Chugai Presents NXT007 Switch Data From Emicizumab Phase I/II Study Supports Safe Transition To NXT007 In Haemophilia A

Chugai Pharmaceutical reported new clinical data from Part C of its Phase I/II NXTAGE study at the 2026 European Association for Haemophilia and Allied Disorders (EAHAD) Congress in Ireland. The data mark the first clinical evaluation of NXT007 in people with hemophilia A who switched directly from emicizumab to the investigational therapy without a washout period.

NXT007 is a next-generation bispecific antibody derived from Hemlibra (emicizumab) and is being developed as a subcutaneous treatment for hemophilia A. The multicenter NXTAGE study is assessing the safety, pharmacokinetics, pharmacodynamics and efficacy of the drug.

Part C enrolled adolescents and adults aged 12 to under 65 years with hemophilia A, with or without factor VIII inhibitors, who had been on continuous emicizumab therapy for at least 12 weeks. Participants were assigned to four dose-escalation cohorts and transitioned directly to subcutaneous NXT007. After a 4–6-week loading phase, they received maintenance doses every four weeks at cohort-specific dose levels. The interim analysis included 14 participants who had been treated with NXT007 for at least 16 weeks.

“The favorable tolerability observed when switching from emicizumab to NXT007 without a washout period is an important finding, and we view it as a key insight for advancing the safety evaluation during the switching period. We are advancing the development of NXT007 with the higher goal of achieving hemostatic function equivalent to that of people without hemophilia. Working closely with Roche, we foucus on advancing three Phase III clinical studies that are planned to start this year, and aim to bring this treatment to patients as soon as possible,” said Dr. Osamu Okuda, Chugai’s President and CEO.

The switch from emicizumab was generally well tolerated. No thromboembolic events were reported, adverse events did not increase with higher doses, and no patients discontinued treatment due to safety concerns. Injection-site reactions were the most frequent NXT007-related events, occurring in 14.3% of participants, and were all mild. One participant developed anti-drug antibodies that affected drug levels, but plasma concentrations remained stable and the individual continued in the study without bleeding episodes.

NXT007 exposure rose with increasing doses, and the two highest-dose cohorts achieved plasma concentrations that, based on nonclinical data,may deliver factor VIII-equivalent activity in the normal range. Importantly, after switching to NXT007, no treated bleeding events were seen in the highest-dose groups.