JAK inhibitors are a major class of medicines, with more than a half dozen approved for a range of conditions and sizable sales forecasts from their developers to match. Yet concern over the drugs’ association with increased risks of major health problems has overhung their market expansion.
Regulators’ scrutiny was drawn by results of a large study testing Xeljanz against TNF inhibitors, another widely used drug class that includes medicines like Humira and Enbrel, which showed treatment with Pfizer’s drug was associated with high risk of heart attacks, stroke and cancer. Additionally, that study and another testing Eli Lilly’s Olumiant indicated risk of blood clots and serious infections.
