The pain and stiffness suffered by a quarter of a million people with the inflammatory spinal condition ankylosing spondylitis can be significantly relieved with a drug already approved for rheumatoid arthritis, according to results of a clinical trial published in The New England Journal of Medicine.
A UCSF study showed that 80 percent of patients taking the immune-blocking drug etanercept (Enbrel®) experienced relief from their symptoms. The drug worked more quickly than the current therapies such as aspirin-like drugs, other immunosuppressives and physical therapy.
And unlike all other current treatments, etanercept relieved intense pain from spinal inflammation in most patients, the study found. The drug may reduce spinal inflammation and actually slow the progress of the disease, the researchers suggest.
Ankylosing spondylitis, or AS, is a chronic inflammatory arthritis characterized by joint stiffness, pain and extra bone growth that can result in partial or complete fusion of the spine. The bones of the spine may grow together, causing the spine to become rigid and inflexible. Other joints such as the hips, shoulders, knees, or ankles also may become involved.
About 300,000 people in the U.S. suffer from the disease. Symptoms appear most frequently in young men between the ages of 16 and 35. There is currently no cure for ankylosing spondylitis, and there is no drug currently approved by the U.S. Food & Drug Administration (FDA) for this disease.
Like rheumatoid arthritis, the condition is an autoimmune disease in which the immune system loses its capacity to control vigilant proteins known as cytokines, and these soldiers start a relentless attack on the body, prompting a damaging increase in inflammation. A key to this lost immune control is a molecule called tumor necrosis factoralpha (TNF-alpha) which normally prompts increased cytokine action. Etanercept, on the market for three years to treat rheumatoid arthritis, blocks the ability of TNF-alpha to connect with its normal target to trigger increased cytokine action.
“Until recently, it has really been disheartening to treat people in so much obvious pain, yet have so few therapeutic options to help them,” said John Davis, MD, UCSF Treatment for Disabling Spine Condition assistant professor of medicine and senior author on the study in NEJM. “Highly targeted biological agents such as etanercept offer a way to block the specific immune reaction that has gone awry and dramatically change the course of this disabling disease.”
The phase 2 clinical trial involved 20 patients given the drug and 20 patients receiving a placebo for four months. Of those receiving etanercept, 80 percent reported less stiffness, less pain and showed improvements in functioning. Only 30 percent of those in the control group showed such improvements, the researchers reported. Side effects were mild, and positive results lasted throughout the study period.
Based on these encouraging findings, a large multi-center phase 3 study is just getting under way. Results are expected in six months.
In April, a German research team reported similarly promising results from a clinical trial to treat ankylosing spondylitis using the immune blocker infliximab, already in use to treat rheumatoid arthritis.
“Both these results are very encouraging for patients with spondylitis,” said Jennifer
Gorman, MD, assistant adjunct professor of medicine at UCSF and lead author on the paper.
“The development of anti-tumor necrosis factor therapies has finally given us the opportunity to effectively treat some of the most disabling symptoms in this disease.”
Co-author on the study is Kenneth E. Sack, MD, UCSF professor of clinical medicine.