Quince Therapeutics, Inc. (Nasdaq: QNCX), a late-stage biotechnology company focused on using patients’ own biology to treat rare diseases, presented safety data from its Phase 3 ATTeST (Ataxia-Telangiectasia Trial with the EryDex SysTem) clinical trial at the 53rd Child Neurology Society (CNS) Annual Meeting. The analysis evaluated treatment-emergent adverse events (TEAEs) in children with Ataxia-Telangiectasia (A-T) treated with EryDex (intra-erythrocyte dexamethasone sodium phosphate) for one year, compared to a placebo group.
Key findings presented in the poster titled Treatment-Emergent Adverse Events (TEAEs) in Children With Ataxia-Telangiectasia Treated for One Year With Intra-Erythrocyte Dexamethasone Sodium Phosphate (EryDex) include:
- EryDex treatment was generally well-tolerated: Most TEAEs were mild to moderate, transient, and similar between EryDex- and placebo-treated patients.
- No steroid-related side effects: Typical side effects of chronic steroid use, such as Cushingoid features, hyperglycemia, hirsutism, and hypertension, were not observed.
- Discontinuations: Three patients were discontinued: one from the low-dose group due to a serious adverse event (SAE) of B-cell lymphoma (unlikely to be treatment-related) and two from the high-dose group with TEAEs of pyrexia, tachycardia, pain, and pruritus (one event likely treatment-related).
- No TEAEs leading to death: There were no reported fatalities due to treatment.
Dr. Dirk Thye, CEO and CMO of Quince, commented, “The safety results from the ATTeST study suggest that EryDex may be a promising treatment option for A-T patients. These findings, combined with the promising efficacy data, support our ongoing Phase 3 NEAT study, and we are excited to continue evaluating EryDex as a potential treatment for patients with chronic steroid use needs.”
Phase 3 NEAT Trial
Quince is currently conducting the pivotal Phase 3 NEAT (Neurologic Effects of EryDex on Subjects with A-T) clinical trial (#IEDAT-04-2022/NCT06193200). The international, multi-center, randomized, double-blind, placebo-controlled trial is designed to assess the neurological effects of EryDex in children with A-T. The trial is enrolling about 86 children aged 6-9 years (primary analysis population) and 20 patients aged 10 or older.
The NEAT trial is being conducted under a Special Protocol Assessment (SPA) agreement with the U.S. FDA. Quince expects topline results by the fourth quarter of 2025, with a potential New Drug Application (NDA) submission to the FDA and a Marketing Authorization Application (MAA) to the European Medicines Agency (EMA) in 2026, assuming positive results. Additionally, EryDex has received Fast Track designation from the FDA for its potential to address the high unmet need in A-T.
About Ataxia-Telangiectasia (A-T)
A-T is a rare, inherited neurodegenerative disorder caused by mutations in the ATM gene, responsible for DNA repair and cell division. Symptoms typically appear before age 5, with children experiencing gait abnormalities and frequent falls. As the disease progresses, A-T patients often become wheelchair-bound and face repeated infections, pulmonary impairment, and malignancies. The median life expectancy for those with A-T is 25-30 years, with death often resulting from infections or cancer. Approximately 4,600 people in the U.S. and 5,000 people in the U.K. and EU4 are affected by A-T, yet no approved treatments exist.
About EryDex for A-T
The EryDex System is a drug/device combination product designed to administer dexamethasone sodium phosphate (DSP) encapsulated in a patient’s own red blood cells. DSP is a corticosteroid with potent anti-inflammatory properties but significant toxicity when used chronically. The EryDex System aims to deliver the benefits of corticosteroids while reducing their adverse effects, such as immune suppression and poor biodistribution.
EryDex leverages Quince’s Autologous Intracellular Drug Encapsulation (AIDE) technology, which uses red blood cells as a vehicle to deliver drugs more safely and efficiently. The AIDE platform is designed to enhance drug delivery, improve tolerability, and extend the circulating half-life of treatments, potentially enabling chronic use of drugs that would otherwise have dose-limiting toxicity.
