Manufacturer:
Astellas Pharma
Pharmacological Class:
Beta-3 adrenergic agonist.
Active Ingredient(s):
Mirabegron 25mg, 50mg; extended-release tablets.
Indication(s):
Treatment of overactive bladder (OAB) with symptoms of urge urinary incontinence, urgency, and urinary frequency.
Pharmacology:
Mirabegron is an agonist of the human beta-3 adrenergic receptor. It relaxes the detrusor smooth muscle during the storage phase of the urinary bladder fill-void cycle by activation of beta-3 AR which increases bladder capacity.
Clinical Trials:
Myrbetriq was evaluated in three, 12-week, double-blind, randomized, placebo-controlled, parallel group, multicenter studies in patients with OAB with symptoms of urge urinary incontinence, urgency, and urinary frequency (Studies 1, 2, and 3). Entry criteria required that patients had symptoms of OAB for at least 3 months duration, at least 8 micturitions per day, and at least 3 episodes of urgency with or without incontinence over a 3 day period. The population included both naïve patients who had not received prior antimuscarinic pharmacotherapy (48%) and those who had received prior antimuscarinic pharmacotherapy (52%).
In Study 1, patients were randomized to placebo, Myrbetriq 50mg, Myrbetriq 100mg, or an active control once daily. In Study 2, patients were randomized to placebo, Myrbetriq 50mg or Myrbetriq 100mg once daily. In Study 3, patients were randomized to placebo, Myrbetriq 25mg or Myrbetriq 50mg once daily.
The co-primary efficacy endpoints in all 3 trials were (1) change from baseline to end of treatment (Week 12) in mean number of incontinence episodes per 24 hours and (2) change from baseline to end of treatment in mean number of micturitions per 24 hours, based on a 3-day micturition diary. An important secondary endpoint was the change from baseline to end of treatment in mean volume voided per micturition.
At Week 12, treatment with Myrbetriq 25mg and 50mg resulted in statistically significant improvement in efficacy parameters of incontinence episodes and number of urinations per 24 hours. In treatment with Myrbetriq 25mg, incontinence episodes were reduced by 1.36 episodes from a baseline of 2.65, a statistically significant reduction of 0.40 vs. placebo. The number of urinations was reduced by 1.65 urinations from a baseline of 11.68, a statistically significant reduction of 0.47 vs. placebo. In treatment with Myrbetriq 50mg, incontinence episodes were reduced by 1.49 episodes from a baseline of 2.71, a statistically significant reduction of 0.40 vs. placebo. Number of urinations was reduced by 1.75 urinations from a baseline of 11.70, a statistically significant reduction of 0.55 vs. placebo.
Legal Classification:
Rx
Adults:
Swallow whole. Initially 25mg once daily. May increase to 50mg once daily as needed or tolerated. Severe renal impairment or moderate hepatic impairment: max 25mg once daily. End-stage renal disease (ESRD) or severe hepatic impairment: not recommended.
Children:
Not established.
Warnings/Precautions:
Severe uncontrolled hypertension: not recommended. Monitor blood pressure periodically. Significant bladder outlet obstruction, patients taking antimuscarinic drugs for OAB: risk of urinary retention. Pregnancy (Category C). Nursing mothers: not recommended.
Interaction(s):
May potentiate CYP2D6 substrates (eg, metoprolol, desipramine). Adjust dose and monitor esp. with narrow therapeutic index drugs metabolized by CYP2D6 (eg, thioridazine, flecainide, propafenone). Concomitant digoxin: use lowest digoxin dose initially (monitor and titrate).
Adverse Reaction(s):
Hypertension, nasopharyngitis, urinary tract infection, headache.
How Supplied:
Tabs—30, 90
Last Updated:
10/15/2012
膀胱过度活动症新药Myrbetriq获FDA批准
近日，美国食品药品管理局（FDA）批准了安斯泰来公司治疗成年人膀胱过度活动症(OAB)的新药Myrbetriq（mirabegron，米拉贝隆）。Myrbetriq是缓释片剂，每日一次用药，该药在膀胱充盈时通过放松膀胱肌肉来提高膀胱存储容量。OAB的症状包括尿频、尿急和尿失禁。
三项双盲、安慰剂对照、多中心临床试验评价了Myrbetriq的安全性和有效性。共有4116名OAB患者参与了试验，患者被随机分到25mg，50mg，100mg Myrbetriq治疗组和安慰剂组，每天用药一次，治疗12周。
结果表明，Myrbetriq 25mg和50mg可有效地减少患者排尿以及在24小时内发生意外排尿的次数。Myrbetriq 50mg组的患者排尿量更加显著，证明该药物可有效提高膀胱存储容量。
在试验中，Myrbetriq最常见的不良反应为血压升高，其他常见的副作用包括感冒症状（鼻咽炎）、尿路感染、便秘、疲劳、心动过速、腹痛。严重不可控的高血压、终末期肾脏疾病或严重肝损伤患者禁用Myrbetriq。