VETmAb Reports Positive Early Clinical Results for Long-Acting Anti-IL-23 Antibody in Dogs

SAN DIEGO, United States — 26 October 2026: Veterinary biotechnology company VETmAb Biosciences has reported positive proof-of-concept results from a small, randomised, masked, placebo-controlled pilot study of VMB-C001a, an investigational long-acting monoclonal antibody targeting interleukin-23 (IL-23) in dogs with naturally occurring chronic inflammatory enteropathy (CIE). The company said 77.8% of treated dogs met its treatment-success criteria, compared with 30.0% of placebo-treated dogs. 

CIE is a group of chronic, often relapsing gastrointestinal disorders associated with signs such as persistent diarrhoea, vomiting and weight loss. The condition may require prolonged dietary management and, in some cases, corticosteroids or other immunosuppressive medicines. VMB-C001a is designed to target an inflammatory pathway implicated in intestinal immune activity.

Pilot study: 19 dogs followed for 105 days

The company reported that 19 client-owned dogs were enrolled, with nine receiving VMB-C001a and 10 receiving placebo. Treatment and follow-up extended over 105 days.

Treatment success was based on improvement in the Canine Inflammatory Bowel Disease Activity Index (CIBDAI) between baseline and the later study period, without additional medication or supplements for CIE clinical signs. Dogs requiring rescue treatment or removed from the study because of inadequate efficacy were classified as treatment failures. The company categorised a reduction of more than 75% in the activity score as remission.

The results are encouraging as an early signal, but the small sample means that each dog materially affects the percentages. The announcement does not establish comparative efficacy with existing treatments, long-term remission or the likelihood of reproducing these outcomes in a larger population.

Safety Findings and Tolerability

VETmAb described VMB-C001a as generally well tolerated in this pilot. One treated dog yelped during an injection on Day 75. The company reported that other adverse events were mild and considered unrelated to the candidate. One dog in the placebo group experienced a serious adverse event and was euthanised on Day 105, reportedly following disease progression.

These observations provide preliminary tolerability information, not a definitive safety profile. A larger and longer study will be needed to evaluate uncommon adverse events, durability of response and safety across a wider range of dogs.

FDA-CVM pathway: Eligibility is Not Approval

VETmAb said VMB-C001a has been granted eligibility for the US Food and Drug Administration’s Center for Veterinary Medicine expanded conditional approval pathway. This is a regulatory development, but eligibility does not mean the product has received conditional approval or is authorised for commercial sale.

If conditional approval is subsequently granted, the pathway may permit marketing while the sponsor completes effectiveness studies required for full approval, subject to applicable regulatory requirements. VETmAb said it intends to advance the candidate towards pivotal development.

Broader Pipeline and Market Implications

The company also reported programmes targeting feline CIE, immune-mediated diseases in dogs and cats through an anti-FcRn antibody, and canine metabolic disease. Its strategy involves developing species-specific biologics against targets with established relevance in human medicine.

For the animal-health industry, the programme illustrates the growing effort to apply targeted biologic therapies to chronic companion-animal diseases with substantial unmet needs. Commercial prospects will depend on pivotal efficacy and safety data, manufacturing economics, veterinary access, pricing and the eventual regulatory outcome.

Bottom line: VMB-C001a has produced a promising early clinical signal in canine CIE, but the findings remain preliminary. The next meaningful milestones are larger controlled studies, a fuller safety assessment and progress through the FDA-CVM regulatory process.

Primary source: VETmAb Biosciences announcement via GlobeNewswire, 26 October 2026