Best Practices for Limiting Treatment Cancellations of Lutetium -177 PSMA-617

Introduction: Radiopharmaceutical therapy using PSMA-617 (Lu-177 PSMA), approved by the U.S. Food and Drug Administration in March 2022, prolongs survival of patients with metastatic castrate-resistant prostate cancer (mCRPC).At a growing theranostic practice in a high-volume cancer treatment center, we notice treatment cancellations are a common occurrence. Without a two-week notice of cancellation to treatment date, an ordered dose will still be delivered to the site and may be discarded, leading to waste, financial loss, and further delays in treatment for patients waiting to access the Our clinical practice team sought to delineate the reasons for treatment cancellations to identify strategies to mitigate cancellations as patient treatment volumes grow.

Methods: A retrospective chart review of patients who had a documented treatment cancelation resulting in a discarded dose was performed to include injection date, dose sequence, reason for cancelation, and how many days prior to injection date the dose was canceled. Cancellations were further delineated into clinical vs. non-clinical causes.

Results: In a five-month period from June 14^th, 2022, to November 13^th, 2022, 119 doses (71 patients) of Lu-177 PSMA were successfully administered, and 28 treatments (26 patients) were cancelled, resulting in discarded doses. 24 doses were discarded for clinical and 2 for non-clinical reasons. Clinical causes included rapid clinical decline prior to or while receiving treatment with transition to hospice or subsequent death (14 doses, 50%), treatment rescheduled or stopped due thrombocytopenia, (4 doses, 14%), ), and disease progression resulting in change of therapy (2 doses, 7%). Both treatments cancelled for . For the remaining 2 doses, the cause could not be determined due to lack of .

Conclusions: Most treatment cancellations were the result of patients with rapidly progressing disease. With the recent FDA approval in 2022, the patients who were referred first had advanced disease, most with no treatment options . Additionally, unprecedented demand relative to supply has caused delays in initiating treatment in a timely manner. This further increased the likelihood of clinical decline or receiving ineffective temporizing treatments. . Creating a pool of eligible patients who are awaiting treatment and reallocating canceled treatments to these patients could also be an effective way of mitigating discarded doses. expect that increased production capacity for Lu-177 PSMA and more inclusive insurance approvals will lead to greater and timely access to Lu-177 PSMA