• The hydrogel resolved lameness in 72% of horses treated
• Horses provide a strong translational model for human osteoarthritis
• Clinical investigation authorized by Belgian regulatory authority
• Allegro’s hydrogel is first-in-class potentially disease-modifying osteoarthritis device candidate

Liege, Belgium – 12 March 2026 (08:30 CET) – Allegro NV, a biomedical company developing transformative nanotechnology treatments for degenerative joint disease, has demonstrated that its proprietary injectable hydrogel significantly improved joint mobility in horses with osteoarthritis. In a proof-of-concept study in 40 mature thoroughbred horses with osteoarthritis, 89.6% showed a reduction in lameness after the treatment, while 72.4% demonstrated complete resolution of lameness four weeks later. Allegro plans to publish the results of the study at a leading medical conference in 2026.

The company is also announcing today it has received approval from the Federal Agency for Medicines and Health Products (FAMHP) in Belgium for an open-label feasibility study with its Hydrocelin hydrogel device candidate in 20 patients with osteoarthritis of the knee. Allegro expects to launch the study in the coming weeks.

“These first efficacy results in horses using Allegro’s osteoarthritis treatment candidate suggest extraordinary promise for use in humans. Osteoarthritis is the leading cause of disability in humans, with no disease-modifying treatment available today. At Allegro, we’re working to demonstrate benefits to patients in our clinical testing this year, and offer better outcomes for the 650 million people affected by the disease,” said Lucas Decuypere, CEO of Allegro.

Horses are a strong translational model for humans in joint disease and Allegro is fully focused on the clinical development of its technology, after signing an exclusive licensing deal for its technology for use in veterinary markets with American Regent, a leading pharmaceutical company in the U.S. specializing in injectables for human and animal health. Allegro will supply American Regent with product from its manufacturing site in Belgium.

In the study, horses received a single injection of the hydrogel in the most affected joint, and hyaluronic acid (Optivisc Single) in the contralateral (healthy) joint as a control.

Among the findings were:

• After four weeks of treatment with Allegro’s hydrogel, 89.6% of horses (26 out of 29 evaluable horses) showed improvement of the AAEP lameness score, while 72.4% (21 out of 29 evaluable horses) showed complete resolution of lameness.
• The difference in the AAEP lameness score after 4 weeks of treatment compared with the score before treatment was statistically significant (p<0.05).
• No adverse effects were observed in pathological joints after the nanogel injection and throughout the 4-week follow-up period.
  
  

Hydrocelin contains cross-linked particles designed to act as tiny shock absorbers in the synovial fluid. Restoring the shock-absorbing capacity of the synovial fluid is intended to provide pain relief and protect cartilage in the joints. In April, Allegro presented positive preclinical data demonstrating the satisfactory safety profile of Hydrocelin at the World Congress on Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (WCO) in Rome. In addition to this pyrogenicity study, the company has also demonstrated a satisfactory safety profile in preclinical studies assessing irritation, delayed sensitization and systemic toxicity.

Allegro NV (www.allegro.bio) is a clinical-stage biomedical company developing transformative treatments for degenerative joint diseases based on its proprietary nanotechnology platform, INTRICATE. The company’s lead product candidate, Hydrocelin, is a first-in-class, potentially disease-modifying injectable treatment for osteoarthritis, a novel performance biomaterial designed to restore the natural protective mechanics of the joint - rather than merely masking symptoms. By altering the trajectory of the disease at its source we aim to redefine the future of osteoarthritis and its care.

For more information please visit www.allegro.bio.

Important information
The contents of this announcement include statements that are, or may be deemed to be, "forward-looking statements". These forward-looking statements can be identified by the use of forward-looking terminology, including the words "believes", "estimates," "anticipates", "expects", "intends", "may", "will", "plans", "continue", "ongoing", "potential", "predict", "project", "target", "seek" or "should", and include statements the Company makes concerning the intended results of its strategy. By their nature, forward-looking statements involve risks and uncertainties and readers are cautioned that any such forward-looking statements are not guarantees of future performance. The company's actual results may differ materially from those predicted by the forward-looking statements. The company undertakes no obligation to publicly update or revise forward-looking statements, except as may be required by law.

Attachment

• 20260312 - Allegro PR equine study (final)