General Information

BESREMi (ropeginterferon alfa-2b-njft) is a monopegylated, long-acting interferon.

BESREMi is specifically indicated for the treatment of adults with polycythemia vera.

BESREMi is supplied as an injection, for subcutaneous use. Recommended starting dose is 100 mcg by subcutaneous injection every 2 weeks (50 mcg if receiving hydroxyurea). Increase the dose by 50 mcg every 2 weeks (up to a maximum of 500 mcg) until hematological parameters are stabilized. 

Mechanism of Action

Interferon alfa belongs to the class of type I interferons, which exhibit their cellular effects in polycythemia vera in the bone marrow by binding to a transmembrane receptor termed interferon alfa receptor (IFNAR). Binding to IFNAR initiates a downstream signaling cascade through the activation of kinases, in particular Janus kinase 1 (JAK1) and tyrosine kinase 2 (TYK2) and activator of transcription (STAT) proteins. Nuclear translocation of STAT proteins controls distinct gene-expression programs and exhibits various cellular effects. The actions involved in the therapeutic effects of interferon alfa in polycythemia vera are not fully elucidated.

Side Effects

Adverse effects associated with the use of BESREMi may include, but are not limited to, the following:

• influenza-like illness
• arthralgia
• fatigue
• pruritus
• nasopharyngitis
• musculoskeletal pain

The BESREMi drug label comes with the following Black Box Warning: Risk of Serious Disorders: Interferon alfa products may cause or aggravate fatal or life-threatening neuropsychiatric, autoimmune, ischemic, and infectious disorders. Monitor closely and withdraw therapy with persistently severe or worsening signs or symptoms of the above disorders.

Clinical Trial Results

FDA approval was based on safety from the PEGINVERA and PROUD/ CONTINUATION-PV studies and efficacy data from the PEGINVERA clinical study program. The study showed that after 7.5 years of treatment with BESREMi, 61% of patients with PV experienced a complete hematological response (defined as hematocrit <45% without phlebotomy for at least 2 months since last phlebotomy, platelets ≤ 400 x 109/L, leukocytes ≤10 x 109/L, normal spleen size (longitudinal diameter ≤12 cm for females and ≤ 13 cm for males). Importantly, 80% of patients achieved a hematological response (based on objective laboratory parameters only, with the exclusion of normal spleen size and thrombosis).