Prescribing guide
Besremi (ropeginterferon alfa-2b-njft)Dosing, hydroxyurea transition, contraindications, monitoring and access for polycythemia veraFor prescribers and their offices treating polycythemia vera: what the pharmacy needs before it ships, what the prior authorization wants documented, the titration and the monitoring the label requires.
Dispensing gate
No REMS in the label or the 2026 approval letters; boxed warning; 5 contraindications to screen; pregnancy test in females of reproductive potential; baseline CBC, liver tests, creatinine and triglycerides; self-injection training; SOURCE enrollment form faxed to 800-700-5065 or a prescription to a specialty pharmacy partner such as Biologics or Onco360.
Example PA threshold
UnitedHealthcare example, effective December 1, 2025: diagnosis of polycythemia vera, or an NCCN Compendium category 1, 2A or 2B use; 12-month authorization; supply limits or step therapy may apply.
Monitoring
CBC at baseline, every 2 weeks during titration and dose modification, then every 3 to 6 months; liver enzymes, creatinine and triglycerides at baseline and during treatment; eye exams before and during therapy; close monitoring for psychiatric symptoms.
Support line
PharmaEssentia SOURCE, 800-700-5053, Monday through Friday 8:00 AM to 8:00 PM ET; fax 800-700-5065; benefits investigation, PA and appeals support, copay as little as $0 per month for commercial plans, PAP, temporary supply for delays or gaps, nurse injection support.
Give your patient their plan
A one-page handout for starting Besremi, in plain language: what the first fill waits on, the first dates, who will call and the symptoms to report, with blank lines for the start date and your office's number. The link opens the patient's full first 90 days page, where their dates become calendar entries.
trialfriend.com/p/besremiBefore the first fill: REMS, labs and enrollment
The steps that the pharmacy, the REMS or the drugmaker's program will wait on, in the order they usually need to happen. A first fill of a specialty drug most often stalls on one of these rather than on the plan.
| Step | What it requires | Source |
|---|---|---|
| Confirm the indication | Treatment of adults with polycythemia vera. Safety and effectiveness in pediatric patients have not been established. | FDA label |
| Screen the 5 contraindications | Existence or history of severe psychiatric disorders, particularly severe depression, suicidal ideation or suicide attempt; hypersensitivity to interferons including interferon alfa-2b or any inactive ingredient; moderate (Child-Pugh B) or severe (Child-Pugh C) hepatic impairment; history or presence of active serious or untreated autoimmune disease; immunosuppressed transplant recipients. | FDA label |
| Screen the avoid-use conditions | Avoid in severe or unstable cardiovascular disease (uncontrolled hypertension, congestive heart failure NYHA class 2 or higher, serious arrhythmia, significant coronary artery stenosis, unstable angina) or recent stroke or myocardial infarction, and in eGFR below 30mL/min. Do not use in active serious or untreated endocrine disorders associated with autoimmune disease. | FDA label |
| Pregnancy test and contraception | Obtain a pregnancy test in females of reproductive potential before initiation. Advise effective contraception during treatment and for at least 8 weeks after the final dose, and no breastfeeding during treatment and for 8 weeks after the final dose. | FDA label |
| Baseline tests | CBC, liver enzymes and hepatic function, serum creatinine and serum triglycerides. Advise an eye examination before therapy, specifically with a retinopathy-associated disease such as diabetes mellitus or hypertension. | FDA label |
| Decide on self-administration and train | Section 2.4: confirm the patient or caregiver is an appropriate candidate, then provide training on storage, preparation and administration technique. Otherwise a healthcare professional administers. | FDA label |
| Choose the presentation | Prefilled syringe 500mcg/mL (NDC 73536-500-01) or Besremi Pen 500mcg/0.5mL (NDC 73536-511-01), one single-dose device per carton, each with one needle. Each has its own Instructions for Use. | FDA label |
| Prescribe by 1 of 3 routes | The SOURCE Enrollment Form, which includes a section that serves as the first prescription; a prescription to a specialty pharmacy partner, including Biologics or Onco360, shipped to the patient; or in-office dispensing for eligible GPO members and authorized health system pharmacies. | SOURCE delivery, for offices |
| Enroll in SOURCE | Fax the Enrollment Form to 800-700-5065 to request reimbursement support and indicate the preferred pharmacy. Questions about pharmacy qualifications: 800-700-5053, 8:00 AM to 8:00 PM ET, Monday through Friday. | SOURCE delivery, for offices |
| Benefits investigation and PA | SOURCE assesses coverage and estimated out-of-pocket costs, determines whether a PA is required and what documentation the submission needs, and helps monitor status after the office submits the request. | SOURCE access, for offices |
Prior authorization criteria and what to document
One public policy as the example: UnitedHealthcare, effective December 1, 2025. Approval 12 months. This policy took effect on December 1, 2025, and cites the April 2024 package insert. It predates the 2026 label changes, which added the Besremi Pen in June and essential thrombocythemia in August, so it does not mention either. The policy says supply limits or step therapy may be in place, and that state mandates and the member's own plan can change the criteria. Other insurers set their own rules, which may differ from this example.
