Phase 3 Study Finds Oral Drug Reduces Joint Damage Caused by Rheumatoid Arthritis

Phase 3 Study Finds Oral Drug Reduces Joint Damage Caused by Rheumatoid Arthritis

Once daily treatment of moderate to severe rheumatoid arthritis with the oral drug baricitinib significantly reduced structural damage to patients’ joints, according to a study presented at the recent EULAR Annual Congress in London.

Data for the presentation came from the RA-BUILD clinical trial (NCT01721057), a Phase 3 study in some 680 patients with moderately to severely active rheumatoid arthritis and with inadequate response to at least one conventional disease-modifying antirheumatic drug. Researchers, led by Dr. Désirée van der Heijde, of Leiden University Medical Center in the Netherlands, investigated the safety and side effects of baricitinib use (2 mg or 4 mg) over 24 weeks.

Trial participants are being invited to continue treatment in the ongoing RA-BEYOND Phase 3 clinical trial (NCT01885078), a multicenter extension study evaluating the long-term safety and efficacy of baricitinib. Those in the earlier study’s treatment arm will stay on the baricitinib dose given them in RA-BUILD, while those in the placebo group are being switched to 4 mg baricitinib. This trial’s primary measure is to evaluate the drug’s safety in long-term use, determined by adverse events over 48 months of treatment. Secondary outcomes are efficacy measures, such as joint space narrowing, disease activity, American College of Rheumatology (ACR) response scores, etc.

Researchers evaluated radiographic progression of structural joint damage for the presentation. Results at 24 and 48 weeks showed significantly lower disease progression, measured by modified total Sharp score, bone erosion, and joint space narrowing in patients treated each day with baricitinib, either 2 mg or 4 mg, compared to those receiving a placebo.

Observations or clinical measures carried forward at week 48 found that treatment at 4 mg resulted in a statistically significant inhibition of progressive radiographic joint damage.

Baricitinib, an oral Janus kinase 1 and 2 inhibitor, inhibits the activity of one or more of the Janus kinase family of enzymes (JAK1, JAK2, JAK3, TYK2), which interfere with the JAK-STAT signaling pathway. The inhibitors are thought to have therapeutic application in inflammatory diseases such as rheumatoid arthritis.

“Together with the improvement of clinical and quality of life symptoms, which are so important for rheumatoid arthritis patients, a key goal of treatment is to restrict the structural damage rheumatoid arthritis causes to joints, a hallmark of the disease,” Dr. van der Heijde said in a news release. “These findings have shown us that, for people with rheumatoid arthritis, baricitinib may, if approved, offer an oral option which could help them restrict joint damage over an extended period of time.”

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