Foresee Pharmaceuticals has reported positive results from its Phase 3 clinical trial assessing FP-001 LMIS — a ready-to-use, testosterone-lowering treatment — in patients with advanced prostate cancer. Suppressing serum testosterone was the single-arm study’s primary goal.

The active agent in FP-001 LMIS, leuprolide mesylate, is a long-acting gonadotropin-releasing hormone (GnRH) agonist. Using GnRH agents for short periods can cause testosterone levels to rise, while sustained use is known to desensitize GnRH receptors and reduce testosterone production to castration levels.

GnRH agonists that are on the market have complicated dosage forms and must be mixed right before they are used, Foresee said on its website. The company said its product is more stable than other treatments, and it can be manufactured in a ready-to-use syringe.

In the open-label, Phase 3 trial (NCT02234115), 137 patients received two doses of FP-001 LMIS, one on the first day and one six months later. Of the initial participants, 124 completed the study.

The primary efficacy endpoint was the percentage of patients whose serum testosterone was suppressed to  50 nanograms per deciliter (ng/dL) by day 28, and from day 28 to 336. Ninety percent of the patients had to hit that mark for the study to reach its endpoint, and results showed 97% of patients did.

By day 28, mean testosterone concentration was suppressed to 17.6 ng/dL — below castrate levels — and 135 patients achieved medical castration. There was no mean increase in testosterone after the second injection.

Overall, the treatment was found to be well-tolerated, with safety data similar to marketed GnRH agonists.

“We are excited about the successful top-line results of FP-001 LMIS,” Ben Chien, PhD, chairman and CEO of Foresee, said in a news release. “Our Stabilized Injectable Formulation platform technology overcomes the technical barriers that our competitors have had over the years in generating a stable, premixed, prefilled version of leuprolide depot for injection.”