- Pfizer put its JAK inhibitor Xeljanz (tofacitinib) up against AbbVie's Humira (adalimumab), hoping for data that would help steal market share away from the bestseller in rheumatoid arthritis. But topline results released in February had shown Xeljanz monotherapy failed to prove non-inferiority to Humira
- Full results from that trial, called ORAL Strategy, were unveiled at the EULAR meeting Friday and gave more detail on where Xeljanz failed to measure up.
- Thirty-eight percent of patients treated with Xeljanz alone met the ACR50 endpoint after six months, compared to nearly 44% of those on Humira plus methotrexate, falling short of marking non-inferiority. Xeljanz combined methotrexate did better, however, meeting its endpoint of non-inferiority and achieving ACR50 in 46% of patients.
Humira is the best-selling drug in the world, with 2016 sales increasing 14.7% to $16.1 billion, despite increased competition from other TNF-alpha inhibitors and newer drugs such as Xeljanz. Recently approved Kevzara (sarilumab), from Sanofi and Regeneron, adds to the crowded field.
The head-to-head study is the first to compare a JAK inhibitor, either as a combination or monotherapy, with Humira. Pfizer was hoping to use the results to help it to catch up with, or even overtake, Humira's share of the market. While the combo with methotrexate met the criteria for non-inferiority, that improvement may not move the needle significantly in Pfizer's favor.
There are other JAK inhibitors coming up behind Xeljanz. AbbVie's upadacitinib met all of its primary and secondary endpoints in a Phase 3 study in rheumatoid arthritis, with ACR50 responses of 38% and 43% at 12 weeks (no data available yet for 6 months). It also showed positive topline results in a Phase 2 trial in Crohn's disease, reducing gut inflammation.
Eli Lilly and Incyte had been hoping to win approval for baricitinib earlier this year, but the FDA rejected the drug in April after a three-month delay. The drug is approved in Europe, however.