SynOx Therapeutics Secures New Funding, Reaches $92M, and Begins Phase 3 Trial

Gilde Healthcare Leads Series B Extension for SynOx Therapeutics

In a significant development for the biopharmaceutical sector, SynOx Therapeutics Limited has successfully concluded the final phase of its Series B financing, amassing a total of $92 million. Gilde Healthcare spearheaded this extension, joining an elite group of existing investors including Forbion, HealthCap, and Bioqube Ventures. The primary utilization of these funds will be directed towards advancing the Phase 3 clinical trial of emactuzumab, a monoclonal antibody targeting the CSF-1 receptor, for the treatment of Tenosynovial Giant Cell Tumour (TGCT).

SynOx, a late-stage clinical biopharmaceutical company based in Dublin and Oxford, has already initiated the TANGENT trial, a crucial Phase 3 study evaluating emactuzumab's efficacy and safety in TGCT patients. The TANGENT study is a global, multi-centre, randomized, double-blind, placebo-controlled trial. The trial aims to measure the overall response rate (ORR) as its primary outcome while also considering secondary outcomes like functional and quality of life measurements, impact on tumour volume, and duration of response. The trial aims to enrol around 130 patients, with initial doses already administered.

TGCT is a rare, non-malignant tumour affecting the synovium in joints such as the knee, hip, and ankle, primarily driven by the overproduction of CSF-1. The condition is debilitating, leading to pain, stiffness, and restricted movement, significantly impacting patients' quality of life. Emactuzumab, which specifically inhibits the CSF-1 receptor, has shown promise in earlier clinical trials by demonstrating a high efficacy rate, rapid onset, and sustained response.

Ray Barlow, Ph.D., CEO of SynOx, expressed his excitement about the new investment and the commencement of the TANGENT trial. He emphasized the potential of emactuzumab to meet the unmet needs of TGCT patients and improve their quality of life. He also noted the dedication of the SynOx team in reaching this critical milestone.

As part of the Series B extension, Arthur Franken, a general partner at Gilde Healthcare, will join the SynOx Board of Directors. Franken brings over two decades of experience in venture and growth capital investment, including numerous public listings and trade sales. He expressed his optimism about emactuzumab's best-in-class profile as a CSF-1R targeted antibody and SynOx's capability to successfully complete its clinical development.

TGCT, previously known as pigmented villonodular synovitis (PVNS), affects the soft tissue lining of joints and tendons, leading to local destruction and aggressive tumour behaviour. The disease often necessitates surgical intervention, with a high recurrence rate post-surgery. If left untreated, TGCT can result in severe joint deformity, degenerative changes, and osteoarthritis, potentially leading to the need for joint fusion or even amputation.

CSF-1, or macrophage colony-stimulating factor, binds to receptors on macrophages and other cells, influencing their production, differentiation, and function. Emactuzumab, a humanized IgG1 antibody targeting CSF-1R, has demonstrated substantial tumour response rates (ORR ~71%) and good tolerability in clinical studies. Additionally, Phase I/II trials showed rapid and robust tumour reduction, clinical benefit, and durable response in TGCT patients.

SynOx is exploring the potential of emactuzumab in other macrophage-driven diseases, including graft-versus-host disease. The company is led by a seasoned team with a track record of developing and commercializing innovative therapeutics. Backed by premier life science investors like Forbion, HealthCap, Bioqube Ventures, Gilde Healthcare, and Medicxi, SynOx is well-positioned to advance its clinical programs and bring new treatment options to patients in need.