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LONDON, April 28 (Reuters) - An experimental shinglesvaccine from GlaxoSmithKline is effective across all agegroups, researchers said on Tuesday, boosting the prospects of akey product in the British drugmaker's development pipeline.
In contrast to Merck's established Zostavax,currently the only product on the market, GSK's vaccine HZ/sushowed no diminution in efficacy with age, according to detailedresults from a large Phase III trial.
Zostavax is less effective among people who are 70 years orolder - a group often at risk from shingles.
Goldman Sachs analysts said in a report on Tuesday thatefficacy across age groups could give HZ/su a meaningful edgeover Zostavax, and GSK's product had the potential to achievepeak sales of around 1 billion pounds ($1.5 billion) a year.
GSK had said in a brief release in December that HZ/sureduced the risk of shingles by 97.2 percent in adults aged 50years and older.
However, the full results of the clinical study givingage-group breakdowns were only disclosed at a medical congressin Copenhagen on Tuesday and published online simultaneously inthe New England Journal of Medicine.
These showed efficacy was maintained across age groups,ranging between 96.6 percent in people aged 50-59 years and 98percent in those 70 years or older.
The vaccine had a clinically acceptable safety profile,researchers on the GSK-funded study said, although reports ofinjection-site redness, swelling and pain were common.
Shingles is caused by the varicella-zoster virus, the samevirus that causes chickenpox. After an attack of chickenpox, thevirus lies dormant in certain nerve tissue but in older peoplein can reappear in the form of shingles.
GSK and Merck's vaccines work in different ways. Zostavax isa so-called live attenuated virus vaccine while HZ/su combines aprotein found on the virus that causes shingles with anadjuvant, or booster, which is intended to enhance theimmunological response.
The adjuvant includes a component from U.S. biotech firmAgenus, which is entitled to royalties on any futuresales.
($1 = 0.6554 pounds) (Reporting by Ben Hirschler; Editing by Pravin Char)
