Safety and Biodistribution Evaluation in Cynomolgus Macaques of rAAV2tYF-PR1.7-hCNGB3, a Recombinant AAV Vector for Treatment of Achromatopsia

• Published in: Human gene therapy. Clinical development
• Main Authors: Ye, Guo-Jie, Budzynski, Ewa, Sonnentag, Peter, Nork, T Michael, Miller, Paul E, Sharma, Alok K, Ver Hoeve, James N, Smith, Leia, Arndt, Tara, Calcedo, Roberto, Gaskin, Chantelle, Robinson, Paulette, Knop, David R, Hauswirth, William W, Chulay, Jeffrey David
• Format: Journal Article
• Language: English
• Published: United States 08.03.2016
• ISSN: 2324-8645
• DOI: 10.1089/hum.2015.164

AGTC is developing rAAV2tYF-PR1.7-hCNGB3, a recombinant adeno-associated virus (rAAV) vector expressing the human CNGB3 gene, for treatment of achromatopsia, an inherited retinal disorder characterized by markedly reduced visual acuity, extreme light sensitivity and absence of color discrimination. We report here results of a study evaluating the safety and biodistribution of rAAV2tYF-PR1.7-hCNGB3 in cynomolgus macaques. Three groups of animals (n=2 males and 2 females per group) received a subretinal injection in one eye of 300 µL containing either vehicle or rAAV2tYF-PR1.7-hCNGB3 at one of two concentrations (4 × 1011 or 4 × 1012 vg/mL) and were evaluated over a 3 month period prior to being euthanized. Administration of rAAV2tYF-PR1.7-hCNGB3 was associated with a dose-related anterior and posterior segment inflammatory response that was greater than that observed in eyes injected with the vehicle control. Most manifestations of inflammation improved over time except that vitreous cells persisted in vector-treated eyes until the end of the study. One animal in the lower vector dose group was euthanized on Study Day 5 based on a clinical diagnosis of endophthalmitis. There were no test article-related effects on intraocular pressure, visual evoked potential responses, hematology or clinical chemistry parameters, or gross necropsy observations. Histopathological examination demonstrated minimal mononuclear infiltrates in all vector-injected eyes. Serum anti-AAV antibodies developed in all vector-injected animals. No animals developed antibodies to CNGB3. Biodistribution studies demonstrated high levels of vector DNA in the injected eye but minimal or no vector DNA in any other tissue. These results support the use of rAAV2tYF-PR1.7-hCNGB3 in clinical studies in patients with achromatopsia caused by CNGB3 mutations.