By Cameron Johnston
FORT LAUDERDALE, FL -- May 14, 2007 -- Intravitreal bevacizumab (Avastin) is now used widely off label for treatment of neovascularisation secondary to age-related macular degeneration. Although the procedure appears to be generally safe and highly effective, it is not without risks.
In a poster session presented here May 7th, Brett Rosenblatt, MD, retinal specialist, Long Island Vitreoretinal Consultants, Great Neck, and an ophthalmologist with Long Island Jewish Medical Center, Long Island, New York, United States, discussed seven cases of retinal pigment epithelial tears (RPE) he has seen recently among patients who were treated with Avastin.
Retinal pigment epithelial tears are not unique to Avastin and have been seen in patients treated with pegaptanib (Macugen), ranibizumab (Lucentis), and photodynamic therapy (verteporfin PDT), Dr. Rosenblatt explained in his poster presentation. Such retinal tears have also been seen in patients who have not had any prior therapy.
However, given the rapid increase in treatment options available to treat AMD over the past couple of years, the number of patients presenting with retinal tears is increasing greatly.
Dr. Rosenblatt explained one hypothesis for what might cause retinal tears is that AMD leaves the retina compromised and weakened, but at the same time, newer treatments offer a more rapid resolution of retinal oedema and thickening. If vitreo-macular traction -- a condition where the vitreous in the eye becomes very "sticky" and adheres tightly to the retina -- is resolved too quickly, it can tear the retina as the vitreous becomes more fluid and pulls away from the retina. "This alternation may predispose [the patient] to retinal pigment epithelial weakening, and subsequent tears," he explained.
In his case report, Dr. Rosenblatt said that all seven patients had pigment epithelial detachments (PED), meaning their retinas were already seriously weakened.
Of the seven patients he reviewed in his presentation, four had no prior treatment, one was treated previously with Macugen and two had previous laser photocoagulation. One patient who had laser treatment had received seven bevacizumab injections, and the patient who had received Macugen treatment had received four injections. The remaining patients had received one or two injections.
The time between the development of retinal tears and the injections varied widely, Dr. Rosenblatt reported. Only one patient had a tear immediately at onset, while in others the tears formed as early as two weeks and as late as three months after an injection.
The patient who had the immediate-onset tear was the only one to have any acute symptoms, namely, a loss in visual acuity, and he was the only one to have a long-lasting outcome. Visual acuity resolved in the other patients to near baseline levels over a period of time.
According to Dr. Rosenblatt, pigment epithelial detachments and vitreo-macular traction should be considered an added risk factor associated with receiving bevacizumab injections.
He concluded that additional studies are needed to determine whether the incidence of RPE tears with bevacizumab is greater than what has been seen with any of the other new treatments for neovascular macular degeneration.
[Presentation title: Retinal Pigment Epithelial Tears Following Intravitreal Bevacizumab (Avastin) Injection. Poster 3381-B528]
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