AS is an autoimmune disorder and a type of arthritis that primarily affects the spine, although other joints can also become involved. It causes inflammation of the spine, which can then cause severe, chronic pain. In the most advanced cases, new bone formations can develop on the spine, causing the spine to fuse and become immobile. AS can also cause inflammation, pain and stiffness in other areas of the body such as the shoulders, hips, ribs, heels and small joints of the hands and feet. Sometimes the eyes can become involved (known as Iritis or Uveitis), and rarely, the lungs and heart can be affected.
There is no known cure for AS, but there are treatments and medications available to reduce symptoms and manage the pain, such as biologic response modifiers like Humira, that can potentially slow or halt the disease progression in some people.
The approval for AS was based on data from a clinical trial called ATLAS (Adalimumab Trial Evaluating Long-Term Efficacy and Safety in AS). According to the Abbott Labs press release, the results of the clinical trial showed that Humira was successful in reducing pain and inflammation in patients with AS after 12 weeks of treatment, the study's primary endpoint. The results also showed significant improvement in measures of disease activity for many patients treated with Humira that were first observed at week two and maintained through 24 weeks. Patients also showed a reduction in the enthesitis, a condition in AS characterized by inflammation of the ligaments that attach to the bone.
The trial also demonstrated that patients have similar side effects as other clinical trials involving Humira. The frequency of adverse events reported by patients taking Humira was higher than for patients taking placebo. The most common adverse events in the trial included nasopharyngitis, injection site reactions, rashes and headaches. Patients taking Humira also have an increased risk of developing tuberculosis and have a two to three times greater risk of developing serious infections such as sepsis, which can be fatal. Humira, like other TNF-inhibitors, also has been associated with an increased risk of various types of cancer such as lymphoma, breast cancer and lung cancer.