Astellas Pharma and Seagen have reported positive topline data from the Phase Ib/II EV-103 clinical trial (KEYNOTE-869) Cohort K of Padcev (enfortumab vedotin-ejfv) plus Keytruda (pembrolizumab) as first-line therapy for unresectable locally advanced or metastatic urothelial cancer (la/mUC) patients. 

A randomised cohort, EV-103 Cohort K is analysing enfortumab vedotin alone or along with pembrolizumab as first-line therapy for unresectable la/mUC patients, ineligible for cisplatin-based chemotherapy. 

According to the trial findings from this cohort, the combination therapy offered a confirmed objective response rate (ORR) per blinded independent central review (BICR) of 64.5%, the primary endpoint. 

Astellas noted that the median duration of response (DOR) per BICR was not attained. 

Rash maculo-papular, anaemia, lipase increased and urinary tract infection among others were the most commonly reported treatment-emergent adverse events Grade 3 or greater reported in over 5% of trial subjects. 

These results are generally in line with priorly reported efficacy and safety data from the EV-103 dose-escalation cohort and expansion Cohort A.

Astellas Development Therapeutic Areas senior vice-president and head Ahsan Arozullah said: “Approximately half of patients with advanced urothelial carcinoma are ineligible for cisplatin-based chemotherapy. 

“We intend to discuss Cohort K results with regulatory authorities as we seek to develop a new first-line treatment combination for these patients.”

Keytruda is an anti-PD-1 therapy of Merck.

Currently, Astellas, Seagen and Merck are analysing enfortumab vedotin plus pembrolizumab as part of a partnership, which includes three Phase III trials.

In May last year, Astellas and Seagen reported data from EV-201 and EV-103 trials where Padcev offered durable responses in locally advanced or metastatic urothelial cancer patients.