Dr Nizam on Enfortumab Vedotin After Maintenance Avelumab in Urothelial Cancer

Amanda Nizam, MD, Department of Hematology and Medical Oncology, Cleveland Clinic, discusses findings from the retrospective UNITE study of enfortumab vedotin-ejfv (Padcev) following switch maintenance avelumab (Bavencio) in patients with advanced urothelial carcinoma who were responsive to initial platinum-based chemotherapy.

Among evaluable patients (n = 41), the overall response rate (ORR) was 54%. In the intention-to-treat population (n = 49), the ORR was 45%. Direct comparisons between these findings and those from the phase 3 EV-301 trial (NCT03474107) are not possible because EV-301 included patients who were not responsive to platinum-based chemotherapy, Nizam says. However, in EV-301, which evaluated enfortumab vedotin vs chemotherapy in patients with previously treated advanced urothelial carcinoma, the ORR with enfortumab vedotin was 41.32% (95% CI, 35.57%-47.25%).

In UNITE, the median progression-free survival (PFS) from the start of enfortumab vedotin therapy was 7.0 months (95% CI, 5.8-13.3), which is similar to the median PFS with enfortumab vedotin in EV-301 of 5.55 months (95% CI, 5.32-6.28), Nizam notes. Furthermore, the median overall survival (OS) from the start of enfortumab vedotin therapy was 13.3 months (95% CI, 10.8-not reached), which was also similar to the median OS with enfortumab vedotin in EV-301, which was 12.91 months (95% CI, 11.01-14.92), Nizam explains.

In UNITE, the median OS from the start of platinum-based chemotherapy was 22.5 months, Nizam says, noting that this finding was observed as an exploratory end point because it was not reported in EV-301. Although this median OS seems relatively short, the UNITE registry included many patients who were eligible to receive enfortumab vedotin because they experienced short times to progression on maintenance avelumab, according to Nizam. Thus, patients in this registry are likely to have a lower median time on maintenance avelumab than what may be observed in the real world, Nizam says.

For instance, in the phase 3 JAVELIN Bladder 100 trial (NCT02603432) of maintenance avelumab in patients with advanced or metastatic urothelial carcinoma, the median time on avelumab was 24.9 weeks (range, 2.0-159.9). In UNITE, the median time on maintenance avelumab was 3.5 months (range, 0.2-22.3), which contributed to the shorter median OS from the start of platinum-based chemotherapy, Nizam explains.

Overall, the findings from UNITE were consistent with those from EV-301, although the designs of these trials prevent direct comparisons, Nizam emphasizes. However, these findings support the use of enfortumab vedotin following platinum-based chemotherapy and checkpoint inhibitors in patients with platinum-responsive disease, Nizam concludes.