First-line sunitinib treatment modification in patients with mRCC: nationwide analysis of the Swedish population

<b>Aim:</b> Assess first-line sunitinib dosing for treatment of metastatic renal cell carcinoma in Swedish clinical practice (2006-2019).<b>Materials & methods:</b> Retrospective analysis of three sunitinib dosing regimens: 2-weeks on, 1-week off (2:1 Start); standard 4-weeks on, 2-weeks off (4:2) and 4:2 start with switch to 2:1 (2:1 Switch).<b>Results:</b> Time-to-treatment discontinuation (95% CI) differed significantly (<i>p</i> < 0.001): 6.2 (5.6-7.2), 13.9 (8.1-20.6) and 4.6 (4.3-5.6) months for 2:1 Start (<i>n</i> = 320), 2:1 Switch (<i>n</i> = 71) and 4:2 (<i>n</i> = 704), respectively. Overall survival (95% CI) differed significantly (<i>p</i> < 0.001): 21.8 (18.1-26.1), 32.2 (25.1-48.3) and 13.5 (12.3-15.8) months for 2:1 Start (<i>n</i> = 320), 2:1 Switch (<i>n</i> = 71) and 4:2 (<i>n</i> = 704), respectively.<b>Conclusion:</b> Alternative dosing does not compromise clinical efficacy and may provide advantages in terms of improved treatment outcomes. However, due to the changing treatment patterns during this long-term study, and the absence of patient risk category data, caution is required when interpreting the main outcomes.