Yesterday, the FDA approved Pfizer’s XELJANZ (tofacitinib) for treatment of RA when methotrexate has failed to work adequately. This oral medicine is in a new class of drugs: Janus kinase (JAK) inhibitor.
Another JAK, ruxolitinib, was approved last year for the treatment of myelofibrosis. Other JAK inhibitors are being tested as treatments for psoriasis, RA, and some cancers. I have to admit that reading about JAKs made my eyes glaze over; all I retained was “just another kinase” having to do with cytokine receptors and “named after the two-faced Roman god Janus.” Perhaps Andrew will write something comprehensible for us laymen (hint). Until then, I know which reading material I’ll select next time insomnia strikes.
Tofacitinab comes with the black-box warning that RA patients are all too familiar with: elevated liver enzymes, lower blood counts, high cholesterol, and increased risk of infection, tuberculosis, lymphoma, and cancers. Post-marketing studies were ordered, so time will tell how effective this medication is, and whether there are other side effects to watch for. Those who have run the gauntlet of every available medicine but found no relief now have a new treatment option.