Quince Therapeutics has announced the publication of long-term safety data for EryDex in pediatric patients with Ataxia-Telangiectasia (A-T). The data, published in Frontiers in Neurology, covers patients treated with EryDex for a minimum of 24 months.
The analysis included data from a Phase 3 clinical trial (ATTeST) and an open-label extension study, highlighting the potential of EryDex to deliver dexamethasone sodium phosphate without the debilitating toxicities often seen with standard corticosteroid treatments.
Long-Term Safety Data
The Frontiers in Neurology publication details the safety of EryDex in treating pediatric A-T patients over an extended period. Key highlights from the publication include:
- EryDex aims to mitigate chronic steroid toxicity while maintaining efficacy through the encapsulation of dexamethasone sodium phosphate (DSP) in autologous erythrocytes.
- The most common treatment-related adverse event was transient infusion-related pruritus, a common steroid side effect, and low serum iron levels, which did not lead to negative clinical outcomes.
- Adverse events typically associated with prolonged glucocorticoid use, such as Cushingoid features, weight gain, hypertension, hirsutism, diabetes, or stunted growth, were infrequently reported over 24 to 61 months of dosing.
- A decline in bone mineral density (BMD) of 0.4 z scores was observed over two years, which was indistinguishable from the natural course of the disease in A-T patients.
- No adverse effects on height, weight, and body mass index were reported, with stable z-scores throughout the two years of treatment.
- Values for glucose, HbA1c, cortisol, and CD4+ lymphocyte counts did not show clinically significant changes during prolonged EryDex treatment.
Ongoing Phase 3 NEAT Trial
Quince Therapeutics is currently enrolling patients in the pivotal Phase 3 NEAT clinical trial (NCT06193200), an international, multi-center, randomized, double-blind, placebo-controlled study. The trial is evaluating the neurological effects of EryDex in A-T patients. The company plans to enroll approximately 86 patients with A-T ages six to nine years old (primary analysis population) and approximately 20 patients with A-T ages 10 years or older.
The Phase 3 NEAT trial is being conducted under a Special Protocol Assessment (SPA) agreement with the FDA. Topline results are expected in the fourth quarter of 2025, with potential NDA submission to the FDA and MAA submission to the EMA in 2026, assuming positive study results. The FDA has granted Fast Track designation for EryDex in A-T treatment, underscoring its potential to address a high unmet medical need.
About Ataxia-Telangiectasia
A-T is an inherited autosomal recessive neurodegenerative and immunodeficiency disorder caused by mutations in the ATM gene, affecting cell homeostasis and DNA repair. It is typically diagnosed before age five, with symptoms including altered gait and frequent falls. Neurological symptoms worsen, often leading to wheelchair dependence by adolescence. The median lifespan is approximately 25 to 30 years, with mortality due to infections and malignancy. There are currently no approved therapeutic treatments for A-T in any global market.
About EryDex
EryDex consists of dexamethasone sodium phosphate (DSP) encapsulated in a patient’s own red blood cells (autologous erythrocytes). The EryDex System aims to provide the efficacy of corticosteroids while reducing or eliminating the significant adverse effects associated with chronic corticosteroid use. The treatment leverages Quince’s Autologous Intracellular Drug Encapsulation (AIDE) technology platform.
