(Reuters) - The U.S. Food and Drug Administration approved GlaxoSmithKline's Shingrix shingles vaccine for use in adults aged 50 and over, a move widely expected after an advisory panel to the agency last month voted unanimously to recommend its approval, the company announced on Friday.
Shingrix is seen as an improvement over Zostavax, the only currently marketed shingles prevention vaccine, sold by Merck & Co.
The vaccine is considered one of the more important products in Glaxo's pipeline, with annual sales forecast to reach $1 billion by 2023, according to Thomson Reuters data.
Glaxo said the U.S. Centers for Disease Control and Prevention's advisory committee on immunization practices is expected to vote on a recommendation for the use of Shingrix at its meeting on Wednesday.
The company said it expects Shingrix "will be available shortly."The vaccine demonstrated its efficacy in two pivotal Phase III studies involving more than 29,000 subjects.
Shingrix has shown greater protection against shingles among older recipients than Zostavax. Four years after injection, the Glaxo vaccine remained about 90 percent effective in people over age 70, while the efficacy of Zostavax declines noticeably over time.
Older adults are most at risk for an outbreak of shingles, a painful, often debilitating blistering rash that results from reactivation of the varicella-zoster virus, which causes chickenpox and remains latent in those who have had that disease.
Given in two doses two months apart, Shingrix also reduces incidence of nerve pain following a shingles outbreak.
Shingrix contains a component used to help boost efficacy from Agenus Inc, which is entitled to royalties on future sales.
The vaccine won its first approval in Canada last week and is awaiting approval decisions in Europe, Japan and Australia.
(Reporting by Bill Berkrot and Deena Beasley; Editing by Sandra Maler)