The long-standing alliance between Sanofi and Regeneron looks to have scored another clinical goal, this time with dupilumab for asthma.

The partners have unveiled Phase IIa data at the American Thoracic Society meeting in Philadelphia on dupilumab, an interleukin 4 receptor which modulates signalling of both the IL-4 and IL-13 proteins, which are linked to inflammation. The 104-patient study enrolled 104 patients with moderate-to-severe, persistent asthma that was not well controlled with inhaled glucocorticosteroids (ICS) and long-acting beta agonist (LABA) therapy, and who had elevated blood or sputum eosinophils.

Patients were treated with dupilumab or placebo on top of ICS and LABA therapy for the first four weeks of the study. The LABA was withdrawn at week four and the ICS was tapered to withdrawal between weeks six and nine. Sanofi noted that dupilumab demonstrated an 87% reduction in the incidence of asthma exacerbations compared to placebo.

Improvements were observed for lung function and other asthma control parameters, such as forced expiratory volume over one second (FEV1). Treatment-linked adverse events were a similar proportion of patients in both groups (76.9% placebo, 80.8% dupilumab).

Sally Wenzel of the University of Pittsburgh and lead investigator of the trial said that "despite existing therapies, a significant number of patients with moderate-to-severe, persistent allergic asthma are not optimally controlled, which puts them at risk of poor clinical outcomes". She added that "these encouraging data support the potential role of IL-4/IL-13 blockade in an important subset of asthma patients".

Dr Wenzel told Reuters that "overall, these are the most exciting data we've seen in asthma in 20 years". She went on to say that "we have been treating asthma with sort of Band-Aid therapies that didn't get at the underlying causes," adding that dupilumab, which in the trial was dosed subcutaneously, weekly at 300mg, could be an important step in tackling the root of the problem.

Dupilumab is also being developed as a treatment for atopic dermatitis. The drug is one of a  number Sanofi and Regeneron have developed together, such as a cholesterol treatment targeting PCSK9,  the late-stage rheumatoid arthritis treatment sarilumab and the already-launched Zaltrap (ziv-aflibercept) for colorectal cancer.