Chelsea wins FDA nod for once-spurned Northera, but success isn't guaranteed

In its second trip through the FDA, Chelsea Therapeutics' ($CHTP) antidizziness drug came out a winner, securing approval to fight faintness in patients with a rare disorder, but not without a daunting label and some strings attached.

Northera is now approved to treat lightheadedness associated with neurogenic orthostatic hypotension (NOH), a blood-pressure-lowering disorder tied to neurodegenerative ailments like Parkinson's disease. Chelsea intends to launch the oral drug in the second half of the year, targeting a U.S. patient population the company said is as large as 150,000. Analysts figure the drug could top out between $300 million and $450 million a year, although Chelsea has yet to discuss its pricing.

But the company may not be able to pull off a speedy launch of the once-rejected drug thanks to Northera's label. The treatment will carry a black-box warning due to its risks of increasing patients' blood pressure while they're lying down, and the FDA is cautioning those taking Northera to sleep with their heads elevated to cut back on the drug's stroke dangers. Furthermore, because the agency approved the drug through its accelerated orphan pathway, regulators looked at only two-week efficacy data and thus consider Northera's long-term benefits undemonstrated.

Investors seemed to struggle with what to make of the strongly worded label, as Chelsea's shares initially dipped on the postmarket announcement before soaring more than 30%. The Northera saga has made for some years-long bipolarity for Chelsea's stock price, but, hovering around $6.70 on Tuesday evening, the company's postapproval value is its highest since January 2011.

No matter Wall Street's reaction, the approval is a net win for Chelsea and Dainippon Sumitomo, which holds Asian rights to the drug. Northera is the first new NOH treatment in nearly 20 years, according to the company. Chelsea has a game plan for expanding its market share, preparing for a placebo-controlled study on about 1,400 patients with hopes of "definitively" proving Northera's lasting clinical benefit, the company said.

Safety concerns are hardly new for Northera, which endured an FDA rejection in 2012 due in part to agency worries about the hypertension risks now spelled out on its label. After piling on more efficacy data, Chelsea still faced some serious skepticism from FDA staff in the second go-round, but a panel of advisers voted in favor of approval in part because of the lack of viable treatments for NOH sufferers.

- read Chelsea's announcement
- here's the FDA's release