Eye On the Cure Research News

Jan 28, 2021

Improvements in Visual Sensitivity Reported for Some Participants in AGTC’s Achromatopsia Gene Therapy Clinical Trials

The company plans to enroll additional patients as young as four years old

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Applied Genetics Technologies Corporation (AGTC), a developer of gene therapies for rare diseases, reported improvements in visual sensitivity for some participants in its two Phase 1/2 gene therapy clinical trials for achromatopsia. One study is for people with mutations in the gene CNGB3. The other trial is for those with mutations in CNGA3. The company is planning to dose younger pediatric patients, as young as four years old, in addition to conducting brain imaging and color brightness tests.

Achromatopsia is a debilitating inherited retinal disease causing extreme light sensitivity, loss of color perception, and poor visual acuity. Approximately 28,000 people in the US and EU are affected by achromatopsia. Five genes, when mutated, can cause achromatopsia. About 75 percent of cases are caused by mutations in CNGB3 or CNGA3.

AGTC reported results for 26 participants across multiple dose groups in its gene therapy clinical trial for people with CNGB3 mutations. Visual sensitivity data was reported from 3 to 12 months after dosing. Seven of the 16 patients in the three highest dose groups in the CNGB3 trial showed improvements in visual sensitivity in the treated area, as measured by static perimetry, which measures retinal sensitivity at various regions in the visual field. No consistent results were seen in the other dose groups.

For its CNGA3 trial, AGTC reported results for 18 participants across multiple dose groups. Visual sensitivity data was reported from 2 to 12 months after dosing. Three patients in the four highest dose groups showed improvements in visual sensitivity. No consistent results were seen in other dose groups.

AGTC’s achromatopsia gene therapies are delivered through a one-time injection of a small drop of liquid underneath the retina. The injections contain healthy copies of CNGB3 or CNGA3 to augment the mutated copies.