Safety and efficacy of perioperative cisplatin/gemcitabine (cis/gem) and durvalumab (durva) for operable muscle-invasive urothelial carcinoma (MIUC): SAKK 06/17.

Abstract

430 Background: The combination of cisplatin-based chemotherapy with immune checkpoint inhibitors is extensively investigated in urothelial carcinoma. Using this combination in the neoadjuvant setting for patients (pts) with MIUC might improve pathological response rate (PaR: <ypT2N0) but carries the risk of increased perioperative morbidity. Methods: SAKK 06/17 is an open-label single arm phase II trial for pts with operable MIUC cT2-T4a cN0-1. Treatment consists of 4 cycles of neoadjuvant cis/gem q3w in combination with 4 cycles durva 1500mg q3w followed by resection. Durva is continued after surgery q4w for 10 cycles. Primary endpoint is event free survival (EFS) at 2 years. 58 pts are needed based on type I error of 10% and a power of 80% for H1 EFS at 2 years ≥ 65% compared to H0 EFS at 2 years ≤ 50%. We report the secondary endoints PaR, pathological complete remission (pCR: ypT0 N0), and safety on the full analysis set (FAS, received at least one dose of durva). Results: 61 pts were included between 7/18 and 9/19 at 12 sites. The FAS consists of 58 pts (79% male, median age 67.5 yrs) with bladder cancer (95%) or upper urinary tract/urethral cancer (5%). Clinical T2, T3, T4 stage were present at diagnosis in 69%, 21%, 10%, respectively, and 17% had cN1. 95% of pts received all 4 doses of neoadjuvant durva, 81% all 4 cycles of cis/gem and 17% switched to carboplatin. In total grade 3 and 4 adverse events (AE) during neoadjuvant treatment occurred in 48% and 27%, respectively. AEs related to durva were G3 in 7 pts (12%) and G4 in one patient (2%). Resection was performed in 53 pts (91%; 51 radical cystectomy, 2 nephroureterectomy), 4 pts refused surgery and one patient was irresectable due to a frozen pelvis. R0 resection was achieved in 52 pts (98%), one had R1. Postoperative complications included Clavien-Dindo III in 13 pts (24%) and IV in 5 pts (9%). PaR was found in 60% (95% CI 46.0%-73.5%) with 18 pts achieving pCR (34%; 95% CI 21.5%-48.3%) and 14 patients (26%) ypT1/ypTis. Conclusions: The first FAS results for neoadjuvant durvalumab in combination with cis/gem for operable MIUC confirm elevated pathological response rates and demonstrate acceptable safety. Postoperative morbidity is relevant but not exceeding the expected frequency or severity. Clinical trial information: NCT03406650.