A cancer medicine called Avastin may have the potential to prevent a condition called retinopathy of prematurity, also known as ROP, blinding babies born before their natural antioxidant systems have a chance to develop.
No More Blindness in Babies Born Before Their Eyes Develop Completely Is a Possibility
ROP most commonly occurs in babies weighing less than 1200 grams (2-3/4 pounds), or those born before the thirty-first week. First diagnosed in 1941, it is the leading cause of childhood blindness in industrialized countries. Every year in the United States alone, about 28,000 babies are born before the thirty-first week of pregnancy, and about 14,000 of these babies suffer partial or total permanent loss of vision. About 500 become legally blind as the result of ROP.
Like other forms of retinopathy, ROP causes the growth of abnormal blood vessels in the retina, the cells on the back of the eye that capture light and send electrical impulses to the brain. The blood vessels in the retina of a healthy fetus grow from the center of the eye outwards.
When the baby is born too soon, these vessels may not have had a chance to reach the periphery of the eye, so the retina lacks a complete connection to the rest of the cardiovascular system. The few blood vessels that are connected may break under the strain of providing nutrients and oxygen to the immature retina. Or the baby's lack of antioxidants may cause the retina literally to "burn out" when the eye is exposed to air.
Retinopathy of prematurity once could not be treated at all. Soul musician Stevie Wonder, jazz singer Diana Schurr, and actor Tom Sullivan are among the famous people who have this disease. The earliest treatments for premature babies, placing them in a high-oxygen incubator, actually created an epidemic of blindness. Even today, the primary treatment for the condition involves laser surgery removing the parts of the retina where blood vessels have not had a chance to grow. But the cancer drug Avastin may change premature babies' prospects.
How Avastin May Remedy Retinopathy of PrematurityThe cancer drug Avastin (bevacizumab) works by stopping the growth of blood vessels that bring oxygen and nutrients to tumors. This medication is actually an antibody to the growth factor that enables blood vessels to form. Injected into the fluid of the eye, Avastin stops the growth of the blood vessels that otherwise could break, depriving the center of the retina of needed nutrients.
Avastin is not the first drug developed for treating ROP. A similar drug, Lucentis (ranibizumab), has FDA approval for treating vascular diseases of the eye. A single injection of Lucentis, however, costs about $1500, while an injection of Avastin costs about $40. Because ROP is a "preexisting condition," many American insurance companies were not paying for Lucentis, and parents and their doctors were left to make frantic searches for another drug that worked.
Infants with ROP get only a tiny dose of the drug, that takes just a few seconds to inject into the eye. In 2007 the maker of Avastin, Genentech, announced it would no longer supply this drug to pharmacies for use in treating babies. But physicians in the American Society of Retinal Specialists fought back and persuaded Genentech to make the drug available to them personally, which they then could supply to the pharmacies.
A study published 17 February 2011 in the New England Journal of Medicine shows that the doctor's demands on the drug maker were worth the effort. In a clinical trial of laser surgery compared to Avastin, laser surgery effectively cured 58 per cent of babies, but Avastin, which is far less stressful on the baby and far less expensive, effectively cured 94 per cent. Avastin is not an appropriate treatment for every case of ROP, but it is a godsend for babies with more serious cases of the disease.