Xerostomia and ocular dryness as predictors of PSA response to Lu177-PSMA-617 in metastatic castration resistant prostate cancer.

Abstract

e17028 Background: Prostate specific membrane antigen (PSMA) is highly expressed in salivary and lacrimal glands. Dry eyes and/or mouth can occur with Lu177-PSMA-617 (PSMA Lu177) therapy in metastatic castration resistant prostate cancer (mCRPC) pts. We evaluated the difference between the presence of dry mouth/eyes with PSA responses in pts with mCRPC treated with PSMA Lu177. Methods: The Indiana University Prostate Cancer database was queried for pts with mCRPC who were treated with PSMA Lu177. Toxicities were documented throughout the course of treatment. Association of xerostomia and ocular dryness with PSA30 and PSA50 response was compared using the Chi Square test, or Fisher’s Exact test, if more appropriate. Results: Between 6/21/22-11/14/23, 107 pts with mCRPC were treated with PSMA Lu177 with at least 2 doses. Median age was 73 (56, 90). 86 pts had metastatic disease in bone, 65 lymph nodes, 11 lungs, 6 liver, and 2 brain. 39 pts had 1 prior ARPI, 68 pts had ≥2 prior ARPI. 17 pts had no prior taxane regimen, 45 had 1 prior taxane, 33 had 2 prior taxanes and 12 had ≥3 taxane regimens. 19 pts had prior PARP inhibitor. Median follow-up from start of PSMA Lu177 treatment was 8.3 months (1.4-18.7). 40 (37%) pts experienced dry mouth, 7 (7%) pts experienced dry eyes, and 6 (6%) pts experienced both. 65 (61%) pts achieved PSA30 response. 57 (53%) pts achieved PSA 50 response. Conclusions: The presence of dry eyes and/or dry mouth in pts with mCRPC treated with PSMA Lu177 was associated with improved PSA response. [Table: see text]