Research Digest

Bevacizumab for Induction with Pegaptanib Sodium as a Maintenance Therapy in AMD

Patients with neovascular AMD treated with bevacizumab (Avastin, Genentech) achieved rapid increase in visual acuity, and were able to sustain improved vision with 54 weeks of pegaptanib sodium ([OSI] Eyetech/Pfizer) maintenance therapy, according to a study published in the November/December issue of Ophthalmic Surgery, Lasers & Imaging.

Mark S. Hughes, M.D., and Delia N. Sang, M.D., injected 20 patients with bevacizumab and followed the single injection with pegaptanib 3 weeks after induction and then every 6 weeks over a 54-week period. “If the greatest linear dimension on fluoroscein angiography grew by more than 15%, the patient qualified for a booster with Avastin,” Dr. Hughes told Ophthalmology Management. “The four patients who required boosters did not require another one after that.”

The average improvement in visual acuity was from a baseline of 20/200 to 20/80, 45% of patients gained three lines of Snellen acuity at the end of 54 weeks. Furthermore, all 20 patients experienced a decrease in retinal thickness, ranging from 47 µm to 297 µm. Since the data were compiled for the study, Dr. Hughes says, “None of the patients from this series has experienced any systemic adverse events.” The results for both visual acuity benefit and OCT measurements parallel those published for Lucentis in both the ANCHOR and MARINA trials.

Dr. Hughes says he used a model of cancer treatment (beginning with a higher-risk drug and then moving to a lower risk agent) in this study. “If we induce with a pan-VEGF agent,” Hughes thought, “then we might achieve a rapid response which can then be maintained with a selective VEGF-blockade agent.” They chose pegaptanib as the maintenance agent, Dr. Hughes said, because it had a much longer safety profile.

The purpose of an induction-maintenance regimen is to optimize both efficacy and safety. Ranibizumab (Lucentis, Genentech) was not available when this study began, Dr. Hughes says, “My primary induction agent today is Lucentis.” Dr. Hughes sees combination therapy as the future of AMD treatment. “I don’t think monotherapy is the future,” Dr. Hughes says. “But it is an important step in the evolution of our treatment of AMD.” Future combination approaches might include steroids, photodynamic therapy, and anti-PDGF agents in combination with anti-VEGF agents. The goal of combination therapy is to improve vision outcomes, and to decrease treatment burden for both the patient and the physician, as well as decrease hypothetical systemic and retinal/RPE risk of continuous pan-VEGF blockade. OM

Topical Gatifloxacin vs. Ciprofloxacin 0.3% for the Treatment of Bacterial Keratitis

In an article appearing in the February 2006 issue of American Journal of Ophthalmology, a study on a total of 104 eyes with bacterial keratitis showed that gatifloxacin had a significantly better action against gram-positive cocci both in vitro and in vivo when compared with ciprofloxacin. The study, comparing the bacteriologic and clinical efficacy of gatifloxacin and ciprofloxacin for the treatment of bacterial keratitis, stated that in view of these organisms being the leading cause of keratitis worldwide, gatifloxacin may be a preferred alternative to ciprofloxacin as the first-line monotherapy in bacterial keratitis. Pragya Parmar, MS, and colleagues found a significantly higher proportion of ulcers in the gatifloxacin group exhibited complete healing compared with those in the CIP group (39 eyes [95.1%] vs. 38 [80.9%]; P=.042). Gatifloxacin demonstrated a significantly better action than ciprofloxacin against grampositive cocci in vitro (P<.001), and the percentage of ulcers caused by these pathogens that healed in the gatifloxacin group was significantly better than in the ciprofloxacin group (P=.009). Mean time taken for healing of ulcer and the efficacy against gram-negative bacteria did not significantly differ between the two groups. OM