Clinical Fellow Barts ECMC, Barts Cancer Institute, Queen Mary University London Hertfordshire, England, United Kingdom
Background: CheckMate-214 trial data supported ipilimumab/nivolumab (IO/IO) approval in treatment-naïve metastatic clear cell renal cell carcinoma (mRCC). After 4 cycles of IO/IO-combination, nivolumab-monotherapy continues until progression or toxicity. In certain circumstances, some patients treated within the National Health Service stop nivolumab at 2 years and the outcomes of these patients are lacking. We explore outcomes of patients who stopped nivolumab at 2 years versus those who continued.
Methods: A retrospective audit was conducted on patients with mRCC who received first-line ipilimumab/nivolumab between 2015-2022 at St. Bartholomew’s Hospital, London, UK. Patients were dichotomised based on treatment duration: those who received nivolumab for greater than 2 years (2y-continue) vs those who stopped at 2 years (2y-stop).
Results: Between 2015-2022, 75 mRCC-patients received ipilimumab/nivolumab. From those, 41 progressed within 2-years and 17 discontinued due to toxicity. 6 patients were in the 2y-stop group versus 5 patients in the 2y-continue group. Baseline IMDC characteristics within both groups were similar. Within 2y-continue, overall response-rate (ORR) at 2-years was 100%, with 80% patients achieving CR (2 following cytoreductive-nephrectomy). This ORR was sustained 6 months later. Within the 2-year stop group, ORR at 2-years was 83%, with no complete response. This ORR was maintained 6 months later. There are no cohort deaths, therefore OS-data is immature. Incidence of IO-toxicity in 2y-stop was lower (66.67% versus 100%), as was incidence of grade 3 IO-toxicities (16.67% versus 20%).
Conclusions: ORR is sustained after stopping nivolumab at 2-years. Despite higher CR rates in the 2y-continue group, risk of IO-toxicity grade 3 or higher is increased in these patients. Although a small cohort, these findings underpin that it is safe to discontinue after 2 years of nivolumab, even if patients have not reached CR.