For example, rifampicin reduced the AUC by 60% in a study.Upadacitinib seems to be a weak inducer of CYP3A4, as it lowers concentrations of other substrates of this enzyme (such as the midazolam AUC by 26%). It has no effect on substrates of CYP1A2, CYP2B6, CYP2C9, CYP2C19 or CYP2D6. Side effects
Common side effects are upper respiratory tract infections such as common cold and sinus infections (13.5% of patients in studies), nausea (3.5%), cough (2.2%), fever, and increased liver enzymes. Serious side effects include infections, including life-threatening ones, such as pneumonia, cellulitis, tuberculosis, as well as shingles and other herpes infections. Pharmacology
Mechanism of action
The Janus kinases (JAKs) are a family of cytoplasmic tyrosine kinases whose function is to transduce cytokine-mediated signals via the JAK-STAT pathway. There are four JAK subtypes, each of which has overlapping receptor responsibilities. Inhibitors of this enzyme family (jakinibs) have shown efficacy in treating certain inflammatory and autoimmune diseases such as rheumatoid arthritis and Crohns disease. However, the first generation of these drugs, tofacitinib and ruxolitinib, lacked subtype selectivity, affecting JAK1/JAK3 and JAK1/JAK2 respectively. This has led to dose-limiting side effects in this otherwise promising class of drugs. Upadacitinib is a second generation Janus kinase inhibitor that is selective for the JAK1 subtype of this enzyme over the JAK2 (74-fold), JAK3 (58-fold) and tyrosine kinase 2 subtypes. Pharmacokinetics
After oral intake, upadacitinib reaches highest concentrations in the blood plasma after two to four hours. A fatty meal has no clinically relevant effect on its resorption.
Primary endpoints were ACR20 and DAS28CRP<2.6 versus placebo at week 12; inhibition of radiographic progression was evaluated at week 26. The study was designed and powered to test for non-inferiority and superiority of upadacitinib versus adalimumab clinically and functionally. At week 12, both primary endpoints were met for upadacitinib versus placebo (p≤0.001). ACR20 was achieved by 71% versus 36%, and DAS28CRP<2.6 by 29% versus 6%. Upadacitinib was superior to adalimumab for ACR50, DAS28CRP≤3.2, ΔPain and ΔHAQDI. At week 26, more patients on upadacitinib vs placebo or adalimumab achieved low disease activity or remission (p≤0.001). Radiographic progression was less and observed in fewer patients receiving upadacitinib versus placebo (p≤0.001). Up to week 26, adverse events (AEs) including serious infections were comparable for upadacitinib and adalimumab. The proportions of patients with serious AEs and AEs leading to discontinuation were highest for adalimumab; the proportion with herpes zoster and CPK elevations was highest for upadacitinib. Three malignancies, five MACE, and four deaths were reported, none on upadacitinib. Six venous thromboembolic events were reported [placebo, one; upadacitinib, two; adalimumab, three]. Upadacitinib was superior to placebo and adalimumab for improving signs, symptoms and physical function in RA patients on background methotrexate, and significantly inhibited radiographic progression versus placebo, while the overall safety profile was generally similar to adalimumab, except for higher rates of herpes zoster and CPK elevations on upadacitinib. SELECT-CHOICE
SELECT-CHOICE was a phase III trial comparing upadacitinib and abatacept in 612 people whose rheumatoid arthritis did not respond to biologic DMARDs.