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# United Therapeutics Petitions FDA to Block Generic Tyvasco
- URL: https://www.fdaweb.com/united-therapeutics-petitions-fda-to-block-generic-tyvasco/
- Published: 2016-01-22T12:00:00.000Z
- Updated: 2026-09-15T02:30:02.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5134537

> United Therapeutics has petitioned FDA urging it to require strict bioequivalence standards for generic copies of its Tyvaso (treprostinil) inhalation solution. Tyvaso is a drug-device combination product indicated for treating pulmonary arterial hypertension in patients with specific symptoms to increase walk distance.  
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> The [petition](http://www.regulations.gov/contentStreamer?documentId=FDA-2016-P-0187-0001&attachmentNumber=1&disposition=attachment&contentType=pdf&ref=fdaweb.com), filed by the law firm Hogan Lovells, says the agency must refrain from approving an ANDA for a drug-device combination product if it “determines that (**a**) the proposed generic device and components differ in critical design attributes; (**b**) differences in the generic delivery system would require patients to be retrained in use of the device; (**c**) the generic product includes different conditions of use or otherwise requires labeling changes not permitted under section 505(j) of the FDCA; or (**d**) in order to be eligible for approval, the ANDA would need to contain human factors studies or other clinical trial data beyond what is required to show bioequivalence.