Solabegron Advances To Phase 2B Trials for Overactive Bladder

James Walker

The novel, once-daily formulation selective beta-3 agonist solabegron is being investigated to fill unmet need in balanced therapy for overactive bladder (OAB).

Velicept Therapeutics, a specialty pharmaceutical company focused on urological and gastrointestinal compound therapies, has announced the initiation of the first of a couple phase 2B clinical studies testing solabegron in patients with OAB. The studies will primarily evaluate the mean change in number of micturitions per day, as logged regularly by patients.

Researchers will compare daily micturition rates from baseline to week 12, James Walker, president and chief executive officer of Velicept Therapeutics, told MD Magazine. Patients with OAB generally urinate more than 8 times per day — a major infliction to their quality of life (QOL).

“You have this condition, a huge quality-of-life issue, and the drugs either don’t provide enough efficacy, or it’s a tolerability issue,” Walker said.

Raoul Concepcion, MD, director of the Comprehensive Prostate Center, told MD Magazine that, depending on the sophistication of a urologist, OAB patients are susceptible to falling through the cracks.

“I think people - especially because I do believe that especially women, do tend to present a little bit later - they think that [OAB] is manageable,” Concepcion said. “If they don't get that feeling like this particular practitioner is interested more than [just giving them first-line therapy], they probably won't come back.”

The field of OAB therapy is dichotomized between antimuscarinics and beta-3 agonists. Though the former is often more efficacious, its clinical history shows an imbalance between efficacy and tolerability, and patients often “end up rolling off the therapy.” Beta-3 agonists are more consistently tolerable, and now Velicept wants solabegron to report stronger efficacy.

Prior phase 2 trials have reported just that, Walker said. A previous study conducted by GlaxoSmithKline, published in 2016, tested twice-daily solabegron in 258 patients with moderate-to-severe incontinence. Patients were experiencing a mean 4.5 wet episodes per day.

Patients to receive solabegron reported statistically significant improvement in wet episodes versus patients on placebo, and a safety and tolerability profile that was similar to the placebo group.

“When you look at side-by-side results, there’s a substantial increase of efficacy we should see in these studies,” Walker said. “Efficacy is what’s going to rule the day in terms of therapies in this area.”

The second phase 2B to be conducted by Velicept will be a multicenter, randomized, double-blind, vehicle-controlled trial that will enroll 375 women aged 18-80, with symptoms of OAB. Women were recruited from 90 health care centers across North America. The patients will receive 125 mg or 175 mg solabegron twice daily, or placebo, over 12 weeks.

Walker said the plan is to present topline data at the end of 2018, or beginning of 2019, and select doses for phase 3 trial.

“If we see those positive results, that will greatly help the OAB space,” Walker said.