A Shortage of Interferon for Myeloproliferative Neoplasms (MPNs)

Myeloproliferative neoplasms (MPNs) are a group of blood cancers that originate in the bone marrow, leading to an overproduction of blood cells. The conditions classified as MPNs include:

• Chronic myelogenous leukemia (CML)
• Polycythemia vera (PV)
• Essential thrombocythemia (ET)
• Primary myelofibrosis (PMF)

What Are Interferons?

Interferons are proteins produced naturally by the body to help regulate the immune system, fight infections, and combat cancer. In medicine, interferons are synthetically produced and used as injections or infusions to treat MPNs by slowing the overproduction of blood cells.

Specifically, interferons:

• Act as a first line of defense against viruses and cancer by blocking their growth and spread.
• Trigger immune cells to identify and destroy abnormal cells.
• "Interfere" with the multiplication of harmful cells, hence their name.

In the context of MPNs, interferons, such as pegylated interferon (e.g., Pegasys), are commonly used for long-term disease control.

Is There a Shortage of Interferon?

Yes, there is currently a temporary shortage of Pegasys (pegylated interferon alpha-2a). This shortage has been caused by changes in the manufacturing processes at the pharmaceutical company responsible for producing Pegasys. The shortage is expected to continue until July 2025.

It's important to note that interferon alpha-2a (non-pegylated) was discontinued in the United States in 2021, further limiting treatment options.

Healthcare teams, including pharmacists and clinicians, are actively working to manage supplies and identify alternative treatments to minimize disruption to patient care.

What Are the Alternatives?

The FDA approved Besremi (ropeginterferon alfa-2b-njft) in October 2021, but its approval in the U.S. is limited to polycythemia vera (PV). It is not currently approved for other MPNs such as essential thrombocythemia (ET) or primary myelofibrosis (PMF). However, healthcare providers may consider Besremi for off-label use in specific cases.

What makes Besremi different?

• It is a pegylated interferon, meaning it is attached to a compound (polyethylene glycol) that prolongs its effects in the body.
• It is injected under the skin every two weeks and is designed for long-term use.
• Besremi works by binding to bone marrow receptors, signaling a reduction in the overproduction of blood cells.

Important Note: Interferon therapies, including Besremi, are not suitable for individuals with severe liver disease or autoimmune hepatitis, as these conditions may worsen with treatment.

Are There Side Effects from Interferon Use?

Interferon therapies, while effective, can have side effects. These include:

Common Side Effects:

• Flu-like symptoms: fever, muscle aches, chills, fatigue, headache, joint pain, nausea.
• Injection site reactions: bruising, redness, swelling, bleeding.
• Hair loss, dizziness, dry mouth, skin changes, and weight fluctuations.

Serious Side Effects:

• Heart problems: cardiac arrhythmias, cardiomyopathy.
• Organ failure: liver or kidney failure.
• Neurological issues: polyneuropathy (nerve damage).
• Myelosuppression: decreased bone marrow activity, leading to fewer blood cells.

Patients should report any severe or persistent side effects to their healthcare team immediately.

Conclusion

The Pegasys shortage has prompted many patients and healthcare providers to consider alternative options. For polycythemia vera (PV) patients, Besremi offers a viable alternative. For other MPNs, such as ET or MF, patients should consult with their specialists to explore tailored treatment options, which may include off-label interferon therapies or other alternatives.

Sources: 

• Interferon supplies – Update 19 August 2024 – MPN Voice
• Your Guide to Interferons