Merck

(MRK) - Get Report

gained Monday despite two reports over the weekend questioning its handling of the now-withdrawn arthritis drug Vioxx.

The CBS News television program

60 Minutes

Sunday broadcast a report saying the company knew Vioxx posed possible health risks before its withdrawal Sept. 30.

The story, citing company documents and a well-known cardiovascular researcher, included the case study of a 39-year-old woman who had been diagnosed with early stage rheumatoid arthritis and died less than a month after she started taking the drug.

In addition,

The New York Times

Saturday reported that Merck decided against conducting a study on the heart risks in 2000 because marketing executives worried it might hurt sales of the drug.

Merck has said it withdrew the drug after a company-sponsored test showed a higher risk of cardiovascular problems, such as heart attack or stroke, among long-term users of Vioxx vs. patients who received a placebo.

The stories are the latest to question what Merck knew about the drug both prior to and after its approval by the Food and Drug Administration. Vioxx was launched in the U.S. in 1999 and has been marketed in more than 80 countries. Worldwide sales of Vioxx in 2003 were $2.5 billion.

The Vioxx recall has pounded Merck's share price down to an eight-year low and triggered calls for the resignation of the company's Chairman and CEO Raymond Gilmartin. Dozens of lawsuits have been filed against the company.

Shares were recently up 67 cents, or 2.5%, to $27.12. They closed at $45.07 the day before the recall was announced.

Fitch Ratings last Thursday downgraded Merck's senior unsecured and bank loan ratings to AA from AAA, making it the second ratings firm in a week to lower the credit rating of the drug giant. Moody's Investors Service cut its rating last Tuesday.

Merck revealed Monday that the Justice Department is investigating the events leading up to the Vioxx withdrawal and that the

Securities and Exchange Commission

has begun an "informal" inquiry.