- Pfizer on Thursday announced its JAK inhibitor Xeljanz (tofactinib citrate) failed to beat out a combo of AbbVie's best-selling Humira (adalimumab) and methotrexate in treatment of moderate to severe rheumatoid arthritis.
- While Xeljanz monotherapy failed to notch a success, Xeljanz plus methotrexate was able to demonstrate non-inferiority to the Humira combo.
- Pfizer is counting on Xeljanz to offset declines in ex-U.S. sales of Enbrel (etanercept), which have dragged down the performance of the pharma giant's inflammation and immunology portfolio. Xeljanz earned $927 million last year, up 77% from 2015.
Humira is the standard-bearer in many inflammatory conditions like rheumatoid arthritis, continuing to hold its claim to the title of best-selling drug in the world despite heavy competition.
Pfizer hoped to show Xeljanz could stand on its own and perform comparably to Humira. While the mixed results from the Phase 3b/4 study failed to deliver that result, Xeljanz as a combination therapy with methotrexate was able to match the Humira combo.
The trial, dubbed ORAL strategy, is the first trial comparing a JAK inhibitor as a monotherapy or in combination with methotrexate against Humira plus methotrexate.
Pfizer plans to release the full results of the study at an upcoming medical meeting and will continue to analyze the monotherapy data, said Michael Corbo, Pfizer's chief development office for the inflammation and immunology unit, in a statement.
More competition could soon be inbound though. Eli Lilly recently won E.U. approval for its JAK inhibitor, known as Olumiant (baricitinib), in rheumatoid arthritis — the first drug in its class okayed for use in the lucrative indication in the E.U. An approval decision in the U.S. has been delayed by three months but could come in the near future.
A forecast from Evaluate Pharma predicts potential sales of baricitnib of $1.78 billion by 2022.