FDA Issues Complete Response Letter for Tyvaso DPI

The agency cited an open inspection issue at a facility that performs analytical testing of drug substance.

The FDA has issued a complete response letter for United Therapeutics’ new drug application for Tyvaso DPI (treprostinil), for the treatment of pulmonary arterial hypertension and pulmonary hypertension associated with interstitial lung disease.

The regulatory agency noted a deficiency related to an open inspection issue at a third-party facility that performs analytical testing of treprostinil drug substance.

Tyvaso DPI is a drug-device combination therapy comprised of a dry powder inhalation formulation of treprostinil. It was developed through a collaboration with MannKind, which developed the inhalation technology that is also used in MannKind’s Afrezza (insulin human) inhalation powder product.

A nebulized formulation of Tyvaso is already available to treat pulmonary arterial hypertension and pulmonary hypertension associated with interstitial lung disease.

United Therapeutics submitted the NDA for Tyvaso DPI in April 2021. The application was based on the BREEZE clinical study evaluating the use of the DPI formulation in patients who transitioned from the inhalation solution, with additional pharmacokinetic data from healthy volunteers.

Company officials expect the DPI version to be available by the summer of 2022. “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, Ph.D., chairperson and chief executive officer of United Therapeutics, said in statement.