Siamak Daneshmand, MD, discusses findings from the interim analysis of cohort 3 of the multicohort phase 2 THOR-2 trial.
Siamak Daneshmand, MD, professor, Urology with Clinical Scholar designation, director, Clinical Research, fellowship director, Urologic Oncology, the University of Southern California, discusses findings from the interim analysis of cohort 3 of the multicohort phase 2 THOR-2 trial (NCT04172675).
Cohort 3 is evaluating erdafitinib (Balversa), a selective pan-FGFR TKI, in 20 patients with recurrent, intermediate-risk non–muscle invasive bladder cancer (NMIBC) with grade 1 or 2 tumors that have FGFR3 or FGFR2 alterations. Patients needed to have less than a 5% risk of progression in the 2 years following enrollment and a risk of recurrence over 50% to be eligible for this cohort. Patients who achieved a partial response (PR) or complete response (CR) within 3 months of starting erdafitinib could continue erdafitinib for up to 2 years, until progressive disease, intolerable toxicity, withdrawal of consent, treatment discontinuation per investigator decision, or trial closure.
Cohort 3 has an exploratory end point of CR rate, with safety as a key secondary end point. At a data cutoff of September 2022, 11 patients have been enrolled and 10 have received erdafitinib. This interim analysis reported findings from the first 8 evaluable patients.
Patients in cohort 3 underwent transurethral resection of their bladder tumors that left a single untouched 5- to 10-mm marker lesion. After their initial marker lesions were photographed, patients in cohort 3 received 6 mg of oral erdafitinib once daily without uptitration in 28-day cycles, Daneshmand says. When assessed at 6 weeks for safety, some patients’ marker lesions showed partial or complete responses, Daneshmand notes.
Patients received erdafitinib for a median duration of 2.9 months. At a median follow-up of 5.7 months from first erdafitinib dose, 7 patients had responded, with 6 achieving CRs, for a CR rate of 75.0%, and 1 achieving a PR, Daneshmand emphasizes. Additional results from all 20 patients in the cohort are still immature, Daneshmand concludes.