Proffered Paper session 1: GU tumours, renal & urothelial

Dr Jeremy Blanc, medical oncologist at the Jules Bordet Institute in Brussels, presented the highlights from the first GU proffered paper session, which focused on recent advances in urothelial carcinoma. 

NMIBC represents approximately 75% of all urothelial carcinomas. It arises from the bladder mucosa without invading the detrusor muscle. The current standard of care involves TURBT followed by intravesical BCG therapy. Two studies—ALBAN and POTOMAC—investigated the potential benefit of adding immune checkpoint inhibitors to standard BCG therapy. The ALBAN trial evaluated one year of atezolizumab combined with BCG, while the POTOMAC trial tested one year of durvalumab plus BCG. Although both included high-risk NMIBC populations (TA, T1, and carcinoma in situ), the ALBAN cohort comprised slightly lower-risk patients. Results diverged significantly: ALBAN was negative, showing no added benefit from atezolizumab, whereas POTOMAC demonstrated improved DFS with durvalumab. These contrasting findings underscore the challenges of integrating immunotherapy in NMIBC and highlight the importance of patient selection. The results complement prior data from the CREST trial and suggest that while some high-risk patients may benefit from checkpoint blockade, lower-risk individuals likely derive sufficient benefit from BCG alone. Importantly, immune checkpoint inhibition is associated with increased toxicity—grade ≥3 adverse events in 20–30% of cases—necessitating careful patient–physician discussions regarding risk–benefit balance.

The remaining three studies addressed MIBC in neoadjuvant, adjuvant, and metastatic settings. The GDFather-NEO trial explored a novel combination of neoadjuvant nivolumab with an anti–GDF-15 antibody, targeting the TGF-β pathway. Conducted in cisplatin-ineligible patients (approximately 30 enrolled), the regimen demonstrated feasibility, manageable toxicity, and encouraging preliminary activity, suggesting a potential strategy for patients lacking standard chemotherapy options.

An updated five-year analysis of the CheckMate 274 trial reaffirmed the durable benefit and safety of adjuvant nivolumab in MIBC. ctDNA analyses further indicated that ctDNA-positive patients derived the greatest advantage, reinforcing ctDNA’s potential role as a predictive biomarker for adjuvant immunotherapy efficacy.

Finally, the DISCUS trial examined the optimal number of chemotherapy cycles preceding avelumab maintenance in mUC, prior to the adoption of the EV–pembrolizumab regimen as the new standard of care. The study compared three versus six cycles of chemotherapy, showing that three cycles provided comparable disease control with improved quality of life and reduced toxicity. Although OS data remain immature, these findings may guide treatment in settings where EV–pembrolizumab is unavailable or contraindicated.