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Clinical Guidance on the Use of Ropeginterferon alfa-2b (Ropeg) and Peginterferon alfa-2a (Pegasys) in MPNs and CTCL

 

Dear Colleagues,

 

We would like to provide updated guidance on the optimal use of Ropeginterferon alfa-2b (Ropeg) and Peginterferon alfa-2a (Pegasys) in patients with myeloproliferative neoplasms (MPNs) such as polycythemia vera (PV), essential thrombocythemia (ET), and myelofibrosis (MF); and cutaneous T-cell lymphoma (CTCL).

 

There has been a shortage of Pegasys since November 2024. To help alleviate this issue, Health Canada has granted an exceptional importation authorization for ropeginterferon alfa-2b (Ropeg). With Ropeg's FDA approval for PV, its role in MPN treatment is expanding, and we aim to ensure clarity on patient selection, transitioning strategies, and therapeutic adjustments, particularly in light of the ongoing Pegasys supply constraints.

 

1. Preferred Use of Ropeginterferon Alfa-2b (Ropeg) in MPNs

• First-line therapy in newly diagnosed PV: Ropeg is now the preferred first-line interferon-based therapy for PV, given its FDA approval, extended dosing schedule (every 2–4 weeks), and sustained hematologic and molecular responses.
• Consideration in ET and MF: While not yet FDA-approved for ET, Ropeg is a reasonable off-label option given its favorable data from European studies.
• Advantages over Pegasys: Ropeg’s extended dosing interval reduces injection burden and helps mitigate supply constraints of Pegasys.

 

2. Continued Use of Peginterferon Alfa-2a (Pegasys) in Specific Populations

• Pregnant patients: Due to the lack of pregnancy safety data for Ropeg, Pegasys remains the preferred interferon option during pregnancy in MPN patients.
• CTCL patients: As no robust data exist on Ropeg’s efficacy in CTCL, Pegasys remains the standard interferon-based approach for CTCL where indicated.

 

3. Guidance on the Pegasys Shortage: Use the Minimum Effective Dose

Given the limited availability of Pegasys, it is crucial to optimize dosing by using the lowest effective dose that maintains response:

• For MPN patients, consider using 45–90 mcg/week rather than higher doses, as lower doses are often sufficient for maintaining hematologic response. Extended dosing intervals are possible in some patients.
• For CTCL patients, individualized dosing remains essential, but clinicians should consider titrating to the lowest effective dose to conserve supply.
• Whenever possible, transition appropriate MPN patients (e.g., PV patients) from Pegasys to Ropeg to preserve Pegasys availability for those who require it (e.g., pregnant patients, CTCL cases).

 

4. Transitioning Between Pegasys and Ropeg

For patients already receiving Pegasys who may benefit from transitioning to Ropeg, consider the following:

• Stable responders to Pegasys can switch to Ropeg at a starting dose of 100–250 mcg every 2 weeks, adjusting based on prior Pegasys dosing and tolerability.

 

Conversely, in cases where a patient on Ropeg needs to transition to Pegasys, although data is limited, it is reasonable to:

• Restart Pegasys at 45–90 mcg/week, adjusting as tolerated.

 

5. Monitoring and Safety Considerations

• Both Ropeg and Pegasys require regular hematologic, liver, and thyroid function monitoring, with dose adjustments based on response and tolerability.

 

We appreciate your attention to these recommendations and your efforts in ensuring optimal patient care despite current supply challenges. Please feel free to reach out with any questions or for further discussion.

 

Dr. Shireen Sirhan

On behalf of the Canadian MPN Group