BESREMI
Clinical safety rating: caution
Comprehensive clinical and safety monograph for BESREMI (BESREMI).
BESREMI (ropeginterferon alfa-2b) is a recombinant interferon alfa-2b conjugated to a 40 kDa polyethylene glycol (PEG) moiety. It binds to interferon alpha receptors (IFNAR1/IFNAR2), activating JAK-STAT signaling, leading to expression of interferon-stimulated genes with antiproliferative, antiviral, and immunomodulatory effects. Specifically, it suppresses the proliferation of hematopoietic progenitor cells, reduces JAK2V617F allele burden, and normalizes blood counts in polycythemia vera.
| Metabolism | Monoclonal antibodies such as ropeginterferon alfa-2b are degraded into small peptides and amino acids via catabolic pathways; not metabolized by CYP450 enzymes. |
| Excretion | Primarily renal (clearance 0.5 L/h/kg), with <1% excreted unchanged in urine; remainder metabolized via proteolysis to small peptides and amino acids. |
| Half-life | Terminal half-life approximately 50-100 hours (mean 70 h) in healthy volunteers; in patients with polycythemia vera, half-life is 50-80 hours, supporting once-weekly dosing. |
| Protein binding | Human interferon alfa-2b is extensively bound to serum proteins, >90% (primarily albumin). |
| Volume of Distribution | Approximately 0.4-0.8 L/kg in steady state, reflecting distribution into total body water with limited tissue penetration. |
| Bioavailability | Subcutaneous: 80-90% relative to intravenous administration. |
| Onset of Action | Subcutaneous: Hematologic response (normalization of hematocrit) observed within 4-8 weeks of starting therapy; maximum effect by 12-16 weeks. |
| Duration of Action | Duration of pharmacodynamic effect (suppression of erythropoiesis) persists for at least 7 days due to long half-life; clinical effect maintained with weekly dosing; residual interferon activity may last 2-4 weeks after cessation. |
Subcutaneous injection of 250 to 350 mcg once every two weeks, with titration based on platelet counts and tolerability.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required for GFR ≥30 mL/min; for GFR <30 mL/min, use with caution and monitor closely, but no specific dose recommendation. |
| Liver impairment | Child-Pugh A: No adjustment; Child-Pugh B and C: Use is not recommended due to lack of data. |
| Pediatric use | Safety and efficacy not established in pediatric patients; no approved dosing. |
| Geriatric use | No specific dose adjustment; elderly patients may have greater sensitivity, monitoring recommended. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for BESREMI (BESREMI).
| Breastfeeding | No data on presence in human milk. Interferon alfa is a large protein likely transferred in low amounts. Consider risk of neonatal adverse effects including myelosuppression. M/P ratio unknown. Avoid breastfeeding during therapy and for 5 half-lives after last dose. |
| Teratogenic Risk | BESREMI (ropeginterferon alfa-2b) is an interferon alpha product. Interferon alfa agents have been associated with increased risk of spontaneous abortion and fetal growth restriction. First trimester exposure may carry risk of fetal malformations, though data are limited. Second and third trimester exposure can cause fetal growth restriction and preterm birth. Use only if benefit outweighs risk. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["History of severe psychiatric disorders (e.g., severe depression, suicidal ideation)","Autoimmune hepatitis","Decompensated liver disease","Known hypersensitivity to ropeginterferon alfa-2b or any excipient"]
| Precautions | ["May cause or aggravate fatal or life-threatening neuropsychiatric, autoimmune, ischemic, and infectious disorders. Monitor for depression, suicidal ideation, autoimmune disorders (e.g., thyroid abnormalities), and infections. May cause myelosuppression, cardiovascular events (hypertension, arrhythmias), hepatotoxicity, and endocrine disorders (e.g., thyroid dysfunction). Monitor blood counts, liver function, and thyroid function periodically."] |
| Food/Dietary | No specific food interactions are documented for BESREMI. However, patients should avoid grapefruit or grapefruit juice as a precaution due to potential CYP interactions (though interferon is not metabolized by CYP450). Alcohol consumption should be minimized or avoided to reduce hepatotoxicity risk. |
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| Fetal Monitoring | Monitor complete blood count with differential, liver function tests, thyroid function tests, and serum creatinine at baseline and periodically. Assess fetal growth by ultrasound every 4-6 weeks if used in pregnancy. Monitor for signs of myelosuppression, hepatotoxicity, and neuropsychiatric effects. |
| Fertility Effects | Interferon alfa may impair fertility in both females and males. Reversible menstrual cycle irregularities and decreased testosterone levels reported. Animal studies show impaired fertility at high doses. Consider impact on spermatogenesis and ovulation. |
| Clinical Pearls | BESREMI (ropeginterferon alfa-2b) is a monopegylated interferon with a prolonged half-life (~133h) allowing every-2-week dosing in polycythemia vera. Premedicate with acetaminophen to mitigate flu-like symptoms. Monitor liver function, thyroid function, blood counts, and depression screening due to neuropsychiatric risks. Not interchangeable with other interferons; use only as a single-use vial. Dose reductions may be needed for hematologic or hepatic toxicity. |
| Patient Advice | Injection technique: rotate sites (abdomen, thigh, arm) and use proper disposal. · Common flu-like symptoms: fever, chills, myalgia; premedicate with acetaminophen or NSAIDs as directed. · Report any signs of depression, suicidal thoughts, or severe mood changes immediately. · Regular blood tests are required to monitor for side effects like low blood counts or liver problems. · Avoid alcohol and hepatotoxic medications; discuss all OTC and herbal supplements with your doctor. · Use effective contraception during treatment and for at least 6 months after last dose if female of childbearing potential. · Do not miss doses; if a dose is missed, contact your healthcare provider for instructions. |