NeurogesX Shares Plunge After FDA Staff Says Pain Patch Might Not Work

NeurogesX Inc. plunged the most in almost three years after U.S. regulators questioned whether the specialty drugmaker proved its patch relieves pain related to nerve damage commonly associated with HIV.

NeurogesX fell 24 percent to 88 cents at the close of New York trading, its biggest decline since March 2009. The company, which hasn’t reported an annual profit since selling shares in 2007, has fallen 83 percent in the past 12 months.

Food and Drug Administration staff raised questions in a report today about whether the prescription-strength capsaicin patch called Qutenza proved “substantial efficacy” in treating pain caused by neuropathy linked to the virus. Advisers to the agency are scheduled to meet Feb. 9 to discuss San Mateo, California-based NeurogesX’s patch.

“It was a mixed data set to begin with so it’s not surprising to see some criticism on the part of the agency,” Gregory Wade, an analyst with Wedbush Securities Inc., said in a telephone interview.

Wade said he expects a panel recommendation in favor of approval. Still, a Qutenza clearance for HIV patients won’t change an “absence of success with its existing marketplace,” he said.

“I don’t think there is a great difference between the market for HIV and what it addresses now,” Wade said.

Nerve Damage

One-third of people with HIV/AIDS experience peripheral nerve damage caused by the virus or drugs used to treat it, according to the Center for Peripheral Neuropathy at the University of Chicago. More than 1.1 million in the U.S. are estimated to be infected with HIV, according to the Atlanta- based Centers for Disease Control and Prevention.

“It would not be in the best interest of these patients for us to approve a product for which substantial evidence of efficacy has not been demonstrated, or one for which the benefits do not clearly outweigh the risks,” Bob Rappaport, director of the agency’s division of anesthesia, analgesia and addiction products, wrote in a letter in the report.

The FDA is scheduled to decide whether to approve Qutenza by March 7. The agency doesn’t have to follow the advisory panel’s recommendation.

No Drugs

No FDA-approved drugs exist for HIV-associated neuropathy, according to NeurogesX. Painkillers and narcotics are recommended to treat the condition, according to the Center for Peripheral Neuropathy. Capsaicin is the chemical that makes chili peppers hot.

The FDA approved Qutenza in November 2009 for lasting pain after a shingles infection. The product sells for $675 a patch and has almost 1,000 customers, Anthony DiTonno, former president and chief executive officer, said at the Lazard Healthcare Conference, according to a Nov. 18 transcript.

The FDA found one test showed Qutenza worked when used for 90 minutes and failed to show effectiveness when used for an hour or 30 minutes. Later analyses based on alternative testing showed the 30-minute application worked, the agency said.

Qutenza failed to show efficacy in both hour-long and 30- minute uses in a second study, according to FDA’s staff report. Again using alternative testing later, the patch showed it worked in the 30-minute application.

The agency is asking the advisory panel to determine whether the studies provided substantial evidence the patch works for HIV-associated neuropathy and whether Qutenza should be approved.

To contact the reporter on this story: Anna Edney in Washington at aedney@bloomberg.net

To contact the editor responsible for this story: Adriel Bettelheim at abettelheim@bloomberg.net

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