Medical Editor: John P. Cunha, DO, FACOEP Last updated on RxList: 11/29/2021
BESREMi Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

What Is BESREMi?

BESREMi (ropeginterferon alfa-2b-njft) is an interferon alfa-2b indicated for the treatment of adults with polycythemia vera.

What Are Side Effects of BESREMi?

Side effects of BESREMi include:

Dosage for BESREMi

The recommended starting dose of BESREMi is 100 mcg by subcutaneous injection every 2 weeks (50 mcg if receiving hydroxyurea). Increase the dose of BESREMi by 50 mcg every 2 weeks (up to a maximum of 500 mcg) until hematological parameters are stabilized. 

BESREMi In Children

Safety and effectiveness of BESREMi in pediatric patients have not been established.

What Drugs, Substances, or Supplements Interact with BESREMi?

BESREMi may interact with other medicines such as:

  • CYP450 substrates, including interferons, 
  • myelosuppressive agents, 
  • narcotics, 
  • hypnotics, and
  • sedatives. 

Tell your doctor all medications and supplements you use.

BESREMi During Pregnancy and Breastfeeding

Tell your doctor if you are pregnant or plan to become pregnant before using BESREMi; it may harm a fetus. Pregnancy testing is recommended prior to BESREMi treatment in females of reproductive potential. Females of reproductive potential are advised to use effective contraception during treatment with BESREMi and for 8 weeks after the final dose. It is unknown if BESREMi passes into breast milk. Because of the potential for serious adverse reactions in breastfed children from BESREMi, breastfeeding is not recommended during treatment and for 8 weeks after the final dose.

Additional Information

Our BESREMi (ropeginterferon alfa-2b-njft) Injection, for Subcutaneous use Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Anemia Symptoms and Signs, Types, Treatment and Causes See Slideshow
BESREMi Professional Information


Clinical Trials Experience

The following clinically significant adverse reactions are described elsewhere in the labeling.

  • Depression and Suicide [see WARNINGS AND PRECAUTIONS]
  • Endocrine Toxicity [see WARNINGS AND PRECAUTIONS]
  • Cardiovascular Toxicity [see WARNINGS AND PRECAUTIONS]
  • Decreased Peripheral Blood Counts [see WARNINGS AND PRECAUTIONS]
  • Hypersensitivity Reactions [see WARNINGS AND PRECAUTIONS]
  • Pancreatitis [see WARNINGS AND PRECAUTIONS]
  • Pulmonary Toxicity [see WARNINGS AND PRECAUTIONS]
  • Ophthalmologic Toxicity [see WARNINGS AND PRECAUTIONS]
  • Hyperlipidemia [see WARNINGS AND PRECAUTIONS]
  • Hepatotoxicity [see WARNINGS AND PRECAUTIONS]
  • Renal Toxicity [see WARNINGS AND PRECAUTIONS]
  • Dental and Periodontal Toxicity [see WARNINGS AND PRECAUTIONS]
  • Dermatologic Toxicity [see WARNINGS AND PRECAUTIONS]
  • Driving and Operating Machinery [see WARNINGS AND PRECAUTIONS]
  • Embryo-Fetal Toxicity [see WARNINGS AND PRECAUTIONS]

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The pooled safety population described in the Warnings and Precautions section reflects exposure to BESREMi as monotherapy for the treatment of polycythemia vera dosed every two to four weeks in 178 patients in two open-label trials [PEGINVERA, PROUD/CONTINUATION PV]. The mean age at baseline was 58.6 years (range 30-85 years), 88 (49.4%) women, 90 (50.6%) men, 177 (99%) Caucasian and 1 (1%) Asian. Among 178 patients who received BESREMi, 80% were exposed for 12 months or longer. The mean dose of BESREMi was 334 mcg SD ± 121 during the treatment period. In this pooled safety population, the most common adverse reactions greater than 10%, were liver enzyme elevations (20%), leukopenia (20%), thrombocytopenia (19%), arthralgia (13%), fatigue (12%), myalgia (11%), and influenza-like illness (11%).

The safety findings described below reflect exposure to BESREMi as monotherapy for the treatment of polycythemia vera in 51 patients in the PEGINVERA study [see Clinical Studies]. Among the 51 patients receiving BESREMi, 71% were exposed for 12 months or longer, 63% were exposed for three years or longer, and 53% were exposed for greater than five years.

