Pegaptanib sodium effective, safe for diabetic macular edema

November 1, 2010

Phase II study data indicate that pegaptanib sodium injection is an effective and safe treatment for diabetic macular edema.

Marla Sultan, MD, MBA, presented the results for the Macugen 1013 Study Team during retina subspecialty day at the annual meeting of the American Academy of Ophthalmology.

"These encouraging phase III results demonstrate that [pegaptanib sodium] has the potential to improve vision in people with DME, a serious complication of chronic diabetes," said Dr. Sultan, global clinical lead for Macugen at Pfizer Inc., and associate adjunct surgeon, New York Eye & Ear Infirmary, New York.

All patients had DME and could receive laser treatment after week 18 at the discretion of the treating physicians. The mean treatment duration was 45 weeks and the average number of injections was eight during year 1 and 13 injections over the 2-year period.

Primary, secondary endpoints

The primary study outcome was determination of the proportion of patients who had an increase in visual acuity exceeding 10 letters or two lines on the EDTRS chart at the 1-year time point.

The investigators found that 37% of patients treated with pegaptanib sodium achieved the primary endpoint of an increase in visual acuity of two lines or more compared with 20% in the sham group. This difference reached significance (p = 0.0047), Dr. Sultan said.

The secondary endpoints of mean visual acuity measure, the degree of change in diabetic retinopathy, and improvement in the quality of life also were in favor of the pegaptanib treatment group.

"On average, the patients treated with pegaptanib sodium gained a mean of 5.2 letters of vision at year 1 compared with a 1.2-letter gain in the sham-treated group (p < 0.05)," Dr. Sultan said. "At year 2, the patients treated with pegaptanib sodium had an average 6.1 gain in letters of visual acuity compared with 1.3 letters in the sham group (p < 0.01)."

Regarding the degree of change in diabetic retinopathy, the investigators evaluated whether the patients had an increase or a decrease of two steps in diabetic retinopathy.

"Taken as a whole, the change in the degree of diabetic retinopathy was either statistically significant or numerically in favor of pegaptanib sodium over the sham treatment," Dr. Sultan said.

The patients' quality of life was seen to increase at year 1, according to Dr. Sultan.

"The increase in the visual acuity at year 1 in patients translated into quality-of-life improvements for patients in the study treated with 0.3 mg of pegaptanib sodium," she said. "They reported clinically meaningful improvements in quality of life as measured by the National Eye Institute (NEI) VFQ-25 questionnaire. The increase in visual acuity among these patients translated into statistically significant improvements in near vision, distance vision, and social functioning at 1 year on the NEI VFQ-25."

She also pointed out that there were positive trends for other subscales including patients' driving ability.

Regarding safety, no new or unexpected problems with the safety of pegaptanib sodium became evident during the study. There were 2.5 times more small transient increases in IOP related to the injection procedure of pegaptanib sodium (n = 17) that resolved. No deaths were related to the injection procedure or the study drug.

The patients currently are continuing in the open-label year 3 study and continuing to take the drug. The data from the extension study are expected to be reported during the fourth quarter of 2011.

"The study showed that pegaptanib sodium was well tolerated, effective, and associated with a three-to-four-times-greater decrease in retinopathy compared with sham treatment," Dr. Sultan concluded. "A higher proportion of pegaptanib-treated patients had improvements in visual acuity compared with the sham-treated group."