Quince Therapeutics has disclosed outcomes from the Phase III ATTeST clinical trial of EryDex (dexamethasone sodium phosphate encapsulated in autologous erythrocytes) for treating Ataxia-Telangiectasia (A-T), a rare paediatric disease.

The randomised, double-blind, placebo-controlled trial involved 175 participants enrolled across 22 academic institutions and medical centres spanning five continents and 12 countries.

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It compared the safety and efficacy of two dose levels of EryDex against a placebo, focusing on the neurological symptoms in A-T patients.

This study revealed that after six months of treatment with EryDex, patients did not exhibit serious safety concerns typically linked with chronic corticosteroid use.

Notably, there were no instances of hyperglycaemia, hypertension, hirsutism or cushingoid appearance in any treatment group.

The primary efficacy endpoint was the change in the modified International Cooperative Ataxia Rating Scale (mICARS) from baseline to month six, comparing the active and placebo control groups.

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Patients receiving a high dose of EryDex experienced a reduction in neurological symptoms, with a -1.40 change in mICARS compared with the placebo group.

Although this result was not statistically significant, with a nominal p-value of 0.077, the per-protocol population that received a high dose of EryDex showed a statistically significant -2.2 change in mICARS and a nominal p-value of 0.019.

A pre-specified subgroup analysis by age indicated a statistically significant reduction in neurological symptoms in patients aged six to nine years receiving high-dose EryDex.

Quince CEO and chief medical officer Dirk Thye said: “The results of this study demonstrate the encouraging efficacy and safety profile of our lead asset, EryDex, for the treatment of patients with A-T, a rare paediatric disease with vast unmet need and no approved treatments.

“These findings provide us with additional confidence in our pivotal Phase III study of EryDex now under way with a primary analysis population comprised of patients with A-T experiencing the most rapid clinical decline, children ages six to nine, in addition to including participants who are ten years of age or older.”

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