CPP-115, for which Catalyst has initiated Phase I trials, might hold even more promise than Catalyst’s vigabatrin formulation CPP-109, which is now in Phase II-B trials, because its increased potency might open the door to more effective routes of administration and because it might be less likely to lead to the visual field defects that have been associated with use of vigabatrin.
A GABA aminotransferase inhibitor, vigabatrin presently is sold under the brand name Sabril as an anticonvulsant and for treatment of infantile spasms (West syndrome). CPP-115 is a second-generation GABA aminotransferase inhibitor.
Addiction professionals who want to see new breakthroughs in medication treatments for substance dependence have been particularly focused to the absence of medication options in the stimulant addiction category. I discussed this with Catalyst executives, who highlighted the overall lack of medication options outside of replacement therapies for most types of substance addiction. Medication compliance issues remain a significant concern for drug companies as they look at product development leads.
“The majority of the drugs out there are replacement therapies, and with the receptors occupied, those drugs don’t have compliance concerns,” says Steven R. Miller, PhD, Catalyst’s chief scientific officer and chief operating officer. “Even alcohol [treatment] has a compliance problem; that’s why [injectable] Vivitrol was developed.”
Compliance issues were at the heart of the setback Catalyst experienced in 2009 when its Phase II-A trial of CPP-109 showed no statistical difference in the effectiveness of the medication and of placebo. Analysis of the results revealed that subjects’ medication compliance rate was less than 40%, and at one of 11 study sites the compliance rate was actually 0%.
Company CEO Patrick McEnany says the Phase II-B research for CPP-109 has included several adjustments made to ensure that researchers are working with a committed, treatment-seeking population, such as the inclusion of clients from facilities that specialize in the treatment of addicts.