Neoadjuvant treatment with enfortumab vedotin (EV) monotherapy has promising antitumor activity in patients with muscle-invasive bladder cancer (MIBC) who are ineligible for cisplatin-based chemotherapy, according to initial results from a phase 1b/2 clinical trial presented at the ASCO Genitourinary Cancers Symposium 2022.
The findings are important because no standard of care exists for neoadjuvant treatment in this patient population, according to principal investigator Daniel P. Petrylak, MD, professor of medicine (medical oncology) at Yale School of Medicine in New Haven, Connecticut.
EV is an antibody-drug conjugate directed to Nectin-4, which is highly expressed in urothelial cancer. Phase 2 and 3 clinical trials have demonstrated that the therapy benefits patients with locally advanced or metastatic urothelial cancer.
The initial results are from an analysis of 22 patients in the EV-103 Cohort H trial (ClinicalTrials.gov Identifier: NCT03288545), which enrolled patients with cisplatin-ineligible cT2-T4aN0M0 MIBC who were eligible for radical cystectomy plus pelvic lymph node dissection (RC+PLND) and had an ECOG score of 0-2. Patients received 3 cycles of neoadjuvant EV (1.25 mg/kg) on days 1 and 8 of every 3-week cycle prior to RC+PLND. The primary endpoint was pathologic complete response (ypT0N0) by central review. All patients underwent surgery, and no surgeries were delayed.
Of the 22 patients, 36% had a pathologic complete response, with no signs of cancer in a microscopic examination of bladder tissue during surgery. Adverse events were consistent with the known safety profile of EV. The most common treatment-related adverse events (TRAEs) with EV were fatigue (45.5% of cases), alopecia (36.4%), and dysgeusia (36.4%).Grade 3 or higher TRAEs with the drug developed in 18.2% of patients.
Petrylak DP, Flaig TW, Mar N, et al. Study EV-103 Cohort H: Antitumor activity of neoadjuvant treatment with enfortumab vedotin monotherapy in patients (pts) with muscle invasive bladder cancer (MIBC) who are cisplatin-ineligible. Presented at ASCO GU 2022; February 17-19, 2022. Abstract 435.