Infex Therapeutics to present new RESP-X Phase IIa data in late-breaking session at ERS Congress 2026

Infex Therapeutics to present new RESP-X Phase IIa data in late-breaking session at ERS Congress 2026

• Presentation will provide additional analysis from the Phase IIa study of RESP-X in Pseudomonas aeruginosa-colonised non-cystic fibrosis bronchiectasis (NCFB) patients, building on the positive topline results announced in May 2026
• ERS Congress 2026 takes place in Barcelona, Spain, from 5-9 September, and is Europe's largest gathering of respiratory medicine specialists

Alderley Park, Cheshire, U.K. – 19 August 2026 – Infex Therapeutics, a leading anti-infectives specialist, today announced that new Phase IIa study data for RESP-X (INFEX702), its first-in-class anti-virulence monoclonal antibody therapy in development for NCFB patients colonised with Pseudomonas aeruginosa (Pa), has been accepted as a late-breaking abstract at the European Respiratory Society (ERS) Congress 2026, taking place in Barcelona, Spain, from 5-9 September.

The presentation will be delivered by Prof Colm Leonard, Chief Clinical Officer, on 8 September. It follows Infex's announcement in May 2026 of positive topline Phase IIa results, which showed RESP-X was safe and well tolerated with encouraging early efficacy signals in Pa-positive NCFB patients.

"Being selected for a late-breaking abstract presentation at ERS is recognition of the significance of the RESP-X programme to the European respiratory community,” said Dr Peter Jackson, CEO of Infex Therapeutics. “RESP-X has the potential to be the first therapy for Pseudomonas-colonised NCFB patients, a significant unmet need, and we look forward to sharing the new analyses from the Phase IIa study at the Congress as we progress our discussions with the regulators on the next stage of development."

Prof Colm Leonard, Chief Clinical Officer of Infex Therapeutics, said, “We are excited by this Phase IIa data on RESP-X’s effects in Pa-colonised patients with NCFB, which strongly supports onward development of this therapy in this clinical area with high unmet need, and which ultimately has significant potential in a much broader range of conditions associated with Pa infection.”

Presentation details

Session: PS-27 (Session 527) – Bronchiectasis: comorbidities, overlap states and health services (Poster session)

Date and time: Tuesday 8 September 2026, 12:30-14:00 CEST

Abstract title: Disarming Pseudomonas aeruginosa (Pa): phase 2a evidence for safe and tolerable Pa type 3 secretion system (T3SS) blockade in non-cystic fibrosis bronchiectasis (NCFB)

Abstract number: PA6105

Presenter: Prof Colm Leonard, Chief Clinical Officer, Infex Therapeutics

About RESP-X

RESP-X (INFEX702) is a first-in-class anti-virulence humanized IgG4 monoclonal antibody in-licensed from Japanese pharmaceutical company Shionogi. RESP-X targets Pseudomonas aeruginosa’s Type 3 Secretion System (T3SS), specifically the PcrV protein, a critical virulence mechanism by which Pa causes organ injury, evades the immune system and gains a foothold in humans.

Unlike traditional antibiotics that kill bacteria directly, RESP-X works by blocking Pa exotoxin delivery through the T3SS. By deactivating this virulence system, RESP-X downgrades the ability of Pa to attack human tissues and restores the ability of immune cells to control Pa, enabling the patient’s own immune system to more efficiently fight the infection.

RESP-X is initially being developed as a long-term preventative treatment to reduce disease flares and exacerbations in NCFB patients colonised with Pseudomonas aeruginosa. The programme has potential for expansion into additional indications, including cystic fibrosis, COPD, and acute settings such as hospital and ventilator-acquired pneumonia and bloodstream infections due to Pa, in addition to Pa involvement in burn injuries, diabetic ulcers, and prosthetic joint infections.

About Non-Cystic Fibrosis Bronchiectasis

Non-cystic fibrosis bronchiectasis (NCFB) is a chronic and debilitating respiratory disease defined by irreversible and progressive dilatation of bronchi due to chronic bronchial inflammation. The disease is characterised by periods of stable disease punctuated by flare-ups, known as exacerbations, that increase in frequency and severity over the patient’s lifetime.

There are currently up to six million NCFB patients in major global markets, of which up to 30% have chronic Pa colonisation. Colonisation with Pa increases the severity of NCFB, leading to recurring episodes of debilitating and life-threatening infection. NCFB exacerbations are closely associated with acute bacterial infections, with Pa being one of the leading causes. In the most severe cases, patients have multiple exacerbations per year, resulting in high hospitalisation and mortality rates.

Despite its prevalence and severity, there are currently no licensed treatments for the prevention of infective exacerbations due to Pa colonisation in NCFB patients, representing a significant unmet medical need.

About Pseudomonas aeruginosa

Pseudomonas aeruginosa is a difficult-to-treat, drug-resistant pathogen recognised by the World Health Organization (WHO) as a serious threat to human health. Pa is a leading cause of healthcare-associated infections and is particularly problematic in patients with chronic respiratory diseases, where it can establish persistent colonisation leading to recurrent, severe infections.

About Infex Therapeutics

Infex Therapeutics Holdings plc is a leader in critical-priority infectious diseases, with a broad and diverse pipeline of innovative best-in-class and first-in-class drug candidates to address the urgent global shortage of novel anti-infective treatments. The Company is building a differentiated pipeline through in-house drug discovery, acquisition, co-development and in-licensing of early stage/pre-clinical candidates, developing them to clinical proof of concept before licensing to commercial pharma partners.

To learn more, visit our website: https://www.infextx.com/

Contact

Infex Therapeutics
Carl Curran, Head of Business Development
E-mail: info@infextx.com

ICR Healthcare
Stephanie Cuthbert, Louis Ashe-Jepson
E-mail: infex@icrhealthcare.com