Why Is Pegasys So Hard to Find? [Explained for 2026]

If you or a loved one relies on Pegasys (Peginterferon Alfa-2a) for chronic hepatitis B, hepatitis C, or a blood disorder like polycythemia vera, you already know how frustrating 2025 and early 2026 have been. Pharmacies are out of stock. Refills are delayed. Specialty distributors are on allocation. And nobody seems to have clear answers.

You're not imagining it — Pegasys is in an active, FDA-confirmed drug shortage, and it has been since late 2024. In this post, we'll explain exactly why Pegasys is so hard to find, what caused the shortage, and what your options are right now.

What Is Pegasys, and Who Needs It?

Pegasys is the brand name for peginterferon alfa-2a, a pegylated interferon that works by stimulating your immune system to fight viral infections and control abnormal blood cell production. It is given as a once-weekly subcutaneous injection (a shot under the skin) and is FDA-approved for:

• Chronic hepatitis C (CHC) in adults and children 5 and older with compensated liver disease
• Chronic hepatitis B (CHB) in adults and children 3 and older

Beyond its FDA-approved uses, Pegasys has become an important off-label treatment for myeloproliferative neoplasms (MPNs) — blood cancers like polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (MF). NCCN clinical guidelines specifically recommend it for these conditions, particularly for younger patients and those for whom other treatments like hydroxyurea aren't appropriate.

Is Pegasys Actually in a Drug Shortage Right Now?

Yes. As of early 2026, Pegasys remains in an active, FDA-confirmed drug shortage. The American Society of Health-System Pharmacists (ASHP) officially listed peginterferon alfa-2a as being in shortage in late 2024, and the situation has not fully resolved. Supply through specialty distributor Summit SD is limited, and most large retail pharmacies have been unable to keep it consistently in stock.

What Caused the Pegasys Shortage?

The shortage is the result of several overlapping factors that hit at roughly the same time:

1. A Change in Ownership and Manufacturing

In 2021, Roche Pharmaceuticals sold the worldwide rights to Pegasys (outside of China and Japan) to zr pharma& GmbH, a smaller European pharmaceutical company. Transitioning a complex biologic injectable — one that requires specialized manufacturing — from one company to another is not a simple handoff. New facilities must be qualified, processes validated, and regulators satisfied.

In October 2024, pharma& proactively notified the US FDA of potential supply constraints as demand had outpaced production capacity at their existing facilities. In April 2025, the European Medicines Agency (EMA) approved pharma&'s new API manufacturing site at Loba biotech GmbH — but US FDA approval of the new facility is still pending as of early 2026, meaning more supply cannot yet flow to American patients.

2. A Surge in Demand from Blood Disorder Patients

While Pegasys was originally developed for hepatitis, it has become one of the most widely prescribed treatments for myeloproliferative neoplasms (MPNs) like polycythemia vera. In August 2024, the European Commission approved Pegasys for these indications in Europe, creating even more demand. With use growing far faster than anyone anticipated — and no new manufacturing capacity yet online — supply simply ran out.

3. No Generic or Biosimilar Alternative Available in the US

For many drugs in shortage, generic manufacturers can step in to fill the gap. That's not an option here. As of early 2026, there is no FDA-approved generic or biosimilar version of peginterferon alfa-2a available in the United States. Patents have expired in some international markets, but no biosimilar application has been approved by the FDA. This means every patient who needs Pegasys depends on a single source of supply.

How Long Is the Pegasys Shortage Expected to Last?

The honest answer is: it's uncertain. Several developments could improve the situation over the next several months. FDA approval of pharma&'s new Loba biotech manufacturing site would be the biggest single relief — it would unlock additional supply for the US market. Growing adoption of BESREMi (ropeginterferon alfa-2b) for polycythemia vera may also relieve some demand pressure on Pegasys. However, there is no confirmed resolution date.

What Can Patients Do Right Now?

If you're having trouble filling your Pegasys prescription, here are the most practical steps you can take:

• Use medfinder to search pharmacies near you. medfinder calls pharmacies on your behalf to check which ones can fill your prescription, saving you hours of phone calls.
• Try independent specialty pharmacies. Large chain pharmacies are often the first to run out during a shortage. Independent specialty pharmacies sometimes access different distributors and may still have stock.
• Contact the manufacturer directly. pharma& operates a patient assistance line at 855-443-7028. They may be able to help locate supply or connect you with their patient assistance program.
• Talk to your doctor about alternatives. For polycythemia vera, BESREMi (ropeginterferon alfa-2b) is FDA-approved and NCCN-recommended as a substitute. For hepatitis C, direct-acting antivirals (Harvoni, Epclusa, Mavyret) are highly effective options.

Is There a Generic or Biosimilar Version of Pegasys?

Not in the United States. As of 2026, there is no FDA-approved generic or biosimilar version of peginterferon alfa-2a. Some international markets have biosimilar or comparable products, but these are not available through US pharmacies. This is one reason why the shortage has been so difficult to resolve — there is no competition that can step in to meet demand.

Bottom Line

The Pegasys shortage is real, it's ongoing, and it's affecting thousands of patients across the country. The cause is a combination of manufacturing transitions, surging demand, and the absence of any generic alternative. If you're struggling to fill your prescription, don't give up — resources exist to help. See our guide on how to find Pegasys in stock near you for step-by-step help.