| Element | What the policy asks | In the chart | Source |
|---|---|---|---|
| Diagnosis | Diagnosis of polycythemia vera is the policy's single criterion for that indication | Diagnosis and ICD-10 code on the request | UnitedHealthcare policy |
| Alternative route | Use recognized by the NCCN Drugs and Biologics Compendium with a category of evidence and consensus of 1, 2A or 2B | Compendium citation, where the request is not for PV | UnitedHealthcare policy |
| Authorization period | 12 months | Calendar the reauthorization date | UnitedHealthcare policy |
| Automated approval | The policy says approval and reauthorization may be based solely on claim or medication history, ICD-10 codes or claim logic | Accurate diagnosis coding on claims | UnitedHealthcare policy |
| Other limits | Supply limits or step therapy may be in place; state mandates and the member's benefit plan may change the criteria | Ask the plan which limit applies; titration changes the dose every 2 weeks | UnitedHealthcare policy |
| Policy currency | Effective December 1, 2025; references the April 2024 package insert; describes Besremi as indicated for polycythemia vera only | Predates the August 2026 label | UnitedHealthcare policy |
| Appeals | Sample Letter of Medical Necessity, Sample Letter of Appeal and Sample Formulary Exception Letter are downloadable | SOURCE Access & Reimbursement page | SOURCE access, for offices |
Besremi dosing and titration
| When | Label | Source |
|---|---|---|
| Day 1, not on hydroxyurea | 100mcg subcutaneously every 2 weeks. | FDA label |
| Day 1, transitioning from hydroxyurea | 50mcg subcutaneously every 2 weeks in combination with hydroxyurea. | FDA label |
| Every 2 weeks | Increase by 50mcg (maximum 500mcg) until hematocrit is below 45%, platelets below 400 x 10⁹/L and leukocytes below 10 x 10⁹/L. | FDA label |
| Weeks 3 to 12 | Taper hydroxyurea by reducing the total biweekly dose by 20% to 40% every 2 weeks. | FDA label |
| Week 13 | Hydroxyurea discontinued by week 13. | FDA label |
| Titration phase | Phlebotomy as rescue treatment to normalize blood hyperviscosity may be necessary. | FDA label |
| After 1 year stable | Maintain the 2-week interval at which stability is achieved for at least 1 year; after at least 1 year of stability on a stable dose, the interval may be expanded to every 4 weeks. | FDA label |
| Interruption | Resume at the previously attained dose level. After a reduction, consider a dose increase to the next higher level after recovery to grade 1 toxicity if efficacy is insufficient. | FDA label |
| Liver enzymes above 5 to 20 x ULN | Decrease by 50mcg, and continue decreasing by 50mcg at biweekly intervals until ALT and AST recover to below 3 x ULN and GGT to below 2.5 x ULN (baseline normal). Above 20 x ULN: interrupt until ALT and AST recover to below 3 x ULN and GGT to below 2.5 x ULN (baseline normal). With concomitant bilirubin elevation or other evidence of hepatic decompensation: interrupt until recovery and restart 50mcg lower. Consider permanent discontinuation if toxicity persists after 4 dose reductions. | FDA label |
| Cytopenia | Hgb below 8g/dL, platelets below 50,000 but at least 25,000/mm³, or WBC below 2,000 but at least 1,000/mm³: decrease by 50mcg at biweekly intervals until Hgb above 10.0g/dL, platelets above 75,000/mm³ and WBC above 3,000/mm³. Platelets below 25,000/mm³, WBC below 1,000/mm³ or life-threatening anemia: interrupt until the same recovery. Consider permanent discontinuation if toxicity persists after 4 dose reductions. | FDA label |
| Depression | Mild without suicidal ideation: consider psychiatric consultation if persistent beyond 8 weeks. Moderate without suicidal ideation: consider dose reduction to 50mcg; psychiatric consultation recommended. Severe, or any severity with suicidal ideation: discontinue and recommend psychiatric consultation. | FDA label |
