US FDA reaffirms hold on oral Proellex trials prompting Repros rethink
The Texan firm mooted the change of development strategy in a financial filing this week, explaining it “is assessing increasing its focus on its uterine fibroid and endometriosis development program utilizing a vaginal drug delivery program for telapristone acetate [Proellex].”
CEO Larry Dillaha said: “Our discussions with the FDA, and their guidance that a large safety data base will be required to continue the development of Proellex, indicate that a much larger clinical trial, with associated time and cost requirements, would be necessary."
Liver concerns
The US Food and Drug Administration (FDA) ordered Repros to halt clinical trials of oral Proellex in 2009 after a number of patients demonstrated increased liver enzyme activity, which can be an indication of toxicity.
The agency later downgraded the clinical hold to a partial clinical hold, allowing Repros to trial a low dose oral version of the drug.
However, Repros subsequent efforts to have the partial hold lifted have not been succesful.
Delivery tech
According to Repros the vaginally-delivered formulation of Proellex has shown promise.
Dillaha explained that: “Clinical work done to date suggests that vaginal delivery of telapristone acetate has the potential to yield good efficacy with significantly lower systemic blood levels.“
He added: “We intend to leverage drug delivery technology that could offer dosing less frequently than once per day."
