Last week, the FDA approved a new drug to treat moderate to severe RA. Pfizer's Xeljanz - brand-name tofacitinib - is the first in a new class of medications called Janus kinase (JAK) inhibitors. It is also the first new RA medication in more than a decade that is taken orally, not by injection or infusion. This is good news for everyone who lives with RA. There is now one more treatment options to explore, increasing the chance of going into remission.
What is Xeljanz?
Xeljanz (pronounces Zel’Jans’) approaches treatment of RA through a different pathway than the Biologics. There are many processes involved in creating inflammation within body. The Biologics inhibit pro-inflammatory cytokines from outside the cell, blocking receptors for various immune cells, such as T and B cells, interleukin and the tumor necrosis factor. The JAK pathway is another inflammatory process. JAK inhibitors are small molecule drugs that fight inflammation from inside the cell by inhibiting the JAK pathway.
Xeljanz has been found to be effective in the treatment of moderate to severe RA for people who have not responded well to methotrexate say or the Biologics. How effective and for how many depended on which criteria were used to define improvement. For instance, two large studies used the criteria of 20 percent improvement in two groups using a 5 mg and 10 mg dose of monotherapy with this drug (i.e., not used in combination with any other medication) at three and six months. They found that Xeljanz met that criteria in 50-65 percent of the people participating in the studies. When using the American College of Rheumatology (ACR) criteria for 50 percent improvement, rates were 31-36 percent at three months. ACR 70 percent improvement was reached by 15-20 percent.
Side Effects and Safety Issues
As any medication, Xeljanz has side effects. The most commonly reported are upper respiratory tract infection (i.e., sinus infections), headache and diarrhea. Many of the newer RA meds pack a bigger punch and therefore also have the potential for serious side effects. Severe side effects with Xeljanz may include tuberculosis, serious infections, lymphoma and elevated liver enzymes. Xeljanz therefore comes with a so-called Black Box warning. If that makes you nervous, keep in mind that medications such as Enbrel, Humira and Rituxan also have a Black Box warning. It's an indication that you and your doctor need to be extra vigilant when taking these medications. Your rheumatologist will be able to tell you more about what to be aware of and how to manage the risks.
When the FDA approved this medication, there were some reservations about safety issue because of the above-mentioned side effects. The FDA is therefore requiring investigation into its long-term effects.
Xeljanz is considered a second-line medications for RA. That means it is indicated if methotrexate hasn't worked or in’t working well enough. You do not need to have taken a biologic before taking this medication. Xeljanz can be used in combination therapy with methotrexate, but should not be used in combination with biologic DMARDs or with other powerful immunosuppressants, such as azathioprine and cyclosporine.