SIU 2017: MP15 – 04- Polymer Delivered, Subcutaneously Administered Leuprolide Acetate Achieves Effective Testosterone Suppression below Castration Levels

Lisbon, Portugal ( Polymer-delivered, subcutaneous leuprolide acetate (SC-LA) has previously been shown to suppress serum testosterone (T) levels in prostate cancer patients. Luteinizing hormone-releasing hormone agonists are currently dosed independently of body weight (BW) or age. Due to the importance of achieving low T during androgen deprivation therapy, the authors attempted to understand whether patient specific factors such as age or weight may need to be taken into consideration when choosing therapy. The objective was to determine if patient weight and age correlates with the pharmacodynamic profile of SC-LA in pivotal trials of all currently available formulations (1,3,4, and 6-month doses).

In 4 open-labels, single-arm, fixed dose, pivotal studies, male prostate cancer patients (age 40-86) were treated with 1, 3, 4, or 6-month SC-LA formulation. Blood was sampled at screening, baseline, 2, 4, 8 hours post dosing, days 1, 2, 3, 7, and every other week until end of each study. Serum T levels were measured by radioimmunoassay. Data were pooled across 4 studies and descriptive statistics were used to summarize concentrations at each time point and to determine time to T suppression.

The mean weight or age of patients was similar across all four studies. When patients were stratified by weight or age, the median serum T levels for all weight subgroups and all age subgroups achieved and maintained castration level by week 4 until the end of the study.

The authors therefore concluded that these results demonstrate that all SC-LA dose formulations consistently achieve and maintain T castration across all weight and age subgroups, including those with the highest BW (>90 kg) and age (>80 years). This suggests that weight does not require SCLA dose adjustment.

Presented by: Atkinson, S.

Written by: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre.Twitter: @GoldbergHanan at the 37th Congress of Société Internationale d’Urologie - October 19-22, 2017- Lisbon, Portugal