Chinese marketing approval sets the stage for technology fees and sales royalties
Imireprovat advancing through Phase 3 for generalized myasthenia gravis, with early responses confirmed in rheumatoid arthritis
An antibody drug developed by HanAll Biopharma (009420) has secured marketing approval in China. As batoclimab, an autoimmune disease treatment, enters the commercialization phase following Phase 3 clinical trials, HanAll is now positioned to receive regulatory milestone payments and royalties tied to future sales. This achievement marks the translation of technology out-licensed to an overseas partner into local commercial approval.
Its successor candidate, imireprovat (IMVT-1402/HL161ANS), is currently undergoing global Phase 3 trials for generalized myasthenia gravis, while early therapeutic responses have been confirmed in a Phase 2b trial targeting rheumatoid arthritis. HanAll’s FcRn antibody business is thus expanding across two main pillars: the commercialization of batoclimab in China and overseas clinical trials for imireprovat.
Approval in China Following Phase 3 Trials Confirms Daily Function and Sustainability Improvements
HanAll Biopharma announced on the 23rd that its batoclimab subcutaneous injection has received marketing approval from China’s National Medical Products Administration (NMPA). The approval targets adult patients with generalized myasthenia gravis who test positive for anti-acetylcholine receptor antibodies. This represents the first marketing approval among the antibody candidates discovered and codeveloped internationally by HanAll.
Generalized myasthenia gravis is a condition in which autoantibodies disrupt signaling between nerves and muscles, causing muscle weakness and fatigue. FcRn, the target of batoclimab, is a protein that facilitates the recycling of immunoglobulin G (IgG) in the body. Batoclimab blocks this mechanism, promoting the degradation of IgG, including the disease-causing autoantibodies.
The regulatory approval is primarily backed by a Phase 3 clinical trial conducted across 27 hospitals in China. Published in the international journal *JAMA Neurology*, the study evaluated improvements in the Myasthenia Gravis Activities of Daily Living (MG-ADL) score—which measures a patient's ability to perform daily activities—by adding batoclimab or a placebo to standard care.
The proportion of patients who achieved and maintained a reduction of 3 points or more in the MG-ADL score for at least four consecutive weeks during the first treatment cycle was 58.2% (39 out of 67 patients) in the batoclimab group, compared to 31.3% (20 out of 64 patients) in the placebo group. The difference, calculated based on patient numbers, was approximately 27 percentage points, which was statistically significant (P=0.001).
Differences in MG-ADL scores between the batoclimab and placebo groups were observed as early as the second week of treatment. Furthermore, sustained improvement in the Quantitative Myasthenia Gravis (QMG) score—a quantitative evaluation scale for the disease—was achieved by 64.2% of the treatment group versus 40.6% of the placebo group. The most frequently reported adverse event in the batoclimab arm was peripheral edema, all cases of which were mild to moderate in severity.
Royalties Linked to Local Sales: Commercialization Proceeds Under Existing Contract
Batoclimab’s Greater China operations are governed by agreements between HanAll and local partners. Harbour BioMed signed a licensing agreement with HanAll in 2017 to handle development in the Greater China region. Subsequently, in 2022, Harbour BioMed entered into a sublicense agreement granting NBP Pharmaceutical, a subsidiary of CSPC Pharmaceutical Group, the marketing and sales rights for mainland China, Hong Kong, Macau, and Taiwan.
HanAll and Harbour BioMed engaged in International Chamber of Commerce (ICC) arbitration proceedings beginning in 2025 regarding fulfillment of development obligations and contract termination hiệu lực (validity). Following an arbitral award in July of this year ruling that HanAll’s notice of contract termination was invalid and that the original licensing agreement remained in effect, both parties continue their business relationship under the existing framework.
Under this agreement, HanAll is slated to receive regulatory milestone payments from Harbour BioMed. Following commercialization, the company will receive tiered royalties based on annual net sales in the Greater China region. Specific milestone amounts and royalty rates were not disclosed in the announcement. Local launches and sales expansions will be managed by NBP Pharmaceutical, with the scale of HanAll’s earnings contribution expected to take shape depending on the timing of the launch and local sales trends.
