There are a wide variety of different conditions for which JAK inhibitors have been proven to work or trials are ongoing. To date JAK inhibitors have FDA-Approval for the following: myelofibrosis, polycythemia vera, rheumatoid arthritis and dermatitis. When it comes to hair loss there are types of hair loss that is caused by an auto-immune response, Alopecia Areata, Totalis & Universalis. For an unknown reason a signal is sent from the hair follicle that causes the immune system to attack the hair follicle. This causes inflammation in the cells that grow the hair follicle, the hair falls out and may never grow back again depending on the severity of the condition. The area of loss varies from person to person and there is no way to predict who it will affect. The extent of the condition can’t be predicted either. Alopecia Totalis and Universalis both involve total loss of the hair on the scalp, with Universalis causing all hair on the body to be affected. Alopecia Areata takes the form of smaller patches on the scalp.
Treatments to date for the different Alopecia conditions that have been mentioned above have focused on trying to control the levels of inflammation. The hope is that preventing the inflammation will help to regrow the hair. There are very mixed results so far with any treatment for these conditions. There are no FDA-Approved treatments so far that actually prevent the signalling process that causes the auto-immune response. That is where the JAK inhibitors come into play. There have been a series of promising clinical trials with Alopecia Areata sufferers that have led to positive results.
77% of 65 patients in one particular clinical trial experienced hair regrowth, with 58% experiencing an improvement of more than 50% regrowth. Another clinical trial with 66 patients taking part, saw 32% have a brisk response to the medication over 3 months. A third trial of 13 adolescents aged between 12-16 had 9 patients experience complete hair growth. There could be some belief that the earlier someone is able to take one of these medications, the better their potential for results will be.
There are still more ongoing clinical trials to fully understand the relationship between Alopecia Areata and the JAK enzymes. There are a number of different JAK inhibitor medications available now that inhibit different JAK enzymes, so more studies using the other medications are necessary. It is worth stating as well that it is not thought that JAK inhibitors would be able to treat Androgenetic Alopecia, the most common cause of hair loss. I’m sure over the next few years we will continue to hear more and more about JAK inhibitors.