Tofacitinib (sold as Xeljanz® in the United States) was approved for use for rheumatoid arthritis in 2012. It’s also being studied for AS.
One of the “joys” of having a chronic illness such as AS is getting to learn a whole new language: medical mumbo jumbo! For example, tofacitinib is what’s known as a Janus kinase (JAK) inhibitor.
I know from my college course in Greek and Roman Mythology that Janus was a god who had two faces—because he represented both beginnings and endings; he looked to both the future and the past. According to Wikipedia, JAKs have “two near-identical phosphate-transferring domains. One domain exhibits the kinase activity, while the other negatively regulates the kinase activity of the first.”
No one really knows what causes AS; although, researchers believe that both genetics and environmental factors play a role.
That’s why finding a treatment can be so challenging. Nobody knows what type of weapon to use when fighting it or where to aim!
AS is in the rheumatology family of diseases, because it involves inflammation of joints (in AS, inflammation affects the sacroiliac joints, where your spine joins your pelvis). That leads doctors to try treatments that have shown success in other rheumatic diseases—a practice that is referred to as off-label use.
Through a process of differentiation (identifying treatments that work for one disease, but not for the other and investigating how the diseases differ), researchers try to get closer to finding THE treatment.
If the response to a drug for one disease is positive in another (rheumatoid arthritis and AS, for example), researchers may run clinical trials specifically for the off-label use.
Trial Results Coming Soon!
That’s what happened with tofacitinib. The drug is currently in Phase 2 clinical studies specifically for AS—and initial findings seemed positive. If all goes as planned, the results will be presented at this year’s meeting, to be held on 10 November 2016.
Hopefully, research into the causes of and potential treatment targets for AS will keep progressing!