SUO 2023: Is Radioligand Therapy Safe for Patients With Prostate Cancer and Baseline Cytopenia?

By: Julia Fiederlein Cipriano, MS
Posted: Friday, December 1, 2023

Toxicity-related discontinuation of treatment with the radiolabeled antibody lutetium-177–PSMA-617 (177-Lu–PSMA-617) seldom occurred among patients with metastatic castration-resistant prostate cancer who had baseline cytopenias, based on the results of a real-world retrospective analysis presented during the 2023 Society of Urologic Oncology (SUO) Annual Meeting (Poster 28). However, according to Mohamed E. Ahmed, MD, of the Mayo Clinic, Rochester, Minnesota, and colleagues, this population has an overall poor prognosis.

“Results from the VISION trial led to the approval of 177-Lu–PSMA-617 for the treatment of metastatic castration-resistant prostate cancer,” the investigators commented. “The trial excluded patients with baseline cytopenias; thus, safety in this frequently encountered patient population was unknown.”

The investigators focused on 273 patients who received at least one dose of 177-Lu–PSMA-617 between April 2022 and December 2022. A total of 12% of this population had at least one cytopenia at baseline prior to their first cycle of treatment. Patients were categorized into the following poor marrow reserve cohorts based on pretreatment hematologic parameters: an anemia cohort with hemoglobin levels of less than 9 g/dL (76%); a thrombocytopenia cohort with platelet counts of less than 100 x 10⁹/L (12%); a leukopenia cohort with white blood cell counts of less than 2.5 x 10⁹/L (6%); or a multiple cytopenia cohort (6%).

Toxicity (n = 5), disease progression (n = 4), and death (n = 8) were reasons for discontinuation of therapy in this study population. Among those who stopped treatment with 177-Lu–PSMA-617 because of toxicity or disease progression, five deaths were documented. Worsening myelosuppression led to dose reductions and treatment delays in 24% and 24% of patients, respectively. A total of 78% of the study population required transfusions of packed red blood cells or platelets. Nearly half of patients (48%) received care in the emergency department or were hospitalized.

Disclosure: No information regarding conflicts of interest was provided.

2023 SUO Annual Meeting