Urovant Sciences said its experimental overactive bladder drug vibegron improved symptoms in a large mid-stage study, a welcome signal for the company as it evaluates the drug further in a phase III initiated earlier this year.
The phase IIb two-stage trial enrolled more than 1,300 patients with OAB symptoms. In the first stage, patients either received once-daily oral vibegron (3 mg, 15 mg, 50 mg or 100 mg), the urinary incontinence drug tolterodine (4 mg); or a placebo for eight weeks. In the second stage, patients were given either vibegron (100 mg); tolterodine (4 mg); a combination vibegron (100 mg) and tolterodine (4 mg); or placebo for four weeks. The objective of the study was to evaluate the safety and efficacy of vibegron as a once-daily oral treatment for OAB patients, regardless of urge incontinence.
Patients given the higher doses of vibegron (50 mg and 100 mg) experienced statistically significant decreases in the daily rate of urination (p=0.007 and p<0.001 respectively), urgency urinary incontinence episodes (p<0.001 and p<0.001 respectively), total incontinence episodes (p=0.005 and p=0.007) and urgency episodes (p=0.024 and p<0.001) at week 8. In the second tranche of the study, the efficacy of vibegron monotherapy on the primary endpoint — reduction in urination — was also statistically significant, the company said.
Tolterodine, sold as Detrol by Pfizer $PFE in the United States, belongs to a class of drugs called antimuscarinics that are designed to inhibit muscle contracture and have been the only available treatments for decades. But they’re not designed specifically for the bladder and are associated with a host of unpleasant adverse-effects, making them an unpopular choice with patients, especially in the elderly.
Trial data indicated that the magnitude of maximal responses with the two higher vibegron doses was often numerically greater than tolterodine, researchers wrote in the journal European Urology. “In addition, these results provide the proof of concept that concomitant dosing of vibegron and an antimuscarinic can produce modest symptom improvement versus an antimuscarinic alone”, they noted.
In the trial, all vibegron doses were well tolerated. The incidence of dry mouth was higher with patients given tolterodine than those on vibegron monotherapy, Urovant said.
The exact cause of OAB is unknown, which makes it difficult to treat. More than 30 million over the age of 40 suffer symptoms in the United States according to Urovant $UROV.
Urovant is one of Vivek Ramaswamy’s many “vants”, which are subsidiaries under the conglomerate Roivant Sciences brand. Last week Ramaswamy told Endpoints News at the #BIIS18 summit that his strategy can be understood as an “Alphabet for healthcare”, a reference to Google co-founder Larry Page’s playbook of setting loose Google, YouTube, and even companies like Calico and Verily as semi-autonomous units that are led by the mothership. To date, Ramaswamy has raised $3 billion for his companies and vibegron is one of 34 programs in the “vant” clinic.
Urovant in-licensed the global rights, including Japan, to vibegron — an oral beta-3 adrenergic agonist — from Merck $MRK. Vibegron is also being tested for the treatment of OAB in men with benign prostatic hyperplasia and the treatment of pain associated with irritable bowel syndrome. Meanwhile, Urovant’s second experimental treatment, hMaxi-K, is a gene therapy for patients with OAB symptoms who have failed oral pharmacologic therapy.
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