FDA Expedites Quince Therapeutics' Rare Ataxia Drug EryDex

The US Food and Drug Administration (FDA) has awarded fast track designation to Quince Therapeutics' Phase III drug candidate, EryDex, designed to treat the rare disease ataxia-telangiectasia (A-T). This status, which facilitates more frequent interactions with the FDA and the possibility of rolling reviews, aims to address the significant unmet medical needs of A-T patients.

Ataxia-telangiectasia is a rare disorder impacting the nervous and immune systems, leading to difficulties in motor movement and speech. EryDex makes use of autologous intracellular drug encapsulation (AIDE) technology. This method involves administering dexamethasone sodium phosphate (DSP) directly into a patient’s red blood cells. These DSP-loaded red blood cells are then reintroduced into the patient, enabling a slow release of steroids over several weeks. This process aims to mitigate the long-term toxicity often linked with chronic steroid usage.

In October 2023, the FDA lifted a partial clinical hold on EryDex, allowing it to advance into the Phase III NEAT study (NCT06193200). The hold was lifted following modifications to the single-use EryKit, which is part of the EryDex system, in order to meet recent European regulatory standards. The NEAT study will include approximately 86 children aged six to nine years as the main analysis group, with an additional 20 participants aged ten years and older. The participants will be randomly assigned to receive either EryDex or a placebo, with treatments administered through six infusions every 21 to 30 days. The primary efficacy measure will be the change from baseline to the final visit assessment on the rescored modified International Cooperative Ataxia Rating Scale (RmICARS).

Quince Therapeutics, a California-based biotech firm, acquired EryDex when it purchased EryDel for $485 million in July 2023. Previously known as Cortexyme, Quince refocused its efforts on rare diseases after facing several setbacks, including a clinical hold on its Alzheimer’s disease drug, atuzaginstat. The company’s name change occurred in 2022.

In an April 2024 business update, Quince indicated that it expects to report topline results from the Phase III NEAT study in the second half of 2025, with a potential New Drug Application (NDA) submission anticipated in 2026.

Quince CEO Dirk Thye remarked on the fast track designation, stating, “The granting of fast track status for the EryDex System marks another important milestone in our endeavour to identify a beneficial therapeutic solution for patients with A-T. We have initiated our pivotal Phase III NEAT clinical trial, which is being conducted in the US, UK, and the European Union.”

This development underscores Quince Therapeutics' commitment to advancing treatment options for rare diseases, particularly for those patients who currently have limited therapeutic options. The fast track designation by the FDA not only accelerates the development process but also brings hope to patients and families affected by A-T.