Harbour BioMed announced positive topline results from its Phase 2 proof-of-concept clinical trial of batoclimab (HBM9161) in Chinese generalized myasthenia gravis (gMG) patients.

Data received from the Phase 2 Study, as the first clinical evidence of anti-FcRn therapies in Chinese patients, showed a statistically significant and clinically meaningful efficacy of batoclimab over placebo, as well as a favorable safety and tolerability profile.

Data from the Phase 2 Study demonstrated that batoclimab has alleviated myasthenic symptoms rapidly with satisfactory safety profile in Chinese patients, supporting batoclimab as a potential novel solution to fill the current treatment gap for gMG patients.

The Phase 2 Study Design

The trial is a multi-center, double-blinded, placebo-controlled study on 30 subjects suffering moderate to severe gMG to receive batoclimab (340 mg, 10 subjects or 680 mg, 11 subjects) or placebo (9 subjects) once per week for a period of 6 weeks (double blinded treatment period), followed by 340 mg every other week for a period of 6 weeks (open-label treatment period) on a random basis.

The primary efficacy endpoint was the improvement of Myasthenia Gravis Activities of Daily Living (MG-ADL) score from baseline. Secondary efficacy endpoints included the improvements from baseline of Quantitative Myasthenia Gravis (QMG), Myasthenia Gravis Composite (MGC), and Myasthenia Gravis Quality of Life (MG-QoL) score. Other endpoints include safety and tolerability profile, pharmacokinetics (PK) and pharmacodynamic (PD).

Key Results of Phase 2 Study

• Analysis of primary endpoint revealed both 340 and 680 mg of batoclimab treatment resulted in rapid, clinically meaningful, and statistically significant improvements over placebo by MG-ADL score reduction from baseline on Day 43 (a week after the last dose of batoclimab (p =0.043)

• Batoclimab induced rapid, substantial and persistent clinical improvement over placebo as measured by all four predefined clinical efficacy scales - MG-ADL, QMG, MGC and MG-QoL15

• 57%, and 76% of patients in the treatment arm showed persistent clinical improvements (≥2 points in MG-ADL and ≥3 points in QMG for a period of 6 consecutive weeks) versus 33% in MG-ADL and 11% in QMG in placebo

• All patients on treatments showed robust IgG reduction (decreased 57% and 74% from baseline on Day 43 in 340 mg and 680 mg groups, respectively) strongly correlated with clinical improvements.

Batoclimab treatment was shown to be overall safe and well-tolerated, with incidence of adverse events (AE) comparable to placebo, majority of AEs characterized as mild, no serious adverse events (SAE) and no discontinuation due to AEs.    

Based on the positive reports of this Phase 2 study, HBM already carried out the "end of Phase 2" meeting with Center for Drug Evaluation, National Medical Products Administration (NMPA), and obtained full support on the Phase 3 study plan. The Phase 3 study will be initiated in the second half of 2021.

"This is a monumental milestone in innovative therapeutics development for myasthenia gravis in China", said the principal investigator Chongbo Zhao, MD, Professor of Neurology at Huashan Hospital of Fudan University in Shanghai. "For decades, there has been lacking high impact clinical studies of myasthenia gravis in China, and this phase 2 study certainly fills the gap. In addition, unmet needs for myasthenia gravis treatment include 10-20% refractory patients, 15-20% potentially progressing to life-threatening crisis, and patients affected by severe side effects associated with long-term use of current therapies. All these challenges require safe and efficacious novel therapeutics. Data from this study demonstrated that batoclimab alleviated myasthenic symptoms rapidly with satisfactory safety profile in Chinese patients, producing more evidence to support batoclimab as the promising potential novel treatment for gMG patients."

"We are extremely pleased to announce the positive reports of this trial," said by Jingsong Wang, Founder, Chairman, and CEO of HBM, "batoclimab is the first anti-FcRn therapy entering clinical development in China and reports positive data in Chinese patients with gMG. The strong evidence generated from this study is quite exciting and further indicates that batoclimab could be a novel therapy with favorable safety profile and substantial clinical improvements. Furthermore, through subcutaneous injection, both doses of batoclimab may offer the flexibilities of dosing strategy, self-administration at home, significantly relieve the burden of healthcare system and transportation challenges of patients. We are committed to further accelerate this exciting novel therapeutic development to help patients in need."  

About Batoclimab (HBM9161)

Batoclimab (HBM9161), a fully human anti-FcRn mAb, blocks FcRn-IgG interactions, accelerating the degradation of autoantibodies and leads to the treatment of pathogenic IgG-mediated autoimmune diseases. Available evidence suggests that reduced levels of pathogenic IgG in patients with myasthenia gravis are associated with clinical benefit. Earlier studies demonstrated that batoclimab is well tolerated and can rapidly reduce total IgG. These findings make batoclimab the first anti-FcRn to demonstrate a sustained IgG reduction in both Chinese and Caucasian populations when administered via subcutaneous (SC) injection. Batoclimab has been granted "Breakthrough Therapy Designation" by the Chinese NMPA in gMG.

About Harbour BioMed

Harbour BioMed (HKEX: 02142) is a global biopharmaceutical company committed to the discovery, development and commercialization of novel antibody therapeutics focusing on oncology and immunology. The Company is building its robust portfolio and differentiated pipeline through internal R&D capability, collaborations with co-discovery and co-development partners and select acquisitions.

The Company's proprietary antibody technology platforms Harbour Mice? generate fully human monoclonal antibodies in two heavy and two light chain (H2L2) format, as well as heavy chain only (HCAb) format. Building upon the HCAb antibodies, the HCAb-based immune cell engagers (HBICE?) are capable of delivering tumor killing effects unachievable by traditional combination therapies. Integrating Harbour Mice? with single B cell cloning platform, our antibody discovery engine is highly unique and efficient for development of next generation therapeutic antibodies.