Kyntra Bio (NASDAQ:KYNB) shares rose 3.9% in after-hours trading Thursday after the company released a post hoc analysis indicating that roxadustat improved transfusion independence in patients with lower-risk myelodysplastic syndromes (LR-MDS) who carry a high transfusion burden.
The data were presented at the European Hematology Association Congress 2026 in Stockholm, Sweden, and derive from the Phase 3 MATTERHORN trial. In the analysis, patients treated with roxadustat demonstrated a durable improvement in transfusion independence when compared with placebo.
Examining disease subtypes, the post hoc assessment showed similar rates of transfusion independence for patients treated with roxadustat regardless of ring sideroblast status. Specifically, among the ring sideroblast negative subgroup - which made up 84 of the 140 patients enrolled in MATTERHORN - treatment with roxadustat produced transfusion independence for at least 8 weeks over a 28-week assessment period in 48% of patients, versus 28% for those receiving placebo.
For patients defined as having a high transfusion burden, the analysis applied the criterion of at least 4 units of packed red blood cells per 8-week period for two consecutive 8-week periods. Within this subgroup, roxadustat achieved higher rates of red blood cell transfusion independence at 8, 12, and 16 weeks compared with placebo.
Safety observations from the post hoc analysis indicated that treatment-emergent adverse events were generally lower grade and could be managed medically, with no new safety signals reported.
These subgroup and post hoc findings complement the initial MATTERHORN analysis, which showed that 48% of patients receiving roxadustat reached transfusion independence compared with 33% for placebo in the broader trial population.
Following the presentation, Kyntra Bio said it is finalizing the protocol for a pivotal Phase 3 trial of roxadustat specifically for the treatment of anemia in patients with LR-MDS and high transfusion burden. The company noted that the trial protocol reflects feedback from the U.S. Food and Drug Administration and that it expects to initiate the pivotal study in the second half of 2026.
Context and next steps
The company’s announced intention to move forward with a pivotal Phase 3 study signals a direct response to regulatory input and the subgroup findings reported at EHA 2026. The forthcoming trial is intended to further evaluate roxadustat’s efficacy and safety in the targeted LR-MDS population with significant transfusion needs.