Biologics bring benefits for psoriasis patients ... if prescribed correctly

December 1, 2005

Las Vegas — With many new treatments for psoriasis now available, dermatologists need to educate themselves about these drugs in order to enable optimal care for their patients, said Mark Lebwohl, M.D., at the annual Fall Clinical Dermatology Conference, here.

The landscape of psoriasis therapy has been changing rapidly in a positive direction with the introduction of the biologics that can be used to treat very problematic disease with better safety and sometimes even greater efficacy than achievable with previous standard medications. However, dermatologists also have to adapt quickly in learning how to prescribe these new agents for the benefit of their patients, says Dr. Lebwohl, professor and chairman, department of dermatology, Mt. Sinai School of Medicine, New York.

Case history

Baseline laboratory testing showed the patient had a serum creatinine of 1.0 mg/dL, and treatment was started with oral methotrexate 15 mg once weekly. The plaque psoriasis cleared, but the psoriatic arthritis remained severe. The methotrexate was stopped, and treatment was switched to alefacept. At that visit, the patient was also given an inhaled live influenza vaccine.

Methotrexate dosing in the elderly

Dr. Lebwohl points out that when prescribing methotrexate in older patients, the medication should always be started at a very low dose, 2.5 mg once a week, and titrated up slowly, as needed, in increments of only 2.5 mg per week. The treatment should also be accompanied by weekly monitoring of the CBC.

He tells Dermatology Times, "Pancytopenia, often fatal, associated with methotrexate, and advanced age has emerged as a common risk factor in those series. Therefore, methotrexate must be administered with caution to older patients using a reduced dose. Remember, renal function is often reduced in the elderly, and although their serum creatinine may be in the 'normal' range, that laboratory value tends to overestimate renal function because of reduced muscle mass in older patients."

Treatment of psoriatic arthritis

Many of the newer biologic agents have efficacy for treating psoriasis as well as psoriatic arthritis. Evidence that alefacept is effective for psoriatic arthritis has been reported recently, although that drug is not approved for treating psoriatic arthritis. Three other biologics - etanercept adalimumab and infliximab now have Food and Drug Administration-approved indications for the treatment of psoriatic arthritis.

Not only do the clinical studies with these drugs show they are effective in improving the symptoms of psoriatic arthritis, but there is also evidence that they slow the radiographic progression of the joint disease, Dr. Lebwohl says.

Transitioning to a biologic

When switching a patient from existing systemic treatment to a new biologic, it is critical to take into account how quickly the biologic works. Current treatment should then be tapered gradually based on that profile of action with the aim of maintaining disease control.

In fact, alefacept is the slowest-acting of the biologics as onset of efficacy is generally not seen until after eight weeks, and a major effect does not occur until 12 weeks. In contrast, responses to adalimumab, efalizumab, etanercept (50 mg twice a week) and infliximab may all be seen after about two to four weeks. Major responses are seen within two to four weeks with infliximab, four weeks with adalimumab, four to eight weeks with etanercept, and at 10 weeks with efalizumab.

Immunization recommendations

Patients who are on immunosuppressive medications for their psoriasis should be given an influenza vaccine. However, live influenza vaccine and other live virus vaccines, including yellow fever, oral polio, BCG, and vaccinia, should be avoided. These patients may receive killed or inactivated vaccines for influenza, pneumococcal infection, hepatitis B, tetanus and diphtheria.

Dr. Lebwohl notes that available data indicates that alefacept does not impair the response to immunizations, whereas the efficacy of administered vaccines may be reduced somewhat in patients who are receiving other biologics.

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