The Teton-2 Study: a new therapeutic approach to idiopathic pulmonary fibrosis
By Prof. Luca Richeldi
In recent years, research into idiopathic pulmonary fibrosis (IPF) has made significant progress, but the available treatment options remain limited. For over a decade, the approved anti-fibrotic drugs – pirfenidone and nintedanib – have represented the standard of care, primarily capable of slowing the decline in lung function without, however, completely halting the progression of the disease.
It is against this backdrop that the TETON-2 study, recently published in the New England Journal of Medicine, evaluated the efficacy of a new therapeutic strategy based on the inhaled administration of treprostinil in patients with IPF.
Study design
TETON-2 is a phase 3, randomised, double-blind, placebo-controlled clinical trial conducted internationally in patients diagnosed with idiopathic pulmonary fibrosis.
The study enrolled 597 patients, with a mean age of 72 years, and a mean forced vital capacity (FVC) of approximately 77% of the predicted value. Approximately three-quarters of participants were already receiving background anti-fibrotic therapy with pirfenidone or nintedanib.
Patients were randomised to receive:
- inhaled treprostinil via a nebuliser
- or placebo
for a duration of 52 weeks.
The primary efficacy endpoint of the study was the change in forced vital capacity (FVC) over time, one of the main indicators of the progression of pulmonary fibrosis.
Key results of the study
The TETON-2 study demonstrated that treatment with inhaled treprostinil is associated with a statistically significant reduction in the decline in lung function compared with placebo.
In particular:
- a significant improvement in FVC was observed compared with the placebo group
- a reduction in events of clinical worsening was recorded
- improvements were also observed in some secondary endpoints, including carbon monoxide diffusion capacity (DLCO) and patients’ quality of life.
Overall, the treatment showed consistent benefits across different patient subgroups, regardless of concomitant use of other antifibrotic agents, smoking status or use of oxygen therapy.
A particularly interesting aspect is that this is the first evidence that an inhaled therapy can slow the progression of pulmonary fibrosis as measured by FVC.
Why the inhaled route is innovative
One of the most distinctive features of the treatment evaluated in the TETON-2 study is its inhaled administration.
This route allows for:
- achieving a higher concentration of the drug in the lungs
- reducing systemic exposure
- potentially improving tolerability.
Treprostinil is a prostacyclin analogue, already used in the treatment of pulmonary arterial hypertension, and possesses vasodilatory, anti-inflammatory and potentially anti-fibrotic properties.
A possible shift in therapeutic paradigm
The results of the TETON-2 study suggest that the addition of inhaled therapy could represent a new complementary strategy to the anti-fibrotic drugs already available.
The possibility of using a drug with a different mechanism of action paves the way for a multimodal approach to the treatment of idiopathic pulmonary fibrosis, similar to that seen in other complex chronic diseases.
Future prospects
The TETON-2 study is just one part of a broader research programme that also includes the ongoing TETON-1 trial, aimed at confirming and expanding these results.
If further studies confirm the current data, inhaled treprostinil could become the first inhaled anti-fibrotic therapy for patients with idiopathic pulmonary fibrosis.
This could help expand the therapeutic arsenal available for a disease that remains one of the most serious and progressive interstitial lung diseases today.
The TETON-2 study represents an important step forward in research into idiopathic pulmonary fibrosis. The introduction of therapies with new mechanisms of action and new routes of administration could herald a new phase in the management of the disease.
Although further data and confirmation from future studies are needed, these results suggest that the combination of different therapeutic strategies could help alter the natural history of pulmonary fibrosis in the coming years.