SUCCINCT: An Open-label, Single-arm, Non-randomised, Phase 2 Trial of Gemcitabine and Cisplatin Chemotherapy in Combination with Sunitinib as First-line Treatment for Patients with Advanced Urothelial Carcinoma

Gemcitabine and cisplatin chemotherapy (GC regimen) represents a standard treatment for advanced urothelial carcinoma. We performed an open-label, single-arm, non-randomised, phase 2 trial evaluating the addition of sunitinib to standard GC chemotherapy (SGC regimen). Overall, 63 treatment-naïve participants were recruited and received up to six 21-d cycles of cisplatin 70 mg/m(2) (intravenously [IV], day 1) and gemcitabine 1000 mg/m(2) (IV, days 1 and 8) combined with sunitinib 37.5 mg (orally, days 2–15). Following review of toxicity after the first six patients, the sunitinib dose was reduced to 25 mg for all patients. Overall response rate was 64%, with response noted in 37 of 58 patients. At 6 mo, 30 of 58 assessable patients (52%; 90% confidence interval [CI], 40–63%) were progression free. Median overall survival was 12 mo (95% CI, 9–15) and was heavily influenced by Bajorin prognostic group. Grade 3–4 toxicities were predominantly haematologic and limited the deliverability of the triple SGC regimen. The trial did not meet its prespecified primary end point of >60% patients progression free at 6 mo. Cumulative myelosuppression led to treatment delays of gemcitabine and cisplatin and dose reduction and/or withdrawal of sunitinib in the majority of cases. The triple-drug combination was not well tolerated. Phase 3 evaluation of the triple SGC regimen in advanced transitional cell carcinoma is not recommended. PATIENT SUMMARY: The addition of sunitinib to standard cisplatin and gemcitabine chemotherapy was poorly tolerated and did not improve outcomes in advanced urothelial carcinoma. Treatment delivery was limited by myelotoxicity.