Clinical Summary:

• Design/Population: This retrospective study evaluated real-world treatment patterns, tolerability, and complete hematologic responses among patients prescribed ropeginterferon alfa-2b for myeloproliferative neoplasms, primarily polycythemia vera, with additional off-label use in essential thrombocythemia and unclassified myeloproliferative neoplasms. 
• Key Outcomes: Complete hematologic response rates were increased between 6 and 12 months of therapy, and most patients remained on treatment at data cutoff. Adverse events were common, with pruritus, elevated liver function tests, and cytopenias reported most frequently. 
• Clinical Relevance: These findings support the effectiveness of ropeginterferon alfa-2b outside the clinical trial setting and suggest that select patients with pre-existing psychiatric conditions may be candidates for treatment with appropriate monitoring, while additional evidence is needed regarding patients with autoimmune conditions. 

Results from a retrospective, real-world study demonstrated increasing complete hematologic response rates with ropeginterferon alfa-2b over time among patients with myeloproliferative neoplasms, with adverse event rates generally consistent with those previously reported in clinical trials.

These results were presented by Katherine Feder, MD, Dana Farber Cancer Institute, Boston, Massachusetts, at the Society of Hematological Oncology (SOHO) Annual Meeting in Houston, Texas.

In this study, investigators identified patients prescribed ropeginterferon alfa-2b through the Mass General Brigham specialty pharmacy and retrospectively abstracted electronic health record data collected between January 2022 and June 2025. The study evaluated real-world prescribing patterns, tolerability, and complete hematologic response rates. 

Of 97 patients identified, 12 were excluded because of incomplete records, inadequate follow-up, or failure to initiate therapy, leaving 85 patients in the analysis. Seventy patients had sufficient follow-up for a 12-month efficacy assessment.

Most patients had polycythemia vera, including 67 of the 85 patiennts. Fifteen patients had essential thrombocythemia and 3 patients had  unclassified myeloproliferative neoplasms. The median age at treatment initiation was 48 years, 47% of patients were female, and 85% were White. Driver mutations included JAK2 (93%), CALR (6%), and  MPL (1%). 

Ropeginterferon alfa-2b was used across different points in the treatment course. Forty percent of patients were treatment naïve, while 46% had received 1 previous therapy.

Most patients initiated treatment at 100 mcg every 2 weeks, while approximately 1/5 began treatment at 50 mcg every 2 weeks. Starting doses ranged from 50 mcg to 300 mcg every 2 weeks, and the median maximum dose was 500 mcg every 4 weeks.

Complete hematologic response increased with longer treatment exposure, from 25% at 6 months to 43% at 12 months. At data cutoff, 70% of patients remained on ropeginterferon alfa-2b,  with a median treatment duration of 18.5 months.

Adverse events occurred in 79% of patients. The most frequently reported events included pruritus (25%), elevated liver function tests (20%), and cytopenias (19%). 

Overall, 30% of patients discontinued treatment. Among those who discontinued, adverse events accounted for 88% of discontinuations, while disease progression and lack of response accounted for 8% and 4%, respectively. The median duration of treatment among patients who discontinued was 8 months.

The analysis also examined treatment among patients with pre-existing psychiatric and autoimmune conditions. Twenty-four patients had a psychiatric condition before initiating ropeginterferon alfa-2b. All 4 patients who subsequently experienced psychiatric toxicity had a pre-existing psychiatric diagnosis, and 3 discontinued therapy due to worsening of the underlying condition. 

Ten patients had pre-existing autoimmune conditions. Four of these patients discontinued treatment because of autoimmune phenomena. The investigators cautioned that the small size and heterogeneity of this subgroup limited conclusions regarding ropeginterferon alfa-2b use in patients with autoimmune disease.

The investigators concluded that real-world CHR and adverse event rates were similar to those observed in published clinical trials. Although most patients received ropeginterferon alfa-2b for PV, the analysis also captured off-label treatment of patients with ET and unclassified MPNs.

Importantly, the findings suggest that a pre-existing psychiatric diagnosis does not necessarily preclude ropeginterferon alfa-2b treatment, although close monitoring for worsening psychiatric symptoms remains warranted.

Source:

Feder K, Freydman J, Ren Y, et al. Real-world experience with ropeginterferon alfa-2b in polycythemia vera and essential thrombocythemia: Practice patterns, tolerability, and hematologic response at a single academic center. Presented at the SOHO Annual Meeting; September 9-12, 2026; Houston, Texas. Abstract MPN-1319.