US FDA approves Avanir involuntary emotion drug

US health regulators on Friday approved Avanir Pharmaceuticals Inc's Zenvia, a treatment for a neurological disorder in which patients cannot control outbursts of crying or laughter. US Food and Drug Administration spokeswoman Sandy Walsh said the agency had approved the long-delayed drug. Zenvia is the first drug approved for the treatment of the little known, but not that rare, condition called pseudobulbar affect (PBA), which is also known as involuntary emotional expression disorder. Analysts expect Zenvia to garner peak US sales of $350 million to $500m ,and Avanir shares rose 15 per cent in light after-hours trading on Friday.

The approval could make Avanir an attractive acquisition target for larger companies desperate for new products that don't carry the risk of FDA rejection faced by promising experimental medicines. PBA affects an estimated two million Americans suffering from multiple sclerosis, Lou Gehrig's disease (ALS), stroke and other neurological disorders or trauma that can cause brain lesions. Avanir suffered a major blow four years ago, when the FDA rejected Zenvia and asked for new trials due to safety concerns. The FDA was uneasy about the heart rhythm impact of quinidine, a component of the drug used to increase the amount of the active ingredient, dextromethorphan, in the body.