Pioneering drugs for overactive bladder and detrusor overactivity: Ongoing research and future directions

Managing urinary incontinence in women - a review of new and emerging pharmacotherapy

INTRODUCTION

The pharmacological treatment of urinary incontinence and overactive bladder (OAB) has been, for a longer time, based on antimuscarinic agents. In recent years, two other pharmacological principles have been introduced for the treatment of OAB and urgency urinary incontinence: the β3-adrenergic agent mirabegron and botulinum neurotoxin. Meanwhile, there is lack of effective drugs for the treatment of stress incontinence.

AREAS COVERED

This literature review presents synthetic compounds aimed to treat female urinary incontinence that are in phase II-III clinical development.

EXPERT OPINION

Antimuscarinic agents will continue to represent the current gold standard for the first-line pharmacological management of OAB and urgency urinary incontinence. The class of β3-agonists will certainly expand with the discovery and clinical development of novel agents. Combination therapy of antimuscarinic agents and β3-agonists could offer an alternative treatment in these patients, including those with symptoms refractory to first-line monotherapy. A huge number of preclinical studies are underway in this field exploring the therapeutic potential of many novel compounds while some have advanced to clinical phases of development.

Purinergic Signalling: Therapeutic Developments

Purinergic signalling, i.e., the role of nucleotides as extracellular signalling molecules, was proposed in 1972. However, this concept was not well accepted until the early 1990's when receptor subtypes for purines and pyrimidines were cloned and characterised, which includes four subtypes of the P1 (adenosine) receptor, seven subtypes of P2X ion channel receptors and 8 subtypes of the P2Y G protein-coupled receptor. Early studies were largely concerned with the physiology, pharmacology and biochemistry of purinergic signalling. More recently, the focus has been on the pathophysiology and therapeutic potential. There was early recognition of the use of P1 receptor agonists for the treatment of supraventricular tachycardia and A2A receptor antagonists are promising for the treatment of Parkinson's disease. Clopidogrel, a P2Y12 antagonist, is widely used for the treatment of thrombosis and stroke, blocking P2Y12 receptor-mediated platelet aggregation. Diquafosol, a long acting P2Y2 receptor agonist, is being used for the treatment of dry eye. P2X3 receptor antagonists have been developed that are orally bioavailable and stable in vivo and are currently in clinical trials for the treatment of chronic cough, bladder incontinence, visceral pain and hypertension. Antagonists to P2X7 receptors are being investigated for the treatment of inflammatory disorders, including neurodegenerative diseases. Other investigations are in progress for the use of purinergic agents for the treatment of osteoporosis, myocardial infarction, irritable bowel syndrome, epilepsy, atherosclerosis, depression, autism, diabetes, and cancer.