Celgene's psoriatic arthritis drug Otezla (apremilast) has failed to hit targets in a late-stage trial assessing its potential in ankylosing spondylitis, a form of arthritis that affects the spine.

Releasing only top-line data from the Phase III POSTURE trial at this time, the drugmaker said that Otezla failed to significantly boost the number of patients experiencing a 20% symptom improvement after 16 weeks' therapy compared to placebo.

On the upside, a pre-specified analysis showed meaningful efficacy at Week 24 in a large subset of patients with early-stage disease, and the independent data monitoring committee (DMC) recommended that the study proceed unchanged based on this finding.

Celgene said despite the failed primary endpoint it is encouraged by the results, especially in patients with shorter disease duration, and that it plans to initiate an additional Phase III trial pending further data analysis, in the hope that the drug may still prove effective some some patients with the condition.