2/1 dose schedule of sunitinib is superior than the 4/2 regimen for the first-line therapy of clear cell metastatic renal cell carcinoma - An Indian experience.

Background: Sunitinib remains the first-line treatment for favorable risk metastatic clear cell renal cell cancer (mccRCC). It was conventionally given in the 4/2 schedule; however, toxicity necessitated trying the 2/1 regimen. Regional variations in treatment response and toxicity are known, and there is no data from the Indian subcontinent about the outcomes of the alternative dosing schedule.

Methods: Clinical records of all consecutive adult patients who received sunitinib as first-line therapy for histologically proven mccRCC following cytoreductive nephrectomy from 2010-2018 were reviewed. The primary objective was to determine the progression-free survival (PFS), and the secondary objectives were to evaluate the response rate (objective response rate and clinical benefit rate), toxicity, and overall survival. A list of variables having a biologically plausible association with outcome was drawn and multivariate inverse probability treatment weights (IPTW) analysis was done to determine the absolute effect size of dosing schedules on PFS in terms of "average treatment effect on the treated" and "potential outcome mean."

Results: We found 2/1 schedule to be independently associated with higher PFS on IPTW analysis such that if every patient in the subpopulation received sunitinib by the 2/1 schedule, the average time to progression was estimated to be higher by 6.1 months than the 4/2 schedule. We also found 2/1 group to have a lower incidence than the 4/2 group for nearly all ≥ grade 3 adverse effects. Other secondary outcomes were comparable between both treatment groups.

Conclusion: Sunitinib should be given via the 2/1 schedule in Indian patients.