Psoriasis is a heavy burden for both the physical and economic health of the nation, affecting about 7.5 million Americans. The annual cost for treating psoriasis in the U.S. in 2008 was $11.25 billion. The average cost per patient, estimated at $5500 per year, is much higher for more severe cases of psoriasis or psoriatic arthritis. While there is still no cure, the last decade has witnessed an explosion of scientific and clinical research leading to the development and FDA approval of an entire new family of medications called Biologics. Biologics are complex proteins or antibodies synthesized in the laboratory that block one or more steps in the immunologic pathway leading to inflammation and the rapid overgrowth of skin cells which results in psoriasis lesions.
Since 2004, six new biologic drugs have been approved for psoriasis. Two have already been withdrawn by their manufacturers because of side effects (Raptiva) or lack of effectiveness (Amevive). Of the four that remain, three work by blocking tumor-necrosis-factor, and one acts by inhibiting interleukin 12 and 23. All are injected into the body by the patient at home or by the doctor in the office. The tumor-necrosis-factor blockers are named Enbrel, Humira, and Remicade. The interleukin inhibitor is called Stelara. The first three are also approved for psoriatic arthritis that affects about 30% of psoriasis sufferers. Psoriatic arthritis is similar to rheumatoid arthritis in terms of symptoms and progressive damage to the joints. Psoriatic arthritis can be quite disabling in its own right. For patients who have predominantly arthritis along with skin disease, we may also prescribe Simponi which is only approved for the former but still helps the latter.
All of these biologics are capable of significantly improving psoriasis in 50-80% of cases after 12 weeks. This represents an advance over all previous conventional treatments for psoriasis: creams, Methotrexate, Cyclosporine, Soriatane—except Ultraviolet light
phototherapy. With phototherapy in the form of narrow band ultraviolet B light, we can achieve 80-90% improvement. All of these therapies are offered at the three Camisa Psoriasis Centers at Riverchase Dermatology.
A new biologic which blocks Interleukin 17 has recently completed phase 2 studies in over 300 patients with moderate to severe psoriasis and significantly improved over 80% of them in 12 weeks. The expectation is that this new drug will have fewer side effects than the established biologics, but the final results must await the completion of phase 3 studies with more patients and longer follow-up.
Currently, the disadvantages of biologics are the increased risk of some infections and cancers as well as their high cost. A typical one-year course of injectable biologic may run upwards of $30,000!