SURPASS-ET trial of ropeginterferon alfa-2b in patients with ET: Positive topline data announced

Positive topline data have been announced from the global, randomized, open-label, phase III SURPASS-ET trial (NCT04285086).¹ This trial assessed the safety and efficacy of ropeginterferon alfa-2b, a monopegylated, long-acting interferon that is currently approved by the U.S. Food and Drug Administration (FDA) for the treatment of patients with polycythemia vera,² vs anagrelide as a second-line therapy for patients with essential thrombocytosis (ET).¹ In total, 174 patients with ET were enrolled and randomized to receive ropeginterferon alfa-2b (n = 91) or anagrelide (n = 83).¹

The primary endpoint was met; among the intent-to-treat population, a higher proportion of patients in the ropeginterferon alfa-2b arm achieved a durable response at Months 9 and 12 using the modified European LeukemiaNet (ELN) criteria compared with the anagrelide arm (42.9% vs 6.0%; p = 0.0001).¹ The safety profile of ropeginterferon alfa-2b was manageable, with a lower rate of treatment-related serious adverse events compared with anagrelide (2.2% vs 10%).¹

In terms of secondary endpoints, the JAK2^V617F allelic burden decreased from 33.7% at baseline to 25.3% at 12 months in the ropeginterferon alfa-2b arm, compared with a decrease from 39.7% to 37.3% in the anagrelide arm.¹

Results from this trial will be submitted to the FDA as supporting evidence for a product label expansion for ropeginterferon alfa-2b in patients with ET.¹

The safety and efficacy of ropeginterferon alfa-2b in patients with ET is also being evaluated in the single-arm, multicenter, phase IIb EXCEED-ET trial (NCT05482971) in North America, with data expected in the second half of 2025.¹