AirNexis AN01 meets primary endpoint in Phase 2b COPD study

AirNexis Therapeutics has reported positive Phase 2b data for AN01, its dual PDE3/4 inhibitor dry powder inhaler, in chronic obstructive pulmonary disease. The study, conducted in China by licensing partner Haisco Pharmaceutical Group, met its primary endpoint, with both doses of AN01 delivering statistically significant improvements in lung function over placebo at four weeks. Results were presented as an ePoster at the European Respiratory Society Congress in Barcelona on 8 September.

The randomised, placebo-controlled trial enrolled 195 patients who remained symptomatic despite receiving single or dual bronchodilator maintenance therapy, split roughly equally between the two background-therapy cohorts. Participants were allocated 1:1:1 to AN01 0.75 mg, AN01 1.5 mg, or placebo over four weeks. The primary endpoint was change from baseline in FEV1 area under the curve from zero to 12 hours post-dose at week four.

Trial results

Both doses outperformed placebo on the primary endpoint: the 0.75 mg arm showed a treatment difference of 116 mL, and the 1.5 mg arm 127 mL. Subgroup analysis found meaningful benefits across both background-therapy cohorts. In patients on single bronchodilators, the improvements were 164 mL and 189 mL for the lower and higher doses respectively. Notably, patients already on dual bronchodilator therapy also showed significant gains of 74 mL and 75 mL, a finding that matters commercially because this population represents a harder-to-treat segment where therapeutic options are limited.

On safety, no treatment-related adverse events were recorded in the 0.75 mg group, which is the dose selected for AirNexis' own Phase 3 programme. The 1.5 mg group showed a treatment-related adverse event rate of 6.1%, comparing favourably with a placebo rate of 7.9%.

Maria Fardis, chief executive of AirNexis, said the data reinforce "AN01 DPI's potential as a convenient, easy-to-administer treatment option for a broader COPD patient population." AN01 has now been administered to more than 600 subjects across the combined Haisco and AirNexis clinical programmes. AirNexis completed a Phase 1 multiple ascending dose study in healthy volunteers in Australia and intends to initiate its own Phase 2 programme in 2027. Haisco's separate Phase 3 programme for the Chinese market is already under way.

Market and competitive context

COPD affects an estimated 300 million people globally and remains a substantial commercial opportunity for inhaled therapeutics. The approved PDE4 inhibitor roflumilast (marketed as Daliresp and Onbrez in various territories) established clinical proof of concept for the target class, though its oral formulation has been associated with gastrointestinal tolerability issues that limit uptake. AN01's inhaled delivery is intended to address that limitation by concentrating drug exposure in the lungs while minimising systemic levels, a design logic shared by several other inhaled anti-inflammatory candidates in development.

The field is competitive. GSK, AstraZeneca and Chiesi all maintain significant COPD pipelines, and a number of smaller biotechs are pursuing novel inhaled anti-inflammatory mechanisms, including selective PDE4 subtypes and CXCR2 antagonists. AirNexis' dual PDE3/4 mechanism is positioned as delivering both bronchodilation and anti-inflammatory benefit in a single molecule, which could differentiate it from single-mechanism approaches, though head-to-head data do not yet exist. The performance in the dual-bronchodilator subgroup will be a key watchpoint for investors, as regulatory agencies and payers increasingly scrutinise incremental benefit over optimised standard of care. The company's 2027 Phase 2 start in markets outside China is the next substantive milestone to watch.