FDA supports the efficacy and safety of Zostavax

January 2006

The FDA’s Vaccines and Related Biological Products Advisory Committee unanimously agreed that data supported the efficacy and safety of the investigational live-attenuated varicella zoster virus (VZV) vaccine Zostavax (Oka/Merck) to prevent herpes zoster in adults; however, the committee restricted its recommendation to men and women aged 60 and older.

Data presented were not sufficient to support the efficacy and safety of the vaccine in adults aged 50 to 59, committee members agreed. The committee also suggested areas for additional analysis, and Merck plans to work with the FDA on these analyses as well as the design of post-licensure studies.

Merck presented data from several studies conducted in more than 40,000 people. Such data included results of the phase-3 Shingles Prevention Study (SPS) of 38,500 men and women aged 60 and older, which found that the vaccine significantly reduced the incidence of postherpetic neuralgia by 66.5%, the burden of illness and discomfort caused by zoster by 61.1% and the incidence of zoster by 51.3%, as reported in June’s Infectious Disease News.

Study sponsors

The Department of Veterans Affairs conducted the study with the National Institute of Allergy and Infectious Diseases and Merck at 22 U.S. research sites over a five-year period. SPS results were published in the June 2, 2005, issue of The New England Journal of Medicine.

The company filed a Biologics License Application with the FDA on April 25, 2005, for Zostavax to reduce the risk, the burden of pain and discomfort associated with zoster and the risk of postherpetic neuralgia, the persistent, often debilitating long-term nerve pain that is the most common complication of zoster.

Merck also filed regulatory applications for Zostavax in several other world markets including the European Union, Canada and Australia.

The FDA is not bound by the committee’s recommendation, but considers its advice when reviewing investigational vaccines.

A recent U.S. study estimated that up to 1 million cases of zoster, or shingles, occur every year. The number of zoster cases is expected to increase as the population ages. zoster can affect anyone who has had chickenpox — more than 90% of adults in the United States — and occurs most frequently in older adults. In fact, it is estimated that up to half of all people who reach age 85 will have developed zoster during their lifetime.

The reactivation of latent VZV causes the disease, and zoster may first appear as abnormal skin sensations ranging from itching or tingling to severe pain on a single area of the body or face. It then progresses to a rash with fluid-filled blisters accompanied by pain that varies in intensity and duration.

Zoster also can lead to severe complications, including postherpetic neuralgia.

“Shingles can be a very painful disease that can lead to serious and long-lasting complications,” said Peter S. Kim, PhD, president of Merck Research Laboratories, in a release.

For more information:

• Oxman MN, Levin MJ, Johnson GR, et al. A vaccine to prevent herpes zoster and postherpetic neuralgia in older adults. N Engl J Med. 2005:352;2271-2284.