Merck & Co won US approval for its shingles vaccine Zostavax ahead of the holiday weekend, the first product of its type to win through to market.
Shingles is caused by latent varicella zoster virus, the same virus that causes chickenpox, and can result in a blistering rash that can last for months or even years. In trials reported last year, Zostavax was able to reduce pain and discomfort in more than 60% of patients, cutting the incidence of persistent pain by two thirds.
The approval by the Food and Drug Administration (FDA) takes Merck closer to its objective of getting three new vaccines approved for marketing this year, with Zostavax following in the footsteps of Rotateq for rotaviral diarrhoea, approved earlier this year. The last member of the trinity, Gardasil for cervical cancer, was recommended for approval in the USA last week.
While Gardasil is predicted to be the biggest seller – potentially bringing in multibillion dollar revenues to Merck – Zostavax looks likely to be a good contributor with analysts predicting annual sales of $500 million or more million by 2009.
Zostavax is also expected to get a green light in the European Union shortly, after it was recommended for approval there in March. In Europe the vaccine will be sold by Sanofi Pasteur MSD.
As expected, the FDA has approved Zostavax only for people aged over 60, rather than over 50 as had been originally requested by the company.
Last December an FDA advisory panel said that the data were not strong enough to support use of the drug in this younger age group, although the incidence of shingles in the latter is low so the commercial impact of the more restrictive labelling is expected to be small.
Around one million cases of shingles are reported in the USA each year and is caused when latent varicella zoster virus re-emerges – often when people have a dip in immune function - and causes symptoms. Zostavax is designed to inhibit this resurgence of the virus, and Merck has shown that it can do so for at least four years.
"This vaccine gives health care providers an important tool that can help prevent an illness that affects many older Americans and often results in significant chronic pain," said Jesse Goodman, director of FDA's Center for Biologics Evaluation and Research.