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Chugai Pharmaceutical Co., Ltd. announced that the first clinical data in people with haemophilia A from a phase I/II study (NXTAGE) of NXT007 was presented at the International Society on Thrombosis and Haemostasis 2025 Congress (ISTH 2025 Congress) in Washington, D.C., United States. NXT007 is a next-generation bispecific antibody for subcutaneous injection, based on Hemlibra (generic name: emicizumab) which is widely used to treat haemophilia A. It is currently under development for haemophilia A.
“We are very excited that this first data in people with haemophilia A, suggests that NXT007 has the potential to provide haemostatic normalization. Based on these data, we plan to initiate three Phase III studies of NXT007 next year, including a head-to-head study with Hemlibra. Treatment in haemophilia A has drastically evolved in recent years, and there are now expectations for treatments with even higher efficacy and even more convenient dosing form. Together with Roche, we will focus on the clinical development of NXT007, aiming to deliver it as a new treatment option as soon as possible to people who need it,” said Dr. Osamu Okuda, Chugai’s president and CEO.
NXTAGE study is a multicenter, phase I/II clinical trial to evaluate the safety, pharmacokinetics, pharmacodynamics, and efficacy of NXT007. The presented data was from Part B of the study, which was the multiple ascending dose part including Hemlibra-naïve people with severe haemophilia A without FVIII inhibitors aged =12 years and <65 years. Participants were included in 4 cohorts, and following 4- to 6-week loading doses, they received subcutaneous maintenance doses of NXT007 at different dosage levels every 4 weeks. The primary analysis was conducted when at least 6 participants had completed 16 weeks of NXT007 treatment in all Part B cohorts.
In Part B, dose dependent increase of NXT007 plasma concentration was observed. Plasma concentrations in the high dose cohorts B-3 and B-4 reached the predicted normal range of FVIII–equivalent activity based on preclinical data1. No treated bleeds were observed in cohorts B-3 and B-4, in the maintenance dose period.
NXT007 was well tolerated in part B. The number of adverse events (AEs) were not dose-dependent, and AEs leading to treatment withdrawal and serious AEs were not related to NXT007. No thromboembolic events were observed, and the safety profile was tolerable.
NXT007 is a bispecific antibody originated from Chugai, designed with the goal of achieving coagulation activities at a level comparable to individuals without haemophilia, while optimizing administration convenience. NXT007 is designed to bind factor IXa and factor X, to provide the cofactor function of factor VIII in people with haemophilia A, who either lack or have impaired coagulation function of factor VIII. By applying Chugai’s proprietary antibody engineering technology, FAST-Ig2 for the first time, the variable region of Hemlibra has been optimized, aiming to further enhance efficacy. ACT-Ig3 was also applied, aiming to further improve antibody pharmacokinetics. Roche decided to in-license the investigational drug in August 2022. phase I/II clinical trials for haemophilia A are currently ongoing, and three phase III clinical trials are to be initiated in 2026.
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