ResearchAndMarkets.com has added a report forecasting OJJAARA (momelotinib) sales and market size from 2026 through 2034 across the United States, Germany, France, Italy, Spain, the United Kingdom and Japan. OJJAARA is approved for adults with intermediate- or high-risk primary or secondary myelofibrosis with anemia, regardless of previous JAK inhibitor treatment. It is the first and only FDA-approved JAK inhibitor (drug targeting Janus kinase signaling) specifically indicated for that population. The report also evaluates potential opportunities in myelodysplastic syndromes, VEXAS syndrome and acute myeloid leukemia. Approval was supported by the MOMENTUM and SIMPLIFY-1 Phase III studies. In MOMENTUM, momelotinib produced transfusion independence in 30% of patients versus 20% with danazol, spleen-volume reduction of at least 25% in 39% versus 6%, and a reduction of at least 50% in total symptom score in 25% versus 9%. OJJAARA inhibits JAK1, JAK2 and activin A receptor type 1, with reported effects on anemia-related outcomes, spleen response and constitutional symptoms. After FDA approval in September 2023, it received approvals from the European Commission, the UK Medicines and Healthcare products Regulatory Agency, and Japan’s Ministry of Health, Labour and Welfare in 2024. The report examines reimbursement, clinical adoption, pricing, patents, generic-entry risks, competition, clinical development and sales assumptions through 2034. In September 2025, GSK announced a letter of intent with the pan-Canadian Pharmaceutical Alliance concerning public reimbursement access for patients with myelofibrosis and anemia, while momelotinib received Orphan Drug Designations in the United States and European Union for VEXAS syndrome.