Dr. Tagawa on the Investigation of 225Ac-J591 and 177Lu-PSMA-I&T in mCRPC

Scott T. Tagawa, MD, MS, FACP, professor of medicine and urology, medical director, Genitourinary Oncology Research Program, Weill Cornell Medical College, attending physician, New York Presbyterian Hospital, discusses the investigation of ²²⁵Ac-J591 and ¹⁷⁷Lu-PSMA-I&T in metastatic castration-resistant prostate cancer in a phase 1/2 trial (NCT04886986).

In the initial dose-escalation phase 1 trial, patients are receiving a fixed dose of 6.8 GBq intravenous (IV) ¹⁷⁷Lu-PSMA-I&T every 3 weeks plus escalating doses of IV ²²⁵Ac-J591 in different cohorts, between 30 and 40 KBq/kg, Tagawa explains. Specifically, the 2 cycles of ²²⁵Ac-J591 are given 8 weeks apart, Tagawa adds.

Although the phase 1 trial is ongoing, ²²⁵Ac-J591 has appeared to be tolerable in 9 patients in 2 cohorts, Tagawa continues. No dose-limiting toxicities (DLTs) were observed in the initial 3 patients treated in the low-dose ²²⁵Ac-J591 cohort, Tagawa says. There have been no clear DLTs in the second cohort in ongoing follow-up. However, in early follow-up, 1 patient presented with grade 3 thrombocytopenia, Tagawa concludes.