A comparative study of hematologic response to ropeginterferon alfa-2b in hydroxyurea-resistant or intolerant...

To compare the hematologic response to ropeginterferon alfa-2b versus available therapies in patients with hydroxyurea-resistant or intolerant polycythemia vera (HU-R/I PV) using propensity-matched real-world data.

This retrospective propensity-matched cohort study compared a single-arm clinical trial cohort with a historical control cohort from five Korean institutions. We included 36 HU-R/I patients from a prospective phase II trial (PV IIT, registration number KCT0006138) and 81 matched historical controls. Propensity score matching and weighted analyses balanced the baseline characteristics (age, sex, disease duration, hematologic parameters, and HU status). The primary endpoint was a complete hematologic response (CHR) at 48 weeks.

At 48 weeks, ropeginterferon alfa-2b achieved significantly higher CHR rates (52%; 95% confidence interval [CI]: 35-70%) than historical controls (15%; 95% CI: 8-27%; odds ratio 0.15; 95% CI: 0.07-0.33; p < 0.0001). This superiority remained consistent across various matching ratios and weighted analyses. Subgroup analyses showed higher response rates to ropeginterferon alfa-2b, regardless of HU status (resistant vs. intolerant), age (< 60 vs. ≥ 60 years), or disease duration (< 5 vs. ≥ 5 years). In the control group, the most common regimen was a combination of HU and phlebotomy (53%) with limited use of ruxolitinib (5.5%). Analyses confirmed robustness with no significant baseline imbalances after matching.

Ropeginterferon alfa-2b demonstrated superior early hematologic efficacy compared with conventional salvage therapies in Korean patients with HU-R/I PV. Extended follow-up is warranted to assess the long-term clinical benefits.