| At a 50mcg dose | If the interrupted dose is 50mcg, refrain from treatment until recovery. | FDA label |
| Syringe dose setting | Markings in 50mcg increments; expel medication until the top edge of the gray stopper lines up with the prescribed dose, then inject at 45 to 90 degrees into pinched skin. Discard the syringe with any remainder. | FDA label |
| Pen dose setting | Delivers in 50mcg increments. Flow check at the drop symbol for 4 cycles, up to 7; dial the dose, inject at 90 degrees, hold the button and count to 5 after the window returns to 0. Residual liquid is normal. | FDA label |
| Sites and storage | Lower abdomen at least 2 inches from the navel, or top of thighs; rotate sites. Refrigerate at 2 to 8°C (36 to 46°F) in the original carton, protected from light; do not freeze. Bring to room temperature (15 to 25°C) in the carton for 15 to 30 minutes before injecting. | FDA label |
| Renal and hepatic | No dose adjustment with eGFR of 30mL/min or higher; avoid below 30mL/min. Contraindicated in Child-Pugh B or C. Discontinue if liver enzyme increases are progressive and clinically significant despite dose reduction, or if Child-Pugh B or C impairment develops. | FDA label |
Monitoring the Besremi label requires
| When | What | What the label says to do with it | Source |
|---|---|---|---|
| Baseline | CBC; liver enzymes and hepatic function; serum creatinine; serum triglycerides; pregnancy test where it applies; eye examination advised | Sections 2.1, 5.4, 5.9, 5.10, 5.11, 5.12 | FDA label |
| Every 2 weeks in titration and dose modification | CBC | Titrate to hematocrit below 45%, platelets below 400 x 10⁹/L, leukocytes below 10 x 10⁹/L; Table 3 for cytopenias | FDA label |
| Every 3 to 6 months in maintenance | CBC, more frequently if clinically indicated | In PV studies: grade 3 or higher thrombocytopenia 2%, anemia 1%, leukopenia 2%; infection 48%, serious infection 8%. Monitor for signs of infection or bleeding | FDA label |
| Throughout | Depression, mood or behavior change, suicidal ideation | Serious neuropsychiatric reactions in 3% of PV patients; consider psychiatric consultation; discontinuation is recommended if psychiatric symptoms worsen | FDA label |
| During treatment | Liver enzymes and hepatic function | Liver enzyme elevations in 36 PV patients (20%), 33 of them at 1.25 to 5 x ULN; discontinue for hepatic decompensation | FDA label |
| During treatment | Serum creatinine | Discontinue if severe renal impairment develops | FDA label |
| Intermittently | Serum triglycerides | Manage when elevated; consider discontinuation for persistently, markedly elevated triglycerides. Pancreatitis in 2.2% of PV patients: interrupt for possible pancreatitis, consider discontinuation if confirmed | FDA label |
| Before and during therapy | Eye examinations; prompt evaluation of eye symptoms | Eye disorders in 23% of PV patients; discontinue for new or worsening eye disorders | FDA label |
| If symptomatic | Thyroid function | Hyperthyroidism 4.5%, hypothyroidism 3.9%, thyroiditis 2.8% in PV; discontinue for endocrine disorders that cannot be adequately managed | FDA label |
| Any time | Hypersensitivity; colitis (abdominal pain, bloody diarrhea, fever); pulmonary infiltrates or pulmonary function impairment | Discontinue. Colitis has occurred as early as 12 weeks with interferon alfa products | FDA label |
| Any time | Cardiovascular and thrombotic events, especially with a cardiovascular or thrombotic history | Monitor closely; boxed warning says to withdraw therapy for persistently severe or worsening signs of ischemic disorders | FDA label |
| Ongoing | Oral hygiene and regular dental examinations; skin; dizziness, somnolence or hallucination | Consider discontinuation for clinically significant dermatologic toxicity; advise against driving or machinery if those symptoms occur | FDA label |
