Phase 3 Trial to Evaluate Overall Survival in 320 Patients with Anti-PD-(L)1-Resistant Disease

EA8231 is an open-label, randomized Phase 3 clinical trial led by the ECOG-ACRIN Cancer Research Group, enrolling 320 patients with unresectable, locally advanced, or metastatic urothelial carcinoma. Participants must have prior exposure to anti-PD-1/PD-L1 therapy and, in principle, prior exposure to an FGFR inhibitor in patients with FGFR3 mutations, reflecting current treatment sequences. The trial commenced in October 2025 and compares a Trodelvy/Keytruda combination arm with an investigator-selected chemotherapy arm in a 1:1 ratio. The primary endpoint is overall survival (OS), with a target hazard ratio (HR) of 0.70, designed to directly demonstrate survival benefit in later-line therapy.

TROP2 ADC and PD-1 Inhibitor: A Strategy to Overcome Resistance

Trodelvy (sacituzumab govitecan-hziy) is an antibody-drug conjugate (ADC) that links a TROP2 antibody to the topoisomerase I inhibitor SN-38. Keytruda (pembrolizumab) is an approved immune checkpoint inhibitor that blocks PD-1 on T cells. In this study, 200mg of Keytruda will be administered every three weeks, and 10mg/kg of Trodelvy will be administered on days 1 and 8 of each cycle. This approach aims to link ADC-induced tumor cell death and antigen release to immune reactivation, thereby circumventing resistance after prior PD-(L)1 therapy. However, the risk of severe neutropenia and diarrhea associated with Trodelvy means that G-CSF prophylaxis and safety management will be crucial for the practicality of the combination therapy.

Re-evaluating a Withdrawn Indication with a Randomized Phase 3 Trial

On April 13, 2021, the FDA granted accelerated approval for Trodelvy in urothelial carcinoma progressing after platinum-based chemotherapy and PD-1/PD-L1 inhibitor therapy. However, because the confirmatory TROPiCS-04 trial did not meet its overall survival endpoint, the approval was withdrawn on November 22, 2024. Therefore, EA8231 is not a study that simply repeats a previous single-agent regimen but rather a high-risk, re-entry strategy to re-establish clinical value with Keytruda combination therapy. The control arm consists of gemcitabine and cisplatin/carboplatin or docetaxel/paclitaxel, directly competing with current later-line treatment options. Keytruda received FDA full approval on December 15, 2023, for its use in combination with Padcev (enfortumab vedotin-ejfv) as a first-line treatment, so a key question is whether the same PD-1-based treatment can be successfully reused in a later-line, resistant setting.

Targeting a Later-Line Treatment Gap in a $3.68 Billion Market

The global market for metastatic urothelial carcinoma was estimated at $3.68 billion in 2025. With the Padcev/Keytruda combination reshaping first-line treatment, patients who progress after this therapy represent a new commercial segment. Competing options include Padcev, a Nectin-4-targeted ADC from Astellas Pharma and Pfizer, Balversa (erdafitinib), an FGFR2/FGFR3 inhibitor from Janssen, and platinum/gemcitabine and taxane-based chemotherapy. EA8231 targets a later-line setting with relatively less competition, including patients who have progressed after Padcev and appropriate FGFR inhibitor therapy. Demonstration of OS superiority is essential to offset the history of withdrawal and the burden of toxicity and to restore the value of Trodelvy in urothelial carcinoma.