Imireprovat Global Phase 3 Trials: Validating Efficacy in Myasthenia Gravis
Imireprovat is an FcRn antibody discovered by HanAll and out-licensed to Roivant Sciences, with Roivant affiliate Immunovant currently leading its global clinical development.
Immunovant is concentrating its development capabilities on imireprovat. Following the failure of two Phase 3 clinical trials of batoclimab in thyroid eye disease to meet their primary endpoints in April of this year, the company announced in May that it was halting all batoclimab development across all indications. Data and trial operational experience accumulated during the batoclimab trials are now being leveraged to advance imireprovat.
In a Phase 1 clinical trial involving healthy adults, imireprovat demonstrated dose-dependent reductions in IgG. Across the evaluated dose ranges, reductions in albumin and increases in LDL cholesterol were absent or limited. Therapeutic efficacy and long-term safety across various diseases are being further evaluated in patient-focused clinical trials.
Among the ongoing late-stage trials is a global Phase 3 study in generalized myasthenia gravis. According to the clinical trials registry ClinicalTrials.gov, the study spans multiple countries, including the US and Europe, with a target enrollment of 231 adult patients. Designed as a randomized, placebo-controlled trial, its primary endpoint is the change in MG-ADL score at week 12 compared to baseline in antibody-positive patients. Secondary measures include changes in the quantitative QMG strength score and the proportion of patients achieving minimal symptom burden. To facilitate patient self-administration, Immunovant is utilizing commercialization-oriented formulations and auto-injectors in the trials.
Refractory Rheumatoid Arthritis Phase 2b: Initial Responses Observed at 16 Weeks
Initial clinical data have emerged for refractory rheumatoid arthritis. Immunovant is conducting a Phase 2b trial of imireprovat in adult patients positive for anti-citrullinated protein antibodies (ACPA). A total of 170 patients were enrolled in the initial 16-week open-label treatment period, with ACR20 responses evaluable in 165 of them.
Announced in May, the ACR20, ACR50, and ACR70 response rates at the 16-week mark were 72.7%, 54.5%, and 35.8%, respectively. These metrics evaluate treatment response based on tender and swollen joint counts, pain, and physical function, with higher numbers indicating more stringent criteria for improvement. Discontinuations prior to 16 weeks were treated as non-responders in the rate calculations. Among 107 patients who had failed both prior JAK inhibitors and TNF inhibitors, the ACR20 response rate was 72.0%, comparable to the overall analysis group.
These published figures reflect the results of the initial period involving the administration of 600mg of imireprovat without a placebo control. The company stated that no new drug-related safety signals were observed during this period.
In the subsequent phase, patients who demonstrate an ACR20 response at both weeks 14 and 16 will be randomized 1:1:1 into three arms: 600mg, 300mg, and placebo. The primary endpoint is the proportion of patients maintaining an ACR20 response at week 28. This design compares whether initial responders sustain their response upon continued drug administration versus transitioning to a placebo.
Continued Development of Key Indications: Attention Focused on 2027 Clinical Readouts
In its development updates announced last August, Immunovant projected that top-line results from its generalized myasthenia gravis and Graves' disease trials will be unveiled in 2027. Regarding the refractory rheumatoid arthritis program, the company indicated plans to release additional updates in the second half of this year. Clinical data emerging from various autoimmune diseases will serve as the basis for determining imireprovat's scope of application and regulatory strategy.
The next milestones for HanAll’s FcRn business hinge on sales expansion in the Chinese market and global late-stage clinical results. If batoclimab successfully establishes itself locally, royalty-driven financial contributions could grow; furthermore, if imireprovat proves its therapeutic efficacy across major indications, commercialization opportunities will broaden. Attention is focused on whether ongoing progress in commercialization and clinical development will successfully elevate the value of HanAll’s proprietary antibody technologies.
*(Note: Part 2 will feature a Q&A interview with HanAll Biopharma detailing its strategy for Chinese commercialization and the development and commercialization of imireprovat.)*
