BOULDER, Col. ( TheStreet) -- An experimental pill from Array BioPharma ( ARRY) improved lung function in patients who suffer from asthma brought on by allergies, according to results from a small mid-stage study announced Tuesday. Array shares rose 15 percent to $6.40 in early trading on the data from the study of ARRY-502 in allergic asthma. The company is seeking a partner to fund the future development of the drug. Asthma affects approximately 25 million, or 8 percent, of the U.S. population but no new oral medication for the disease has been approved since Merck's ( MRK) Singulair in 1998. Singulair was a $5 billion-plus drug for Merck before its patent expired and generic copies became available. Array's ARRY-502 is designed to block the inflammatory activity of Th2 T cells, which in turn, reduces the coughing and breathing difficulties seen in asthma patients. This represents a potentially new way of treating asthma, Array said. Drugs with similar mechanisms of action developed by Amgen ( AMGN) and Actelion were not successful. In the study, 184 patients with mild, moderate and persistent allergic asthma were randomized to treatment with ARRY-502 taken twice per day or a placebo. After four weeks of treatment, lung function in patients treated with ARRY-502 improved by 3.9 percent relative to placebo. The benefit was statistically significant. Lung function was assessed by FEV1, which measures the amount of air that can be exhaled by a patient in one second. Array did not disclose the absolute improvement or decline in FEV1 function for the patients treated with ARRY-502 or placebo. Approximately half of the asthma patients enrolled in the study had an undisclosed biomarker associated with Th2 activity, suggesting they might benefit more from a drug like ARRY-502. In these patients, treatment with Array's drug led to a 6.8 percent relative improvement in lung function compared to placebo. Array says its research indicates that about 25 percent of all asthma patients possess this biomarker for enhanced Th2 activity. On the safety side, there were not serious adverse events in patients treated with ARRY-502, while all treatment-related adverse events were mild or moderate, the company said, without providing details. Elevent patients in the placebo group and four patients in the ARRY-502 arm discontinued the study early.