"Cost is an issue for our health care system as a whole and also, often, for the patient," said Dr. Naresh Mandava, at the Rocky Mountain Lions Eye Institute in Colorado.
"Many patients are unable to pay the co-pay for such an expensive drug," Mandava said.
Some doctors said that the extra cost of Lucentis is enough to make them shy away from prescribing it.
"The difference in cost between the drugs exceeds $1,800 and is a factor for patients who do not have complete drug coverage," said Dr. Jayakrishna Ambati, vice chairman of the department of ophthalmology and visual services at the University of Kentucky.
For patients who do have insurance coverage, Lucentis can still be too costly.
Said Ambati, "Even their 20 percent co-pay is a significant burden for a drug that requires 12 injections a year at nearly $2,000 per visit for the drug alone!"
So Ambati goes with the less-expensive but FDA-unapproved option.
"I offer Avastin to such patients while informing them that Lucentis is the FDA-approved drug: Most patients choose Avastin in this circumstance," Ambati said
But cost isn't the only thing that matters. An expensive drug might be worth it if it works better than the alternatives.
Experts couldn't say for sure if Lucentis works better than Avastin, but they suggested that it might.
"We are currently in the position of having a proven, FDA-approved treatment and a less expensive off-label treatment that has similar biologic activity and seems to have a similar treatment effect but has not been carefully studied in the eye," Ferris said
So scientists need to see more research that compares the two drugs side by side. But some doctors already believe that Lucentis might be a better choice.
And studies suggest it could also be safer than Avastin.
But only a controlled experiment that tests Lucentis against Avastin would tell doctors whether one drug is better than another.
Since the drug company Genentech makes both of the drugs, it's not likely to sponsor such an experiment.
But the government will. The U.S. National Eye Institute plans to compare the two drugs under controlled conditions.
"The NEI has received a grant application to study Avastin versus Lucentis, and that has been approved after peer review. Current evaluation of the feasibility of this trial is under way," Ferris said.
In the meantime, AMD patients have something that can save their clouding eyesight.