Chicago—The pegaptanib sodium (Macugen, OSI/Eyetech Pharmaceuticals) exploratory phase II data indicate that the drug seems to be successful for treating diabetic macular edema (DME), according to Steven D. Schwartz, MD. He reported the findings of the Macugen Diabetic Retinopathy Study Group during the retina subspecialty day at the American Academy of Ophthalmology annual meeting.
"There is a large body of basic science evidence that suggests that the level of vascular endothelial growth factor (VEGF) 165 is elevated in experimental diabetes and in the human condition," Dr. Schwartz explained.
In a 39-center, national and international, randomized, masked, clinical trial, patients were studied who had diffuse DME of greater than one half of a disc area that involved the foveal center and best-corrected visual acuity (BCVA) between 20/50 and 20/320 in the affected eye and 20/100 or better in the fellow eye. The presence of diffuse DME was confirmed by the reading center.
The investigators evaluated the following key outcomes: visual acuity, foveal thickness as seen by optical coherence tomography (OCT), severity levels of retinopathy, fluorescein leakage, the need for application of focal photocoagulation during the study, and safety, according to Dr. Schwartz, who is chief of the Retina Division, Jules Stein Eye Institute/David Geffen School of Medicine at University of California Los Angeles.
Patients were excluded if there was a need for panretinal photocoagulation at the patient's entry into the study or during the ensuing 9 months and presence of any retinal abnormalities that confounded the assessment, such as nonperfusion or epimacular traction.
More than 90% of the patients in each active treatment group completed the study. Only nine participants did not complete the study, and all participants except four received more than three injections. The mean and median numbers of injections administered were similar in all treatment groups.
Dr. Schwartz focused on the data from the group that received the 0.3-mg dose because of its efficacy.
"There was a shift toward better vision in the patients who received the 0.3-mg dose compared with the sham treatment group. There was a clinically and statistically significant increase in the visual acuity in the eyes treated with the 0.3-mg dose compared with the sham-treated eyes," he said.
"There was also an absolute change in retinal thickness that seemed to mirror what was expected in terms of the OCT central point in the central subfield. When we looked at the mean change in the retinal thickness against the center point of the central subfield, we found a mean decrease of 68 µm in the treatment group compared with an increase of 4 µm in the sham-treated group," he said.
"Only 25% of eyes in the treated group needed focal photocoagulation at 12 weeks compared with almost 50% of eyes in the sham-treatment group. This indicated a potential reduction in the need for photocoagulation in eyes treated with pharmacotherapy," he continued.
No serious systemic safety issues occurred. One case of endophthalmitis developed as well as vitreous hemorrhages, which occurred at a higher rate in the sham-treated group. There were no retinal detachments or retinal tears. The visual acuity improvement persisted for almost 1 year after the last injection of pegaptanib sodium.