Infex Therapeutics is pushing ahead with development of a non-cystic fibrosis bronchiectasis (NCFB) drug candidate after posting phase 2a data, advancing efforts to add to the options for treating patients who recently gained access to Insmed’s Brinsupri.
The British biotech, which is based at the Alderley Park site AstraZeneca sold in 2014, ran the study to assess the safety, tolerability and pharmacokinetics of anti-PcrV antibody RESP-X. After licensing the drug candidate from Shionogi, Infex began assessing its ability to tackle an opportunistic, multidrug-resistant pathogen, Pseudomonas aeruginosa, that can cause life-threatening infections.
Infex’s phase 2a trial randomized NCFB patients colonized with the pathogen to receive one of two doses of RESP-X, also known as INFEX702, or placebo. Patients had fewer exacerbations across the 180-day trial compared to the 12 months before dosing, although the p value was slightly above the typical threshold for statistical significance. Infex called the efficacy signals encouraging.
The study met its primary and secondary objectives. No participants had severe or life-threatening treatment-emergent adverse events related to the study drug, and no adverse events led to withdrawals from the study. Adverse events linked to RESP-X were mild to moderate. No infusion reactions, either systemic or at the infusion site, were seen after RESP-X dosing.
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Pharmacokinetic data support quarterly dosing, Infex said. The antibody exhibited a half-life of 28.8 days and the higher dose provided serum coverage to support dosing every three months. Tests showed the drug reached lung epithelial lining fluid within 48 hours.
Infex plans to talk to regulators about further development. Last week, the company raised 4.3 million pounds ($5.8 million) to fund continued development of its pipeline, which includes a broad-spectrum metallo-beta-lactamase inhibitor.
The biotech’s work on PcrV builds on years of research into the target. PcrV is essential to the function of a key virulence factor associated with disease severity, leading companies including KaloBios—which Martin Shkreli briefly pushed into the headlines in 2015—and AstraZeneca’s MedImmune to study the target over the years. Current programs include mRNA-encoded PcrV-targeting monoclonal antibodies.
Applied to NCFB, anti-PcrV antibodies could dampen the impact of a pathogen responsible for some of the exacerbations that drive high hospitalization and mortality rates in the patient population. Insmed has tackled the challenge of reducing exacerbations from another angle, targeting enzymes that mediate inflammation. The FDA approved Insmed’s Brinsupri, the first treatment for NCFB, last year.
