From trials to practice: Immune checkpoint inhibitor therapy for melanoma patients in Norway.

Background and purpose: Norway has one of the highest rates of cutaneous melanoma (CM) incidence and mortality globally. Immune checkpoint inhibitor (ICI) therapy for CM was introduced between 2014 and 2017 to improve treatment and patient prognosis, but knowledge about its clinical usage is limited. This study investigates patient's characteristics and treatment patterns in real-world practice compared to clinical trial results.

Material and methods: All adult (≥18) CM patients treated with ICI therapy in Norway from 2014 to 2021 were included, utilizing high-coverage data from multiple national registries to describe patients' health, socioeconomic factors, and treatment management, stratified by first ICI therapy. We compared patient and tumour characteristics with findings from five randomized controlled trials (RCTs).

Results: Among 2,083 patients receiving ICI therapy, 975 (47%) received nivolumab as their first treatment in the metastatic setting. Patients on combination therapy were younger and had higher education and income levels compared to those on monotherapy. Overall, real-world patients were older and had a higher incidence of brain metastases than those in RCTs. Approximately, 1 in 5 patients would have been excluded from RCTs due to pre-existing autoimmune diseases. Targeted therapy was the most common secondary systemic treatment after first-line PD-1 inhibitors.

Interpretation: This study details ICI therapy in Norway, highlighting differences between real-world ICI users and clinical trial participants, raising questions about the effectiveness of this treatment for patients not eligible for trials.