— Phase IIb results hint at faster recovery, even improved survival
October 20, 2026 • 3 min read
PHOENIX -- A novel exosome-based immunomodulatory agent appeared promising in speeding recovery from acute respiratory distress syndrome (ARDS), a phase IIb trial showed.
The inhaled therapy substantially increased the proportion of patients free of respiratory failure at day 7 compared with placebo (85% vs 33.3%, P<0.0001), reported Shiran Shapira, PhD, of drug developer Nano24 and Tel-Aviv Medical Center in Israel, at the CHEST annual meetingopens in a new tab or window hosted by the American College of Chest Physicians.
In addition, the agent dubbed EXO-CD24 reduced length of hospital stay (mean 6.5 vs 14.4 days, P=0.0001). Of note, patients who took the inhaled agent were less likely to die through day 28 (6.7% vs 30%) and 6 months (13.3% vs 43.3%, HR 0.28, 95% CI 0.084-0.902, P=0.033).
The treatment, which involves 5-minute nebulized inhalation twice a day, was well-tolerated, without any treatment-related or dose-related serious adverse events in the accumulated clinical experience of the 90 patients across both groups in the phase IIb trial or the other 178 patients in the prior phases of study.
The safety and efficacy appeared promising, said Alice Gallo De Moraes, MD, a pulmonologist and critical care expert at the Mayo Clinic in Rochester, Minnesota, who was not involved in the study.
"If this would pan out, it will be very exciting," she told MedPage Today. "It's been a while since we have found any medication that could help in ARDS at all."
Shapira noted that the drug is rapidly and directly delivered to affected tissue without systemic exposure that could lead to toxicity.
Exosomes are membrane-bound vesicles that act like cargo containers to transport proteins, lipids, and nucleic acids between cells. In this case, the exosomes were engineered to express the immunomodulatory protein CD24 that helps distinguish "self" from "foreign" tissue to regulate damage-driven inflammation and act on a key signaling pathway in the production of cytokines and chemokines while preserving pathogen recognition.
"We are trying to harness the natural communication system of our body," Shapira said. "They are very efficient in drug delivery. They can cross any barrier in our body. We can engineer them very efficiently at their surface and their lumen, both of them simultaneously. So actually the exosomes are better than any other synthetic or polymeric drug carriers."
The trial included 90 patients with ARDS who were randomly assigned to receive either aerosolized saline or 1010 particles of EXO-CD24 in 1.5 mL of saline from days 1-5 for a total of up to 10 twice-daily inhalation doses. Patients who left the intensive care unit before day 5 could complete their treatment at home. Patients were followed out to day 28 for safety monitoring and had a final safety check at 6 months.
Shapira called the findings proof of concept and pointed to plans to advance EXO-CD24 into a larger, international phase III trial. She noted that her team also plans to explore other indications for the exosome carrier beyond ARDS.
"Actually the CD24 is only the first therapeutic candidate in our pipeline," she added. "It can be a lot of drugs."