Two prescription creams to treat eczema will now carry strong warnings about the possible risk of skin cancer, lymphoma and other cancers, their manufacturers and U.S. regulators said on Thursday.

The creams, Novartis AG’s Elidel (pimecrolimus) and Astellas Pharma Inc.‘s Protopic (tacrolimus), will come with a “black-box” warning - the strongest type used in the United States - 10 months after the agency first called for them.

Food and Drug Administration officials said while a clear link between the drugs and cancer risk had not been found, there have been enough cancer reports to warrant the change. A total of 78 cases were reported for both products as of October 2005, they said.

“The concern that is being highlighted today is that the long-term safety of these products has not been established,” Dr. Julie Beitz, an acting office director within the FDA’s office of drug evaluation, said.

The labels also include changes to make clear that both treatments are only supposed to be used after other drugs are tried first. They also say the creams are not recommended for children younger than 2 years old.

Eczema, a rash-like inflammation that causes itchy, red skin, can also be treated with antihistamines, oral and topical steroids and over-the-counter products.

Both companies continued to defend their drugs as safe, but agreed to make the change anyway after months of negotiation with the FDA.

“While Novartis believes this action is not substantiated by scientific or clinical evidence, Novartis has agreed to make the requested changes and will communicate them to physicians and patients so that they can continue to use Elidel as labeled to effectively manage eczema,” the company said.

Joyce Rico, an Astellas vice president for research and development, said the data did not show any cancer link.

“I believe that the information that is available continues to show that Protopic is a safe and effective medication when used as prescribed, and that the causal relationship with lymphoma has not been documented,” she said.

The new warnings come after the agency called for the change in March, one month after its panel of outside experts recommended them. At the time, Novartis disputed the request.

FDA’s Beitz said the agency then had to create an internal review panel to reassess all of the data, which took time. “We really wanted to be sure we understood what the data was telling us,” she said.

Beitz added that the FDA recognized the companies disagreed with its analysis.

“We certainly acknowledge that there have been differences in opinion on whether there is or is not a cancer risk,” she said. “But in the end, what the agency is saying is that we really wanted to convey the reported cancer cases that occurred.”

Novartis and Astellas, the result of the merger between Yamanouchi Pharmaceutical Co. and Fujisawa Pharmaceutical Co., are conducting long-term safety studies for their products.

The FDA said it could not wait for those results before taking action.

“Although studies are being conducted by the manufacturers of both drugs to try to answer questions about cancer risk, it could be many years before the research is concluded,” the agency said in a statement.