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Pegaptanib Sodium Leads to Significant Increase in Intraocular Pressure in Patients With Pre-Existing Glaucoma: Presented at ARVO

By Earl R. Nichols

FT. LAUDERDALE, F.L. -- May 1, 2006 -- Patients whose age-related macular degeneration (ARMD) is treated with pegaptanib sodium (Macugen) may run the risk of significantly increased intraocular pressure (IOP) that could eventually spell trouble for their optic nerves.

In a presentation here April 30^th at the Association for Research in Vision and Ophthalmology (ARVO) annual meeting, investigators discussed how the use of Macugen can lead to increases in IOP that could ultimately prove harmful to patients with pre-existing glaucoma.

Macugen is meant to be delivered via intravitreal injections of 0.09 mL every 6 weeks for a period not to exceed 2 years. While it is known that such injections will lead to some "spiking" of IOP, the degree or duration of spiking has never been measured.

Allison Toler, optometrist, East Florida Eye Institute, Stuart, Florida, and Ronald Frenkel, MD, ophthalmologist, Bascom Palmer Eye Institute, University of Miami, Miami, Florida, enrolled 8 patients with glaucoma who were being treated with Macugen.

Patients' IOP levels were measured 1 minute after the Macugen injection, and then every 5 to 10 minutes until IOP returned to baseline. Over a 7-month period, the patient received a total of 31 injections.

Mean pre-injection IOP was 12.9 mm Hg and mean postinjection IOP was 39.4 mm Hg. One patient's IOP spiked as high as 55 mm Hg, requiring immediate anterior chamber paracentesis.

All patients received at least one IOP-lowering medication prior to the injection, and though this was helpful it did not prevent the increase in IOP, according to the researchers.

In most cases, the IOP returned to baseline, or near baseline levels within 30 minutes of the injection. Mean IOP within the first 10 minutes of the injection was 31.8 mm Hg, within 11 to 20 minutes it was 23.6 mm Hg, and by the 30-minute mark it was 20.9 mm Hg. By the time the patients returned for their first follow-up examination, their IOP had returned to baseline levels.

The researchers reported that when Macugen was compared with Avastin (bevacizumab), another agent used to prevent macular degeneration, the spikes in IOP were similar, but the spike following Avastin dissipated faster.

They concluded that physicians treating patients with glaucoma must be cautious in maintaining IOP at safe levels, and although there was no suggestion in this study that having IOP levels remain elevated to this degree for a relatively short period of time might be harmful, it would be wise to keep the IOP low at all times.

This study involved only patients with pre-existing glaucoma and for those patients, any change in IOP should be viewed with concern, according to the researchers. While they would not say this should definitely preclude such patients from receiving Macugen in the treatment of macular degeneration, physicians should view each case individually, and they may want to exercise added caution in offering such injections to patients with glaucoma.


[Presentation title: IOP Effects of Macugen in Glaucoma Patients. Poster B167]

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