Indications for Singulair(R) Expand with FDA Approval for Perennial Allergic Rhinitis

Merck & Co, Inc announced today that the US Food and Drug Administration (FDA) has approved SINGULAIR(R) (montelukast sodium) for the relief of symptoms of perennial allergic rhinitis (PAR), or indoor allergies, in adults and children six months of age and older. A convenient once-a-day tablet, SINGULAIR has been proven to help relieve a broad range of indoor and outdoor allergy symptoms for up to 24 hours.

"Allergic rhinitis is one of the most common allergic conditions today, with approximately 50 million people in the United States suffering some form of the condition," said Gailen Marshall Jr., M.D., Ph.D., director of the Division of Clinical Immunology and Allergy at the University of Mississippi Medical Center in Jackson, MS. "Experts have estimated that 55 to 80 percent of these patients suffer from perennial, or year round, allergic rhinitis which is commonly triggered by indoor allergens such as dust, pet dander or mold. The approval of SINGULAIR for the relief of symptoms of perennial allergic rhinitis provides healthcare providers with a new, effective option to help bring relief to patients who suffer from indoor allergies and for whom SINGULAIR is appropriate."

SINGULAIR, which was approved for the treatment of the symptoms of seasonal allergic rhinitus (SAR) in 2003, is different from most oral allergy medications, which block histamine, in that it blocks leukotrienes, an important contributor to allergy symptoms. SINGULAIR is the only medication indicated for allergic rhinitis that specifically targets this particular underlying contributor to allergy symptoms. SINGULAIR is approved for SAR in adults and children two years and older, and for PAR in adults and children six months and older. For treatment of symptoms of allergic rhinitis, SINGULAIR is available in tablet form for adults (10 mg), as a cherry-chewable tablet (4 or 5 mg) for children aged two to 14 years and in oral granules (4 mg) for children six months to five years.

SINGULAIR helps relieve a broad range of indoor and outdoor allergy symptoms

In separate clinical trials of PAR and SAR, SINGULAIR (10 mg) has provided significantly greater symptom relief compared to placebo. The efficacy of SINGULAIR for treatment of PAR was evaluated in two randomized, double-blind, placebo controlled studies in patients age 15 to 82 years with PAR. In one of these studies, SINGULAIR demonstrated effectiveness in improving daytime nasal symptoms score, the primary endpoint, measured as the average of individual scores for nasal congestion, runny nose and sneezing.

The efficacy of SINGULAIR for treatment of symptoms of SAR was previously established in placebo and active-controlled clinical studies of patients age 15 to 82 years. In these studies, SINGULAIR demonstrated effectiveness in improving daytime nasal symptoms score, the primary endpoint, measured as the average of individual scores for nasal congestion, runny nose, nasal itching and sneezing.

Safety profile of SINGULAIR in allergic rhinitis studies similar to that seen with placebo

In clinical studies for both SAR and PAR, SINGULAIR was generally well tolerated with a safety profile similar to that of placebo for both children and adults. The incidence of sleepiness was similar to placebo in all studies for adults and adolescents 15 years of age and older with SAR and PAR. In these studies, the most frequently reported side effects included headache, ear infection, sore throat and upper respiratory infection. These events varied by age, and were reported at a frequency greater than or equal to two percent, and at an incidence greater than placebo in either the SAR or PAR studies.

Important information about SINGULAIR for treatment of asthma SINGULAIR is also indicated for the prevention and chronic treatment of asthma in adults and pediatric patients 12 months and older. The use of SINGULAIR for asthma may not eliminate the need for inhaled or oral corticosteroids. Patients should be advised to take SINGULAIR daily as prescribed even when they have no symptoms, as well as during periods of worsening asthma, and to contact their health care provider if their asthma is not well controlled. SINGULAIR should not be used for the fast relief of acute asthma attacks or used alone to treat and manage asthma made worse by exercise. Patients with known aspirin sensitivity should continue avoidance of aspirin or non-steroidal anti-inflammatory agents while taking SINGULAIR.

In clinical studies for asthma, side effects in adults and children taking SINGULAIR were usually mild and generally did not cause patients to discontinue therapy. The most commonly reported side effects varied by age and included headache, ear infection, sore throat and upper respiratory infection.

About allergic rhinitis

Allergic rhinitis, an inflammation of the mucous membranes of the nose due to allergens, is one of the most common allergic conditions in the U.S., affecting approximately 50 million Americans. Allergic rhinitis is classified as either seasonal or perennial depending upon the type of trigger and duration of symptoms. SAR symptoms occur in the spring, summer and/or early fall and are triggered by outdoor allergens such as airborne tree, grass and weed pollens while PAR is usually persistent and chronic with symptoms occurring year-round and is commonly associated with indoor allergens such as dust mites, animal dander and/or mold spores. Symptoms of allergic rhinitis may include runny nose, nasal itching, sneezing, watery eyes and nasal congestion.

About Merck

Merck & Co., Inc. is a global research-driven pharmaceutical company dedicated to putting patients first. Established in 1891, Merck discovers, develops, manufactures and markets vaccines and medicines in over 20 therapeutic categories. 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 http://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 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, 2004, and in its periodic reports on Form 10-Q and Form 8-K which the company incorporates by reference.

SINGULAIR(R) (montelukast sodium) is a registered trademark of Merck & Co., Inc.

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