The third ATS 2026 International Conference Clinical Year in Review session, held on Tuesday, May 19, featured experts discussing updates to guidelines and impactful studies in cystic fibrosis (CF)/non-CF bronchiectasis, interstitial lung disease (ILD), lung transplant, and occupational/environmental lung diseases.

CF/Non-CF Bronchiectasis

Shelby MacRae, MD, assistant professor of clinical medicine at LSU Health Sciences Center, focused on three bronchiectasis trials — ASPEN, CLEAR, and EMBARC-BRIDGE — the 2025 updates to the European Respiratory Society (ERS) guidelines for adult bronchiectasis, and a study on the impact of CF transmembrane conductance regulator (CFTR) modulators on pregnancy outcomes.

Dr. MacRae said, “These five papers highlight where the field is moving, toward disease-specific therapy, individualized care, and better understanding of bronchiectasis biology.”

The ASPEN trial, which supported the approval of the first mechanism-based pharmacologic therapy for bronchiectasis by both the US Food and Drug Administration and the European Medicines Agency, Dr. MacRae said, “is one of the most significant bronchiectasis publications in years.”

Dr. MacRae reviewed the mechanism of action of brensocatib, which targets the neutrophil serine proteases that drive tissue damage. “Brensocatib inhibits dipeptidyl peptidase 1, preventing activation of neutrophil serine proteases before neutrophils ever reach the airway.”

Although neither hypertonic saline nor carbocisteine significantly reduced exacerbation rates compared with standard care alone in the CLEAR study, she clarified that this isn’t the whole story. Hypertonic saline showed about a 22 percent relative reduction in exacerbations, which did not reach statistical significance but is clinically notable, especially in a trial where participants received airway clearance education,” Dr. MacRae concluded.

While not an interventional trial, the EMBARC-BRIDGE study “expands our thinking about where bronchiectasis disease activity lies,” Dr. MacRae said. The study evaluated the relationships between the upper airway microbiome, mucociliary function, and bronchiectasis outcomes.

Dr. MacRae shared additional analysis about the updated ERS bronchiectasis guidelines: Airway clearance is an important recommendation for all patients, and it is crucial to rule out nontuberculous mycobacterial lung disease before starting long-term macrolide therapy.

ILD

Lida P. Hariri, MD, PhD, associate professor of pathology at Harvard Medical School, said it had been an exceptional year in the ILD research space. “First, we had a new classification document for interstitial pneumonias (IP), which is the first [update] since 2013. Second, we have had numerous positive therapeutic clinical trials that target multiple [mechanisms of] actions within the lung antifibrotic and immunomodulatory vascular [pathways], [as well as] symptom targeting.”

The ERS and ATS published a Joint Statement in 2025 that updated the classification scheme for IP. “We identified new subcategories and updated terminology. The big one, which was probably the most controversial one,” Dr. Hariri said, “is the addition of a new pattern — bronchiolocentric interstitial pneumonia (BIP).”

Dr. Hariri explained that adding BIP as a new category allows for the separation of the imaging findings and disease patterns from etiology. Also, acute IP was replaced with idiopathic diffuse alveolar damage.

Readouts from the two paired phase 3 trials in the FIBRONEER program — FIBRONEER-ILD and FIBRONEER-IPF — showed that nerandomilast, an oral inhibitor selective for phosphodiesterase 4B, attenuated the decline in FVC compared with placebo over a period of 52 weeks in patients with ILD and idiopathic pulmonary fibrosis (IPF), respectively.

In both studies, there was a reduction in the FVC decline regardless of background therapy.

While diarrhea remained the most common adverse effect of nerandomilast in both trials, “the severity and the tolerance data were much better,” Dr. Hariri said.

Dr. Hariri also discussed the TETON-1 and TETON-2 trials of inhaled treprostinil in patients with IPF. The first report of the primary analysis of TETON-1 was shared in the “Breaking News: Clinical Trial Results in Pulmonary Medicine” session at the ATS 2026 International Conference and published concurrently in the New England Journal of Medicine.

