NeoVista Epi-Retinal Strontium 90 Treatment for AMD: Update 3
Posted Oct 01 2008 5:07pm
During the 2008 Retina Society Meeting, held last weekend, NeoVista, Inc. provided eighteen-month data from its Phase II feasability study of the company’s novel beta radiation epi-retinal therapy for the treatment of the wet form of age-related macular degeneration (AMD). The long-term data from the study, which was initiated to test the safety and efficacy of their therapy when used in conjunction with Avastin (bevacizumab), showed a marked advancement in mean visual acuity results at month 18, while only a limited number of patients required additional injections of Avastin.
The data were presented at the Retina Society Meeting by Nelson R. Sabates, MD, Professor and Chairman, Department of Ophthalmology, University of Missouri-Kansas City (UMKC) School of Medicine and the lead investigator in NeoVista's ongoing Phase III study, CABERNET (CNV Secondary to AMD Treated with BEta RadiatioN Epiretinal Therapy).
"The data released demonstrate that NeoVista's concomitant approach has the potential to offer patients a less frequent treatment option that is just as effective, if not more effective, than the current standard of care," said Dr. Sabates. "It's highly encouraging to continually see patient outcomes improving as the study progresses."
"We're very delighted with the latest data from our Phase II study, as not only did the visual acuity improve in our patients over the long-term, but very few patients received additional injections as well," said John N. Hendrick, President and CEO of NeoVista. "The ultimate pledge of this therapy continues to be demonstrated as the long-term data hold promise in minimizing the treatment burden both for patients and physicians, not to mention the overall financial burden for the healthcare system."
NeoVista's revolutionary therapy applies a targeted dose of beta radiation to the leaking blood vessels that affect central vision; concomitantly, two injections of an anti-vascular endothelial growth factor (anti-VEGF) agent are delivered to maximize the acute therapeutic response. Preliminary data show that NeoVista's targeted radiation therapy can be safe for both the patient and the physician, and may be able to restore the patient's vision. The current standard of care for wet AMD requires persistent injections of anti-VEGF drugs for an indefinite period.
The ongoing multicenter feasibility study enrolled 34 trial participants (with a mean age of 72 years) from June 2006 to April 2007 at two centers in Brazil and one in Mexico. These patients, with predominantly classic, minimally classic, or occult (with no classic) choroidal neovascularization (CNV), received a single 24 Gy treatment of NeoVista's epiretinal brachytherapy in combination with two intravitreal injections of Avastin, one dose prior to or at the time of radiation delivery and another one month later, depending on which arm of the trial the patient was enrolled in. Additional therapy was delivered based upon the investigator's evaluation of disease activity.
Analysis of 18-month follow-up on the first 25 trial participants to reach that milestone, as shown in Graph 1 below, shows a mean improvement in visual acuity of 10.7 letters using the Early Treatment Diabetic Retinopathy Study (ETDRS) test; 96 percent of patients lost 15 letters or fewer, 76 percent gained some letters, 44 percent gained 15 or more letters, and 8 percent gained 30 or more letters. Of particular interest, 68 percent of the patients in the study did not require additional injections of Avastin throughout the 18-month period and the average number of additional injections within this subset was only 2.4 injections by month 18.
The visual acuity data after 18 months compares favorably with the results reported after 12 months, as shown in Graph 2 below. (This graph compares the Epi-Rad treatment without Avastin (purple color), with Epi-Rad plus Avastin (blue color) and the Marina (green) and Anchor (red) studies, which both used Lucentis.)
Most of the limited number of adverse events were related to the vitrectomy procedure (retinal tear, retinal detachment, subretinal hemorrhage, and vitreous hemorrhage), rather than the epiretinal brachytherapy. To date, no instances of radiation toxicity have been reported by the Doheny reading center.
In contrast to other forms of radiation therapy for wet AMD, NeoVista's approach delivers the peak dose of energy directly to the lesion without damaging the normal retinal vasculature. Utilizing strontium 90, the focused energy is delivered to a target area up to 3 mm in depth and up to 5.4 mm in diameter. Importantly for patients, the systemic exposure to radiation is minimal, as the effective dose to the entire body from NeoVista's epiretinal device is less than that from a typical chest x-ray.
With the continued promise of these Phase II trial results, NeoVista continues to enroll patients in the company's pivotal trial, CABERNET. CABERNET is a multicenter, randomized, controlled study that will enroll 450 subjects at 45 sites worldwide, evaluating the safety and efficacy of NeoVista's epiretinal brachytherapy delivered concomitantly with the FDA-approved anti-VEGF therapy Lucentis (ranibizumab) versus Lucentis alone.