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Avastin promising as anti-VEGF approach to AMD, early results show
Treatment with a drug approved for colon cancer may be sufficient in some neovascular AMD patients.
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MONTREAL – An initial course of intravenous bevacizumab may be sufficient in some patients as a treatment for subfoveal choroidal neovascularization in age-related macular degeneration, according to one clinician speaking here.
Andrew A. Moshfeghi, MD, of the Bascom Palmer Eye Institute, reported the 6-month efficacy results of 18 patients treated with systemic Avastin (bevacizumab, Genentech), a humanized monoclonal antibody with anti-VEGF binding characteristics. Avastin is the first anti-angiogenic therapy approved in the United States for the treatment of cancer, and is currently marketed for the treatment of metastatic colorectal cancer.
An open-label, single-center, uncontrolled clinical study was conducted at the Bascom Palmer Eye Institute to evaluate the short-term safety of intravenous Avastin and its effects on visual acuity in 18 patients with CNV secondary to AMD. Improvements were observed in mean visual acuity letter scores, central retinal thickness measurements by optical coherence tomography and leakage from CNV by fluorescein angiography. Mild, easily controlled hypertension was observed by the 3-month follow-up point, according to the researchers. However, the study was not powered to identify frequent serious adverse events with rates as high as 10%.
Patient selection, methods
Patients were included in the study if they had subfoveal CNV and a baseline visual acuity of 20/40 to 20/400, Dr. Moshfeghi said. Patients had to be at least 50 years old with a baseline diagnosis of subfoveal CNV. In addition, all patients were either ineligible for Visudyne (verteporfin for injection, QLT/Novartis) photodynamic therapy or refused PDT.
All patients were treated with an initial course of two or three infusions of Avastin (5 mg/kg) at 2-week intervals. Follow-up visits were every week for the first 6 weeks, every 2 weeks for the following 6 weeks, and every 4 weeks after that. Initial treatment was stopped after the second or third infusion, Dr. Moshfeghi said here at the American Society of Retina Specialists meeting.
“The question we posed for this portion of the study was: After the initial two or three infusions, are additional treatments necessary?” he said. “And if so, would these re-treatments produce similar results to those seen after the initial therapy?”
Of primary importance in this study, Dr. Moshfeghi said, was to determine “the durability of a single re-treatment.”
“Patients were re-treated if there was a loss of five letters observed [associated with leakage], or if there were an increase in central retinal thickness of at least 100 µm from one visit to the next. It should be noted that only one dose was given at the time of re-treatment,” he said.
At the 6-month follow-up point, 12 of the 18 patients did not require re-treatment. Of the six who were re-treated, four received intravenous Avastin, one was treated with intravitreal Avastin, and one was given Macugen (pegaptanib sodium for injection, Pfizer/Eyetech). Patients have now been followed for at least 6 months.
“The patients who were re-treated did have restoration of their initial improvements, and one re-treatment appeared to improve outcomes for 12 to 17 weeks. We also noted the improvement after intravitreal Avastin. The durability of this approach is unknown,” Dr. Moshfeghi said.
Philip J. Rosenfeld, MD, PhD, principal investigator of the Avastin trials at the Bascom Palmer Eye Institute, said that the patient who received intravitreal Avastin had the same positive response as when the drug was infused intravenously. The advantage of intravitreal administration is that 400- to 500-fold less drug can be used, he said.
For Your Information:
- Andrew A. Moshfeghi, MD, and Philip J. Rosenfeld, MD, PhD, can be reached at Bascom Palmer Eye Institute, University of Miami School of Medicine, 900 N.W. 17th St., Miami, FL 33136; 305-326-6148; Web site: www.bascompalmer.org; e-mail: amoshfeghi@med.miami.edu, prosenfeld@med.miami.edu.
- Michelle Dalton is Managing Editor of OSNSuperSite.com. She writes daily updates on developments in all aspects of ophthalmology.