Recently, China's National Medical Products Administration (NMPA) approved a new indication for obinutuzumab beta injection (trade name: Beijiexin®, development code: MIL62), an innovative biologic independently developed by Beijing Mabworks Biotech Co., Ltd. The drug is now indicated for the treatment of adult patients with primary membranous nephropathy (pMN) who are at risk of disease progression. This approval makes MIL62 the world's first approved targeted therapy specifically indicated for pMN and represents a significant milestone in the development of innovative therapies for kidney diseases in China.

MIL62 is a novel third-generation anti-CD20 monoclonal antibody and the first domestically developed third-generation CD20 antibody in China. Through a unique glycoengineering platform, the Fc region of the antibody is completely afucosylated, significantly enhancing its binding affinity to FcγRIIIA receptors on immune effector cells. This modification improves antibody-dependent cellular cytotoxicity (ADCC) and enables more efficient and profound depletion of aberrantly activated B cells. Preclinical studies demonstrated that MIL62 exhibits stronger B-cell depletion activity and immunomodulatory effects than the first-generation anti-CD20 antibody rituximab.

In February 2026, MIL62 received its first marketing approval in China for the treatment of neuromyelitis optica spectrum disorder (NMOSD), becoming the first CD20 antibody approved worldwide for this indication. The approval in pMN further expands its therapeutic potential in autoimmune diseases.

The pMN approval was primarily supported by a Phase III multicenter, randomized, controlled clinical trial. At Week 76, the complete remission (CR) rate in the MIL62 monotherapy group reached 49.4%, significantly higher than the 3.9% observed in the cyclosporine control group. At Week 52, CR rates were 37.7% and 6.6%, respectively. Long-term follow-up data showed that the CR rate in the MIL62 group further increased to 57.1% at Week 104, while the overall remission rate reached 85.7%.

In addition to its clinical efficacy, MIL62 demonstrated remarkable immunological responses. The immunological complete remission rate peaked at 90.6% at Week 52. By Week 104, the immunological remission rate and immunological complete remission rate reached 87.5% and 84.4%, respectively, both substantially outperforming the control group. Furthermore, MIL62 exhibited a rapid onset of action, with a median time to immunological remission of approximately 1.1–1.2 months, compared with approximately 3 months in the control group. The median time to clinical remission was approximately 3.8 months, also shorter than that observed with the comparator treatment.

MIL62 also showed significant advantages in preserving renal function. During the study period, estimated glomerular filtration rate (eGFR) remained stable and tended to improve in the MIL62 group, whereas a continuous decline was observed in the cyclosporine group. The annualized changes in eGFR were 0.648 and -2.998 mL/min/1.73 m², respectively, suggesting that MIL62 may effectively slow renal function deterioration while controlling disease activity. In addition, the median time to treatment failure was not reached in the MIL62 group, compared with only 11.14 months in the cyclosporine group, indicating more durable disease control.

Regarding safety, MIL62 demonstrated a favorable tolerability profile with no new safety signals identified. Most adverse events were Grade 1 or Grade 2 in severity, and no increase in the risk of infections or serious infections was observed. Overall, the safety profile was comparable to existing treatment options.

Primary membranous nephropathy is an autoimmune glomerular disease whose incidence has been increasing in recent years and is one of the leading causes of end-stage kidney disease (ESKD). China is among the regions with the highest disease burden worldwide. Approximately 30%–40% of patients may progress to ESKD within 5 to 15 years after diagnosis. Historically, treatment has relied primarily on non-specific therapies such as corticosteroids and calcineurin inhibitors, while no targeted therapy had been approved specifically for pMN. The approval of MIL62 marks the beginning of a new era of precision-targeted treatment for pMN and offers patients a promising new therapeutic option with the potential for long-term clinical benefit.

According to the China Marketed Drug Patent Information Registration Platform, one patent related to obinutuzumab beta injection has been listed, with the patent grant number CN108138186B and an estimated expiration date of August 28, 2037. Claims 1–6 are directed to sequence structure protection of the biologic active ingredient, whereas Claims 7–8 relate to medical uses of the biologic product. Notably, the indications recited in Claims 7–8 include B-cell lymphoma, non-Hodgkin lymphoma, chronic lymphocytic leukemia, follicular lymphoma, rheumatoid arthritis, multiple sclerosis, and systemic lupus erythematosus, but do not encompass primary membranous nephropathy, the newly approved indication. In addition, corresponding patent applications have been pursued and granted in the United States, the European Union, Austria, and Germany.