Avastin Safety
Earlier this week, the Washington Post and other papers reported that Genentech temporarily halted recruitment into a study testing Avastin® combined with two types of chemotherapy for the treatment of metastatic colon cancer. The recruitment was halted because four patients in one arm of the study died suddenly. One of our blog readers wrote to ask if this means that Avastin® could be dangerous to his father who was being treated with the drug for AMD.
The sudden deaths were only among patients in one arm of the study. Another large group of patients who were also taking Avastin® (with a different type of chemotherapy) didn’t show this increased risk. Overall, there were relatively few deaths in the 2000 patients in the study. Therefore there is a good chance that the deaths were not due to Avastin®. Genentech was just being extra careful.
The main thing to remember however, is that patients who have colon cancer are treated with intravenous Avastin® at a dose of 5mg per kilogram of body weight. A 154 pound person weighs about 70 kilograms which means that person would receive 350 milligrams of Avastin® intravenously every two weeks. The dose we use for AMD is 1.25 mg (280 times less) given every four weeks. So our dose is 560 times less per month. The Avastin® is also placed into the eye so it would first have to leak out of the eye and into the bloodstream to cause systemic complications. Therefore I believe that a systemic complication from the Avastin treatment that we use in AMD would have to be exceedingly rare.
Another article (PMID: 16458968) that will be published by Dr. Robert Avery and colleagues in the March Ophthalmology issue states that Avastin® was found to be safe and effective in the treatment of 79 patients with AMD. The patients, at the time the article was written, had only been followed for about two months so we don’t know what the long-term outcome will be. The early results look encouraging however and any side-effects should have occurred within a week or two after the injection.
In summary, right now, Avastin® looks to be both effective and safe for the treatment of wet AMD. We do need to follow more patients for longer periods of time though to be absolutely sure.
Avery RL, Pieramici DJ, Rabena MD, Castellarin AA, Nasir MA, Giust MJ. Intravitreal Bevacizumab (Avastin) for Neovascular Age-Related MacularDegeneration.Ophthalmology. 2006 Feb 1; [Epub ahead of print] PMID: 16458968
The sudden deaths were only among patients in one arm of the study. Another large group of patients who were also taking Avastin® (with a different type of chemotherapy) didn’t show this increased risk. Overall, there were relatively few deaths in the 2000 patients in the study. Therefore there is a good chance that the deaths were not due to Avastin®. Genentech was just being extra careful.
The main thing to remember however, is that patients who have colon cancer are treated with intravenous Avastin® at a dose of 5mg per kilogram of body weight. A 154 pound person weighs about 70 kilograms which means that person would receive 350 milligrams of Avastin® intravenously every two weeks. The dose we use for AMD is 1.25 mg (280 times less) given every four weeks. So our dose is 560 times less per month. The Avastin® is also placed into the eye so it would first have to leak out of the eye and into the bloodstream to cause systemic complications. Therefore I believe that a systemic complication from the Avastin treatment that we use in AMD would have to be exceedingly rare.
Another article (PMID: 16458968) that will be published by Dr. Robert Avery and colleagues in the March Ophthalmology issue states that Avastin® was found to be safe and effective in the treatment of 79 patients with AMD. The patients, at the time the article was written, had only been followed for about two months so we don’t know what the long-term outcome will be. The early results look encouraging however and any side-effects should have occurred within a week or two after the injection.
In summary, right now, Avastin® looks to be both effective and safe for the treatment of wet AMD. We do need to follow more patients for longer periods of time though to be absolutely sure.
Avery RL, Pieramici DJ, Rabena MD, Castellarin AA, Nasir MA, Giust MJ. Intravitreal Bevacizumab (Avastin) for Neovascular Age-Related MacularDegeneration.Ophthalmology. 2006 Feb 1; [Epub ahead of print] PMID: 16458968
posted by James C. Folk, M.D. at 11:53 AM
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