Last updated: September 8, 2026
Fedratinib hydrochloride, marketed as Inrebic by Bristol Myers Squibb, is an oral Janus kinase 2, or JAK2, inhibitor approved for adults with intermediate-2 or high-risk primary myelofibrosis, post-polycythemia vera myelofibrosis, or post-essential thrombocythemia myelofibrosis. The product occupies a second-line and treatment-intolerant segment dominated by Jakafi, while Ojjaara and Vonjo have expanded competition across anemia and thrombocytopenia subgroups.
Inrebic has generated steady but modest commercial growth since launch. Its revenue base remains small relative to BMS’s oncology portfolio, but the drug benefits from orphan-disease pricing, chronic treatment duration, limited branded competition in specific patient segments, and a regulatory indication with no approved interchangeable biologic substitute. The principal long-term risks are generic entry, competition from momelotinib and pacritinib, treatment discontinuation caused by gastrointestinal toxicity, and the limited size of the myelofibrosis market.
What is fedratinib hydrochloride and what is Inrebic approved to treat?
Fedratinib hydrochloride is the hydrochloride salt of fedratinib, an orally administered selective inhibitor of JAK2 and FLT3. Inrebic is supplied as 100 mg capsules and is dosed at 400 mg once daily for patients with a baseline platelet count of at least 50 x 10^9/L.[1]
The FDA approved Inrebic on Aug. 15, 2019, for adults with intermediate-2 or high-risk primary or secondary myelofibrosis.[2] The product is used primarily when patients have inadequate response, intolerance, or loss of response to ruxolitinib, although the prescribing information does not limit treatment solely to the post-ruxolitinib setting.
The key label risks are:
- Encephalopathy, including Wernicke’s encephalopathy, linked to thiamine deficiency
- Severe gastrointestinal toxicity, especially nausea, vomiting, and diarrhea
- Anemia and thrombocytopenia
- Hepatic toxicity
- Pancreatitis
- Drug-drug interactions involving CYP3A4 inhibitors and inducers
The need for thiamine assessment and supplementation creates a clinical-management burden that is less prominent in competing JAK inhibitor products.
How large is the fedratinib hydrochloride market?
The addressable market is the global myelofibrosis population eligible for pharmacologic treatment. Myelofibrosis is a rare myeloproliferative neoplasm, and treatment is concentrated in hematology centers. Commercial demand is driven less by broad population screening than by disease progression, symptom burden, splenomegaly, cytopenias, and failure of first-line therapy.
The market has four economically distinct patient segments:
| Segment |
Main commercial need |
Key competitors |
| Newly diagnosed patients with symptomatic splenomegaly |
Spleen and symptom control |
Jakafi, Ojjaara, Inrebic |
| Patients progressing after ruxolitinib |
Alternative JAK inhibition |
Inrebic, Vonjo, Ojjaara |
| Patients with anemia |
Symptom control with reduced anemia burden |
Ojjaara |
| Patients with severe thrombocytopenia |
Spleen and symptom control at low platelet counts |
Vonjo |
Fedratinib’s strongest commercial position is in patients previously treated with ruxolitinib who retain adequate platelet counts. That segment is clinically meaningful but narrower than the total myelofibrosis market.
What are Inrebic sales and the financial trajectory?
BMS does not position Inrebic as a major revenue driver, but annual product-sales disclosures indicate a gradual commercial ramp after launch.
| Period |
Approximate Inrebic sales trend |
Commercial interpretation |
| 2019 |
Launch year |
Limited partial-year contribution |
| 2020 |
Growth from launch base |
Initial hematology adoption |
| 2021 |
Approximately $75 million to $85 million |
Expansion in post-ruxolitinib use |
| 2022 |
Approximately $95 million to $105 million |
Continued uptake and durable treatment demand |
| 2023 |
Approximately $110 million to $120 million |
Stable growth despite competitive pressure |
| 2024 |
Approximately $120 million to $135 million |
Mature branded-product trajectory |
BMS product-sales disclosures place Inrebic in the low-hundreds-of-millions revenue range, far below Revlimid, Eliquis, Opdivo, and other core products.[3,4] The product’s revenue profile is therefore more consistent with a durable specialty asset than with a mass-market growth franchise.
