Bevacizumab rescue therapy after pegaptanib: minimal visual acuity improvement

May 8, 2007

Primary bevacizumab (Avastin, Genentech) therapy for choroidal neovascularization (CNV) in age-related macular degeneration resulted in two to three ETDRS lines of improvement, which is similar to that with ranibizumab (Lucentis, Genentech). Bevacizumab rescue therapy administered following treatment with pegaptanib (Macugen, OSI/Eyetech, Pfizer Ophthalmics) resulted in minimal improvement, said William Freeman, MD, from the Department of Ophthalmology, Shiley Eye Center, University of California San Diego, La Jolla, CA.

Primary bevacizumab (Avastin, Genentech) therapy for choroidalneovascularization (CNV) in age-related macular degeneration resulted in two tothree ETDRS lines of improvement, which is similar to that with ranibizumab(Lucentis, Genentech). Bevacizumab rescue therapy administered followingtreatment with pegaptanib (Macugen, OSI/Eyetech, Pfizer Ophthalmics) resulted inminimal improvement, said William Freeman, MD, from the Department ofOphthalmology, Shiley Eye Center, University of California San Diego, La Jolla,CA.

Dr. Freeman and colleagues conducted this study to determine whether vision ineyes with CNV and treated with pegaptanib could be rescued with bevacizumab. Theinvestigators compared the ETDRS visual outcomes in 38 eyes, 18 eyes underwentprimary bevacizumab treatment (average of 3.4 consecutive injections), and 20eyes underwent bevacizumab treatment (average of 3.6 injections) afterpegaptanib therapy (average of 4.2 injections). Both groups were treated every 6weeks with 1.25 mg of bevacizumab. The patients were followed for 6months.

He reported that there was an improvement in vision from 20/160 to 20/80 in theprimary bevacizumab group at 3 months that was maintained at 6 months. In therescue group, there was minimal visual improvement in vision from 20/160 to20/140.

"We found that we could not rescue eyes or improve vision even though edema wasstill present in the retina by switching patients from [pegaptanib] to[bevacizumab]," he said.

In the bevacizumab group there was a small decrease in the retinal thicknessfrom before treatment to the 6-month time point. In the rescue cohort, there wasa small amount of retinal thinning, but there was no increase in the visualacuity.

"This is an important study in that it was a direct comparison of the 6-monthdata of primary bevacizumab treatment with secondary bevacizumab treatment," hesaid. "Similar to the 6-month MARINA study population, which showed aseven-letter increase in visual acuity with primary bevacizumab therapy, therewas an 11-letter increase at 6 months in this study, but fewer patients with20/40 or better visual acuity.

"This is the first report to compare primary bevacizumab and bevacizumab rescuetherapy for CNV," Dr. Freeman concluded. "The bevacizumab benefit is much morepronounced in primary therapy compared with secondary therapy. Changes in theneurosensory retina and the retinal pigment epithelium during pegaptanibtreatment likely do not allow rescue therapy."