New research, which was presented at the British Society for Rheumatology’s annual meeting, focuses on Janus Kinase (JAK) inhibitor baricitinib, for which the U.S. Food and Drug Administration recently isused a “complete response letter” in declining to approve the drug. JAK inhibitors, which are taken in pill form, limit certain enzymes that can cause rheumatoid arthritis symptoms.
Researchers studied how effective and safe it is to take baricitinib alone (as “monotherapy”) compared to taking it with methotrexate — a disease-modifying antirheumatic drug (DMARD)
which is often the first treatment rheumatologists prescribe after an RA diagnosis. They found baricitinib alone, or in conjunction with methotrexate, to be statistically superior to methotrexate alone after a year or treatment.
(Learn more about common methotrexate myths and facts.)
In the study — sponsored by pharmaceutical company Eli Lilly, which makes baricitinib jointly with Incyte — 584 rheumatoid arthritis patients, whose exposure to DMARDs was restricted to up to three methotrexate doses, were given one of three treatments.
For 52 weeks, 159 patients received 4 mg of baricitinib, which they took daily as a single pill; 210 took a weekly dose of methotrexate; and 215 took both. Roughly three-quarters were women, and the average participant age was 50 years. Patients had moderate- to severe disease, “with at least six tender and swollen joints. Two-thirds had at least one joint erosion,” notes Medpage. Results were as follows:
- Both those who took baricitinib alone and those who combined it with methotrexate achieved ACR20 — meaning a 20 percent improvement — at a rate of 73 percent; that number dropped to 56 percent among those who took methotrexate alone.
- The rates for ACR50, or a 50 percent improvement, were 57 percent (only baricitinib), 62 percent (baricitinib and methotrexate), and 38 percent (methotrexate alone).
- A similar scale characterized ACR70 — a 70 percent improvement — 42 percent (only baricitinib), 46 percent (both drugs), and 25 percent (methotrexate alone).
- Of greatest concern, 11 patients in the study had herpes zoster infection at week 52; four were in the baricitinib-only group, five in the combined treatment group, and two in the methotrexate-only group.
“When I looked at this data I said, I’d know what I’d do if I got [RA] tomorrow: I’d be on the phone to Lilly asking if I could have baricitinib, then I’d debate whether I’d take methotrexate or not,” study co-author David Walker, of Newcastle upon Tyne Hospitals in the UK, said. (Dr. Walker disclosed attending speaker meetings and advisory boards for several companies, including Lilly.)
Some of the benefits of baricitinib started showing up even at week one. “The most striking thing is speed of onset — in only four weeks you see a huge response,” Dr. Walker said.