High doses of bevacizumab

November 15, 2007

A small group of patients given 2.5-mg injections of bevacizumab (Avastin, Genetech) to treat age-related macular degeneration had less frequent injections and slightly better visual acuity than those receiving a 1.25-mg injection over an 8-month follow-up period.

Key Points

Boston-In a study comparing two doses of intravitreal bevacizumab (Avastin, Genentech) for treatment of exudative age-related macular degeneration (AMD), the 2.5-mg dose resulted in a greater improvement in visual acuity (VA) than the 1.25-mg dose, and patients required fewer injections over a follow-up period of about 8 months, according to Pradeepa Yoganathan, MD, who presented data here at the annual meeting of the Retina Society.

Patients who received 2.5-mg bev a ciz u mab injections had a mean increase in VA of 3 lines and a mean of 2.2 injections at the last follow-up (7.8 months). Patients receiving 1.25-mg injections had a mean gain of 1 line of VA and 3.4 treatments. In addition, 31% of eyes in the 2.5-mg group needed only one injection, compared with 6% in the 1.25-mg group, said Dr. Yoganathan, a surgical retina fellow at the University of Toronto. She performed the study during her residency at North Shore-Long Island Jewish Health System in New York prior to beginning her fellowship in Toronto. The patients in the study were treated at Long Island Vitreoretinal Consultants, the retina surgery group for the hospital.

Dr. Yoganathan's co-authors in the New York practice had switched to the higher dose of bev a ciz u mab and believed, based on preliminary anecdotal evidence, that the results were superior. Dr. Yoganathan performed a retrospective review to see whether the data would support that theory. She said since only 2 years of data are available on bev a ciz u mab, which is not FDA-approved for the treatment of AMD, it is important to determine what dose and frequency seems to be most effective in the long term.

In the full group of 88 eyes, 42 were treated with 2.5-mg bev a ciz u mab injections and 46 with 1.25 mg. After the initial injection, treatments were given as needed, determined by clinically evident subretinal fluid, optical coherence tomography (OCT), or fluorescein angiography. No loading regimen was performed.

At monthly follow-up visits, the investigators evaluated VA, conducted a clinical exam, measured blood pressure, and inquired about any change in hypertensive medication. Thromboembolic events were noted.

Median age of the patients was 79 years, and 57 (65%) were women. More than one-half of the patients (54%) had hypertension that was being treated with systemic medication. Lesion types included occult cho roid al neovascularization (CNV) in 56 eyes (64%), minimally classic CNV in 15 eyes (17%), predominantly classic CNV in 14 eyes (16%), and retinal angiomatous proliferation in three eyes (3%). Mean follow-up was 7.9 months (range, 5 to 14 months) in the 2.5-mg group and 7.7 months (range, 6 to 13 months) in the 1.25-mg group.

Twenty-four eyes in the 2.5-mg group were treatment-naïve. The remaining 18 had prior treatment with 1.25 mg bev a ciz u mab, photodynamic therapy (PDT), pegaptanib sodium (Macugen, OSI Eyetech/Pfizer), or a combination. One patient had undergone treatment with all three. Fourteen eyes in the 1.25-mg group were treatment-naïve, whereas 32 had prior treatment with either PDT or pegaptanib.