Treatment of Manifestations
For All Individuals with RPE65-LCA/EOSRD
Diet and micronutrients. Individuals with any type of inherited retinal dystrophy are advised to eat a healthy balanced diet to reach the minimum Reference Daily Intake (RDI) for nutrients, as recommended by the USDA (D Hoffman - Visions 2016). The RDI can include one to two servings of omega-3 fatty acid rich fish, as well as antioxidant- and lutein-rich foods such as dark green leafy vegetables. Docosahexaenoic acid (DHA) / eicosapentaenoic acid (EPA) supplements to 500 mg/day as well as lutein supplements to 10 mg/day can be considered if dietary intake is not sufficient.
Use of illumination devices. Due to poor night vision, patients are advised to use a flashlight for illumination.
Developmental Delay / Intellectual Disability Management Issues
Children with RPE65-LCA/EOSRD are usually of normal intellect, but may experience learning delays due to visual impairment. Those who have learning difficulties benefit from referral to a developmental pediatrician and enrollment in a continuing program of care and support.
Advice on learning / intellectual disability / educational issues will vary from country to country, or even region to region within a country, depending on support services available. Overarching principles should include the following:
Involving child development and educational specialists at the earliest available opportunity, often with specialist teachers/schools for the visually impaired
Early referral to low vision services to access low visual aids, especially with improving technologies, such as the refreshable Braille display
As patients grow older, identifying further assistance including financial and/or employment (available in some countries through certification/registration processes)
Registration with services to record population data on the causes and effects of visual impairment (available in some countries)
The following information represents typical management recommendations for individuals with developmental delay / intellectual disability / educational issues in the United States.
Ages 0-3 years. Referral to an early intervention program is recommended for access to occupational, physical, and speech, as well as infant mental health services, special educators and sensory impairment specialists. In the US, early intervention is a federally funded program available in all states that provides in-home services to target individual therapy needs.
Ages 3-5 years. In the US, developmental preschool through the local public school district is recommended. Before placement, an evaluation is made to determine needed services and therapies and an individualized education plan (IEP) is developed for those who qualify based on established motor, language, and social delay. The early intervention program typically assists with this transition. Developmental preschool is center-based; home-based services are provided as needed.
All ages. Consultation with a developmental pediatrician is recommended to ensure the involvement of appropriate community, state, and educational agencies (US) and to support parents. Some issues to consider:
Individualized education plan (IEP) services:
An IEP provides specially designed instruction and related services to children who qualify.
IEP services will be reviewed annually to determine if any changes are needed.
Special education law requires that children participating in an IEP be in the least restrictive environment feasible at school and included in general education as much as possible, when and where appropriate.
Vision and hearing consultants should be a part of the child's IEP team to support access to academic material.
PT, OT, and speech services will be provided in the IEP to the extent that the need affects the child's access to academic material. Beyond that, private supportive therapies based on the affected individual's needs may be considered. Specific recommendations regarding type of therapy can be made by a developmental pediatrician.
As a child enters teen years, a transition plan should be discussed and incorporated in the IEP. For those receiving IEP services, the public school district is required to provide services until age 21.
A 504 plan (Section 504: a US federal statute that prohibits discrimination based on disability) can be considered for those who require accommodations or modifications such as front-of-class seating, assistive technology devices, classroom scribes, extra time between classes, modified assignments, and enlarged text.
Developmental Disabilities Administration (DDA) enrollment is recommended. DDA is a public agency that provides services and support to qualified individuals. Eligibility differs by state but is typically determined by diagnosis and/or associated cognitive/adaptive disabilities.
Families with limited income and resources may also qualify for supplemental security income (SSI) for their child with a disability.
Social/Behavioral Concerns
Children who are legally blind may have difficulty integrating and socializing with peers in school. Children may qualify for and benefit from interventions used in treatment of autism spectrum disorder, including applied behavior analysis (ABA). ABA therapy is targeted to the individual child's behavioral, social, and adaptive strengths and weaknesses and is typically performed one on one with a board-certified behavior analyst.
