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Bevacizumab's impact felt despite lack of clinical data
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NEW ORLEANS — Citing the downturn in sales of verteporfin and pegaptanib, a surgeon speaking here explained how bevacizumab has greatly impacted age-related macular degeneration treatment, despite the fact that is has not gained U.S. approval for treating the disease and the lack of clinical trial data to support its use.
"In 2005 and early 2006, mostly anecdotal reports existed regarding the efficacy of intravitreal bevacizumab (Avastin, Genentech) for neovascular AMD. However, the favorable short-term clinical efficacy was so apparent that use of intravitreal bevacizumab spread rapidly among the retina community," David F. Williams, MD, said here at Retina Subspecialty Day preceding the annual American Academy of Ophthalmology meeting.
Dr. Williams said, while there are no data that show the dominance of bevacizumab use to treat neovascular AMD, indirect evidence can be found in sales trends for other primary treatments that were in use in 2005 when bevacizumab first emerged.
"The cost differential between off-label bevacizumab and the other pharmacological treatments for neovascular AMD was striking," he said.
From the time bevacizumab efficacy data were introduced by Philip J. Rosenfeld, MD, PhD, until the last quarter of 2006, pegaptanib sales fell 26% while verteporfin sales fell 63%.
In addition, the approval of ranibizumab in July 2006 pushed verteporfin sales down 82% while pegaptanib sales fell 92%.
"The unprecedented growth of off-label bevacizumab as a primary therapy for AMD occurred in the setting of anecdotal reports, reports of non-randomized, non-controlled, small clinical series, and individual personal clinical experience," Dr. Williams said. "It has persisted in the setting of the availability of a highly efficacious, but expensive, [U.S. Food and Drug Administration-approved] product."
Dr. Williams pointed to four reasons for this growth: the value of evidence-based medicine, the value of mass clinical experience, pricing of FDA-approved drugs and the power of physician choice.