5 Pulmonology Headlines You Missed in May 2026

May 2026 was defined largely by the American Thoracic Society (ATS) International Conference, held May 15–20 in Orlando, Florida, which delivered some of the most consequential late-breaking data in respiratory medicine in recent years. The most significant finding of the month came from the phase 3 TETON-1 trial, in which nebulized treprostinil (Tyvaso; United Therapeutics) — a prostacyclin mimetic with proposed antifibrotic properties — reduced FVC decline by 130.1 mL relative to placebo (95% CI, 82.2 to 178.1; P <.001) and cut the risk of a composite clinical worsening endpoint by 33% (HR, 0.67; 95% CI, 0.52 to 0.88; P =.003) over 52 weeks in patients with IPF, many of whom were already receiving background antifibrotic therapy; a combined analysis with TETON-2 further demonstrated a 48% reduction in acute exacerbations (HR, 0.52; 95% CI, 0.30 to 0.91; P =.0223) and the first statistically significant improvement in DLCO seen in any phase 3 IPF trial. United Therapeutics has indicated plans to submit a supplemental NDA to the FDA by summer 2026 seeking priority review for the IPF indication — which, if granted, would make nebulized treprostinil the first inhaled therapy approved for the condition.

The month also brought significant movement across obstructive airways disease, pulmonary vascular disease, infectious pulmonology, and public health. Also at ATS, ralinepag — an investigational once-daily oral prostacyclin receptor agonist — reduced PAH clinical worsening risk by 55% vs placebo in the phase 3 ADVANCE OUTCOMES trial (HR, 0.45; P <.0001), with a United Therapeutics NDA submission planned for the second half of 2026. The anti–IL-33 biologic itepekimab cut moderate-to-severe exacerbation rates by 27.1% in former smokers in phase 3 AERIFY-1 but failed to replicate that result in the parallel AERIFY-2 trial, a discordance attributed in part to COVID-19-era variability that complicates the biologic's regulatory path in COPD. Phase 4 PASSAGE data showed that tezepelumab, which targets the upstream epithelial cytokine TSLP, reduced annualized exacerbation rates by 70% (95% CI, 63 to 75) over 52 weeks across a real-world cohort that included active smokers and patients with comorbid COPD — populations historically excluded from biologic trials. ENCORE data presented at ATS demonstrated that amikacin liposome inhalation suspension (ALIS) achieved 88% culture conversion at 6 months in newly diagnosed MACLD, supporting earlier initiation rather than reserving use for refractory disease.

Away from the conference, the American Lung Association's 2026 State of the Air report found that 44% of Americans — approximately 152.3 million people — live in counties receiving failing grades for ozone or PM2.5 levels, with clinicians called upon to engage patients and advocate for regulatory protections. Check out this May 2026 pulmonology month in review for full coverage of these stories and more.

1. HCPLive Five: Pulmonology Updates at ATS 2026

The 2026 ATS International Conference in Orlando delivered a wave of late-breaking data spanning OSA, PAH, tuberculosis, MACLD, and COPD, covered here in 5 expert interviews. Highlights included a 39.3% AHI reduction with the investigational once-nightly oral combination AD109 (aroxybutynin + atomoxetine) vs 12.6% with placebo in CPAP-intolerant adults, a 55% clinical worsening risk reduction with ralinepag in PAH (HR, 0.45; P <.0001), and 88% culture conversion with ALIS in newly diagnosed MACLD at 6 months. The itepekimab AERIFY program also featured prominently, with the discordant results between AERIFY-1 and AERIFY-2 raising questions about the biologic's near-term regulatory path in COPD.

2. Mixed AERIFY Data Delay Itepekimab Approval Pathway in COPD, With Klaus Rabe, MD, PhD

Itepekimab, an investigational anti–IL-33 monoclonal antibody targeting airway inflammation outside the conventional type 2 eosinophilic pathway, reduced annualized moderate-to-severe COPD exacerbation rates by 27.1% in former smokers in the phase 3 AERIFY-1 trial but failed to replicate statistically significant results in the near-identical AERIFY-2 trial. Klaus Friedrich Rabe, MD, PhD, of LungenClinic Grosshansdorf, attributed the divergence in part to COVID-19 pandemic-era variability in exacerbation rates across study sites, noting that current smokers showed minimal benefit in both trials. The discordance complicates a near-term FDA filing and underscores the challenge of running parallel phase 3 programs across a period of global respiratory disease disruption.

3. ALA State of the Air 2026: Clinician Action

The American Lung Association's 27th annual State of the Air report found that 44% of Americans — approximately 152.3 million people — live in counties receiving failing grades for ozone or fine particulate matter (PM2.5) levels, with failing ozone grades now spanning 219 counties across 36 states, the broadest distribution since 2016. Approximately 33.5 million children live in affected counties, with Hispanic and Latino children roughly 3 times more likely than white children to reside in a community failing all 3 pollutant grades. Pulmonologists Juanita Mora, MD, and Vin Gupta, MD, MPA, discussed the clinical and advocacy implications of the findings, with Mora urging clinicians to engage legislators on EPA funding and clean air protections and Gupta emphasizing fact-centered public communication as the more durable path toward policy change.

4. Inhaled Treprostinil Improves IPF Outcomes in Phase 3 TETON-1 Trial

Nebulized treprostinil (Tyvaso; United Therapeutics), a prostacyclin mimetic hypothesized to carry antifibrotic properties beyond its established vasodilatory effects, reduced FVC decline by 130.1 mL vs placebo (95% CI, 82.2 to 178.1; P <.001) and cut the risk of a composite clinical worsening endpoint — encompassing a ≥10% relative FVC decline, respiratory hospitalization, and all-cause mortality — by 33% (HR, 0.67; P =.003) over 52 weeks in the phase 3 TETON-1 trial. In a combined analysis with TETON-2 involving more than 1000 patients, the program achieved statistical significance in 5 of 6 secondary endpoints, including a 48% reduction in acute exacerbations (HR, 0.52; P =.0223) and the first significant DLCO improvement demonstrated by any IPF therapy in a phase 3 trial. United Therapeutics plans to submit a supplemental NDA to the FDA by summer 2026, with both the FDA and the European Medicines Agency having previously granted orphan designation for treprostinil in IPF.

5. Tezepelumab Reduced Severe Asthma Across Phenotypes in Phase 4 PASSAGE

Tezepelumab, an anti–TSLP monoclonal antibody that blocks an upstream epithelial cytokine involved in both allergic and non-allergic inflammatory pathways, reduced annualized asthma exacerbation rates by 70% over 52 weeks (95% CI, 63 to 75) in the phase 4 PASSAGE study, a single-arm open-label trial enrolling 286 patients with severe uncontrolled asthma in a diverse US real-world cohort. Reductions ranged from 54% to 77% across inflammatory phenotypes and traditionally underrepresented populations — including active smokers with ≥10 pack-years and patients with mild-to-moderate comorbid COPD — regardless of eosinophil count or allergic status. Clinically meaningful improvements were also observed in asthma control and quality-of-life measures, with findings suggesting tezepelumab may be appropriate for patients previously considered poor biologic candidates due to smoking history or airflow obstruction