🔬 Great summary by @niklas_kluemper on KEYNOTE-905/EV-303 at #ESMO2026. Let me add the pathology angle, because his key question is ours to answer.
The ad hoc analysis, 255 concurrently randomised, cisplatin-ineligible:
📊 2-yr EFS 41% / 56% / 76% (cystectomy / pembro / EV+P)
🔬 pCR 10% / 25% / 59%
📉 EFS HR 0.71 (0.47–1.07) for pembro, 0.40 (0.25–0.65) for EV+P
⚠️ Grade ≥3 TEAEs 42% / 70% / 69%
Two things I keep coming back to 🧠
1️⃣ The toxicity numbers look reassuring and are not. 70 vs 69% grade ≥3 says EV adds no extra severe events, but a single rate collapses two very different profiles. Neuropathy, skin and metabolic toxicity in a curative-intent setting are not interchangeable with immune-related events, and they persist in survivors. Equal rates, unequal consequences.

2️⃣ 41% of patients on EV+P still have residual disease. We will not find them just with a IHC cutoff. Membranous Nectin-4, read on the membrane only, together with histological subtype and divergent squamous differentiation, is the most informative combination we already have and routinely leave unmeasured.
And a pathology point that follows directly: once pCR carries this much weight, ypT0N0 at cystectomy becomes a high-stakes diagnosis. Thus, Sampling protocols and regression assessment need to be standardised and centrally reviewed, not left to local practice. 🎯

Also worth stating plainly: this is an ad hoc comparison, not a powered head-to-head. Pembro alone did not separate from surgery here (CI crosses 1). Interpret the three-arm ranking accordingly.
Looking forward to Sunday's symposium. 🎤
ESMO 2026 | KEYNOTE-905/EV-303 | Abstract 4733O
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