94%, one-year relapse-free survival was 84%, and one-year distant metastasis-free survival was 86%. No previously listed adverse events were reported. Adverse events led to therapy discontinuation in only 11.7% of cases. ATT did not reduce patients' quality of life. In the subgroup analysis, the effectiveness of the combination of dabrafenib and trametinib after removal of distant metastases (equivalent to stage IV resectable) was found, in particular, the one-year relapse-free survival rate was 83%, and the one-year overall survival rate was 100%, which is comparable to these indicators for stage IIIB-D (72–86 and 78–100%, respectively). Conclusion. The effectiveness and favorable safety profile of the combination of dabrafenib and trametinib in ATT after radical surgical treatment was confirmed in a population of Russian patients with SM in the RW settings.