Recent noteworthy studies to stimulate discussion and debate.
■ CATT out of the bag? We are still several months away from getting interim data from the head-to-head Lucentis vs Avastin CATT trial, but two studies published recently may indicate what the findings might be.
In the September 2009 issue of Ophthalmology, retinal physicians from the Johns Hopkins School of Medicine have published the results of a murine study comparing the efficacy of bevacizumab and ranibizumab, finding that efficacy was equal between the two drugs, but also that the effects of bevacizumab had a longer duration.
Meanwhile, in Retina in the same month, a team from the Bascom Palmer Eye Institute in Miami published a retrospective study of 84 eyes of patients with wet AMD treated first with bevacizumab and subsequently with ranibizumab. These scientists concluded that switching patients from bevacizumab to ranibizumab made no statistically significant difference in either visual acuity or frequency of injections.
Both studies stressed that larger (and, in the case of the first, human) studies would be needed to draw any larger conclusions. The CATT results will serve this purpose.
■ Macugen in DME. Despite its diminishing use of late, Macugen may have efficacy in treating diabetic macular edema, according to an Italian study published in the September 2009 issue of Acta Ophthalmologica.
The authors conducted a retrospective analysis using OCT and measuring BCVA in 63 eyes of 48 patients with DME who were treated with pegaptanib sodium. Sixty of the 63 eyes required three injections over a six-month period. Statistically significant findings included improved BCVA and a highly statistically significant (P<.001) lessening of central retinal thickness.
The authors conclude that it is Macugen's limited inhibition of VEGF165 that is most important in their findings, arguing that this VEGF isoform's relationship to increased vascular permeability in diabetic retinopathy was a key cause of their findings.
■ Nerves and dyes. Physicians in Germany and the United States have co-authored a seven-year retrospective study on the use of indocyanine green (ICG) staining of the internal limiting membrane during macular surgery, finding that use of the dye may be linked to optic-nerve atrophy. This link was published in the October 2009 issue of Retina.
Sixteen patients operated on by Anselm Kampik, MD, of the Department of Ophthalmology at Ludwig-Maximilian-University in Munich, were followed up at a mean time of 7.3 years. Patients were evaluated on the bases of BCVA, Goldmann perimetry, Arden color contrast, OCT and fundus photography. Of the 16 eyes, 10 had undergone surgery for macular hole, and the rest for macular pucker.
Ten of the 16 patients had large visual field defects at follow-up, and 11 patients were found on further examination to have nonglaucomatous optic nerve atrophy. Finally, there was a significant effect on the ability to differentiate color in all but one patient.
While the authors concede that their study is small, they urge readers to proceed with caution in using ICG when doing ILM peels during macular surgery and recommend longer-term observation in similar cases.
■ Druse on first. Drusen are a common early sign of AMD, but they're not always indicative of a retina that is going to get worse or even remain damaged, conclude a team of retinal physicians from the United Kingdom, Hungary, and Israel, in the October 2009 issue of the British Journal of Ophthalmology.
The UK-based authors collected data from 14 patients who had drusen that had regressed, and photopic and scotopic fine-matrix mapping were carried out on their eyes. Upon examination of these patients, who were followed up for an average of nearly six years, it was discovered that there was no statistically significant difference between eyes in scotopic sensitivity between the parts of the macula that had never developed drusen and those parts that had.
The authors of the study concede that their sample size is too small for any specific conclusions, but they do note that the fact that patients who have had drusen and not suffered a significant loss of macular sensitivity may need to be considered when making prognoses of patients who present with drusen.
■ OCT vs FA vs the sun. Summer is over, but solar retinopathy appears year round. A group of doctors at the Jules Stein Eye Institute at UCLA have presented the findings of a small imaging study in the October 2009 issue of Retina.
Twenty-one affected eyes from 11 patients were subjected to both optical coherence tomography and fluorescein angiography — the largest case series ever done on solar retinopathy using both imaging protocols.
While all 11 patients' macular damage appeared on OCT, only 90% of the patients' damage appeared when fluorescein angiography was used. Furthermore, on OCT, the team detected an absent OCT signal at the inner hyperreflective layer. RP
Retinal Physician, Issue: November 2009