Development

Revagenix opens first clinical trial of LpxC inhibitor for Pseudomonas-driven bronchiectasis

Edited by Robert McTiernan··3 min read
Revagenix opens first clinical trial of LpxC inhibitor for Pseudomonas-driven bronchiectasis

San Francisco-based Revagenix, Inc. has dosed the first participant in a Phase I trial of Rev-56, an inhaled therapy targeting chronic Pseudomonas aeruginosa infection in non-cystic fibrosis bronchiectasis (NCFB), according to a company announcement.

The two-part trial will first assess safety, tolerability, and pharmacokinetics of nebulized Rev-56 in healthy volunteers, with topline data expected by year-end 2026. Part B will assess pharmacodynamic metrics in NCFB patients with confirmed P. aeruginosa infection. Revagenix describes Rev-56 as first-in-class with a novel mechanism of action and potential for once-daily dosing.

The program has received support from the National Institute of Allergy and Infectious Diseases (NIAID) which indicates Rev-56 targets LpxC, a zinc-dependent metalloenzyme essential for lipid A biosynthesis in Gram-negative bacterial outer membranes. Revagenix has not publicly confirmed this target. The company is backed by Novo Holdings and Tenmile.

P. aeruginosa chronic infection represents the most severe phenotype within NCFB, independently associated with accelerated lung function decline, higher exacerbation rates, increased hospitalizations, and approximately threefold greater mortality risk. The pathogen occupies a central role in the "vicious cycle" model of bronchiectasis: structural airway damage impairs mucociliary clearance, enabling Pa colonization, which drives neutrophilic inflammation that further worsens airway architecture. Interrupting this cycle at the infectious driver is a well-supported therapeutic rationale.

No FDA-approved therapy is specifically indicated for P. aeruginosa in NCFB. Brensocatib (Brinsupri), approved by the US FDA in August 2025 as the first-ever NCFB treatment, targets dipeptidyl peptidase 1 (DPP-1) to reduce neutrophil serine protease activity — addressing downstream inflammation rather than the bacterial trigger. Inhaled antibiotics including tobramycin and colistimethate sodium are used off-label but were developed for cystic fibrosis and have demonstrated inconsistent benefit in NCFB trials; inhaled ciprofloxacin dry powder failed to achieve approval following Phase III results that were inconclusive and raised antibiotic resistance concerns.

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LpxC inhibition offers a mechanistically distinct approach. Because lipid A is essential for Gram-negative bacterial viability and absent in mammalian cells, LpxC represents a selective antibacterial target. Two prior clinical-stage LpxC inhibitors — ACHN-975 (Achaogen) and RC-01 (Rempex Pharmaceuticals) — were both terminated in Phase I due to cardiovascular toxicity linked to systemic exposure from hydroxamic acid scaffolds. Rev-56's inhaled delivery is designed to achieve high local pulmonary concentrations while limiting systemic exposure, which may address the safety liability that ended earlier programs. Neither FG-2101 (Blacksmith Medicines) nor LPC-233 (ValanBio Therapeutics), both next-generation LpxC inhibitors with non-hydroxamate scaffolds, has yet entered clinical trials, leaving Rev-56 as the only active clinical-stage LpxC inhibitor globally.

In the broader NCFB competitive landscape, Armata Pharmaceuticals has completed a Phase II trial of AP-PA02, an inhaled multi-phage therapeutic targeting P. aeruginosa, with encouraging topline results reported in late 2024. Boehringer Ingelheim's verducatib (BI 1291583), a DPP-1 inhibitor in the same mechanistic class as brensocatib, is in Phase III with FDA Breakthrough Therapy Designation, but like brensocatib targets neutrophilic inflammation rather than the pathogen directly. Rev-56's anti-infective mechanism targeting a novel bacterial pathway differentiates it from both the anti-inflammatory DPP-1 inhibitor class and from conventional inhaled antibiotics facing resistance and efficacy limitations in this population.

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