Clinical implementation of 177Lu-PSMA-617 (LuPSMA) at a major academic center: Initial experiences.

108 Background: LuPSMA received FDA approval in March 2022 for patients with PSMA-positive metastatic castrate-resistant prostate cancer (mCRPC). Clinical implementation of this treatment requires multidisciplinary team (MDT) involvement and has been beset by challenges in drug supply. We established a joint DFCI GU/Nuclear Medicine Tumor Board (GU-NM TB) to review patients for therapy, and our initial experiences are described. Methods: A joint GU-NM TB was established. All patients with mCRPC who had received at least one prior chemotherapy and a novel hormonal agent were considered eligible and referred to TB through an online referral system after undergoing PSMA-PET/CT. Case details, including prior treatment history, performance status and organ function, and PET/CT imaging were reviewed at TB, with patients either being approved, deferred, or declined for LuPSMA therapy. Patients were scheduled for therapy on a first-come first-served basis. Treatment was delivered per standard-of-care at 180-200 millicurie doses every 6 weeks within NM. A questionnaire was sent to 25 referring physicians 2 months after implementation of the TB to evaluate the referral process. Results: Between May-September 2022, a total of 108 patients were referred for LuPSMA therapy. Median age at time of referral was 73 (range 52-93), and 90% of patients were Caucasian. Median duration between PSMA-PET/CT and TB review was 10 days (IQR 6-17). 84 patients (78%) were approved for therapy, 16 (15%) were deferred and 7 (6%) were declined (reasons including absence of prior chemotherapy, high risk for toxicities, poor performance status); 1 patient died before TB review. Prior therapies included docetaxel (84%), cabazitaxel (56%), abiraterone (67%), enzalutamide (57%), darolutamide (23%), radium-223 (21%) and apalutamide (7%). Median number of prior treatments was 4 (range 2-12). Sites of disease on PSMA-PET/CT included bone (81%), pelvic lymph nodes (42%), extrapelvic lymph nodes (88%), lung (27%) and liver (22%). As of September 2022, a total of 40 patients (48%) have received at least 1 cycle of therapy and 17 (20%) have received 2 cycles; 6 patients (7%) approved for therapy died before receiving 177Lu-PSMA-617. Of the patients that have received 1 cycle of therapy, median duration between TB acceptance and C1 was 52 days (range 32-114). Out of 13 survey respondents, all 13 (100%) reported that their overall experience of the referral process was positive or very positive, and 12 (92%) noted that the Tumor Board had provided additional clinical insights on occasion or frequently. Conclusions: Due to drug supply shortages, <50% of patients approved for LuPSMA therapy have started treatment to date. Median time between TB approval and start of therapy was 7-8 weeks, with 7% of patients dying before receiving therapy. Establishment of a GU-NM TB to review cases and facilitate treatment was viewed favorably by treating physicians.