Consultation with a developmental pediatrician may be helpful in guiding parents through appropriate behavior management strategies or providing prescription medications, such as medication used to treat attention-deficit/hyperactivity disorder (ADHD), when necessary.
Subretinal Gene Supplementation Therapy
Rationale. RPE65-LCA/EOSRD subretinal gene supplementation therapy does not replace the native gene (which may still have some function), but provides a functional copy of the gene using recombinant adeno-associated virus (AAV) vectors to the cells that produce the RPE65 protein product. In this way, the functional copy of the gene compensates for the loss-of-function RPE65 pathogenic variants, increases the amount of the protein product, and improves vision. Using standard vitreoretinal surgical techniques, the AAV vectors are injected in each eye one time only subretinally (i.e., under the retina) in the foveal region (i.e., the cone-rich portion of the retina that mediates central vision).
Data supporting the utility of gene supplementation therapy
Availability of gene supplementation therapy. Currently the recombinant AAV vectors are only:
Requirements for consideration of subretinal gene supplementation therapy
Third-party payor issues regarding eligibility for payment of subretinal gene supplementation therapy
Meeting eligibility requirements for treatment
Prior authorization from the third party payer to approve coverage of this treatment
Determination of the amount of the cost covered by the third party payor versus the amount covered by the patient / patient's family
Therapies Under Investigation
Clinical investigations of variations of the FDA-approved gene replacement therapy treatment for RPE65-LCA/EOSRD (i.e., subretinal injection of an AAV2 vector expressing full-length RPE65 protein) are underway. One is a Phase I/IIb clinical trial (NCT02781480) of an AAV2 vector with an AAV5 capsid (AAV2/5) with a codon-optimized RPE65 driven under an RPE-specific promoter (which has shown increased RPE65 expression compared to previous vectors in mice) [Georgiadis et al 2016].
Oral retinoid supplementation is being investigated as a possible replacement for the enzyme product of RPE65. The dramatic therapeutic efficacy of oral 9-cis retinoid supplementation in Rpe65-deficient mice demonstrated proof of concept [Van Hooser et al 2000, Van Hooser et al 2002]. Of note, 9-cis retinal was used instead of 11-cis retinal, which is very unstable and, therefore, not suitable for pharmaceutical development; furthermore, 9-cis retinal binds with iso-rhodopsin, which is also capable of phototransduction.
A Phase I clinical trial was conducted using oral supplementation of QLT091001 (synthetic 9-cis retinal acetate) for one week in 14 patients with either RPE65- associated LCA (n=7) or LRAT-associated LCA (n=7) [Koenekoop et al 2014]. The drug was well tolerated and, in a majority of patients, visual acuity and Goldmann visual field testing were improved. In six of the 14 patients these improvements persisted for more than one year following a single one-week treatment.
In a Phase Ib follow-up multicenter trial, 18 patients with either RPE65-associated LCA (n=13) or LRAT-associated-LCA (n=5) received oral supplementation with QLT091001 for one week [Scholl et al 2015]. Results were consistent with the previous Phase I study: the majority of patients demonstrated visual improvement in the first two months. In addition, treatment responders had significantly longer photoreceptor outer segment lengths as measured by OCT compared to non-responders, suggesting that intact photoreceptor integrity may predict response to treatment. Note that acute, retina-wide improvements in rod-mediated function have been also documented in patients following this treatment [Jacobson et al 2015a]. Reversible side effects were frequent and included headache, fatigue, photophobia, photopsia, erythema, flushing, nausea and vomiting, elevations in triglyceride, LDL, cholesterol, AST and ALT levels, and reductions in HDL and thyroxine levels. Intracranial hypertension, a known class-effect of retinoids, was also reported.
A Phase III trial for this oral retinoid is being planned. In addition to potentially serving as a monotherapy for inherited retinal diseases with defects in the visual cycle, this oral retinoid could also be combined with gene therapy to provide a potentially synergistic effect.
Search ClinicalTrials.gov in the US and EU Clinical Trials Register in Europe for access to information on clinical studies for a wide range of diseases and conditions. Note: There may not be clinical trials for this disorder.