Induction/maintenance therapy strategies for AMD to be explored

NEW YORK— A clinical trial to evaluate an induction/maintenance therapy strategy for age-related macular degeneration is planned to begin in 2006, according to officials at OSI Pharmaceuticals.

“Pfizer and OSI have agreed to initiate, in the second half of this year, a prospective trial to establish the safety and efficacy of Macugen [pegaptanib sodium injection, OSI/Pfizer] in an induction/maintenance cycle,” said Paul G. Chaney, chief operating officer for (OSI) Eyetech, speaking at OSI R&D Day here.

Some physicians have already begun using Macugen as maintenance therapy for AMD after initial induction therapy with another agent, said David S. Guyer, MD, executive vice president of OSI and president of (OSI) Eyetech, also speaking at the meeting.

Macugen specifically blocks the 165 isoform of vascular endothelial growth factor (VEGF), while other therapies such as ranibizumab and bevacizumab are pan-VEGF blockers, Dr. Guyer said. In the induction-maintenance treatment model, patients are started on a pan-VEGF blocker and then maintained on Macugen, he said.

This strategy takes advantage of the safety of Macugen, which has been shown in more than 50,000 patients treated through the end of 2005, said Anthony Adamis, MD, chief scientific officer of (OSI) Eyetech, also speaking at the meeting.

“Multiple centers have now shown enhanced Macugen efficacy in early disease,” Dr. Guyer noted. Further reports of its efficacy with early AMD patients will be presented at the upcoming meeting of the Association for Research in Vision and Ophthalmology, he said.

Carmen Puliafito, MD, the guest speaker at OSI R&D Day, said that both Macugen and off-label Avastin (bevacizumab, Genentech) are in use at his institution, Bascom Palmer Eye Institute.

Dr. Puliafito noted that pharmacologic treatment of AMD is relatively new to ophthalmology, with photodynamic therapy introduced only 6 years ago and other agents even more recently. He said physicians have mostly been using monotherapy with one or another agent to date, but the field is evolving toward use of multiple therapies.

At Bascom Palmer, he said, Macugen is used to treat patients with early disease, and off-label Avastin is used in patients with advanced disease. In some cases, he said, the induction-maintenance strategy of Avastin followed by Macugen is also used at Bascom Palmer.

Dr. Puliafito said more studies are needed, including head-to-head comparisons of the available agents, to determine what will be the best long-term strategy for pharmacologic treatment of AMD.