Merck & Co., Inc., Again Reduces Price of STOCRIN (efavirenz) for Patients in Least Developed Countries and Countries Hardest Hit by Epidemic.

Second Reduction in Less Than a Year

Will Help Expand Access to HIV/AIDS Care and Treatment

WHITEHOUSE STATION, N.J. -- Merck & Co., Inc.1, today announced a reduction in the price of its HIV/AIDS medicine, STOCRIN (efavirenz), in the least developed countries of the world and those hardest hit by the epidemic.

The price of the 600 mg formulation of STOCRIN has been reduced by 14.5 percent to US $0.65 per day, or US $237.25 per patient per year, from $0.76 per day, for purchasers in countries in the low category of the Human Development Index (HDI) and in medium HDI countries with an adult HIV prevalence of 1% or greater. In medium HDI countries with an adult HIV prevalence of less than 1%, the price of the 600 mg formulation of STOCRIN will be reduced by 5.8%, to US $1.80 per day, or US $657.00 per patient per year, from US $1.91 per day.

Merck is lowering the price of the 600 mg formulation of STOCRIN due to efficiencies resulting from improved manufacturing processes. This is the second time that the Company has reduced the price of this formulation in less than a year. The prices of other formulations of STOCRIN and Merck's other HIV/AIDS medicine, CRIXIVAN (indinavir sulfate), remain unchanged.

"Merck has long been a leader in efforts to broaden access to our medicines for those who need them around the world," said Merck Chief Executive Officer and President Richard T. Clark. "Today's price reductions reflect our continuing commitment to improve the lives of people living with HIV/AIDS throughout the developing world."

As a result of Merck's differential pricing policy, at the end of 2006 some 500,000 patients in 76 developing countries were being treated with antiretroviral regimens containing STOCRIN and CRIXIVAN.

Merck pricing policy for its HIV/AIDS medicines

These prices are available to all HIV/AIDS care and treatment providers who can demonstrate with reasonable assurance their capacity to ensure increased patient access. For example, providers include governments, international organizations, non-governmental organizations (NGOs) and private sector organizations (such as employers, insurers and hospitals). Under the MSD HIV/AIDS pricing policy, the medicines must be used in the country where they are sold and may not be exported.

Merck first announced that it was reducing the prices of STOCRIN and CRIXIVAN in developing countries to prices at which the Company makes no profit on March 7, 2001. Since then, access to HIV medicines has accelerated in the least developed countries and those countries where HIV/AIDS has hit hardest.

Improving access through public-private partnerships

In addition to Merck's ongoing HIV/AIDS antiretroviral and vaccine research programs, the Company continues to work in many public-private partnerships focused on increasing access to treatment and care. These partnerships play a critical role in the developing world by helping to build the health systems capacity necessary to ensure sustainable access to health care and treatment. Some of these programs include: African Comprehensive HIV/AIDS Partnerships (ACHAP) in Botswana, Merck Mectizan Donation Program, China/Merck HIV/AIDS Partnership, Merck Vaccine Network-Africa and Merck Medical Outreach Program (MMOP). (For further details, see www.merck.com/about/cr.)

About STOCRIN

STOCRIN is a once-daily, non-nucleoside reverse transcriptase inhibitor (NNRTI) used in combination treatment for HIV. People living with HIV/AIDS have the option of taking one 600 mg STOCRIN tablet once-daily instead of three 200 mg capsules. The 600 mg tablet is approved in more than 90 countries.

STOCRIN in combination with other antiretroviral agents is indicated for the treatment of HIV-1 infection. This indication is based on two clinical trials of at least one-year duration that demonstrated prolonged suppression of HIV-RNA. STOCRIN should not be administered concurrently with astemizole, cisapride, triazolam, midazolam, or ergot derivatives because competition for CYP3A4 by efavirenz could result in inhibition of metabolism of these drugs and create the potential for serious and/or life threatening adverse events (e.g., cardiac arrhythmias, prolonged sedation or respiratory depression).

The chemical entity of STOCRIN, efavirenz, was discovered by Merck Research Laboratories in 1992 and licensed to The DuPont Merck Pharmaceutical Company (now Bristol-Myers Squibb Company) in 1994 for development and marketing in certain countries. Bristol-Myers Squibb has exclusive marketing rights to efavirenz in the United States (including territories and possessions), Canada, United Kingdom, Republic of Ireland, France (continental only), Spain, Italy and Germany, and markets efavirenz under its trademark Sustiva. Through its subsidiaries and marketing partners, Merck has exclusive marketing rights in all other countries worldwide, and markets efavirenz under the trademark STOCRIN.

About Merck

Merck & Co., Inc. is a global research-driven pharmaceutical company dedicated to putting patients first. Established in 1891, Merck currently discovers, develops, manufactures and markets vaccines and medicines to address unmet medical needs. The Company devotes extensive efforts to increase access to medicines through far-reaching programs that not only donate Merck medicines but help deliver them to the people who need them. Merck also publishes unbiased health information as a not-for-profit service. For more information, visit www.merck.com.

Forward-Looking Statement 

This press release contains "forward-looking statements" as that term is defined in the Private Securities Litigation Reform Act of 1995. These statements are based on management's current expectations and involve risks and uncertainties, which may cause results to differ materially from those set forth in the statements. The forward-looking statements may include statements regarding product development, product potential or financial performance. No forward-looking statement can be guaranteed, and actual results may differ materially from those projected. Merck undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events, or otherwise. Forward-looking statements in this press release should be evaluated together with the many uncertainties that affect Merck's business, particularly those mentioned in the cautionary statements in Item 1 of Merck's Form 10-K for the year ended Dec. 31, 2005, and in its periodic reports on Form 10-Q and Form 8-K, which the company incorporates by reference.

1 Merck & Co., Inc., Whitehouse Station, NJ, USA, operates in most countries outside of the United States as Merck Sharp & Dohme, or MSD.