Besremi Shortage: What Providers and Prescribers Need to Know in 2026

The interferon landscape for myeloproliferative neoplasms has shifted significantly over the past two years, and Besremi (Ropeginterferon Alfa-2b-njft) now sits at the center of that shift. As a prescriber managing polycythemia vera patients, you need to understand where Besremi supply stands, what drove us here, and what practical steps can keep your patients on track.

This briefing covers the current availability picture, prescribing implications, cost and access considerations, and tools you can use to help your patients navigate the supply landscape.

Timeline: How We Got Here

Understanding the current Besremi access situation requires context on the broader interferon shortage affecting hematology-oncology:

• November 2021: FDA approves Besremi (Ropeginterferon Alfa-2b-njft) as the first interferon specifically indicated for polycythemia vera in adults. Manufactured by PharmaEssentia Corporation.
• 2021: Non-pegylated Interferon Alpha-2a is discontinued in the United States, removing one interferon option for PV.
• 2024: Pegasys (Peginterferon Alfa-2a), the most commonly used off-label interferon for PV, enters a drug shortage with supply disruptions reported across specialty pharmacies.
• January 2025: NCCN updates Clinical Practice Guidelines to recommend substitution of Ropeginterferon Alfa-2b-njft (Besremi) for Pegasys when the latter is unavailable. Besremi is listed as a Category 1 preferred first-line cytoreductive option.
• March 2025: PharmaEssentia publicly positions Besremi as the available interferon alternative for patients affected by the Pegasys shortage.
• 2025-2026: Increased patient transitions from Pegasys to Besremi drive demand above pre-shortage baseline, leading to sporadic access challenges at specialty pharmacies.

Prescribing Implications

Besremi Is Not in a Formal Shortage

Besremi does not appear on the FDA Drug Shortage Database. The access challenges being reported are demand-driven rather than supply-chain or manufacturing failures. PharmaEssentia has been scaling production capacity to meet the influx of patients transitioning from Pegasys.

Dosing Considerations for Transitioning Patients

For patients transitioning from Pegasys to Besremi, the recommended approach:

• Starting dose: 100 mcg subcutaneously every 2 weeks (standard), or 50 mcg if the patient is transitioning from or concomitantly receiving Hydroxyurea
• Titration: Increase by 50 mcg every 2 weeks based on hematologic response, up to a maximum of 500 mcg every 2 weeks
• Monitoring: CBC with differential every 2 weeks during titration, then at least monthly once stable. Liver function tests, renal function, thyroid function, and triglycerides should be monitored per the prescribing information.
• Note: Besremi uses a biweekly dosing schedule versus the weekly administration of Pegasys, which may require patient education during the transition

Contraindications Worth Reviewing

Before prescribing Besremi, confirm the absence of:

• History of severe psychiatric disorders (depression, suicidal ideation) — Boxed Warning
• Serious or untreated autoimmune disease
• Decompensated liver disease
• Organ transplant with immunosuppressive therapy
• Uncontrolled cardiovascular disease (hypertension, CHF, serious arrhythmia, severe CAD, recent MI/stroke)

For a comprehensive review of drug interactions relevant to your PV patient population, see our clinical reference on Besremi drug interactions.

Current Availability Picture

Besremi is distributed exclusively through specialty pharmacies. It is not available at retail pharmacies. Key distribution facts:

• Dispensing model: Specialty pharmacy to patient (home delivery) or buy-and-bill through physician offices
• Storage: Refrigerated (2°C to 8°C). Shipped with cold chain packaging.
• Formulation: 500 mcg/mL solution in prefilled syringe, with dose markings at 50 mcg intervals
• Lead time: New prescriptions typically take 1-3 weeks to process (including prior authorization and shipping). Refills are faster when started 7-10 days ahead.

PharmaEssentia SOURCE can assist your practice with availability tracking and pharmacy coordination. Contact them at 1-833-546-7473.

Cost and Access Considerations

Insurance Coverage

Besremi has broad national payer coverage across commercial, Medicare, and Medicaid plans. However:

• Prior authorization is required by most payers
• Step therapy requirements may necessitate documented trial and failure of Hydroxyurea
• Some plans cover Besremi under the medical benefit (buy-and-bill), while others route through the specialty pharmacy benefit
• Appeals may be necessary for denials — PharmaEssentia SOURCE provides assistance with appeals and prior authorization

Patient Financial Assistance

PharmaEssentia offers two key programs:

• Copay Assistance Program: Eligible commercially insured patients can pay as little as $0/month. Covers copay, coinsurance, and deductible expenses. Enrollment at BESREMiCopay.com. Not available to patients on Medicare, Medicaid, TRICARE, or VA.
• Patient Assistance Program (PAP): Provides Besremi at no cost to eligible uninsured or underinsured patients.

For patients struggling with cost, direct them to our guide on saving money on Besremi, or for provider-specific guidance, see the provider's guide to helping patients save.

Tools and Resources for Your Practice

Medfinder for Providers

Medfinder for Providers offers real-time specialty pharmacy availability tracking for Besremi. Your staff can use it to identify pharmacies with current stock, reducing the time spent on phone calls and faxes. It's a free resource designed to streamline the medication access workflow.

PharmaEssentia SOURCE (Provider Line)

PharmaEssentia's provider support program assists with:

• Identifying specialty pharmacies with Besremi in stock
• Prior authorization support and appeals assistance
• Patient enrollment in copay and PAP programs
• Injection training resources for patients

Provider line: 1-833-546-7473

NCCN Guidelines Reference

The NCCN Myeloproliferative Neoplasms guidelines (Version 1.2025, January 21, 2025) include:

• Ropeginterferon Alfa-2b-njft as a Category 1 preferred first-line cytoreductive option for PV
• Guidance on substituting Besremi for Pegasys during shortage conditions
• Recommendations for transitioning patients between interferon formulations

Looking Ahead

Pipeline Developments

• Rusfertide: Hepcidin mimetic in Phase III trials for PV. If approved (potentially late 2026), it would offer a novel mechanism of action — iron metabolism regulation rather than cytoreduction or immune modulation.
• Besremi for ET: PharmaEssentia is pursuing expanded FDA labeling for essential thrombocythemia. Already included in NCCN guidelines as Category 1 preferred regimen for ET.
• Jakafi (Ruxolitinib): Incyte continues to explore combination approaches and expanded indications.

Supply Outlook

PharmaEssentia has publicly committed to meeting increased demand and has been expanding manufacturing capacity. If the Pegasys shortage resolves and Rusfertide gains approval, the combined supply pressure on Besremi should ease. In the interim, proactive ordering and strong pharmacy coordination remain the best strategies.

Final Thoughts

Besremi remains available and continues to be the only FDA-approved interferon for polycythemia vera. The access challenges are real but manageable with proactive planning. As a prescriber, your most impactful steps are: starting the prescription and prior authorization process early, leveraging PharmaEssentia SOURCE for pharmacy coordination, and utilizing Medfinder for Providers to track real-time specialty pharmacy availability.

For a practical workflow guide on helping patients access Besremi, see our companion article: How to Help Your Patients Find Besremi in Stock.