Top-Line Study Results Show Baricitinib Effective in the Treatment of Rheumatoid Arthritis

Phase 3 study results show that baricitinib met the primary endpoint of improved ACR20 scores after 12 weeks of treatment in patients with rheumatoid arthritis.

Baricitinib improved American College of Rheumatology scores (ACR20) after 12 weeks of treatment in patients with moderate to severe rheumatoid arthritis, Eli Lilly and Incyte Companies announced in a press release.

Patients were enrolled in the study to determine if baricitinib improved ACR20 response to placebo in patients with moderate to severely active rheumatoid arthritis (RA). Baricitinib is a once daily, oral, selective JAK1 and JAK2 inhibitor. There are 4 known JAK enzymes, which have been implicated in the pathogenesis of several inflammatory and autoimmune diseases. Researchers believe this suggests treatment for these diseases lies in JAK enzyme targeting.

The 527 participants in the study had previously failed one or more tumor necrosis factor (TNF) inhibitors and were taking stable doses of conventional disease modifying antirheumatic drug (cDMARD) therapy. The full results and disclosures from this ongoing study will be released at scientific meetings in 2015, where baricitinib will be tested on more than 3,000 patients with RA.

“People with rheumatoid arthritis who have had an inadequate response to TNF inhibitors are generally considered to be the least responsive to subsequent treatments,” David Ricks, Lilly senior vice president, and president, Lilly Bio-Medicines, continued in the statement. “These results give us further confidence in the potential for baricitinib to be a meaningful treatment option for those suffering from this debilitating condition.”

A large percentage of the patients involved in the study had received prior treatment with one or several non anti TNF biologic agents. They received either one of 2 doses of once daily baricitinib or placebo in addition to their background cDMARDS.

Serious adverse events and discontinuation rates reported with the use of baricitinib were similar to those reported in the placebo group, the press release went on. Throughout the study, there were no opportunistic infections or gastrointestinal perforations. More frequent incidents of treatment emergent adverse events were observed in the baricitinib group compared to the placebo counterpart. Side effects common in the baricitinib group included headaches, upper respiratory tract infections, and nasopharyngitis. Many patients included in the short term study, which lasted 6 months, opted to participate in the long term extension study.

“We are very pleased by these results,” Rich Levy, MD, chief drug development and medical officer, Incyte Corporation, explained in the press release. “Over the next 12 months we look forward to seeing the data from additional Phase 3 studies of baricitinib in RA, including patients who have had an inadequate response to cDMARDs and in those with earlier stage disease.”