Andrew Pollack / New York Times News Service

In an unusual move, a big drug company said it would effectively cut in half the price of a new cancer drug after a leading cancer center said it would not use the drug because it was too expensive.

The move — announced Thursday by Sanofi for the colon cancer drug Zaltrap — could be a sign that the marketplace is becoming resistant to the unfettered increase in the prices of cancer drugs over the past decade. Some of the newest cancer drugs cost more than $100,000 a year and increase survival by a few months at best.

Zaltrap came to market in August at a price of about $11,000 a month. Soon afterward, the prestigious Memorial Sloan-Kettering Cancer Center in New York decided not to use the drug, saying it was twice as expensive but no more effective than a similar medicine, Avastin from Genentech. Both drugs improved median survival by 1.4 months, they said.

Three doctors at Sloan-Kettering publicized the decision last month in an op-ed article in The New York Times.

“Ignoring the cost of care is no longer tenable,” they wrote. “Soaring spending has presented the medical community with a new obligation. When choosing treatments for patients, we have to consider the financial strains they may cause alongside the benefits they may deliver.”

Sanofi executives argued that the price they set was very similar to that of Avastin.

“The intent was not to charge a premium,” Christopher Viehbacher, the chief executive of Sanofi, said in an interview last month.

He said his company had set the price to be roughly equivalent to that of Avastin. Sloan-Kettering, he said, was basing its price comparison on a dose of Avastin that was half the dose Sanofi used in its own comparison.

On Thursday, Sanofi backed down.

“We believe that Zaltrap is priced competitively as used in real-world situations,” it said in a statement. “However, we recognize that there was some market resistance to the perceived relative price of Zaltrap in the U.S. — especially in light of low awareness of Zaltrap in the U.S. market. As such, we are taking immediate action across the U.S. oncology community to reduce the net cost of Zaltrap.”

The decision was first reported Thursday by The Cancer Letter, a newsletter that covers cancer issues. While it will not change the official price, the company said it would offer discounts of about 50 percent.