Shares of Westlake Village-based MannKind Corp. dropped 18% on Oct. 18, after the U.S. Food and Drug Administration did not approve a hypertension treatment the company is developing with United Therapeutics.
In a complete letter response, the FDA declined to approve a new drug application for Tyvasio DPI, a treatment being developed by MannKind and United for pulmonary arterial hypertension and pulmonary hypertension associated with interstitial lung disease, MannKind said in a statement.
The FDA’s letter detailed just one deficiency in the companies’ application, related to an open inspection issue at a third-party facility that performs analytical testing for United of treprostinil, the active ingredient of Tyvaso DPI, according to the statement. Tyvaso is a drug-device combination consisting of a dry powder formulation of treprostinil and MannKind’s inhaler as a delivery device.
The FDA did not cite any deficiencies or issues related to operations performed at MannKind’s facilities for manufacture, testing, and packaging of finished Tyvaso DPI, including its associated device, according to the company’s statement.
“There’s not much we could have done,” MannKind CEO Michael Castagna told the Business Times. “That’s just part of the industry.”
Castagna said he spoke with shareholders on Oct. 18, and they understood the FDA letter did not reflect issues with the treatment itself.
“Our shareholders understand the benefit now, since we know this drug is approvable, we know there’s no major issues, so there’s more positives than negatives at this point,” Castagna said.
But that didn’t stop the market from reacting negatively.
MannKind’s stock closed at $4.16 on Oct. 18, down from $5.09 the day before.
The stock was near its high point for the year during the previous week, closing at $5.35 on Oct. 13. Even with the 18% drop on Oct. 18, the stock has more than doubled in value in the past year.
United Therapeutics will be moving the treprostinil testing to its own facility, Castagna said, and will file again with the FDA. The company originally filed its new drug application in April.
In a company statement, United CEO Martine Rothblatt said she hopes the testing issue can be resolved in time for the FDA to approve Tyvaso DPI in the summer of 2022, if not earlier.
Castagna said United has been “a great partner,” and this setback won’t stop the companies from pursuing approval for the treatment.
“I think the anger that comes from stuff like this when it happens, it will get you that much more excited to see this become successful,” Castagna said. “In three years we went from signing a deal to almost getting that drug to market. … Now it’s just a matter of how quickly we can turn it around.”
In better news for the company, Castagna told the Business Times that United Therapeutics has agreed to a 10-year agreement to supply Tyvaso. This is a longer-term commitment than the companies’ original five-year deal, he said.
“This shows the long-term commitment to manufacturing here in Danbury, Connecticut, with the expectation that it’ll be here for a while,” Castagna said.