By Nancy M. Holekamp, MD
This article adds to the growing ophthalmic literature suggesting that combination therapy can reduce the number of sessions required to successfully treat exudative AMD. The study demonstrates stabilization or improvement in visual acuity in the majority of patients treated with a combination of Visudyne photodynamic therapy (PDT) (Novartis Pharmaceuticals Corp, East Hanover, N.J.) and an intravitreal Avastin injection (Genentech, Inc., South San Francisco, Calif.) just a mere one or two times - a significantly reduced treatment burden compared with monthly injections of anti-VEGF monotherapy.
A retrospective case series, the study included 40 eyes of 40 patients with recently diagnosed and previously untreated juxtafoveal or subfoveal choroidal neovascularization secondary to AMD. Each eye was given a 1.25-mg intravitreal Avastin injection within two weeks of receiving full-fluence PDT and followed for six to 12 months. Thirty-three percent received one Avastin-PDT combination re-treatment, and 2 percent (one eye) received two re-treatments. Forty-eight percent of the 23 eyes followed for 12 months required only one combination treatment compared with 88 percent of those followed only for six months.
At the final follow-up visit, visual acuity had stabilized, defined as having improved or remained the same, in 83 percent of eyes, and improved in 73 percent. The mean visual acuity gain was 1.73 lines among the 29 eyes that improved. Visual acuity stabilized in 74 percent of the eyes followed for 12 months and improved in 40 percent, with improvement a mean of 1.22 lines.
The authors recognize the weaknesses of this study and other related ones as being small retrospective case series without controls, refracted ETDRS visual acuity testing, or standardized long-term follow-up. Unfortunately, these factors make it impossible to compare their visual acuity results with standard-of-care anti-VEGF monotherapy.
We know combination therapy requires fewer treatments, but which treatment approach provides the best visual outcome? Interestingly, a randomized, prospective clinical trial of combination therapy has already been completed. The FOCUS trial, which was sponsored by Genentech, compared PDT alone to a combination of PDT plus the company's Lucentis injections. In the study's combination arm, the percentage of patients with visual gains of three or more lines and the percentage with 20/40 or better visual acuity after 12 months was not as high as in randomized clinical trials of monthly Lucentis monotherapy.
The current question is whether patients and doctors will be faced with a choice between fewer treatments resulting in slightly less vision or a larger number of treatments resulting in slightly better vision. The answer awaits the results of larger, prospective clinical trials that are currently under way comparing combination therapy to anti-VEGF monotherapy.
Financial Disclosures
Dr. Holekamp is a consultant to Alcon Laboratories, Inc., Genentech, Inc., Pfizer Ophthalmics, and OSI Eyetech, and receives lecture fees from Genentech.