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July 9 (Reuters) - Celgene Corp said a drug being tested to treat a type of arthritis that affects the spine failed to meet the main goal in a late-stage trial, sending the company's shares down 3 percent premarket.
The drug, Otezla, failed to show improvement of at least 20 percent at week 16 when tested on patients with ankylosing spondylitis, or arthritis of the spine, compared to those on a placebo, the company said.
The company said an analysis of the data showed "meaningful efficacy" in a large subset of patients with early-stage disease at week 24.
Celgene said it would continue the study unchanged based on a recommendation by an independent data monitoring committee.
The drugmaker also said it planned to start another late-stage trial for further data analysis.
Otezla is already approved by U.S. health regulators for treatment of adults with active psoriatic arthritis and is being studied for use in psoriasis and other indications including Behcet's disease and Crohn's disease.
Ankylosing spondylitis affects the joints in the spine and the pelvis. It can cause rigidity in the vertebrae that may result in a hunch-forward posture.
The company's shares were trading at $84.31 before the bell after closing at $85.72 on the Nasdaq on Tuesday. (Reporting By Penumudi Amrutha; Editing by Sriraj Kalluvila)