The FDA declined to approve United Therapeutics’ application for its dry powder inhalation version of Tyvaso after finding a problem during a manufacturing site inspection.
The agency’s complete response letter cited an issue at the “third-party” facility that conducts analytical testing for the medicine, United said.
United Therapeutics filed for FDA approval of Tyvaso DPI in April and was gearing up to double the number of patients on the drug through a potential launch of the new version next year. The application was for use of Tyvaso DPI in pulmonary arterial hypertension and pulmonary hypertension associated with interstitial lung disease.
“We are confident that the single deficiency identified in the complete response will be resolved quickly and that Tyvaso DPI can receive approval by the summer of 2022, if not earlier,” Martine Rothblatt, chief executive of United Therapeutics, said in a statement.
As part of the complete response, the FDA noted it continues to review a Citizens Petition submitted to the agency in July regarding the safety of an ingredient in Tyvaso DPI, the company said.
United Therapeutics has bet heavily on the success of the drug, having spent $105 million to acquire a voucher from Y-mAbs Therapeutics that would shorten its FDA review by four months.
Meanwhile, a potential rival from Liquidia Technologies has experienced its own struggles with gaining FDA approval. The agency handed down a complete response letter to Liquidia last year, citing issues in the chemistry, manufacturing and controls data on the drug product and device compatibility.