In December 2020, Urovant gained FDA approval of its NDA (New Drug Application) for once-daily 75mg GEMTESA® (vibegron), which is a beta-3 receptor agonist. The medication will be available April 2021. The onset of action is faster like current anti-cholinergics without the often-intolerable side effects of dry mouth, dry eyes and constipation. In my practice the only available beta-3 agonist (Mirabegron) is the OAB medication of choice 95% of the time due to the increased risk of dementia with tertiary amine anticholinergics (~46% with only 3 months of use). With a quicker onset of action 2-week samples will be utilized over 4-week samples (Mirabegron 50mg) which will hopefully engage more patients and reduce attrition.

Clinical data for GEMTESA demonstrated clear efficacy for reducing the OAB symptoms of urinary frequency, urge urinary incontinence, and urgency. The medication relaxes the detrusor bladder muscle allowing for more urine storage thus reducing OAB symptoms. There were no adverse hypertension events compared to placebo during the EMPOWUR study, which is a positive given the risk of increased blood pressure with Mirabegron which often limits its use. Also, GEMTESA did not interact with medications metabolized by CYP2D6 which Mirabegron can thus narrowing its use. The trial leading to FDA approval involved 4,000 OAB patients in a 12-weekdouble blind, placebo-controlled Phase 3 trial. A long-term extension study was also performed with sustained results. The most common adverse reactions in ≥2% of patients were headache, nasopharyngitis, diarrhea, nausea, and upper respiratory tract infection. Patients with poor emptying might not be suitable candidates given the increased risk of urinary retention (inability to urinate). Also, patients on digoxin should not take GEMTESA.

OAB occurs when the bladder muscle contracts involuntarily which causes symptoms of urinary urgency, urge incontinence (loss of urine associated with urgency), frequent urination (>8X in 24 hours) and nocturia (>2X waking up to urinate). More than 30 million American suffer from bothersome chronic OAB yet up 72% of patients quit OAB meds within 6 months due to poor efficacy, intolerance or cost.

Hopefully, GEMTESA pricing will be reasonable since coverage for Mirabegron can be very poor or a prior authorization nightmare preventing its use even when efficacious, tolerated and the desired patient treatment option. Given GEMTESA’S competitive efficacy and more acceptable side effect profile we anticipate treating more patients with this OAB medication depending on affordability. I look forward to updating my Care pathway with a 2-week samples of GEMTESA for most. Also, many patients need to fail 2 OAB medications prior to PTNS authorization so instead of a toxic Anti-Cholinergic trial I plan on using Mirabegron as the 2nd medication to try and fail given its safer profile. Even if patients will eventually need a 3rd line therapy (PTNS, SNM or Botox) due to poor efficacy, rare side effects or high cost, GEMTESA will hopefully improve 3rd line penetration, decrease attrition and shorten follow-up times. I look forward to adding this evolved medication option to my OAB toolbox and using it to treat more patients overall since so many remain frustrated and poorly managed.

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