Safety and Efficacy of a Single Subretinal Injection of rAAV.hCNGA3 in Patients With CNGA3-linked Achromatopsia

Title: Safety and efficacy of a single subretinal injection of rAAV.hCNGA3 in patients with CNGA3-linked achromatopsia investigated in an exploratory, dose-escalation trial

Phase: I/II

Indication: CNGA3-linked achromatopsia

Aim: To proof the safety and efficacy of rAAV.hCNGA3 in patients with achromatopsia

Study design: open, mono-center trial with fellow-eye comparison

Study Population:

Inclusion Criteria (Study Eye)

• clinical diagnosis of achromatopsia
• ≥ 18 years of age
• confirmed mutation in CNGA3
• BCVA ≥ 20/400
• a minimal outer nuclear layer thickness of 10µm at 3° eccentricity in the study eye (normal = 38±6µm)
• ability to understand and willingness to consent to study protocol
• no infection with Human Immunodeficiency Virus (HIV)
• negative pregnancy test in women with childbearing potential (a woman who is two years post-menopausal or surgically sterile is not considered to be of childbearing potential)

Exclusion Criteria

• additional interfering eye conditions (e.g. uveitis, advanced cataract) in the study eye
• systemic conditions (e.g. coronary heart disease, autoimmune disorders) which may affect study participation or outcome measures
• current or recent participation in other study/or administration of biologic agent within the last three months
• recent (6 months) ocular surgery, intravitreal or subretinal implantation of a medical device
• known sensitivity to any compound used in the study
• contraindications to systemic immunosuppression
• subject/partner of childbearing potential unwilling to use adequate contraception for four months
• nursing or pregnant women
• any other cause that, in the investigator's opinion, renders potential subjects not suitable for the study
• mutations in another achromatopsia gene
• contraindications in view of the planned surgery (e.g. anaemia Hb<8g/dl, severe coagulopathy, severe blood pressure fluctuations)
• ocular opacity and mature cataract
• history of ocular malignancies
• disorders of the internal retina (e.g. retinal detachment in the patients history)
• glaucoma defined as damage of the optic nerve
• vascular retinal occlusion
• diabetic patients suffering from retinopathy and/or macula edema
• patients treated with oral corticoids within 14 days prior inclusion
• systemic illness or medically significant abnormal laboratory values in blood analysis including renal and hepatic functions at inclusion
• absence of vision on the other contralateral eye

Patient Number: Nine patients will be assigned to three cohorts of three patients respectively.

Treatment:

Each cohort will receive a different, increasing dosage of viral vector genome particles. Three cohorts of patients are planned with low, medium and high dose administration levels up to 1x10e11 of rAAV8 incorporating the therapeutic expression cassette.

After standard three-port 23G pars plana vitrectomy, balanced salt solution will be used to induce a localized primary retinal detachment in a controlled fashion. Vector solution will be applied using disposable 41G extendible subretinal injection needles within a standard 23G body to fit the port system. Administration will be unilateral (worse eye) in each patient.

Primary Endpoint: Safety as the primary endpoint will be assessed by clinical examination of ocular inflammation (slit lamp, fundus biomicroscopy, angiography, perimetry or electrophysiology). Systemic safety will be assessed by vital signs, routine clinical chemistry testing (including C reactive proteine, ESR) and full/differential blood counts. Immunopathology essays will include specific enzyme-linked immunosorbent assays for humoral antibodies against rAAV8 capsid protein and/or CNGA3 gene product and specific enzyme-linked immunosorbent spot assays to monitor cellular immune reactivity against rAAV8 capsid protein and/or CNGA3 gene product. Biodistribution will be monitored by polymerase chain reaction studies on rAAV8 genome in blood, urine, saliva and lachrymal fluid.

Statistical Methods: Adverse Events and Serious Adverse Events will be documented using line listings and tabulations (MetraCad code will be applied). Descriptive analysis will include line charts for individual patients. Standard errors and means will also be displayed using line charts. This will be done for the raw measurements and for the difference between treated and untreated control eye within each patient.

Descriptive parameters will be given for the full cohort (n=9) but not for the sub-cohorts (n=3). Additionally correlation analysis will be performed in a purely descriptive manner for the comparison of subjective and objective measurements. For each subject and measurement, the delta of the value for the interventional eye minus the mean of control eye values over time will be determined. In scatter plots for pairs of variables (measurements pooled over subjects) the association between these deltas will be displayed.

Time Schedule: Start of trial November 2015, end of recruitment November 2016, end of trial November 2017, duration of trial per patient: one year with four years of follow-up.