More Treatments for Wet AMD from the AAO Meeting

Retinal experts are trying various combinations of VEGF inhibitors, (Macugen®, Avastin®, Lucentis®), Visudyne®, and intraocular steroids. The goal of these combination treatments is to either obtain better visual results than Lucentis or obtain the same visual results with fewer intraocular injections.

Augustin and Offerman, reported at the AAO meeting, the results of their treatment of 186 patients with triple therapy. The patients first had Visudyne, (PDT). The next day, the doctors performed a small vitrectomy followed by intraocular injections of 800µg of dexamethasone, (a steroid), and 1.5mg of Avastin. They reported the results on 104 of the patients. Presumably the other 82 patients were eliminated from the analysis because of short follow-up but whenever patients are eliminated from a study, it casts doubt upon the results. The 104 patients were followed for a mean of 40 weeks after treatment. The average visual gain was nine letters which is the same or a little better than seen with Lucentis. Only 18 patients needed another single injection of Avastin and only 5 needed another round of PDT, Avastin, and dexamethasone to control the neovascularization. This means that 81 of the 102 patients were stable after the first combination treatment. This would be an advantage over monthly injections over a long period of time.

Other retinal experts are going to try this triple treatment. The vitrectomy part however, is probably not necessary. It’s too early to determine however, whether patients with wet AMD should ask for this triple treatment rather than intraocular Avastin or Lucentis.

The consensus at the meeting is that Visudyne (PDT) should be given first followed by the VEGF inhibitor and/or a steroid. The VEGF inhibitor and steroid can be given right after the PDT or a day later. If the VEGF inhibitor is given before the PDT, the results don’t seem to be as good. That may mean, that the VEGF inhibitor is all used up by the time the PDT is given. Therefore, when the PDT causes the production of more VEGF, there is nothing to block its effect. Or it may mean that the VEGF inhibitor causes the vessels in the neovascularization to close off which reduces the accumulation of dye in the vessels and thus the effect of the subsequent PDT.

A few months ago, I wrote that two patients who received full-dose PDT develop choroidal capillary loss and vision loss. Both of these patients have recovered their pre-op VA, (20/80, 20/100) but one had a recurrence of the neo in the very center of the atrophy. As I mentioned, many clinicians are using half-dose PDT in combination treatments. There may be less of a risk from full-dose however, when it’s done before the injection of the VEGF inhibitor.

Typically for PDT, 1000µ is added to the greatest linear diameter of the CNV to determine the size of the laser spot. Therefore a lot of normal choroid surrounding the CNV is treated with the laser. Recently with combination treatments, I have been adding only 500µ to the greatest linear diameter provided that I can easily see the margins of the CNV. This results in less area that is treated and presumably less inflammation and VEGF production. Reducing the margin for error could be risky however since most of the recurrences after PDT are edge recurrences. We don’t know however, if these edge recurrences are from areas of the CNV that were not fully covered by the laser. I would argue that the recurrences are due to damaged surrounding choroid and VEGF production. Treatment with anti-VEGF therapy after the PDT may also allow for a reduced spot size. We will see.

I tried to play the slots with my quarter but the slots now only take bills or prepaid cards. I left the casino in a huff.