Is adalimumab (Humira) safe and effective for rheumatoid arthritis?
Combined with methotrexate, subcutaneous adalimumab at a dosage of 40 mg every two weeks slows the progression of rheumatoid arthritis at one year. The combination is more effective than adalimumab monotherapy. Limited evidence suggests that adalimumab is also safe and effective when combined with other disease-modifying antirheumatic drugs (DMARDs).
Management of rheumatoid arthritis has shifted toward initiation of DMARDs within three months of diagnosis.1 Adalimumab is a new anti–tumor necrosis factor (TNF) medication that is similar to etanercept (Enbrel) and infliximab (Remicade). It is approved for reducing symptoms and inhibiting structural-damage progression of rheumatoid arthritis in adults with moderately or severely active rheumatoid arthritis who have had an inadequate response to one or more other DMARDs. Adalimumab can be used alone or in combination with methotrexate or other DMARDs.
To assess the safety and effectiveness of adalimumab, Navarro-Sarabia and colleagues conducted a review of controlled trials of adalimumab compared with placebo as monotherapy or in combination with other drugs. Six trials were included, with a total of 2,381 patients. Improvements were assessed using the American College of Rheumatology (ACR) scores ACR 20, ACR 50, and ACR 70 (representing the percentage improvement in tender and swollen joints, pain, health assessment results, and active phase reactants).2 Results were given in terms of the number of patients needed to receive treatment (NNT) for one patient to have a response.
At 24 weeks, the NNT with adalimumab (40 mg subcutaneously every two weeks) plus methotrexate for one patient to have an ACR 20 improvement ranged from 2 to 5. The NNT for an ACR 50 response ranged from 2 to 6, and the NNT for an ACR 70 improvement ranged from 5 to 13. After 52 weeks, the results were similar. Adalimumab monotherapy also was effective, but the size of the effect was lower. The number of patients needed to be treated to harm one patient with serious infection was 30.
The British Society of Rheumatology guidelines3 state that patients with rheumatoid arthritis are candidates for anti-TNF therapy if they have active, ongoing disease that has failed to respond to two of the following standard DMARD regimens: methotrexate and intramuscular gold, hydroxychloroquine (Plaquenil), sulfasalazine (Azulfidine), penicillamine (Cuprimine), azathioprine (Imuran), or leflunomide (Arava). No anti-TNF therapy has been shown to be more effective than any other. Adverse effects of anti-TNF therapy include serious infection and reactivation of latent tuberculosis. Anti-TNF medications may increase the risk of malignancy, systemic lupus erythematosus, cardiovascular disease, demyelinating or neurologic disease, and hematologic complications.
Management of rheumatoid arthritis is an area of rapidly developing research and changing treatment recommendations, and management decisions generally should be made with a consultant who is following these changes closely.