Phase 2 Data on ESO-101 Suggests Efficacy Among Adults with Eosinophilic Esophagitis

New phase 2 findings from the ACESO trial, published in the Alimentary Pharmacology & Therapeutics journal, suggest that ESO-101 is an efficacious and safe treatment for adults with active eosinophilic esophagitis (EoE).1,2

These data were announced by Swiss biotechnology company EsoCap AG. The analysis itself was designed to assess the safety, tolerability, and efficacy of ESO-101 in adults with this chronic immune-mediated condition resulting in esophageal dysfunction.2

“The detailed results of the ACESO trial provide robust evidence for the efficacy and safety of ESO-101, a novel drug delivery device for the long-lasting, targeted delivery of the anti-inflammatory corticosteroid mometasone furoate directly to the esophageal mucosa,” Alfredo J. Lucendo, MD, PhD, from the department of gastroenterology at the Hospital General de Tomelloso in Spain, and coordinating principal investigator of the ACESO trial, said in a statement.1

Background and Design Details

Individuals with EoE are known to typically report symptoms including food impaction, difficulty swallowing (dysphagia), occurrences of heartburn, and vomiting, all of which are believed to result from eosinophil-dominated inflammation within the esophagus. Especially among children and young adults, EoE is increasingly viewed as a leading cause of dysphagia and food impaction.

The ESO-101 drug is designed using a delivery system involving a capsule containing a thin mucoadhesive film which will unroll to provide the corticosteroid mometasone furoate directly to users’ esophageal lining. The phase 2 ACESO analysis of this medication was designed as a randomized, double-blind, placebo-controlled trial involving a total of 43 adult subjects located in 14 medical centers in 5 European countries.

Lucendo and colleagues randomized participants with a peak eosinophil count of 15 eosinophils per high-power field (hpf) at least in a 2:1 ratio, providing either ESO-101 or a placebo once-per-day over the course of 28 days.

Notable Findings on ESO-101

By its conclusion, the study was found by the research team to have successfully met its primary endpoint. Specifically, it demonstrated a statistically significant reduction in eosinophil count among individuals who had been in the ESO-101 treatment arm of the study.

The team highlighted that, on average, ESO-101 cohort participants were found to have a reduction of 49.1 ± 88.4 eosinophils/hpf (P = .0318), and no subjects featured in the placebo cohort successfully achieved histological remission. In contrast, the team noted that 48% of those given ESO-101 achieved fewer than 15 eosinophils/hpf.1

The investigators added that 44% had fewer than 6 eosinophils/hpf, noting that both results reached statistical significance (P = .0028 and P = .0035, respectively). Lucendo et al. further highlighted substantial improvements after using ESO-101 in participants’ endoscopic outcomes, as measured by the eosinophilic esophagitis endoscopic reference score (EREFS).1

This finding indicates the drug’s potential to remodel the esophagus even after a brief duration of treatment. The investigative team did find that some relief in dysphagia symptoms was observed following the 4-week mark, although a high placebo response indicated that longer treatment periods could yield more definitive successes in related symptoms such as swallowing problems.

Adherence among subjects to treatment protocol was also found by the investigators to be exceptionally high. They highlighted the full compliance seen in the ESO-101 arm and the 93% rate of compliance in the placebo arm, adding that the high level of satisfaction with ESO-101's ease of use reflects the delivery system’s potential.

In a notable element highlighted by the team, ESO-101 was shown to have an excellent safety and tolerability profile. They reported no cases of oropharyngeal, oral, or esophageal candidiasis, a set of side effects which are often linked to utilization of topical corticosteroids.

“The trial’s rigorous design demonstrated significant improvements in inflammatory, histological, and endoscopic parameters compared to placebo, which underscores the potential of this treatment approach,” Lucendo said in a statement. “For patients with eosinophilic esophagitis, this approach offers the potential for more effective disease management in a field where treatment options are scarce.”1

References

1. EsoCap announces publication of comprehensive Phase II results demonstrating ESO-101’s effectiveness in eosinophilic esophagitis. EsoCap. December 17, 2024. https://www.globenewswire.com/news-release/2024/12/17/2998035/0/en/EsoCap-announces-publication-of-comprehensive-Phase-II-results-demonstrating-ESO-101-s-effectiveness-in-eosinophilic-esophagitis.html. Date accessed: December 17, 2024.
2. Lucendo AJ, el al. Clinical trial: Safety and efficacy of a novel oesophageal delivery system for topical corticosteroids versus placebo in the treatment of eosinophilic oesophagitis. Aliment Pharmacol Ther 2025; https://doi.org/10.1111/apt.18443.