Shares of San Diego-based Apricus Biosciences ($APRI) were crushed this morning after the biotech reported that its experimental testosterone-boosting drug had failed both the primary and secondary endpoints in a Phase IIb study among men with secondary hypogonadism and sexual dysfunction. And the setback raises some additional issues for the entire drug class.
Researchers noted that fispemifene at 450 mg did boost testosterone among the men in the study, but failed to improve erectile function or low libido, missing out on providing a clear clinical benefit--an urgent necessity in the wake of the FDA's increased vigilance on testosterone therapies. As a result, the biotech plans to bury the program and focus on other work.
The biotech's shares were routed on the news, plunging by about half. The drop left the company's shares in penny stock territory.
"We are obviously disappointed with these results," said Apricus CEO Richard Pascoe. "As a consequence of these results, we will discontinue all development of fispemifene in symptomatic secondary hypogonadism, and focus our resources on our other homegrown pipeline assets."
Testosterone replacement therapies have come under scrutiny at the FDA, where regulators have grown increasingly alarmed at the prospect of the overuse of the treatments, worried about evidence of increased risk of heart attacks and strokes. As a result, regulators have sought to limit treatment to a narrow group of patients who would clearly benefit from their use.
After the FDA rejected Repros' testosterone therapy recently, Apricus says it affirmed its study design on fispemifene with regulators, centering on clinical benefit measures. That raised regulatory bar will likely plague other developers in the field. And Apricus signaled that their failure could have significant implications for the class.
"While we did see statistically meaningful changes in testosterone levels into the low normal ranges with fispemifene, the compound's ability to increase those levels sufficiently to demonstrate clinical benefit is limited, and may be an issue with the entire SERM class," said Dr. Barbara Troupin, chief medical officer of Apricus. "The regulatory benchmark for approval of a compound in secondary hypogonadism in men is the achievement of a symptomatic clinical benefit, using patient-reported outcome measures in a defined patient population. Achievement of biochemical or PK normalization of testosterone into the low normal range is not sufficient for regulatory purposes."
- here's the release