The financial trajectory has four characteristics:
- Low absolute revenue but attractive specialty economics. Orphan oncology drugs generally support high gross margins because manufacturing volumes are limited and pricing is specialty-pharmacy based.
- A concentrated prescriber base. Revenue depends on hematologists and academic treatment centers rather than primary-care prescribing.
- Moderate volume growth. The market can expand through diagnosis and treatment penetration, but the underlying patient population limits the ceiling.
- Increasing competitive pressure. Ojjaara directly addresses anemia, while Vonjo targets patients with severe thrombocytopenia. These differentiated profiles can reduce Inrebic’s ability to expand beyond its core post-ruxolitinib population.
BMS does not separately disclose Inrebic operating profit, gross margin, patient counts, or net price. Revenue should therefore not be interpreted as a direct measure of product profitability.
How does fedratinib compare with Jakafi, Ojjaara, and Vonjo?
| Product |
Active ingredient |
Sponsor |
FDA approval |
Commercial advantage |
Main limitation |
| Inrebic |
Fedratinib |
Bristol Myers Squibb |
2019 |
Strong post-ruxolitinib positioning |
Gastrointestinal toxicity and thiamine-related encephalopathy risk |
| Jakafi |
Ruxolitinib |
Incyte |
2011 |
Established first-line use and broad physician familiarity |
Anemia, thrombocytopenia, and loss of response over time |
| Ojjaara |
Momelotinib |
GlaxoSmithKline |
2023 |
JAK1/JAK2 and ACVR1 activity with anemia differentiation |
Newer commercial infrastructure and competitive positioning |
| Vonjo |
Pacritinib |
Sobi |
2022 |
Indicated for adults with severe thrombocytopenia |
Narrower eligible population and developing adoption |
Jakafi remains the reference product for myelofibrosis treatment. Its first-mover advantage, long clinical history, and broad prescriber base create a high barrier to displacement. Inrebic competes most effectively after Jakafi failure or intolerance.
Ojjaara presents the clearest competitive threat in patients with anemia. Its mechanism and label position address a major unmet need in myelofibrosis, and anemia is a frequent reason for treatment modification. Vonjo is less directly substitutable with Inrebic because it targets patients with platelet counts below 50 x 10^9/L, a population in which standard JAK inhibitor use is constrained.
What is the FDA regulatory and exclusivity status of Inrebic?
Inrebic is an FDA-approved small-molecule drug with orphan-drug designation. It is not a biologic and therefore is not exposed to biosimilar substitution under the Biologics Price Competition and Innovation Act.
The principal regulatory milestones are:
| Milestone |
Date |
| FDA approval |
Aug. 15, 2019 |
| Approved dosage form |
100 mg oral capsule |
| Approved disease area |
Intermediate-2 or high-risk primary or secondary myelofibrosis |
| Regulatory pathway |
New drug application |
| Orphan-drug framework |
Applicable |
| Biosimilar pathway |
Not applicable |
The approval benefited from five-year new chemical entity exclusivity and seven-year orphan-drug exclusivity, subject to the scope of the approved indication and statutory exceptions.[2] The orphan exclusivity period is expected to extend into 2026 based on the 2019 approval date. Regulatory exclusivity does not prevent all patent-based entry and does not automatically block an ANDA containing a Paragraph IV certification after relevant exclusivity periods expire.
What patents protect fedratinib hydrochloride and when could generic entry occur?
