More than 20 different wet (exudative) age-related macular degeneration (AMD) products are in both the middle and late stages of development, and an onslaught of diabetic macular edema (DME) and diabetic retinopathy (DR) drugs are also expected, reports Frost & Sullivan, an international market consulting firm.

According to Frost & Sullivan, a combined total of nearly 20.5 million Americans have AMD, DME and DR.

The report also says the retinal disease drug industry saw revenues of $224.9 million in 2003 and expects market revenues to reach $1,836.4 million by 2010. With these statistics in mind, pharmaceutical companies are working eagerly to offer new and effective drugs to treat retinal disease.

In the case of AMD, Visudyne (verteporfin for injection, Novartis) is currently the only FDA-approved medication used for predominantly classic AMD. Still, only 25% of those with wet AMD have this form. Therefore, 75% of those with either the minimally classic or occult forms of wet AMD are in need of effective treatments.

To that end, Pfizer, Oxigene, Genentech, Eyetech, Alcon, Acuity and Genaera are working on meeting the needs of these patients.

Here is a list of those drugs currently in the pipeline:1

AG-013958 (Pfizer), a drug that hinders the activity of the tyrosine kinase of VEGF receptor 2, which is believed to add to the formation of choroidal neovascularization in AMD.

Combretastatin A4 prodrug, or CA4P (Oxigene), an agent that prevents neovascularization and promotes blood vessel regression.

Lucentis (ranibizumab, Genentech), a recombinant humanized anti-VEGF monoclonal antibody injection that binds to and deactivates VEGF isoforms.

Macugen (pegaptanib sodium, Eyetech), an aptamer that binds to receptors on endothelial cells to prevent VEGF uptake, and hinders the growth and leakage of blood vessels.

Retaane (anecortave acetate, Alcon). An angiostatic steroid injection that hinders endothelial cell division and extracellular matrix breakdown, but does not increase intraocular pressure.

siRNA, or Cand5 (Acuity), a small intervening RNA agent that shuts down the genes that make VEGF.

Squalamine (Genaera), an antiangiogenic agent that blocks growth factor signaling, including both integrin and VEGF expression, and reverses cytoskeleton formation. The FDA has recently granted squalamine fast-track status to hasten its development.

1. Singerman LJ. Pharmacology for age-related macular degeneration. A Clinicians Guide to Retinal Disease, supplement to Rev Ophthalmol 2004 Sept;11(9):12-15.

Vol. No: 141:10Issue: 10/23/04