AGTC And The Medical College of Wisconsin Announce Publication Of Natural History Study Data Evaluating Residual Photoreceptor Cone Status In Patients With CNGB3-Associated Achromatopsia
GAINESVILLE, Fla., and CAMBRIDGE, Mass., Aug. 02, 2016 (GLOBE NEWSWIRE) -- Applied Genetic Technologies Corporation (Nasdaq:AGTC), a biotechnology company conducting human clinical trials of adeno-associated virus (AAV)-based gene therapies for the treatment of rare diseases, and the Medical College of Wisconsin (MCW) today announced the publication of data from studies evaluating the density of cone photoreceptors in patients with CNGB3-associated achromatopsia (ACHM). The peer-reviewed study results appear in the current issue of Investigative Ophthalmology and Visual Science.
“Patients living with achromatopsia today have no effective treatment options, but a growing body of evidence suggests that emerging gene therapies may have significant potential,” said Joseph Carroll, PhD, Richard Schultz, MD/Ruth Works Professor in Ophthalmology, professor of ophthalmology & visual sciences, biophysics, and cell biology, neurobiology and anatomy, and co-director of the Advanced Ocular Imaging Program, MCW. “Current data show significant variation in the degree of residual cone photoreceptor structure among patients with CNGB3-associated ACHM. As such, imaging tools that can accurately quantify the remaining cone population may aid in selecting patients who are most likely to benefit from gene therapy clinical trials and expedite the development of new therapies.”
Previous studies of gene-based therapies in animal models of ACHM have shown that the presence of viable cone photoreceptors is required for restoration of cone function. The current multi-center natural history study, conducted by researchers at MCW, the University of Alexandria in Egypt, Oregon Health & Science University, The Chicago Lighthouse, the University of Miami and the University of Florida, was designed to evaluate residual cone structures in patients with ACHM resulting from CNGB3 mutations. AGTC's clinical program for achromatopsia caused by mutations in the CNGB3 gene continues enrollment, and the company is on track to release interim data in 2016. Additional information on the study is available at ClinicalTrials.gov.
Researchers used high-resolution imaging (optical coherence tomography [OCT]) and adaptive optics scanning light ophthalmoscopy (AOSLO) at MCW to evaluate peak cone density, inter-cone spacing, foveal outer nuclear layer thickness and photoreceptor layer integrity in 51 patients with CNGB3-associated ACHM. Analyzable images were obtained in 26 of the 51 patients, with nystagmus (repetitive uncontrolled eye movement) the major obstacle to obtaining high-quality images in the remaining subjects.
Peak foveal cone density ranged from 7,273 to 53,554 cones/mm2, which is significantly lower than normal (ranging from 84,733 to 234,391 cones/mm2). Results also show that these cones may occur contiguously or be sparsely arranged within the fovea. Cones were less evenly spaced and generally sparser in patients in the ACHM group compared with six normal subjects. The data also show that the ACHM patients had significantly thinner outer nuclear layers (ONL) compared with previously reported normal values (p <0.0001).
Statistical analyses of OCT measurements, a method for examining retinal structure in vivo, found significant differences in peak cone density when comparing OCT grade I to grade II (p = 0.0143) and grade I to grade IV (p = 0.0022). Differences in ONL thickness as a function of OCT grade were also observed between grade I and II (p = 0.0289) and grade I and IV (p = 0.0096). Consistent with suggestions that ACHM is a progressive disease, a significant association was observed between age and OCT grade, with grades II, IV and V differing from grade I (p=0.018, 0.0155, and 0.0205, respectively). Grade III results not included in these analyses due to sample size restrictions.
Study researchers concluded that residual foveal cone structure varies greatly among patients with CNGB3-associated ACHM. Additionally, the use of split-detection AOSLO, which allows noninvasive imaging of rods and cones with cellular resolution, may be an important tool for evaluating residual cone structure in patients with ACHM and other retinal diseases. The authors noted that cellular resolution imaging will become an important tool for patient selection, monitoring and evaluation in future clinical trials.
“AGTC is committed to developing innovative AAV-based gene therapies to treat achromatopsia and other inherited diseases without adequate treatment options,” said study co-author Jeffrey D. Chulay, M.D., DTM&H, Vice President and Chief Medical Officer at AGTC. “The development of tools that can help assess individual patient status will be important for helping patients and physicians make informed decisions about the risks and benefits of enrolling in gene therapy clinical trials for ACHM. We believe the results of this study will help to enhance the design and recruitment of current and planned clinical trials to evaluate AGTC’s gene-based therapies for achromatopsia resulting from CNGB3 mutations.”
AGTC is a clinical-stage biotechnology company that uses its proprietary gene therapy platform to develop products designed to transform the lives of patients with severe diseases, with an initial focus in ophthalmology. AGTC's lead product candidates are designed to treat inherited orphan diseases of the eye, caused by mutations in single genes that significantly affect visual function and currently lack effective medical treatments.
AGTC's product pipeline includes six named ophthalmology development programs across five targets (X-linked retinoschisis (XLRS), X-linked retinitis pigmentosa (XLRP), achromatopsia, wet age-related macular degeneration and blue cone monochromacy), two non-ophthalmology programs (alpha-1 antitrypsin deficiency and adrenoleukodystrophy) and AGTC is continuing to develop early research studies in additional indications. The company is also exploring genetic defects in cells in the inner ear that lead to deafness and expects to advance several product candidates into development within the next few years. AGTC employs a highly targeted approach to selecting and designing its product candidates, choosing to develop therapies for indications having high unmet medical need, clinical feasibility and commercial potential. AGTC has a significant intellectual property portfolio and extensive expertise in the design of gene therapy products including capsids, promoters and expression cassettes, as well as, expertise in the formulation, manufacture and physical delivery of gene therapy products.
For information about currently enrolling clinical trials, please visit agtc.com/patients-and-caregivers.
Forward Looking Statements
This release contains forward-looking statements that reflect AGTC's plans, estimates, assumptions and beliefs. These statements relate to a variety of matters, including but not limited to, the anticipated utility of AAV vectors made using AGTC's proprietary manufacturing method in the treatment of various therapeutic indications. Forward-looking statements include all statements that are not historical facts and can be identified by terms such as "anticipates," "believes," "could," "seeks," "estimates," "expects," "intends," "may," "plans," "potential," "predicts," "projects," "should," "will," "would" or similar expressions and the negatives of those terms. Actual results could differ materially from those discussed in the forward-looking statements, due to a number of important factors, which include, but are not limited to, the following: no gene therapy products have been approved in the United States and AGTC cannot predict when or if it will obtain regulatory approval to commercialize a product candidate; AGTC relies on third parties to conduct research, conduct, supervise and monitor its clinical trials and to conduct certain aspects of its product manufacturing and protocol development; and increased regulatory scrutiny of gene therapy and genetic research could damage public perception of AGTC's product candidates or adversely affect AGTC's ability to conduct its business. Additional factors that could cause actual results to differ materially from those described in the forward-looking statements are set forth under the heading "Item 1A—Risk Factors" in AGTC's Annual Report on Form 10-K for the fiscal year ended June 30, 2015, as filed with the SEC. Given these uncertainties, you should not place undue reliance on these forward-looking statements. Also, forward-looking statements represent management's plans, estimates, assumptions and beliefs only as of the date of this release. Except as required by law, AGTC assumes no obligation to update these forward-looking statements publicly or to update the reasons actual results could differ materially from those anticipated in these forward-looking statements, even if new information becomes available in the future.
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