Treatments for retinal diseases are expected to overtake those of glaucoma by 2014, “making retinal disease the most lucrative sector of the ophthalmic drugs market, overtaking the glaucoma sector,” according to the report, “Macular Degeneration (AMD) and Diabetic Retinopathy (DR): World Drug Market 2011–2021.”
The age-related macular degeneration (AMD) and diabetic retinopathy segment of that market generated just over $3 billion in 2010. Visiongain projects those revenues to climb to nearly $5.1 billion by 2014. The overall market for ophthalmic therapeutics is expected to reach $18.7 billion this year. Ten-year forecasts for ocular disease therapeutics predict steady growth.
Interest in these diseases is driven by the success of drugs like Genentech’s Lucentis®, which generated $1.5 billion in 2011, as well as an aging population with an increasing prevalence of ocular disorders and increased global demand for innovative therapeutics.
“Back-of-the- eye diseases are the leading cause of blindness in the developed world, but they’re very difficult to treat,” according to Paul Ashton, Ph.D., president and CEO, pSiveda. The challenge is delivering drugs to the back of the eye.
“There have been big advances in wet AMD therapies recently, targeting vascular endothelial growth factor (VEGF),” Dr. Ashton says. Excessive VEGF production causes blood vessels to become fragile, allowing fluids to leak into surrounding tissues where they may damage the macula and create blind spots in central vision.
Standard therapy has been Genentech’s VEGF inhibitors Lucentis (ranibizumab) and the off-label use of Avastin® (bevacizumab). These are equally effective at improving vision, but the improvement only lasts six to eight weeks.
Regeneron, in collaboration with Bayer HealthCare, is challenging these drugs with a similar VEGF inhibitor, Eyela® (aflibercept). Aflibercept is a fusion protein that binds all forms of VEGF and placental growth factor (PlGF), which are involved in the abnormal growth of new blood vessels in ocular and other diseases. It gained FDA approval last November for wet AMD and may be injected every 8 to 10 weeks. This improvement over Lucentis and the slightly lower cost is expected to generate significant savings in healthcare costs. The therapy is in Phase III trials for central retinal vein occlusion and diabetic macular edema.
In another approach, Acucela is in Phase II trials using visual cycle modulators to lighten the metabolic load on the retina by reducing the activity of the rod visual system. This protects the retina from light damage, improves retinal vasculature, and reduces the accumulation of A2E and other retinal-related toxic by-products.
GlaxoSmithKline has two drugs in Phase II trials for ocular therapy: darapladib, an oral Lp-PLA2 inhibitor for diabetic macular edema, and pazopanib (Votrient®), a multi-kinase angiogenesis inhibitor in eye drop form for AMD. Early-stage work also is under way for neovascular AMD, dry AMD, diabetic retinopathy, diabetic macula edema, uveitis, and glaucoma, as well as for technologies for drug delivery.