Zura Bio Submits Phase 2 Tibulizumab Study Protocol to FDA for Systemic Sclerosis

HENDERSON, Nev.--(BUSINESS WIRE)--Zura Bio Limited (Nasdaq: ZURA), a clinical-stage immunology company engaged in developing innovative dual-pathway antibodies for autoimmune and inflammatory conditions, has announced the submission of a protocol to the U.S. Food and Drug Administration (FDA) for a Phase 2 clinical trial. This trial will evaluate tibulizumab, a novel humanized tetravalent bispecific dual antagonist antibody, designed to neutralize both IL-17A and BAFF, for the treatment of systemic sclerosis (SSc) in adults.

Systemic sclerosis is a rare autoimmune disease that affects around 300,000 people globally, including approximately 100,000 individuals in the United States. It is characterized by chronic inflammation and progressive fibrosis of connective tissues, primarily impacting the skin and lungs, but also potentially affecting the heart, liver, kidneys, digestive tract, and vascular system. Common symptoms include skin thickening and extreme sensitivity to cold in the extremities. The disease can also lead to muscle numbness and swelling, joint stiffness and reduced mobility, lung and heart fibrosis, kidney dysfunction, and gastrointestinal problems such as difficulty swallowing, heartburn, bloating, constipation, and diarrhea.

Currently, there are limited treatment options available for systemic sclerosis, and only two FDA-approved therapies address severe lung complications (SSc-ILD). There is no effective treatment that comprehensively addresses the disease across multiple organ systems, underscoring the substantial unmet medical need.

Tibulizumab, the subject of Zura Bio's Phase 2 trial, is a bispecific dual antagonist antibody, combining elements of Taltz® (ixekizumab) and tabalumab. It is engineered to neutralize IL-17A and BAFF, which are key drivers of immune dysregulation and fibrosis in systemic sclerosis. The planned double-blind, randomized, placebo-controlled study will enroll approximately 80 participants with early diffuse cutaneous systemic sclerosis (dcSSc). The trial aims to evaluate the safety, tolerability, and efficacy of tibulizumab, with a focus on improving skin and lung symptoms, the primary complications of SSc. An open-label extension will also be included. The study is anticipated to commence in the fourth quarter of 2024, with an Orphan Drug Designation request already submitted to the FDA in the same period.

Tibulizumab has not yet received regulatory approval, and its safety and efficacy for treating systemic sclerosis remain unestablished. However, if successful, this Phase 2 trial could pave the way for a first-in-class therapeutic option that addresses both immune dysregulation and fibrosis in systemic sclerosis.

Zura Bio, the company behind tibulizumab, is a clinical-stage immunology enterprise focused on developing dual-pathway antibodies for autoimmune and inflammatory diseases. The company is advancing a portfolio of therapeutic candidates, including tibulizumab (ZB-106), crebankitug (ZB-168), and torudokimab (ZB-880). Each asset has completed Phase 1/1b studies, and Zura Bio aims to demonstrate their efficacy, safety, and dosing convenience in treating systemic sclerosis and other conditions with significant unmet needs.

In addition to systemic sclerosis, tibulizumab's clinical development plan includes a Phase 2 trial for hidradenitis suppurativa, expected to begin in the second quarter of 2025. Prior Phase 1/1b studies of tibulizumab were conducted in patients with Sjögren’s syndrome and rheumatoid arthritis. Zura Bio's ongoing efforts reflect their commitment to developing innovative therapies that can bring meaningful improvements to patients suffering from complex autoimmune and inflammatory diseases.