AMBASSADOR / Alliance A031501
After radical surgery for high-risk muscle-invasive urothelial carcinoma, does adjuvant pembrolizumab improve DFS versus observation?
Biomarker / PD-L1
PD-L1 was centrally assessed with the Dako PD-L1 IHC 22C3 pharmDx assay. PD-L1-positive was defined as CPS ≥10; 57.5% of enrolled patients were PD-L1-positive. DFS benefit was not restricted to PD-L1-positive disease: HR 0.81 (95% CI 0.61–1.08) for CPS ≥10 versus HR 0.71 (95% CI 0.53–0.95) for CPS <10. PD-L1 status was therefore not predictive of pembrolizumab benefit in this trial.
Absolute Effect
No fixed-time DFS percentage was reported in the primary abstract, so an NNT is not manufactured from the median DFS or HR.
Clinical burden: The absolute increase in grade ≥3 AEs was 19.0 percentage points, but this is not labelled NNH because the Atlas rule reserves NNH for a clearly defined clinically central fixed-time harm endpoint.
Key limitation: The trial's perioperative risk population was heterogeneous and included patients with and without prior neoadjuvant cisplatin-based chemotherapy.
Primary source
Apolo AB, et al. N Engl J Med. 2024;391:1534–1546.