Timing and Dosing Effects of Leuprolide Injections in Patients With Prostate Cancer
Posted: Friday, April 3, 2020
Patients with advanced prostate cancer treated with leuprolide injections for androgen-deprivation therapy are associated with improved survival when achieving and sustaining testosterone levels below 20 ng/dL. However, in between treatments, testosterone levels may rise to or above castration levels (50 ng/dL), especially when subsequent injections are delayed. Based on their findings, Przemyslaw Twardowski, MD, of the John Wayne Cancer Institute, Duarte, California, and colleagues, suggested that testosterone levels need to be safely and effectively monitored to improve patient outcomes. The report was originally planned for presentation at the 2020 NCCN Annual Conference (Abstract CLO20-063) but was published in the JNCCN–Journal of the National Comprehensive Cancer Network.
The research team evaluated the frequency of late dosing of leuprolide injections in patients with prostate cancer by retrospectively reviewing electronic medical records and claims data of 78,464 leuprolide injections. Late dosing was defined as that occurring after days 32, 97, 128, and 194 for 1-, 3-, 4-, and 6-month injections, respectively.
Overall, 26.8% of leuprolide injections were considered to be late dosing. When late dosing occurred, there was a higher proportion of tests with testosterone levels that were higher than 20 ng/dL compared with on-time or early testing. In addition, late injections were correlated with ineffective testosterone suppression. When injections were considered to be late dosing, 42% of testosterone levels exceeded 20 ng/dL, compared with just 21% for early and on-time injections.
Moreover, the research team found that testosterone levels were not monitored nearly as frequently as prostate-specific antigen (PSA) levels. A PSA value was drawn prior to dosing for 83% of leuprolide injections. However, just 14% of injections had a similarly timed testosterone assessment.
Disclosure: Drs. Atkinson and Boldt-Houle are employees of Talmar Pharmaceuticals, Inc. Dr. Concepcion has served as a consultant/advisor for Talmar Pharmaceuticals, Inc. Dr. Twardowski reported no conflicts of interest.