Fedratinib is protected by a patent estate covering the active compound, pharmaceutical compositions, and therapeutic use. The relevant intellectual-property categories are:
- Composition-of-matter protection for fedratinib and related chemical structures
- Salt and solid-form protection, including hydrochloride forms
- Oral pharmaceutical compositions
- Methods for treating myelofibrosis and related myeloproliferative neoplasms
- Dosing and safety-management methods
The FDA Orange Book is the controlling source for patents listed against NDA 212327. Public patent records indicate that relevant protection extends beyond the FDA’s initial five-year NCE exclusivity period, with later-expiring claims potentially covering methods of treatment and pharmaceutical formulations.[5]
Generic launch timing will depend on four factors:
- The expiration and enforceability of Orange Book-listed patents
- Whether an ANDA applicant files a Paragraph IV certification
- Whether BMS or another patent owner files Hatch-Waxman litigation within 45 days
- Whether a settlement grants an agreed entry date before patent expiration
A Paragraph IV filing would provide an earlier litigation signal but would not guarantee market entry. A generic could also file a Paragraph III certification and wait for listed patents to expire.
Are there Paragraph IV challenges or patent litigation affecting Inrebic?
No major public Hatch-Waxman litigation has established an earlier generic launch date for Inrebic in the principal publicly available regulatory and court records reviewed for this analysis. The absence of a disclosed challenge does not eliminate future Paragraph IV risk.
The litigation exposure is lower than for very large primary-care products because the addressable market is small and the commercial return from an early generic launch may be limited. A challenger would still have economic incentives if:
- The ANDA applicant receives 180-day first-filer exclusivity
- The product retains high orphan-drug pricing
- BMS maintains a large share of post-ruxolitinib patients
- The challenger can avoid or invalidate method-of-use claims
Patent risk is therefore moderate rather than negligible. Composition patents carry the highest blocking value. Formulation and method-of-use patents are more vulnerable to design-around strategies, label carving, or narrower treatment claims.
What licensing deals and ownership changes affect fedratinib?
Celgene acquired Impact Biomedicines in 2018 for approximately $1.1 billion upfront, with potential milestone payments of up to approximately $1.25 billion.[6] Bristol Myers Squibb acquired Celgene in 2019, making Inrebic part of the BMS hematology and oncology portfolio.
The transaction gave Celgene and later BMS control over a late-stage JAK2 inhibitor with an orphan-disease indication. It also placed Inrebic alongside other hematology assets, allowing BMS to use its oncology sales force, specialty-pharmacy infrastructure, and reimbursement capabilities.
No major subsequent out-licensing transaction has materially changed global control of Inrebic. Commercial rights remain associated with BMS in the principal markets where the product is sold.
How strong is the fedratinib patent and commercial estate?
The commercial estate is stronger than the product’s revenue scale suggests, but it is not exceptionally broad.
Strengths include:
- FDA approval in a defined high-risk hematology indication
- Orphan-drug exclusivity
- A clinically established post-ruxolitinib position
- Specialized distribution and prescriber relationships
- Potential patent coverage extending beyond regulatory exclusivity
Weaknesses include:
- A limited patient population
- Competition from differentiated JAK inhibitors
- Safety-monitoring requirements
- No biologic-style interchangeability barrier
- Potential generic substitution once enforceable patents and exclusivities expire
- Dependence on a single core indication
The strongest barrier is the combined regulatory, clinical, and commercial infrastructure. Patent protection alone is unlikely to support premium pricing indefinitely if generic fedratinib becomes available.
What generic launch scenarios exist for fedratinib hydrochloride?
Scenario 1: No early Paragraph IV challenge
BMS retains branded sales through patent and exclusivity expiry. Revenue grows slowly or stabilizes as Ojjaara and Vonjo gain share. This is the most favorable scenario for the originator.
Scenario 2: First-filer Paragraph IV challenge
A generic applicant files before patent expiry and triggers Hatch-Waxman litigation. BMS may obtain a 30-month stay, settle for a delayed entry date, or litigate through a final judgment. A settlement could preserve value while establishing a defined generic-entry date.
Scenario 3: Multiple generic entrants
Once the main composition and formulation barriers expire, several ANDA applicants enter. Net price declines rapidly, although the orphan market may support a smaller number of suppliers than a high-volume primary-care drug.
Scenario 4: Label-limited generic entry
A generic launches with carved-out method-of-use language. This could reduce patent infringement exposure while limiting promotion for protected uses. Pharmacist substitution and payer behavior would determine the commercial impact.
What geographic markets and manufacturing barriers matter?
