First patient dosed in BX004 trial for CF-related lung infection
About 60 patients with P. aeruginosa, reduced lung function to be enrolled
The first participant has been dosed in a Phase 2b clinical trial testing BiomX’s experimental inhaled therapy BX004 in adults with cystic fibrosis (CF) and chronic Pseudomonas aeruginosa lung infection.
“This first patient dosing marks a significant milestone for our BX004 program and for CF patients with chronic P. aeruginosa infections who desperately need new options,” Jonathan Solomon, BiomX’s CEO, said in a company press release.
Up to 63 CF patients with chronic P. aeruginosa infection and reduced lung function are expected to be enrolled in the Phase 2b trial (NCT06998043) at sites in the U.S. The results are expected in early 2026.
“We’re seeing tremendous enthusiasm from both patients and investigators based on our encouraging Phase 1b/2a results, in which 14.3% of patients cleared infections completely after 10 days of treatment,” Solomon said. “Notably, this included individuals who had been living with chronic infections for over a decade, making these outcomes particularly meaningful and rarely seen in this population.”
CF is a genetic disorder where abnormally thick, sticky mucus is produced that can build up in organs, including the lungs, and lead to a variety of symptoms. Lung infections and respiratory problems are common in CF, as mucus in the lungs provides a breeding ground for bacteria.
Although P. aeruginosa is abundant in the environment and doesn’t typically cause illness, more than 60% of adults with CF may have a P. aeruginosa infection. Chronic infections can last for years and often contribute to lung disease. Standard antibiotics may treat a P. aeruginosa infection, but the bacterium can rapidly evolve to be resistant to them.
What makes BX004 different against bacterial infections?
BX004 uses an alternative strategy and employs a cocktail of bacteriophages, a type of virus that can infect and kill bacteria, while leaving human cells unharmed. The BX004 combination includes bacteriophages, or phages, that target P. aeruginosa.
Data from a Phase 1b/2a trial (NCT05010577) that tested BX004 against a placebo in adults with CF and chronic P. aeruginosa lung infections showed a greater P. aeruginosa reduction.
Ten days of BX004, taken twice a day, was also associated with an average 5.67% improvement in lung function relative to a placebo, letting 14.3% of patients test negative for P. aeruginosa after treatment. No participant in the placebo group tested negative. The participants generally tolerated the therapy well and no serious adverse events reported. There were no signs the bacterium developed resistance to BX004 over time.
The ongoing Phase 2b trial is evaluating the safety and efficacy of BX004 against a placebo in CF patients with chronic P. aeruginosa lung infections and reduced lung function who saw the greatest benefit in the initial trial. The participants are randomly assigned to either BX004 or a placebo, taken twice daily for eight weeks.
The main goal is to assess changes in P. aeruginosa burden in the lungs after treatment. Secondary goals include changes in lung function, respiratory symptoms and their impact on quality of life, along with rates of P. aeruginosa-negative patients and safety measures.
BiomX is working with the U.S. Food and Drug Administration (FDA) to identify the best way to analyze trial data and accelerate BX004’s approval pathway.
“In the second half of 2025, we anticipate feedback from the FDA regarding our plans on the analyses of real-world evidence to link bacterial reduction to clinical outcomes,” Solomon said. “Regulatory alignment on a microbiological endpoint would streamline the approval pathway and provide a means of addressing these patients with urgent unmet needs.”
BX004 has been granted orphan drug and fast track status by the FDA for treating chronic P. aeruginosa lung infections with cystic fibrosis. The designations are intended to expedite its clinical development and regulatory review.
“With both fast track and orphan drug designations already secured, we believe we are well positioned to further develop our phage-based therapy for these life-threatening infections, pending positive top-line trial readout,” Solomon said.
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