ASCO20: LuPSMA Versus Cabazitaxel in Metastatic Castration-Resistant Prostate Cancer
Posted: Friday, June 5, 2020
According to findings from the TheraP trial, presented during the ASCO20 Virtual Scientific Program (Abstract 5500), lutetium Lu 177–prostate-specific membrane antigen–617 (LuPSMA) may result in survival benefits for patients whose metastatic castration-resistant prostate cancer progressed after docetaxel treatment. LuPSMA is a radiolabeled small molecule that targets PSMA-expressing tumors.
“In men with docetaxel-treated [metastatic castration-resistant prostate cancer], LuPSMA was more active…than cabazitaxel, with relatively fewer [grade 3 or 4 adverse events], and [prostate-specific antigen [PSA] progression-free survival] favoring LuPSMA,” concluded Michael S. Hofman, MBBS, of the Peter MacCallum Cancer Centre, Melbourne, and colleagues.
The phase II trial included 200 men with metastatic castration-resistant prostate cancer who were randomly assigned to receive either 6 to 8 GBq of LuPSMA every 6 weeks for up to 6 cycles (n = 99) or 20 mg/m2 of cabazitaxel every 3 weeks for up to 10 cycles (n = 101). A total of 17 participants died or withdrew from the study prior to receiving treatment.
Patients who received LuPSMA had the higher PSA response rate by a significant margin (66% vs. 37%). At a median follow-up of 11.3 months, the group treated with LuPSMA also experienced improvement in PSA progression-free survival (hazard ratio = 0.63; P = .007). Outcomes with LuPSMA remained superior when analyses were limited to include men treated per-protocol alone. Overall survival could not yet be calculated; 57 deaths had occurred at the time of presentation, and none were thought to be related to treatment.
A total of 31 men in the LuPSMA group and 42 men in the cabazitaxel group experienced grade 3 or 4 adverse events. One patient who received LuPSMA and three patients who received cabazitaxel discontinued treatment due to toxicity.
Disclosure: The study authors reported no conflicts of interest.
