FDA Panel Approves Glaucoma Drug Despite Odd Side Effect
SILVER SPRING, Md. (AP) _ Glaucoma patients who may get a new drug to battle the blinding disease should be prepared to take long, hard looks in the mirror.
The potion could turn their blue eyes brown and a panel of eye experts says patients should know that before taking the medicine.
Despite the strange side effect of changing eye color, the committee urged the Food and Drug Administration on Friday to approve latanoprost because the drug works significantly better than standard therapy.
A second advisory committee, meanwhile, pressed the FDA to approve an eye implant to help AIDS patients fight a common cause of blindness, saying the capsule appeared to work three times as well as current treatment.
The FDA is not bound by advisory panel decisions but usually accepts them.
The first panel voted 4-2 in favor of latanoprost, but insisted that the eye-color change be clearly labeled so patients understand the risk. It also told maker Pharmacia & Upjohn Inc. to prove just what the drug causes.
``It’s just a step away from being a first-line drug, if we had the answer to this problem,″ said Dr. Joel Mindel of Mount Sinai Medical Center.
Glaucoma, which blinds 80,000 Americans yearly and steals sight from 900,000 others, happens when fluid builds up inside the eyeball and causes dangerous pressure. Over time, the pressure pushes against the delicate optic nerve until it is damaged, and the person begins to lose eyesight.
Standard therapy is timolol, an eyedrop that makes the eye produce less fluid and reduces the pressure. But it has numerous side effects, and people with heart or respiratory problems cannot use it.
Latanoprost is the first of a new class of drugs based on the natural chemical prostaglandin, which helps the eye drain off its fluid. In a study of 829 patients, those who took latanoprost had a 37 percent greater drop in inner eye pressure than timolol patients, and fewer side effects.
But a startling result was that blue eyes turned brown, as did green, hazel and even yellowish ones. The color change hit 15.5 percent of patients after a year of latanoprost use _ and it appeared permanent.
``This is a very strange side effect,″ acknowledged Dr. Johan Stjernschantz, Pharmacia & Upjohn Inc.’s lead researcher.
The company theorizes that latanoprost increased the amount of melanin in peoples’ eyes. Melanin is a chemical that gives people skin color, and every eye has some.
Pharmacia & Upjohn, which hopes to sell latanoprost under the brand name Xalatan, said patients whose eye color remains unchanged after 18 months of drug use are probably OK.
The second FDA advisory panel recommended, by a 6-1 vote, that the agency approve Chiron Vision’s Vitrasert implant for sale for AIDS patients.
But it warned that sufferers getting the implant must also receive additional treatment because the cytomegalovirus that threatens their eyesight can silently invade other organs and kill them.
Most people eventually get cytomegalovirus and never know it, but the virus devastates and even kills AIDS patients because their immune systems cannot fight it. The virus spreads inside the eyes of about 40 percent of AIDS patients until they go blind.
The virus is fought with two drugs, one taken intravenously and one taken orally and intravenously. The injected drugs, ganciclovir and foscarnet, must be taken twice a day for weeks or months through a catheter that leaves patients open to infection. They also cause numerous, severe side effects. The oral ganciclovir isn’t absorbed well by the body.
The Chiron implant would allow ganciclovir to seep directly onto the retina. Patients would undergo a 45-minute, outpatient eye surgery to stick the capsule behind their retina and it works for about eight months.
A study of 173 patients showed the implant prevented progression of the eye infection about three times longer than intravenous ganciclovir _ for 220 days vs. 72 days. But none of the participants also took oral ganciclovir to keep the virus from spreading. Eleven percent were diagnosed with such a spread, mostly to their lungs and colons.