Besremi drug interactions and contraindications
| Label category | Agents and what the label says | Source |
|---|---|---|
| CYP450 substrates with a narrow therapeutic index | Interferons can suppress CYP450 enzymes and raise exposure of some substrates; monitor to inform dose modification of the concomitant drug | FDA label |
| Myelosuppressive agents | Additive myelosuppression; avoid use, and monitor patients receiving the combination for excessive myelosuppression | FDA label |
| Hydroxyurea | The labeled transition gives Besremi 50mcg with hydroxyurea, tapering hydroxyurea over weeks 3 to 12 and stopping by week 13 | FDA label |
| Narcotics, hypnotics or sedatives | Additive neuropsychiatric effects; avoid use, and monitor patients receiving the combination for excessive CNS toxicity | FDA label |
| In vitro | Time-dependent inhibitory potential on CYP2A6; no inhibition of CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1 or 3A4. No clinical drug interaction studies have been conducted | FDA label |
| Lactation | Advise women not to breastfeed during treatment and for 8 weeks after the final dose | FDA label |
Why a first fill stalls, and the fix
- Prior authorization not yet filedPharmaEssentia SOURCE coordinates with your insurance company to find out whether a prior authorization is required. It helps the office learn the submission process and any extra documents, and the office submits the request. After that, SOURCE is available to help the office monitor the status of the request.
- The diagnosis is not on the requestUnitedHealthcare's public policy, effective December 1, 2025, approves Besremi on one criterion, a diagnosis of polycythemia vera. Other plans set their own rules, so the office confirms what your plan asks for.
- A supply limit or step therapy ruleThe UnitedHealthcare policy says supply limits or step therapy may be in place under some plans. Your hematologist's office can ask the plan which rule applied and what it needs to review it.
- A denial, or Besremi is not on the plan's drug listSOURCE can work with the office to identify the steps needed to appeal the plan's decision. PharmaEssentia offers the office sample letters of medical necessity, appeal and formulary exception.
- The enrollment form is missing informationPharmaEssentia says a Case Manager may follow up with you or your doctor to complete the enrollment. The company says complete and accurate enrollment details help SOURCE begin the process right away.
- The prescription went to a pharmacy that cannot fill itPharmaEssentia names specialty pharmacy partners, including Biologics and Onco360, that ship Besremi directly to patients. Offices with questions about pharmacy qualifications can call SOURCE at 800-700-5053.
- A copay you cannot payWith commercial insurance that covers Besremi, the Copay and Coinsurance Assistance Program may lower the cost to as little as $0 per month. You must live in the United States or a US territory and have a valid prescription from a US physician.
- Medicare, Medicaid, TRICARE or Veterans Health coverageThe copay program is not available to people whose prescription coverage comes from any federal or state healthcare program. SOURCE says it will work with you to identify organizations that may help with treatment-related costs.
- No insurance, or the plan does not cover BesremiPharmaEssentia's Patient Assistance Program offers Besremi at no cost to eligible people, including those without insurance. You must also meet its financial eligibility criteria, and restrictions apply.
- An approval delay or a gap in coverageSOURCE can check whether you are eligible for a temporary supply of Besremi during an insurance approval delay or a coverage gap. PharmaEssentia says restrictions apply to the temporary supply and are subject to change.
