The drug company Genentech is using secret — but perfectly legal — rebates to eye doctors to get them to prescribe Lucentis, a drug for age-related macular degeneration that is 100 times more expensive than another, equally effective drug, according to an article in Wednesday’s New York Times.

There’s a twist to this story: The second drug, Avastin, is also made by Genentech, although it’s been approved only to treat cancer. Ophthalmologists use Avastin off-label to treat macular degeneration because they have found it works as well as Lucentis and because each injection costs only $20 to $50, compared to $2,000 per injection for Lucentis. Macular degeneration patients need these injections as often as once a month.

Although off-label uses of drugs are often problematic, a recent British study found Avastin to be safe for the treatment of macular degeneration.

The secret rebate program started Oct. 1 and can reap individual doctors tens of thousands of dollars each calendar quarter, notes Times reporter Andrew Pollack, who has read a copy of a confidential document that outlines the program.

Some opthalmologists are, however, seeing red. “There’s no way to look at that without calling it bribery,” Dr. Greg Rosenthal, a retina specialist in Toledo, Ohio, told Pollack. Dr. David W. Parke II, chief executive of the American Academy of Ophthalmology, said his organization was reviewing the program. “The issue,” he told Pollack, “is really does this constitute a financial inducement that in some way alters delivery of care in a way that is not in the patient’s best interest?”

Some doctors, Pollack reports, “thought the company might be worried about the results, expected next spring, of a clinical trial comparing Avastin and Lucentis in treating macular degeneration. If the drugs are proven equivalent, the rebates might help slow the defection to the cheaper alternative.”

Medicare alone saves more than $500 million each year by using Avastin rather than Lucentis.

It will be difficult to know which doctors are receiving the rebates — at least until the Physician Payments Sunshine Act, part of the national health care bill passed earlier this year, becomes fully operational in 2013.

That is, if the bill isn’t overturned by the new Congress.

You can read the Times article here.