FUTURE TREATMENTS FOR AMD
In addition to current FDA-approved treatments researchers are studying new treatments. Among the new treatments on the horizon for wet AMD are additional anti-angiogenesis drugs, which are aimed at decreasing blood vessel growth and leakage before it damages the retina. Most of those on the horizon do so by blocking the VEGF protein and are, thus, “anti- VEGF” or “VEGF inhibitors.” Others are steroids that may modify the behavior of the abnormal blood vessels.
Bevacizumab, marketed as Avastin by Genentech, is the full-length monoclonal antibody that binds VEGF and that is the molecule from which ranibizumab was fragmented. It is FDA approved for intravenous use in the treatment of metastatic colorectal carcinoma. In the quest to help patients with neovascular AMD who do not respond to current therapies, injections of bevacizumab into the eye have been employed. There are no long-term results on safety and effectiveness of the use of intravitreal bevacizumab for neovascular AMD, but short-term data indicate that it may be of value. Further studies of bevacizumab appear to be indicated.
VEGF-Trap, being developed by Regeneron Pharmaceuticals, is a molecule which binds to all forms of VEFG before it attaches to the receptor on the vascular endothelial cell. It has been created to have high affinity and prolonged binding of the VEGF molecule in the hope that a more prolonged effect can be achieved with each treatment.
RNA interference-based therapeutics (currently being developed by Acuity Pharaceuticals and SIRNA Pharmaceuticals) – This new treatment, which began testing in 2005, would also target the protein VEGF. However, unlike the other anti-VEGF therapies, these drugs do not act by binding directly to VEGF, but instead target the RNA required to produce the VEGF molecule or its receptor, thus inhibiting its development, and the resultant angiogenic process 40.
Anecortave acetate (to be marketed as Retaane® by Alcon Inc) – This investigational angiostatic cortisene is a steroid derivative delivered as a depot outside the eye every six months to inhibit the abnormal growth of blood vessels by blocking signals from multiple growth factors. It is currently in Phase III clinical trials for the treatment of wet AMD as well as under investigation for its role in reducing the risk of progression from dry to wet AMD in patients at high risk for this conversion.
The drugs listed here reflect public knowledge of U.S. products in the pipeline as of May 2006. The list is not intended to be all-inclusive and does not constitute an endorsement of any drug or treatment.
Other Investigational Treatments
The following therapies are also being investigated to treat dry and/or wet AMD:
Injections of triamcinolone (a corticosteroid) into the eye
Low-intensity laser for dry AMD
“Retinal chip” inserted for either very advanced dry or wet AMD
Transpupillary thermotherapy (low-dose infrared light) for wet AMD
Radiation therapy (low-dose external beam radiation) for wet AMD
Retinal translocation (surgical relocation of the retina away from the abnormal blood vessels and/or damaged macula.