NEW YORK (AP) -- Pfizer Inc. confirmed that one patient who was taking its drug candidate tofacitinib, a pill designed to treat rheumatoid arthritis, died during a recent clinical trial and said the death was connected to the drug.
The world's largest drugmaker said the patient died of respiratory failure. Three other patients who were treated with tofacitinib during the study died as well, but those deaths were not determined to be drug-related. Two of those deaths occurred several weeks after the patients stopped taking tofacitinib. Tofacitinib, formerly called tasocitinib, is being tested as a treatment for moderate to severe rheumatoid arthritis, a chronic autoimmune disease that causes inflammation, usually of the hands and feet.
Just a reminder for Incyte followers: the Pfizer drug mostly inhibits JAK 3, which is more closely associated with response to infection than the targets of Incyte's drugs (JAK 1 and JAK 2). At correct dosages, neither 424ib nor '050 interfere with control of existing infections (there's a slight possibility that 424ib may delay initial response to infection).
The classic case of drugs in the same general class with small selectivity differences that lead to important differences in side effects is probably Celebrex vs Vioxx.