Merck & Co.'s Zostavax approved in the US

Merck & Co. received FDA approval for its herpes zoster vaccine Zostavax in patients 60 years and older.

Results from the largest study conducted by Merck to evaluate the safety and efficacy of Zostavax involved 38 546 patients aged 60 and over with no previous history of herpes zoster, who were randomised to receive a single dose of Zostavax or placebo. Data showed that after a median follow-up period of 3.1 years, Zostavax "significantly" reduced the risk of developing herpes zoster by 51 percent, compared to patients who received placebo. Merck noted in a statement that the vaccine's protective properties are documented through four years of follow-up, but the duration of protection after administration of the vaccine is "unknown," and that revaccination requirements have not been defined. Zostavax is the first product to garner approval for the prevention of herpes zoster.

Dr. Jeffrey Silber, Merck's senior director of clinical research, noted that the drugmaker "will be working with the FDA to talk about an indication beginning at age 50, and what it is specifically the FDA would like to see in addition," The New York Times reports. The drugmaker originally sought the vaccine's approval for patients 50 years and older, but an advisory panel last December said that Merck did not provide the data required to support the vaccine's use in people aged 50 to 59.

Miller Tabak analyst Les Funtleyder remarked that "while not unexpected, this approval shows that the company is capable of developing new therapeutics and also deliver on product guidance," as reported in CNN Money.

Additionally, Merck announced that the vaccine received approval in the EU and Australia earlier this month, and the company has filed the vaccine in other world markets. Marketing of Zostavax in regions outside of the US will begin in 2007, the company said.

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