Dr. Hariri reviewed the phase 2b CORAL trial. The “compelling data” showed a mean relative decrease in cough count of 60 percent with the highest dose of nalbuphine. The potential to address symptoms beyond the primary disease and improve patients’ quality of life makes these findings “incredibly exciting,” Dr. Hariri concluded.

Lung Transplant

Carli J. Lehr, MD, PhD, associate professor of medicine at the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, segmented her review of lung transplant studies into four themes: Transplant allocation, transplant referrals for pulmonary arterial hypertension (PAH), lung transplant considerations in specific subpopulations, and chronic lung allograft dysfunction (CLAD).

“In 2023, we performed 3,080 lung transplants in the U.S., but there was a seismic change in how lung transplant allocation occurred in this year,” Dr. Lehr said.

The U.S. lung allocation system supplanted the Lung Allocation Score (LAS) with the Composite Allocation Score (CAS) in 2023 to decrease geographic variability and address access disparities in lung transplant practice.

In the allocation simulation study that Dr. Lehr reviewed, an alternative CAS scoring framework that accounted for both blood type and height — “supply-adjusted CAS” — decreased waitlist mortality and increased transplant rates compared with the ABO-Modified CAS framework that assigns maximum points to transplant candidates with type O blood.

Future CAS revisions may need to account for additional parameters to address biologic disadvantages among transplant candidates, Dr. Lehr said.

The second allocation study focused on lung allocation Out of Sequence (AOOS), a protocol that bypasses waitlist rankings, to avoid donor lung discard. The study highlighted the need for continued monitoring of AOOS; the data showed improvements in some outcomes, such as shortened hospital stays and lower odds of early organ rejection, but potential exacerbation of inequities.

Although early transplant referral is recommended for patients with PAH, referral rates remain low, according to an analysis of data from the Pulmonary Hypertension Association Registry. Only 12 percent of eligible patients were referred for transplant, and of the referred subset, only 30 percent received a lung transplant.

Dr. Lehr also reviewed a study of chronic lung allograft dysfunction — “the Achilles heel of lung transplant.”

Occupational and Environmental Lung Diseases

Maeve G. MacMurdo, MBChB, MPH, staff physician and pulmonologist at the Cleveland Clinic, prefaced her presentation, stating, “In occupational and environmental lung disease, we do not have a lot of clinical trials. My goal today is to give you an overview of what is new in the field.”

Dr. MacMurdo discussed “natural experiments” in which researchers analyzed the impact of the closure of industrial enterprises, such as steel mills and coal coking plants, on the respiratory health of residents in nearby communities.

When the Shenango coking plant in Pennsylvania shut down, for instance, rates of respiratory hospitalization in the surrounding communities decreased by 16 percent. All-age asthma-related hospitalizations also decreased, by 56 percent, as did long-term COPD hospitalization rates and pediatric asthma emergency room use.

While the adverse impact of air pollution on lung health is well-recognized, Dr. MacMurdo said that the impact of pollutants other than particulate matter, such as carcinogens and other toxic chemicals, may be underappreciated.

“Roughly one in 10 of all of us lives within one kilometer of a fossil fuel facility. We are all exposed to this,” Dr. MacMurdo said.

Extreme heat can increase morbidity and mortality, but its impacts on lung health are less well understood.

An analysis of Medicare data showed that high-heat days — a temperature change corresponding to the 95th percentile for the season — were associated with a 1.22 percent increase in the risk of hospitalization for all-cause respiratory disease. The adverse impact was pronounced in people aged 85 years or older.

Dr. MacMurdo’s final selection for the lineup of impactful studies focused on engineered stone silicosis.

Use of engineered stones has increased in recent years. So have the rates of silicosis associated with exposure to the “almost 100 percent crystalline silica” released when working with this man-made material.

In a study conducted in Australia, where engineered stone has been banned since 2024, the median age of young workers most affected by engineered stone silicosis was 42 years.

This form of silicosis is not “your grandfather’s silicosis,” Dr. MacMurdo said, but rather a rapidly progressive form that predominantly affects younger workers and is associated with substantial individual and health care system-level costs.