medwireNews: Updated data from the phase 3 EV-301 study show that treatment with enfortumab vedotin (EV) remains associated with improved outcomes relative to standard chemotherapy in individuals who have received prior treatment for advanced urothelial carcinoma (UC).
“After a median follow-up period of ≈2 years, EV maintained a clinically meaningful and significant OS [overall survival] benefit versus chemotherapy consistent with findings from the primary efficacy results” in a prespecified interim analysis, said Jonathan Rosenberg (Memorial Sloan Kettering Cancer Center, New York, USA) and colleagues in a poster presented at the 2022 ASCO Annual Meeting, held in Chicago, Illinois, USA.
In the trial, 608 patients with locally advanced or metastatic UC that had progressed after platinum-based chemotherapy and PD-1 or PD-L1 inhibitor therapy were randomly assigned to receive either EV at a dose of 1.25 mg/kg on days 1, 8, and 15 of each 28-day cycle or investigator’s choice of docetaxel 75 mg/m2, paclitaxel 175 mg/m2, or vinflunine 320 mg/m2 on the first day of each 21-day cycle.
The current analysis – conducted at a median follow-up of 23.75 months – showed a significant 30% reduction in the risk for death with EV versus chemotherapy as well as a median OS time that was 3.97 months longer with EV, at 12.91 and 8.94 months, respectively.
The risk reduction was identical to that seen in the earlier analysis at a median follow-up of 11.1 months, and the median OS durations were similar, at 12.88 months for EV and 8.97 months for chemotherapy.
Furthermore, EV continued to be associated with a significant improvement in progression-free survival relative to chemotherapy in the updated analysis, with a hazard ratio for progression or death of 0.63, as well as with a significantly higher overall response rate, at 41.3% versus 18.6%.
Rosenberg and co-investigators highlighted that “EV adverse events continued to be manageable and no new safety signals were observed.”
They added that “[r]ates of treatment-related adverse events (TRAEs) were unchanged from the interim analysis,” with grade 3 or more severe TRAEs experienced by 52.4% of EV-treated participants and 50.5% of those given chemotherapy. Maculopapular rash was the most common TRAE of this severity in the EV group, observed in 7.4% of patients, while decreased neutrophil count was most frequent in the chemotherapy group, at 14.1%.
TRAEs led to discontinuation in 15.2% and 12.4% of the EV and chemotherapy arms, respectively, and these rates were slightly higher than the corresponding 14.0% and 11.0% rates reported in the previous analysis. But the investigators highlighted that there were “no additional TRAEs leading to death” in either treatment group with longer follow-up, and the respective rates remained at 2.4% and 1.0%.
Matthew Milowsky (The University of North Carolina at Chapel Hill, USA) – who commented on the poster at a discussion session – said that “enfortumab vedotin remains a standard of care for patients with metastatic urothelial cancer, with a sustained magnitude of benefit and similar safety profile as initially reported in EV-301.”
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This independent news story was supported by an educational grant from Pfizer and Merck Healthcare KGaA, Darmstadt, Germany