The role of anti-VEGF medications in the treatment of AMD

April 29, 2006

While early data show that vascular endothelial growth factor(VEGF) may prevent vision loss and even produce gains in patientswith wet age-related macular degeneration (AMD), much remains to belearned about the class of VEGF inhibitors. Only one drug in thisclass, pegaptanib sodium (Macugen, OSI/Eyetech Pharmaceuticals) hasbeen approved, while others are in the clinical trials pipeline.

While early data show that vascular endothelial growth factor (VEGF) may prevent vision loss and even produce gains in patients with wet age-related macular degeneration (AMD), much remains to be learned about the class of VEGF inhibitors. Only one drug in this class, pegaptanib sodium (Macugen, OSI/Eyetech Pharmaceuticals) has been approved, while others are in the clinical trials pipeline.

With relatively little long-term data on VEGF inhibitors, it is essential for clinicians to be able to interpret what information is available so far and to weigh the risks and benefits of VEGF inhibition, particularly in a population of older patients, according to panelists at a Saturday evening CME symposium held at the Hyatt Regency Pier Sixty-Six Hotel in Fort Lauderdale, FL.

"Pegaptanib has been shown in large randomized clinical trials to reduce the risk of vision loss," said Mark W. Johnson, MD, professor, vitreoretinal diseases and surgery, the University of Michigan Kellogg Eye Center, Ann Arbor. "The results support an important role for VEGF in the pathogenesis of neovascular AMD. However, the treatment effect was modest, only 15% over sham, and there were inconsistent trial results for some lesion subtypes. The safety profile over 2 years was quite favorable, but [a drawback] of pegaptanib was that improvement in vision was not seen in a clinically meaningful portion of patients."

SriniVas R. Sadda, MD, director, medical retina unit and ophthalmic imaging unit, University of Southern California, Los Angeles, discussed results of two large trials of ranibizumab (Lucentis, Genentech), including one in which ranibizumab was combined with photodynamic therapy (PDT).

"There appears to be a benefit of ranibizumab compared with controls observed across all subgroups," Dr. Sadda said.

These outcomes also suggest that a shift in the clinical endpoint away from simply preserving vision may be timely.

"The results of these trials have really raised the bar for treatment of wet AMD, and visual improvement is now becoming an expectation for our patients," Dr. Sadda said.

The anatomic outcomes from these trials are also important, said Jennifer I. Lim, MD, associate professor of ophthalmology, medical and surgical retina, medical director of clinical trials, University of Southern California, Los Angeles.

"It appears that the anatomic outcomes were consistent with the visual acuity outcomes," Dr. Lim said. "The total lesion area, the amount of choroidal neovascular leakage, the absence of leakage, total lesion size, and optical coherence tomography data were all in favor of ranibizumab over sham or over PDT. It appears that the anatomic outcomes support the fact that there is evidence of efficacy for ranibizumab treatment having an effect on the choroidal neovascular membrane itself."

The moderator of the program, Susan Bressler, MD, the Julia G. Levy, PhD, professor of ophthalmology, Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, described results of a quality of life study of patients in the MARINA trial of ranibizumab. Outcomes of patient surveys showed meaningful improvement in binocular visual function over baseline in the two drug treatment groups.

"These results increase our confidence that this is a meaningful therapy to be offering individuals," Dr. Bressler said. "When you ask the patients themselves, they are more apt to report to you that in a daily perception, their lives have improved by undergoing this therapy."

The program was jointly sponsored by The New York Eye and Ear Infirmary and CME2, an independent subsidiary of Advanstar Communications Inc., publisher of Ophthalmology Times, and supported through an educational grant from Genentech Inc.