Quince Therapeutics Announces Lancet Neurology Publication of Phase 3 EryDex Trial Data for A-T Treatment

Quince Therapeutics, Inc. (Nasdaq: QNCX), a biotechnology company focusing on treating rare diseases, has announced the online publication of data in The Lancet Neurology from its Phase 3 ATTeST clinical trial. This trial evaluates the safety and efficacy of EryDex, a treatment for Ataxia-Telangiectasia (A-T), a rare pediatric disease with no approved treatments.

Dirk Thye, M.D., CEO and Chief Medical Officer of Quince, expressed optimism about the study's findings, which highlight the potential of EryDex in addressing the unmet needs of A-T patients. The ongoing pivotal Phase 3 study focuses on patients aged six to nine years, who experience rapid clinical decline, and includes participants aged ten and older.

The Lancet Neurology publication, titled "Safety and efficacy of intra-erythrocyte dexamethasone sodium phosphate in children with ataxia-telangiectasia (ATTeST): a multicenter, randomized, double-blind, placebo-controlled phase 3 trial," presents significant insights from the trial. Key highlights include:

The ATTeST trial, the largest of its kind for A-T, involved 175 participants across 22 institutions in 12 countries on five continents. This randomized, double-blind, placebo-controlled Phase 3 trial explored two doses of EryDex compared to placebo concerning neurological symptoms in A-T patients.

After six months of EryDex treatment, no serious safety concerns usually linked to chronic corticosteroid use were observed. There were no instances of hyperglycemia, hypertension, hirsutism, or cushingoid appearance.

The primary efficacy endpoint was measured through changes in the modified International Cooperative Ataxia Rating Scale (mICARS) from baseline to six months, assessing posture, gait, kinetic functions, and speech. Higher scores indicate a greater burden of neurological symptoms.

Patients receiving high-dose EryDex showed a reduction in neurological symptoms, with a -1.40 change in mICARS compared to the placebo, though this result was not statistically significant. However, a statistically significant -2.2 change in mICARS was observed in the per-protocol population.

A subgroup analysis by age revealed a significant reduction in neurological symptoms for patients aged six to nine receiving high-dose EryDex, with a -2.8 and -4.4 change in mICARS in the modified intent-to-treat (mITT) and per-protocol populations, respectively.

The overall treatment effect might have been impacted by treatment delays and omissions, partly due to travel difficulties and the COVID-19 pandemic. In the mITT population, 35% did not receive the planned treatment due to these factors.

Dr. William Whitehouse from the University of Nottingham highlighted the promising clinical data, which suggest progress towards a treatment option for A-T patients, a disorder marked by neurological decline, impaired motor control, speech difficulties, and a reduced life expectancy.

Quince is currently enrolling participants for the Phase 3 NEAT study, a global, multi-center, randomized, double-blind, placebo-controlled trial evaluating EryDex's effects on A-T patients. The study plans to enroll about 86 patients aged six to nine and approximately 20 patients aged ten or older. Seven participants have enrolled so far. The NEAT trial is conducted under a Special Protocol Assessment (SPA) agreement with the U.S. FDA, with topline results expected in the fourth quarter of 2025 and potential regulatory submissions in 2026, provided the results are positive. The FDA has granted Fast Track designation to EryDex for its potential to address significant unmet medical needs in A-T patients.

Ataxia-Telangiectasia (A-T) is a rare, inherited neurodegenerative and immunodeficiency disorder caused by mutations in the ATM gene. A-T patients typically experience progressive neurological decline, frequent infections, pulmonary impairment, and malignancies, with a median lifespan of 25 to 30 years. There are currently no approved treatments for A-T globally.

EryDex consists of dexamethasone sodium phosphate encapsulated in a patient's red blood cells, offering the benefits of corticosteroids while minimizing adverse effects. This innovative approach utilizes Quince's Autologous Intracellular Drug Encapsulation (AIDE) technology, which aims to enhance drug delivery and reduce toxicity.

Quince Therapeutics is committed to developing treatments for rare diseases by leveraging the body's own biology. The company’s ongoing research and development efforts aim to bring new therapeutic options to patients with unmet medical needs.