PharmaEssentia SOURCE
- A Case Manager who answers questions, explains your insurance coverage and helps find resources for financial support
- A SOURCE Nurse who can walk you through the injection step by step, with refreshers at any time during treatment SOURCE getting started
- A Welcome Kit with the Instructions for Use, a supplies placemat and a treatment tracker with reminder stickers SOURCE enrollment
- Copay help with commercial insurance that covers Besremi, as little as $0 per month if eligible, not for Medicare, Medicaid, TRICARE, Veterans Health or other government plans SOURCE financial help
- The copay offer is also not valid for cash-paying patients or where the plan reimburses the entire cost of Besremi SOURCE financial help
- A Patient Assistance Program, Besremi at no cost for eligible people with no prescription coverage or whose insurance does not cover it SOURCE financial help
- A possible temporary supply during an insurance approval delay or a gap in coverage, with restrictions SOURCE getting started
- Help with delivery of the prescription directly to your door each month SOURCE getting started
Questions prescribers' offices ask about Besremi
What is the Besremi starting dose and titration in polycythemia vera?
100mcg subcutaneously every 2 weeks, or 50mcg in combination with hydroxyurea for patients transitioning from it, per the August 2026 label. Increase by 50mcg every 2 weeks to a maximum of 500mcg until hematocrit is below 45%, platelets below 400 x 10⁹/L and leukocytes below 10 x 10⁹/L.
How is hydroxyurea tapered when starting Besremi?
By 20% to 40% of the total biweekly dose every 2 weeks during weeks 3 to 12, with hydroxyurea discontinued by week 13, per the August 2026 label. Besremi starts at 50mcg every 2 weeks alongside hydroxyurea and rises by 50mcg every 2 weeks.
What monitoring does the Besremi label require?
A CBC at baseline, every 2 weeks during titration and dose modification, and every 3 to 6 months in maintenance, per the August 2026 label. Liver enzymes and hepatic function, serum creatinine and triglycerides are checked at baseline and during treatment, with eye examinations before and during therapy and a pregnancy test before initiation.
When can Besremi move to every 4 weeks?
After at least 1 year of hematological stability on a stable dose, per the August 2026 label; until then the 2-week interval is maintained. In PEGINVERA, 28 eligible patients extended the interval at a median of 21.5 months.
What do insurers ask for to approve Besremi?
1 criterion in the UnitedHealthcare policy effective December 1, 2025: a diagnosis of polycythemia vera, with authorization for 12 months. The policy cites the April 2024 package insert, predates the August 2026 label and notes that supply limits or step therapy may be in place.
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Sources
- BESREMi (ropeginterferon alfa-2b-njft) injection, for subcutaneous use, prescribing information, Medication Guide and Instructions for Use, Revised 8/2026, PharmaEssentia USA, via DailyMed and openFDA, 2026-08-25.
- BLA 761166/S-013 supplement approval, Besremi (ropeginterferon alfa-2b-njft) injection, new indication for essential thrombocythemia, FDA, 2026-08-28.
- BLA 761166/S-010 supplement approval, Besremi (ropeginterferon alfa-2b-njft) injection, new single-dose prefilled pen injector, FDA, 2026-06-25.
- BESREMi® (ropeginterferon alfa-2b-njft) Patient Support, PharmaEssentia, 2026-11-12.
- How Do I Get Started With PharmaEssentia SOURCE™?, PharmaEssentia, 2026-11-12.
- Getting Started on BESREMi® (ropeginterferon alfa-2b-njft), PharmaEssentia, 2026-11-12.
- Financial Assistance for BESREMi® (ropeginterferon alfa-2b-njft), PharmaEssentia, 2026-11-12.
- PharmaEssentia SOURCE™: Access & Reimbursement Support, PharmaEssentia, 2026-11-12.
- How to Prescribe BESREMi® (ropeginterferon alfa-2b-njft), PharmaEssentia, 2026-11-12.
- Besremi® (ropeginterferon alfa-2b-njft), Prior Authorization/Notification, Program Number 2025 P 1048-16, UnitedHealthcare Pharmacy, Clinical Pharmacy Programs, 2025-12-01.
A reference drawn from the August 25, 2026 label, the drugmaker's published program and one public insurer policy shown as an example, checked on November 12, 2026. Labels and policies change; the label on DailyMed and the plan's current policy govern. Trial Friend is not a medical provider. It reports what these documents say and does not judge whether a drug is safe or right for any patient; that is the prescriber's decision. Not a substitute for the prescribing information.