SynOx Therapeutics Granted Fast Track Designation by U.S. FDA for Emactuzumab in Treating Tenosynovial Giant Cell Tumours (TGCT)
Monday, April 14, 2025
SynOx Therapeutics Limited, a late-stage clinical biopharmaceutical company, has received Fast Track Designation (FTD) from the United States Food and Drug Administration (FDA) for its investigational therapy, emactuzumab. This designation applies to the treatment of patients with Tenosynovial Giant Cell Tumours (TGCT) who cannot undergo surgery or are unlikely to benefit from it.
Emactuzumab is a monoclonal antibody that targets the CSF-1 receptor (CSF-1R) and is currently being assessed in a Phase 3 global clinical trial known as the TANGENT study. This is a multi-centre, randomised, double-blind, placebo-controlled trial.
TGCT is a rare, non-cancerous but aggressive tumour that affects the synovium, tendon sheaths, and bursa membranes, mainly in joints such as the knee, hip, and ankle. It results from an overproduction of the CSF-1 protein and can cause joint pain, stiffness, and loss of function. Although surgery is often the standard treatment, some patients do not respond well or experience tumour recurrence. Over half of those with diffuse TGCT may see the tumour return within three years after surgery.
Fast Track Designation was granted based on earlier clinical trial results, which showed that emactuzumab led to rapid and lasting tumour reduction, along with a manageable safety profile. Emactuzumab has also previously received Orphan Medicinal Product status from the European Medicines Agency.
The FDA’s Fast Track programme is designed to speed up the development and review of medicines that aim to treat serious conditions and address unmet medical needs. This designation enables closer communication between the regulator and the company, with the aim of bringing promising treatments to patients sooner.
TGCT, previously known as pigmented villonodular synovitis (PVNS), is classified by the World Health Organization as a fibrohistiocytic tumour. It is further divided into localised and diffuse forms depending on growth pattern and location. TGCT can be destructive and significantly impacts quality of life. If untreated, the condition may lead to joint damage, deformity, and in severe cases, joint fusion or amputation.
Emactuzumab is a humanised IgG1 monoclonal antibody developed to block CSF-1R, which is found on certain immune cells such as macrophages. By targeting this receptor, the treatment aims to reduce the number of macrophages in tumour tissue. Originally developed by Roche, emactuzumab has shown encouraging results in clinical studies, with an objective response rate of around 71%, significant tumour shrinkage, and improvement in joint function. It also demonstrated good safety and tolerability.
SynOx Therapeutics is also exploring the potential of emactuzumab for other diseases that involve macrophage activity.
Source: globenewswire.com
