KaloBios Pharmaceuticals, Inc. announced the completion of the randomized, double-blind placebo-controlled Phase 2 study of KB003, its anti-GM-CSF monoclonal antibody (mAb), in patients with severe asthma. While the study showed that KB003 was generally safe and well tolerated, it did not meet its primary clinical endpoint of improvement in FEV(1) (a measurement of pulmonary function) compared to placebo in the overall study population. The company also evaluated improvement in FEV(1) compared to placebo in a number of pre-specified subgroup analyses.

Of those subgroups, eosinophilic patients (Baseline Blood Eosinophils >=0.3 GI/L) and patients demonstrating high reversibility at baseline (>20%) showed a statistically significant improvement compared to placebo. Other subgroups such as atopic or non-atopic patients did not demonstrate a statistically significant improvement in FEV(1) from baseline as compared to placebo. In the key secondary endpoints evaluated, there was no meaningful reduction in exacerbations observed in patients receiving KB003 in the overall study population or in any material subgroup as compared to those receiving placebo, and there was no statistically significant improvement in asthma control questionnaire (ACQ) scores in the overall patient population.