NIAGARA Trial Overview
Design: A global, randomized, open-label Phase III trial (NCT03732677) including cisplatin‑eligible adult patients with clinical stage T2–T4a N0/1 M0 muscle-invasive urothelial carcinoma. Participants were randomized 1:1 to: Experimental arm: Neoadjuvant durvalumab (1500 mg IV every 3 weeks) + gemcitabine/cisplatin for 4 cycles → radical cystectomy → adjuvant durvalumab (8 cycles, every 4 weeks). Control arm: Gemcitabine/cisplatin for 4 cycles → radical cystectomy alone. Endpoints: Co‑primary: Event-free survival (EFS) and pathologic complete response (pCR). Key secondary: Overall survival (OS), metastasis‑free survival (MFS), disease‑specific survival, and safety.
Key Efficacy Findings
Pathologic Complete Response (pCR): Durvalumab + chemo: 37.3% Chemo alone: 27.5% (Odds Ratio ~1.6; P = 0.0005) Event-Free Survival (EFS): HR = 0.68 (95% CI: 0.56–0.82; P < 0.0001) 24‑month EFS: 67.8% vs. 59.8% Median EFS not reached in the durvalumab group versus 46.1 months in control. Overall Survival (OS): HR = 0.75 (95% CI: 0.59–0.93; P = 0.0106) 24‑month OS: 82.2% vs. 75.2% Metastasis‑Free Survival (MFS): HR = 0.67 (95% CI: 0.54–0.83; P < 0.001) 24‑month MFS: 75.1% vs. 65.1% Disease‑Specific Survival: HR = 0.69 (95% CI: 0.52–0.91; P = 0.008) 24‑month rate: 89.2% with durvalumab vs. 82.2% with chemo alone. Benefit Regardless of pCR Status: Patients who achieved pCR still had improved outcomes with durvalumab (EFS HR 0.58; OS HR 0.72). Those who did not achieve pCR also benefited (EFS HR 0.77; OS HR 0.84).
Safety & Surgical Outcomes
Radical cystectomy completion: Durvalumab arm: 88% Control arm: 83% Adverse events (AEs): Grade 3–4 AEs: ~69% in durvalumab vs. 68% in control. Treatment‑related AEs: ~41% in both arms. Immune-related AEs (e.g., hypothyroidism) occurred in ~21% (mostly low grade). No significant increase in surgical complications or delays.
Regulatory Impact
Based on these results, the FDA approved durvalumab in March 2025 for use with gemcitabine‑cisplatin as neoadjuvant therapy followed by adjuvant durvalumab post-cystectomy in resectable muscle‑invasive bladder cancer.
Bottom line: The NIAGARA trial supports the addition of perioperative durvalumab to standard chemotherapy as a new, potentially practice‑changing standard of care for cisplatin‑eligible muscle‑invasive bladder cancer, offering significant improvements in survival outcomes with manageable safety.