by David Wallace
Two-year results from the Phase 3 SURPASS-ET trial suggest that earlier initiation of ropeginterferon alfa-2b may provide deeper molecular responses and more durable disease control for some patients with high-risk essential thrombocythemia (ET).
The findings were presented by Harinder Gill, MD, at the 2026 European Hematology Association Congress in Stockholm.
What Did SURPASS-ET Study?
SURPASS-ET evaluated patients with high-risk essential thrombocythemia who were resistant or intolerant to hydroxyurea and had leukocytosis. The original randomized Phase 3 trial compared ropeginterferon alfa-2b with anagrelide as second-line therapy.
If you are newer to ET, see our Essential Thrombocythemia overview for information on ET symptoms, mutations, risk factors and treatment options.
For the extended SURPASS-ET analysis, researchers compared patients who received ropeginterferon from the beginning with patients who initially received anagrelide and later switched to ropeginterferon.
One distinction is important for patients: “early treatment” in this study does not mean starting ropeginterferon immediately after an ET diagnosis. It refers to beginning ropeginterferon earlier after hydroxyurea resistance or intolerance.
Key 2-Year Findings
One of the most striking findings involved progression-free survival.
- 76.9% estimated progression-free survival at 24 months for patients who received ropeginterferon from baseline
- 43.1% for patients whose ropeginterferon treatment was delayed
The investigators also reported progressively deeper molecular responses with longer exposure to ropeginterferon.
Among evaluable patients with JAK2 V617F, partial molecular response at Month 24 was reported in 34.7% of the earlier-treatment group compared with 15.4% of the delayed-treatment group.
Progression-free survival should not be confused with overall survival. These results concern remaining free of the progression events defined in the study, not simply whether a patient was alive at two years.
Why Could This Matter for ET Patients?
The findings raise an important question in ET treatment: Could earlier use of interferon affect the underlying disease rather than simply control elevated blood counts?
Interferon can reduce elevated blood counts while also reducing the burden of disease-driving mutations such as JAK2 V617F in some patients. Learn more in our patient-friendly guide, Interferon Treatment for MPNs: What You Need to Know.
The SURPASS-ET results suggest that longer exposure to ropeginterferon may be associated with deeper molecular responses and improved disease control.
Key Takeaway
The two-year SURPASS-ET data strengthen the evidence that ropeginterferon may do more in ET than simply lower blood counts. Patients who received ropeginterferon earlier showed deeper molecular responses and substantially higher estimated progression-free survival than patients whose treatment with ropeginterferon was delayed.
However, the extended analysis was not a newly randomized study specifically created to compare early versus delayed interferon. Patients who crossed over from anagrelide represented a selected group. The results are encouraging, but they do not prove that starting ropeginterferon earlier will improve long-term outcomes for every patient.
For people with high-risk ET who no longer respond adequately to hydroxyurea or cannot tolerate it, these findings add important evidence to the growing discussion around interferon as a potential disease-modifying treatment strategy.
Talk With an MPN Specialist
ET treatment decisions depend on age, blood counts, mutation status, previous blood clots, symptoms, cardiovascular risks, treatment history and other individual factors.
If you would like an expert opinion, use the PV Reporter MPN Specialist Directory to find an MPN-focused hematologist near you.
Source
Gill H. Early versus delayed initiation of ropeginterferon alfa-2b in high-risk essential thrombocythemia: Two-year results from the Phase 3 SURPASS-ET study. Oral Abstract S219. European Hematology Association Congress; June 11–14, 2026; Stockholm, Sweden. View the EHA presentation(opens in new tab).
This article is for educational purposes and is not medical advice. Treatment decisions should be discussed with an MPN specialist familiar with your individual diagnosis and medical history.
Editorial note: This article was organized with AI-assisted research, then reviewed, edited, and approved by David Wallace.