Chelsea Therapeutics (NASDAQ:CHTP) won’t meet with a U.S. Food and Drug Administration advisory committee to discuss drug candidate Northera for another 10 days, but CEO Simon Pedder used a biosciences conference today to preemptively defend the drug amid emerging agency concerns about Chelsea’s trials.

Pedder, speaking at the BIO CEO and Investor Conference in New York, said Chelsea was “surprised by the FDA’s characterization” of Northera’s safety profile.

The FDA briefing documents are not yet public but Pedder said that the FDA was concerned about the short duration of Chelsea’s clinical trials and the limited size of the study population. He said the FDA has put additional emphasis on safety data from long-term studies and post-marketing surveillance of the drug in Japan, where the compound was first developed and commercialized.

Northera is under a priority review as a treatment to help Parkinson’s patients who experience dizziness and fainting due to a sudden drop in blood pressure. The condition, called neurogenic orthostatic hypotension, or NOH, is common among Parkinson’s disease patients. The FDA granted the drug candidate orphan drug status in 2007. Last November, the FDA granted priority review for the drug candidate with a targeted March 28 decision date.

The compound that Chelsea calls Northera was licensed from Japanese pharma company Sumitomo Pharma Co., which called the drug droxidopa. The drug has been available in Japan since 1989. Chelsea said that its own studies showed that patients treated with Northera showed statistically significant improvement compared to those given a placebo. He added that serious adverse events were consistent with the study population.

Pedder did disclose that 19 patients died over the course of Northera’s development. But he emphasized that those deaths were not linked to the drug. One patient died prior to receiving Northera; another died after discontinuing Northera and resuming treatment on another drug. Of the remaining deaths, 11 were patients diagnosed with multiple system atrophy, a disease in which patients have a survival rate of seven to nine years from diagnosis. Investigators noted only three deaths as being possibly related to Northera. The drug has a strong safety record in Japan. A 10-year, post-marketing evaluation found no serious adverse events linked to droxidopa’s use.

“Based on all this information, we continue to believe that droxidopa is a very safe medication,” Pedder said.

Chelsea will find out if the Cardiovascular and Renal Drugs Advisory Committee feels the same way. The company’s meeting with the advisory committee is scheduled for Feb. 23. If the committee and the FDA continue to have lingering questions about Chelsea’s clinical safety data, those questions could delay Northera’s approval.

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