Utilization and toxicity patterns of 2-weekly (Q2W) versus 4-weekly (Q4W) nivolumab for treatment of adjuvant and metastatic melanoma at BC cancer

Background Nivolumab, an immune checkpoint inhibitor used to treat several malignancies, is associated with immune-related adverse events (IrAEs). Original dosing for melanoma was 3 mg/kg (maximum 240 mg) every 2 weeks (Q2W). Based on simulation studies depicting similar efficacy and toxicity to original dosing, extended interval dosing of 6 mg/kg (maximum 480 mg) every 4 weeks (Q4W) was introduced. Objective This study will compare safety between Q2W and Q4W dosing at BC Cancer in melanoma patients. Methods Retrospective chart review for reported incidence, onset, and severity of IrAEs in melanoma patients treated with nivolumab Q2W and Q4W dosing was completed. Fisher's test was conducted for first incidence IrAEs using Microsoft Excel. Results Seventy-one patients were identified (Q2W n = 35, Q4W n = 36). Baseline characteristics were similar in both groups. No statistically significant difference was found in incidence of IrAEs between Q2W and Q4W dosing (Q2W 40% vs Q4W 50%, p = 0.477). Rash was most common (Q2W 79% vs Q4W 50%) followed by hypothyroidism (Q2W 33% vs Q4W 20%). Median onset of IrAEs seemed later with Q4W dosing (Q2W cycle 1 vs Q4W cycle 4). Regardless of dosing, most IrAEs were grade 1–2 in severity (Q2W 100% vs Q4W 89%). Conclusion Q4W dosing is associated with comparable incidence and potentially later onset of IrAEs compared to Q2W dosing. Most IrAEs in both dosing groups were similar and mild. Therefore, Q4W dosing offers a safe alternative to Q2W dosing while providing benefits including decreased workload for staff, decreased clinic visits, and viral exposure by patients.