Salix Pharmaceuticals (NASDAQ:SLXP) says it is working with the Food and Drug Administration on a path forward for a constipation drug blocked from approval last year.
While the outcome of those talks is unclear, CEO Carolyn Logan is firm that the company believes no additional clinical trials on Relistor are necessary.
“We think we’ve got enough to get an approval,” she said on a conference call to discuss first quarter financial results in which Salix reported increased sales.
Last July, the FDA declined approval on the Raleigh company’s application to expand use of Relistor. Salix licensed Relistor from New Jersey pharma Progenics in 2011. The drug is already approved for patients who manage advanced illness with opioids, pain-killing drugs that can also cause constipation by interacting with receptors in the gastrointestinal tract. Relistor counteracts those constipating effects without diminishing the pain-relieving properties of opioids. The drug is used in patients when laxatives don’t work.
Salix wants to expand use of the drug to patients taking opioids for non-cancer pain. The FDA issued a complete response letter asking for more data. Logan said on Thursday that Salix has appealed the FDA decision.
Despite Salix’s position, the FDA might insist on more tests for Relistor. After a meeting last fall with the FDA’s Division of Gastroenterology and Inborn Errors Division, Salix said that the division expressed concern that there may be a risk associated with the chronic use of such drugs in patients taking opioids for chronic pain. The division believes a chronic administration trial will be needed to assess the safety. Salix has said it believes currently available pre-clinical and clinical data, along with post-marketing studies will be enough to expand Relistor’s use. On Thursday, Logan said it isn’t possible to determine how long the appeals process will take, but she said the company expects a path forward could be reached this year.
The FDA’s decision on Relistor last summer led Salix to halt plans to hire a sales force of 160 representatives to market the drug. Expanded use of Relistor would help Salix continue to grow sales of the product. Prescriptions of the drug were up 52 percent year over year, according to first quarter financial results. CFO Adam Derbyshire said the drug accounted for $7.6 million in first quarter sales.
Most of Salix’s revenue comes from its top drug Xifaxan, approved to treat traveler’s diarrhea as well as hepatic encephalopathy, a a brain disorder associated with severe liver disease. Of the company’s $202.6 million in first quarter revenue, $153.3 million came from Xifaxan.
But the FDA stymied Salix’s attempt to expand uses of for Xifaxan. The FDA in 2011 did not approve the Salix’s application to add irritable bowel syndrome with diarrhea as a new indication for the drug. The agency called for another clinical trial. Enrollment is continuing and Logan said Salix expects an FDA decision on Xifaxan in mid-2014.
Meanwhile, Salix continues other efforts to expand Xifaxan’s use. The company has developed a new extended intestinal release formulation that could be used to treat Crohn’s disease. A phase II dose-ranging study is expected to start in the second quarter.
