Biosimilars are designed to mimic biologic agents, but they are not precise duplicates of these drugs. Biosimilars may prove useful for treating skin conditions such as psoriasis, but clinicians are waiting for guidance on the drugs from the Food and Drug Administration, which was still pending at press time.
Biologics, which are generated from human and/or animal proteins, have revolutionized the treatment of chronic diseases by targeting specific abnormal responses in the immune system that trigger conditions such as psoriasis and psoriatic arthritis.
Mark G. Lebwohl, M.D., professor and chairman, department of dermatology, Mount Sinai School of Medicine, New York, says he is concerned about the safety and efficacy of biosimilars, which would be "clinically similar," but not exact copies of branded biologics.
The current roster of biologic agents are effective at treating psoriasis, providing benefit even for people with severe disease, Dr. Lebwohl says. The FDA has approved several biologics for the treatment of adults with psoriasis and/or psoriatic arthritis. The approved drugs include etanercept (Enbrel, Amgen/Pfizer); adalimumab (Humira, Abbott); infliximab (Remicade, Janssen Biotech); golimumab (Simponi, Janssen Biotech); and ustekinumab (Stelara, Janssen Biotech).
In November 2011, Amgen/Pfizer was granted a 17-year patent extension for Enbrel. Dr. Lebwohl says this is the oldest biologic in the U.S. indicated for the treatment of dermatologic conditions. Biosimilars are available in Europe, but not for skin diseases.
Efalizumab (Raptiva, Genentech) was withdrawn from the market after it was linked to the development of progressive multifocal leukoencephalopathy. Astellas Pharma recently announced it would no longer manufacture alefacept (Amevive). Currently, no biologics are indicated for the treatment of pediatric psoriasis.
Adalimumab, golimumab, etanercept and infliximab target tumor necrosis factor-alpha (TNF-alpha); alefacept targets T-cells; and ustekinumab targets interleukin-12 and -23, all of which are inflammatory molecules that play a role in the development of psoriasis.
When companies create generic versions of chemical compounds, the generic version is an exact copy of the original branded medication, and, therefore, the companies do not have to perform safety and efficacy studies.