Serious adverse reactions were reported in 16% of patients in the PEGINVERA study. The most common serious adverse reactions observed during the study (> 4%) included urinary tract infection (8%), transient ischemic attack (6%) and depression (4%).

Adverse reactions requiring permanent discontinuation in >2% of patients who received BESREMi included depression (8%) arthralgia (4%), fatigue (4%), and general physical health deterioration (4%) In the PEGINVERA study, patients were not pre-screened for depression or anxiety disorders.

The most common adverse reactions reported in ≥10% of patients in the PEGINVERA study are listed in Table 2.

Table 2 : Adverse Reactions in > 10% of Subjects with Polycythemia Vera in the PEGINVERA Study Over 7.5 Years

Adverse Reactions* BESREMi
N=51 %
Influenza-like illness a 59
Arthralgia 47
Fatigue b 47
Pruritis 45
Nasopharyngitis c 43
Musculoskeletal pain d 41
Headache e 39
Diarrhea 33
Hyperhidrosis f 29
Nausea 28
Upper respiratory tract infection g 27
Local administration site reactions 26
Dizziness 22
Abdominal pain h 20
Depression 20
Sleep disorder i 20
Leukopenia 18
Decreased appetite 18
Alopecia 16
Edema j 16
Hypertension k 16
Muscle spasms 16
Neutropenia 16
Rash l 16
Transaminase elevations m 16
Urinary tract infection 16
Thrombocytopenia 12
Vertigo 12
*Adverse Reactions defined as all treatment emergent adverse events
Grouped Term Definitions
a Includes pyrexia, chills, and influenza-like illness.
b Includes asthenia, malaise, and fatigue.
c Includes pharyngitis and nasopharyngitis.
d Includes musculoskeletal pain, back pain, pain in extremity, bone pain, flank pain, and spinal pain.
e Includes headache, migraine, and head pain.
f Includes night sweats and hyperhidrosis.
g Includes upper respiratory tract infection, rhinitis, bronchitis, and respiratory tract infection.
h Includes abdominal pain upper, abdominal pain lower, and abdominal pain.
i Includes insomnia, sleep disorder, and abnormal dreams.
j Includes peripheral edema and generalized edema.
k Includes hypertension and hypertensive crisis.
l Includes rash, maculopapular rash, and pruritic rash.
m Includes transaminase increase, hepatic enzyme increase, GGT increase, AST increase, and ALT increase.

Clinically relevant adverse reactions in < 10% of patients include:

Cardiovascular System: Atrial fibrillation


As with all therapeutic proteins, there is potential for immunogenicity. The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors, including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, comparison of the incidence of antibodies in the studies described below with the incidence of antibodies in other studies or to other interferon alfa-2b products may be misleading.

The incidence of binding antibodies to ropeginterferon alfa-2b-njft was 1.4% (2/146) and they were observed as early as 8 weeks post-dosing. Among the patients who tested positive for binding antibodies, none developed neutralizing antibodies.


Drugs Metabolized By Cytochrome P450

Certain proinflammatory cytokines, including interferons, can suppress CYP450 enzymes resulting in increased exposures of some CYP substrates [see CLINICAL PHARMACOLOGY]. Therefore, patients on BESREMi who are receiving concomitant drugs that are CYP450 substrates with a narrow therapeutic index should be monitored to inform the need for dosage modification for these concomitant drugs.

Myelosuppressive Agents

Concomitant use of BESREMi and myelosuppressive agents can produce additive myelosuppression. Avoid use and monitor patients receiving the combination for effects of excessive myelosuppression [see WARNINGS AND PRECAUTIONS].

Narcotics, Hypnotics Or Sedatives

Concomitant use of BESREMi and narcotics, hypnotics or sedatives can produce additive neuropsychiatric side effects. Avoid use and monitor patients receiving the combination for effects of excessive CNS toxicity [see WARNINGS AND PRECAUTIONS].

Read the entire FDA prescribing information for BESREMi (Ropeginterferon Alfa-2b-njft )


What is hemophilia? See Answer

© BESREMi Patient Information is supplied by Cerner Multum, Inc. and BESREMi Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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