Zenas secures $200m for autoimmune therapy development

Zenas BioPharma, a US-based company, has successfully raised $200 million in a Series C funding round to advance the clinical development of its leading investigational drug, obexelimab. This significant funding will enable Zenas to conduct mid to late-stage clinical trials for obexelimab, a bispecific antibody designed to target CD19 and FcγRIIb. The funding round saw participation from several venture capital firms, including SR One, New Enterprise Associates (NEA), Norwest Venture Partners, and Delos Capital.

Zenas acquired the rights to obexelimab from Xencor in 2021. Since then, the company has focused on evaluating its efficacy in treating various autoimmune disorders. The autoimmune conditions under investigation include IgG4-related disease (IgG4-RD), systemic lupus erythematosus (SLE), and other related diseases.

Recently, in September 2023, Bristol Myers Squibb (BMS) obtained the developmental and marketing rights for obexelimab in several Asia Pacific regions, such as Australia, Hong Kong, Japan, Singapore, South Korea, and Taiwan. As part of this agreement, BMS made an equity investment in Zenas and provided an upfront payment of $50 million. Zenas is also entitled to additional milestone-based payments as part of this deal.

One of the main clinical trials involving obexelimab is the Phase III INDIGO trial (NCT05662241), a placebo-controlled study that aims to assess the drug as a subcutaneous treatment for IgG4-RD. This chronic fibroinflammatory disease affects various organs, and the study is expected to enroll approximately 200 participants. Another significant trial is the open-label Phase II/III SApHiAre trial (NCT05786573), which is evaluating obexelimab for the treatment of warm autoimmune hemolytic anemia (wAIHA). Both of these trials are projected to conclude between late 2025 and early 2026.

In addition to these ongoing trials, Zenas plans to initiate Phase II studies to explore obexelimab’s potential in treating multiple sclerosis and systemic lupus erythematosus (SLE). Previously, in a 2018 Phase II trial (NCT02725515), obexelimab did not meet the primary endpoint of maintaining improvement in SLE patients. However, the trial did achieve a secondary endpoint, with treated patients experiencing a median delay of 76% longer in showing losses of improvement.

The recent $200 million in Series C funding complements the $118 million that Zenas raised in a Series B round in 2022. This financial support will also aid in the development of other autoimmune therapies within Zenas’s portfolio. These include ZB002, an anti-TNFα therapy, and ZB004, a cytotoxic T lymphocyte-associated antigen-4 immunoglobulin (CTLA-4-Ig) fusion protein. Both therapies were also acquired from Xencor, expanding Zenas’s potential to address a range of autoimmune diseases.

Through these significant investments and ongoing clinical trials, Zenas BioPharma aims to make meaningful advancements in the treatment of autoimmune disorders, potentially offering new therapeutic options for patients suffering from these debilitating conditions.