Best known for making frown lines disappear, Botox, or Botulinum toxin A, may have the power to treat psoriasis plaques. Results from a mouse study on psoriasis by Case Western Reserve University researchers, published in the Journal of Investigative Dermatology in July 2012, found significant improvement in inflammation and scaling of psoriasis after just one injection. Now the race is on to find out whether men and women — not just mice — can benefit from Botox for psoriasis.
How Does Botox Work?
When used as a cosmetic treatment to eliminate wrinkles, Botox works by blocking chemical signals between nerves and muscles, explained Christopher G. Nelson Jr., MD, a St. Petersburg, Fla., dermatologist. “Recently it was discovered that Botox also inhibits the release of other chemicals from nerves, which are important in stimulating inflammation in psoriasis.”
According to the Case Western Reserve study, not only was there improvement in inflammation and turnover of skin cells associated with psoriasis after one Botox injection, but there was also a decrease in the number of infiltrating CD4 T cells and CD11c dendritic cells, the small white blood cells that carry out responses for the immune system and are typically seen in large numbers during the early stages of psoriasis lesions, when plaques form. By blocking these signals, Botox could reduce inflammatory cells in psoriasis and improve the microscopic appearance of psoriasis, Dr. Nelson said.
Next Steps in Botox Injections for Psoriasis
Researchers are hopeful that Botox treatments for psoriasis will earn approval from the U.S. Food and Drug Administration (FDA) in the not-so-distant future, Nelson said. Although studies on humans to evaluate the effectiveness of the treatment are under way, he noted that "unfortunately, these studies are in their early stages, and much work is necessary to determine the possible role of Botox for psoriasis."
A human study being conducted at the University of Minnesota is a phase 1 clinical trial. Before FDA approval would be possible, these phases must be completed:
- Phase 1: 20 to 80 healthy participants. During this phase, researchers will determine accurate dosing, note how Botox is metabolized in the body and excreted, and identify side effects.
- Phase 2: 100 to 300 participants with psoriasis. At this point researchers will gather additional safety data and document evidence of the drug’s effectiveness. If this phase demonstrates successful results, with a level of risk deemed acceptable, the drug will move on to Phase 3.
- Phase 3: 1,000 to 3,000 participants with psoriasis. A larger pool of participants tested over a longer period of time typically reveals less common side effects that may not show up in Phase 2 trials. During this phase, side effects are monitored, and in certain cases the product’s performance is compared with that of an existing standard treatment.
- Phase 4: This final phase is occasionally conducted after a drug has been approved and is on the market. During Phase 4, researchers continue to study the long-term effects of the treatment. They may also test the product for specific populations of people, such as children or the elderly.
Once all trials are completed and ready to present, the FDA begins its review. The Prescription Drug User Fee Act (PDUFA), enacted in 1992, established a two-tiered system for the FDA drug approval process. A standard review applies to products that offer minor improvement over existing treatments on the market. A 2002 amendment to the act set a 10-month target for completing this type of review. A priority review is reserved for drugs that present major advances in treatment or offer treatment where none previously existed. Target completion for priority reviews is six months after human trials.
Insurance Coverage of Treatments
Once FDA approval is granted, there may still be a delay before your insurance carrier will cover Botox treatments for psoriasis. Individual insurance providers are allowed to determine whether they will cover any portion of the cost of a drug. Once the drug has FDA approval, if your insurance carrier refuses to provide coverage, it may be helpful to send a letter to the company that explains your need for the medication and requests that it reconsider.