Baricitinib vs Upadacitinib
## Overview
Baricitinib (JAK1/2) and upadacitinib (JAK1-selective) are both once-daily JAK inhibitors. Upadacitinib has broader FDA-approved indications; baricitinib has unique approvals for alopecia areata and COVID-19 hospitalization.
## Mechanism of Action
Baricitinib: JAK1 + JAK2 inhibition. Upadacitinib: highly selective JAK1. Baricitinib's JAK2 inhibition affects EPO/TPO signaling, potentially causing mild anemia/thrombocytosis differences from JAK1-selective agents.
## Pharmacokinetics
Both once-daily oral tablets. Baricitinib: half-life ~12 h, ~75% renal excretion. Upadacitinib: half-life ~9–14 h, CYP3A4.
## Indication Comparison
Upadacitinib: RA, PsA, AS, nr-axSpA, AD, UC, Crohn's. Baricitinib: RA, alopecia areata, COVID-19 hospitalized (2 mg approved in EU and US). Head-to-head in RA: RA-BEYOND trial (baricitinib vs upadacitinib): similar efficacy with some upadacitinib advantages at 15 mg.
## Safety
Both have class-wide boxed warnings. Baricitinib's JAK2 inhibition may affect hematopoiesis (mild anemia, platelet changes). Upadacitinib is associated with higher rates of herpes zoster.
## Key Takeaways
- Upadacitinib: JAK1-selective, broadest indications, once daily
- Baricitinib: JAK1/2, unique alopecia areata and COVID-19 approvals, once daily
- Both suitable for RA; selection driven by comorbidities and indication
Заключение
Upadacitinib is preferred when broader indications (Crohn's, ankylosing spondylitis, atopic dermatitis) are needed. Baricitinib is the only JAK inhibitor approved for alopecia areata and hospitalized COVID-19. For RA, both are equally effective; selection should be based on comorbidities, renal function (baricitinib renally cleared), and indication-specific needs.