United Therapeutics is vying for approval of Tyvaso (treprostinil) in idiopathic pulmonary fibrosis (IPF) after a positive Phase III trial.
During the TETON-2 study (NCT05255991), the inhaled prostacyclin mimetic provided significant improvements to forced vital capacity (FVC), causing a 95.6mL increase from baseline. FVC is a key measure of breathing restriction – a characteristic symptom of IPF.
The systemic vasodilator also prolonged the time to a patient’s first clinical worsening event, meeting its key secondary endpoint.
After 52 weeks, Tyvaso was also demonstrated to heighten predicted King’s Brief Interstitial Lung Disease quality of life questionnaire (K-BILD) and diffusion capacity of lungs for carbon monoxide (DLCO) scores.
Tyvaso failed to meet its other secondary endpoints of time to first acute exacerbation and overall survival (OS), however, United noted that both trended towards the drug over placebo.
Following the positive results of the TETON-2 study, United is seeking approval from the US Food and Drug Administration (FDA) for Tyvaso in IPF. However, the company is still awaiting results from the TETON-1 trial (NCT04708782), which is testing a nebulised form of the drug, before submitting. TETON-1 is set to read out in the first half of 2026.
In the meantime, United plans to meet with the US regulator before the end of 2025 to discuss the potential expedition of the regulatory review process once these results are available. Both the FDA and the European Medicines Agency (EMA) have granted the drug orphan designation in IPF.
Tyvaso was first approved by the FDA in 2009 for the treatment of pulmonary arterial hypertension (PAH) (WHO Group 1). It gained a second approval for pulmonary hypertension with interstitial lung disease (PH-ILD) (WHO Group 3) in 2021.
Tyvaso’s future potential
Though around 3 million people are affected by IPF globally, treatment options are currently limited. Currently, only Boehringer Ingelheim’s Ofev (nintedanib) and Roche-owned Genentech’s Esbriet (pirfenidone) plus its generics are available to patients.
Filippos Maniatis, senior healthcare analyst at GlobalData, noted that Tyvaso could alter the treatment paradigm significantly. “Tyvaso’s Phase III TETON-2 data in IPF is a major advance, as the therapy achieved a significant improvement in FVC versus placebo, while meeting several key secondary endpoints – including quality of life,” he said.
Maniatis also celebrated Tyvaso’s capacity to both improve outcomes in patients on background anti-fibrotic therapy and maintain a consistent safety profile, which he believes could position the drug as a “transformative addition to the limited treatment landscape for IPF – holding the potential to quickly redefine the SoC for this disease”.
Though Maniatis believes that these Phase III results could allow United to acquire market share from Boehringer and Roche, subject to approval, he noted that the route and administration and dosage in IPF patients “may not be ideal” due to issues with patient compliance.
If Tyvaso were to be approved in IPF, it would likely face stiff competition from Boehringer’s Ofev follow-up nerandomalist, which is currently under FDA priority review in the indication. This follows the positive results of two Phase III trials involving the phosphodiesterase 4B (PDE4B) inhibitor, which were debuted earlier this year.
