Patients with moderate to severe asthma in a clinical trial testing a new drug by Regeneron Pharmaceuticals Inc. and Sanofi SA showed promising results, according to a report released Tuesday.

The drug called Dupilumab reduced asthma attacks by 87 percent in a 12-week period compared with those getting a placebo, according to the study which was published online in The New England Journal of Medicine and presented at the annual meeting of the American Thoracic Society in Philadelphia.

The drug works by blocking proteins that lead to respiratory tissue inflammation, dupilumab has also shown promise in treating severe eczema. Regeneron and Sanofi, have also partnered to co-develop certain experimental drug program and have said dupilumab could eventually be applied to other allergic conditions. Asthma affects more than 24 million people in the U.S., but current medicines and therapies are unable to offer relief to as many as 10 percent to 20 percent of patients, according to the study's authors.

Dr. Sally Wenzel, lead investigator for the 104-patient study of dupilumab said the preliminary results are "the most exciting data we've seen in asthma in 20 years," Reuters notes.

However, some physicians cautioned further research would need to be done to see how effective the treatment may ultimately be, and the test group was too small with only 104 participants.

A commentary on the asthma study, also published in The New England Journal of Medicine on Tuesday, said it was "too early to tell if this therapy will be of clinical value," though it was probably "on the right path."

Larger trials will have to be conducted before the drug can be submitted for Food and Drug Administration approval. The drug is also reported to have improved lung function in patients, reducing the need for other respiratory medicines.