2007年10月18日

万有製薬株式会社

「米国で新たな作用機序を持つ経口HIV-1インテグラーゼ阻害剤
ラルテグラビルが承認」に関するお知らせ

United StatesFDA Approves ISENTRESS^TM (raltegravir) Tablets,
First-in-Class Oral HIV-1 Integrase Inhibitor

WHITEHOUSE STATION, N.J., U.S.A., 12 October 2007 -- Merck & Co., Inc., also known as Merck Sharpe & Dohme (MSD), announced today that the United States (U.S.) Food and Drug Administration (FDA) granted ISENTRESS^TM (raltegravir) tablets accelerated approval for use in combination with other antiretroviral agents for the treatment of HIV-1 infection in treatment-experienced adult patients in the U.S. who have evidence of viral replication and HIV-1 strains resistant to multiple antiretroviral agents.[1]

This indication is based on analyses of plasma HIV-1 RNA levels up through 24 weeks in two controlled studies of raltegravir.  These studies were conducted in clinically advanced, three-class antiretroviral [nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs)] treatment-experienced adults.  The use of other active agents with raltegravir is associated with a greater likelihood of treatment response.  The safety and efficacy of raltegravir have not been established in treatment-naïve adult patients or pediatric patients.  There are no study results demonstrating the effect of raltegravir on clinical progression of HIV-1 infection.  Longer term data will be required before the FDA can consider traditional approval for raltegravir.

Raltegravir is the first medicine to be approved in a new class of antiretroviral drugs called integrase inhibitors.[1][2] Raltegravir works by inhibiting the insertion of HIV DNA into human DNA by the integrase enzyme.[1] Inhibiting integrase from performing this essential function limits the ability of the virus to replicate and infect new cells.[3] There are drugs in use that inhibit two other enzymes critical to the HIV replication process – protease and reverse transcriptase – but raltegravir is the only drug approved that inhibits the integrase enzyme.[4][2]

The U.S. FDA's decision was based on a 24-week analysis of clinical trials in which ISENTRESS in combination with optimised background therapy (OBT) in treatment-experienced patients, provided significant (p<0.001) reductions in HIV RNA viral load and increases in CD4 cell counts.[1]

 “Raltegravir is the first drug in a new class of antiretroviral therapies that when used in combination with other effective antiretroviral agents, offers a new opportunity for individuals whose HIV infection is no longer adequately controlled and whose virus is resistant to multiple agents, ," said Peter S. Kim, Ph.D., president, Merck Research Laboratories.  "This approval builds on our long standing commitment to research in HIV/AIDS, with the goal of making truly differentiated therapies available to patients in need."

MSD HIV research

MSD is committed to developing innovative therapies that offer advances in the treatment of infectious diseases – including HIV.  MSD'sefforts to develop investigational treatments for HIV/AIDS have been under way for more than 20 years and continue today.  MSD began its HIV integrase inhibitor research in 1993 and was the first to demonstrate inhibition of HIV integrase in vitro and in vivo.

Raltegravir is one part of MSD's history in HIV research, which includes the development of CRIXIVAN®  (indinavir sulfate), a PI; STOCRIN^TM, a NNRTI; and research currently underway on additional treatment options.

Prevalence of HIV/AIDS

An estimated 40 million people are infected with HIV/AIDS worldwide, and more than four million new infections occurred worldwide in 2006.[7] AIDS is one of the top causes of infectious disease-related mortality worldwide, responsible for nearly three million deaths last year alone.[8]

About Merck & Co., Inc., Whitehouse Station, N.J., U.S.A.

Merck & Co., Inc., which operates in many countries as Merck Sharpe & Dohme (MSD), is a global research-driven pharmaceutical company dedicated to putting patients first.  Established in 1891, MSD 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 onlydonate MSD medicines but help deliver them to the people who need them.  MSD 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 onmanagement's current expectations and involve risks and uncertainties, which may causeresults 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.  MSD 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 MSD's business, particularly those mentioned in the risk factors and cautionary statements in Item 1A of MSD's Form 10-K for the year endedDec. 31, 2006, and in its periodic reports on Form 10-Q and Form 8-K, which the company incorporates by reference.

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