Zenas Targets Lupus and MS with New Dual-Targeting Antibody Funding

Zenas BioPharma, a biotechnology startup, has successfully raised $200 million to advance the clinical testing of its dual-targeting antibody drug, obexelimab, aimed at treating inflammatory diseases. This significant funding, part of a Series C round, will support late-stage trials for various conditions and expand the company's research scope.

Acquired from Xencor two and a half years ago, obexelimab is already in late-stage trials for IgG4-related disease, an inflammatory condition. Additionally, Zenas has announced plans to initiate Phase 2 trials for multiple sclerosis (MS) and a common form of lupus. These new trials will complement an ongoing trial focused on a rare type of anemia.

The company, led by Lonnie Moulder, the former head of the cancer biotech Tesaro, which was acquired by GSK in 2018, has two other drugs in clinical testing through partnerships with other biotech firms. Zenas also maintains an alliance with Bristol Myers Squibb, which not only invested in Zenas but also acquired partial rights to obexelimab last year.

In the landscape of autoimmune disease treatment, there's been a growing interest in innovative approaches. Typically, patients with conditions like lupus and MS receive long-term treatments aimed at suppressing the immune responses that cause their symptoms. However, recent academic research has highlighted the potential of cellular medicines to eliminate malfunctioning B cells, offering possibly more effective and lasting relief.

For instance, a study published in The New England Journal of Medicine earlier this year reported that 15 patients with challenging forms of lupus, inflammatory myositis, or systemic sclerosis went into remission after a single infusion of CAR-T therapy. Despite the small sample size, these results have spurred significant interest and investment from both large and small pharmaceutical companies in exploring new cell therapies for autoimmune diseases. Currently, more than a dozen such therapies are either in clinical testing or expected to begin trials soon.

Bispecific antibodies, which target two different proteins, are another promising avenue. These protein drugs have already been approved for treating blood cancers, where they are seen as more convenient, more affordable, and potentially safer alternatives to cell therapy. Proponents believe these attributes could also make bispecific antibodies suitable for treating autoimmune conditions, which usually have less tolerance for the severe side effects sometimes associated with CAR-T treatments.

Early evidence of their potential was demonstrated last month in the European Journal of Cancer, which described a case where Amgen's Blincyto showed promising results in a systemic sclerosis patient. Zenas BioPharma is now among the companies investigating whether similar outcomes can be achieved in larger studies for other autoimmune conditions.

Obexelimab, Zenas' drug candidate, aims to deplete B cells by targeting the proteins CD19 and FcRIIb. Even though a Phase 2 trial for lupus in 2018 did not meet its primary endpoints, the company remains optimistic. "The funding enables us to complete multiple potentially value-driving clinical programs," said CEO Lonnie Moulder in a statement.

The Series C funding round was led by SR One, NEA, Norwest Venture Partners, and Delos Capital, signaling strong investor confidence in Zenas BioPharma’s innovative approach to tackling complex autoimmune diseases.