The United States is the most important market because of its orphan-drug pricing, centralized patent system, and established specialty-pharmacy channel. European and other international markets may have separate regulatory exclusivity, patent, reimbursement, and compulsory-licensing outcomes.
Manufacturing barriers are moderate. Fedratinib is an oral small molecule rather than a complex biologic, so the active pharmaceutical ingredient and finished-dose product should be technically reproducible by experienced generic manufacturers. The main barriers are:
- Control of impurity profiles and polymorphic forms
- Stable capsule formulation
- Regulatory bioequivalence
- Sourcing of active pharmaceutical ingredient
- Patent clearance for salt, formulation, and therapeutic-use claims
Manufacturing complexity is therefore unlikely to preserve long-term exclusivity after core patent barriers fall.
What is the investment and revenue outlook for fedratinib?
Inrebic is likely to remain a stable specialty-hematology product rather than a high-growth asset. The most probable trajectory is low-single-digit revenue growth or flat sales before generic entry, followed by a material decline after generic competition.
The asset’s value depends on:
- Retention of second-line JAK2 demand
- Adoption in patients intolerant of ruxolitinib
- Differentiation from momelotinib in anemic patients
- Continued access under specialty reimbursement
- The timing and strength of generic patent challenges
For BMS, the financial exposure is limited relative to the company’s total revenue. For a potential generic entrant, the product may offer attractive unit economics but limited absolute volume. For licensors or acquirers, the asset is more valuable as part of a hematology portfolio than as a standalone blockbuster.
Key Takeaways
- Fedratinib hydrochloride is marketed as Inrebic by Bristol Myers Squibb.
- FDA approval covers adults with intermediate-2 or high-risk primary or secondary myelofibrosis.
- Revenue has risen from a launch-stage base to approximately $120 million to $135 million annually.
- The main commercial opportunity is post-ruxolitinib treatment, not broad first-line replacement of Jakafi.
- Ojjaara is the strongest competitive threat in patients with anemia; Vonjo targets severe thrombocytopenia.
- Orphan-drug exclusivity is expected to extend into 2026, while patent protection may extend beyond regulatory exclusivity.
- Fedratinib is a small molecule, so biosimilar risk is irrelevant; generic ANDA risk is the applicable pathway.
- The patent estate is commercially meaningful but unlikely to prevent substantial price erosion after generic entry.
- BMS’s financial exposure is modest relative to its broader oncology portfolio.
- The product’s likely long-term profile is stable specialty revenue followed by a sharp decline after generic competition.
FAQs About Fedratinib Hydrochloride
Is fedratinib hydrochloride the same drug as Inrebic?
Yes. Inrebic is the branded product containing fedratinib hydrochloride as the active pharmaceutical ingredient.
Is fedratinib chemotherapy?
No. Fedratinib is an oral targeted kinase inhibitor. It is not conventional cytotoxic chemotherapy.
Can fedratinib replace ruxolitinib?
Fedratinib can be used in patients with myelofibrosis who have inadequate response or intolerance to ruxolitinib. It is not a universal replacement because treatment choice depends on platelet count, anemia, symptoms, spleen response, and toxicity.
Does fedratinib have biosimilar competition?
No. Fedratinib is a small-molecule drug. Future competition would come through abbreviated new drug applications for generic products, not biosimilar applications.
What is the main clinical risk affecting Inrebic sales?
The main commercial risks are gastrointestinal toxicity, anemia, thrombocytopenia, and the boxed warning concerning encephalopathy, including Wernicke’s encephalopathy. These risks can increase monitoring and discontinuation rates.
References
- Bristol Myers Squibb. (2024). Inrebic prescribing information. U.S. Food and Drug Administration.
- U.S. Food and Drug Administration. (2019, August 15). FDA approves fedratinib for myelofibrosis.
- Bristol Myers Squibb. (2023). 2022 annual report.
- Bristol Myers Squibb. (2024). 2023 annual report.
- U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book, NDA 212327.
- Celgene Corporation. (2018, May 22). Celgene to acquire Impact Biomedicines. Celgene press release.
