Alderley Park, Cheshire, U.K., August 19, 2026

Infex Therapeutics will present new Phase IIa data for RESP-X (INFEX702) in a late-breaking session at the European Respiratory Society (ERS) Congress 2026, highlighting continued clinical development of its potential first-in-class anti-virulence therapy for patients with non-cystic fibrosis bronchiectasis (NCFB) colonised with Pseudomonas aeruginosa. The new analysis builds on positive topline Phase IIa results announced in May 2026 and is expected to provide additional clinical evidence on RESP-X’s ability to target Pseudomonas aeruginosa without directly killing the bacteria. The ERS Congress will take place in Barcelona, Spain, from September 5-9, 2026, with the RESP-X presentation scheduled for September 8.

RESP-X Selected for Late-Breaking ERS Presentation

The selection of the RESP-X study as a late-breaking abstract places Infex Therapeutics’ anti-infective program among the clinical developments being highlighted to the European respiratory medicine community. The presentation, titled “Disarming Pseudomonas aeruginosa (Pa): phase 2a evidence for safe and tolerable Pa type 3 secretion system (T3SS) blockade in non-cystic fibrosis bronchiectasis (NCFB)”, will be presented by Professor Colm Leonard, Chief Clinical Officer at Infex Therapeutics. The presentation is scheduled for Tuesday, September 8, 2026, from 12:30 to 14:00 CEST in the bronchiectasis session, with abstract number PA6105. The company said the new analysis will build on its earlier Phase IIa findings, which demonstrated that RESP-X was safe and well tolerated and showed encouraging early efficacy signals in patients with Pseudomonas-positive NCFB..

RESP-X Targets Pseudomonas Virulence Instead of Killing Bacteria

RESP-X is a first-in-class anti-virulence humanized IgG4 monoclonal antibody licensed from Shionogi and designed to target the Type 3 Secretion System (T3SS) of Pseudomonas aeruginosa. Specifically, RESP-X targets the PcrV protein, which plays an important role in the pathogen’s ability to deliver damaging exotoxins, evade immune responses and establish infection. Rather than functioning as a conventional antibiotic that directly kills bacteria, RESP-X is designed to block the bacterial virulence mechanism, potentially reducing the pathogen’s ability to damage host tissue while allowing the patient’s immune system to control the infection. Infex is initially developing RESP-X as a long-term preventative treatment intended to reduce disease flares and exacerbations in NCFB patients with chronic Pseudomonas colonisation.

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Infex Targets Significant Unmet Need in Bronchiectasis

The RESP-X program addresses a significant unmet need in Pseudomonas-colonised NCFB, a chronic respiratory disease characterised by progressive airway damage, inflammation and recurring exacerbations. Infex estimates that up to six million patients have NCFB across major global markets, with as many as 30% experiencing chronic Pseudomonas colonisation. Persistent Pseudomonas infection can contribute to more frequent and severe exacerbations, hospitalisation and increased disease burden. According to the company, there are currently no licensed treatments specifically designed to prevent infective exacerbations caused by Pseudomonas colonisation in NCFB, creating an opportunity for a targeted anti-virulence approach. Beyond NCFB, Infex sees potential for RESP-X in additional Pseudomonas-associated conditions, including cystic fibrosis, COPD, hospital-acquired and ventilator-acquired pneumonia, bloodstream infections, burn injuries, diabetic ulcers and prosthetic joint infections..

Source: Infex Therapeutics press relese