UPDATED: GSK's shingles candidate more effective than Merck's Zostavax in older adults, study says

Merck's ($MRK) Zostavax is the only shingles vaccine approved in the U.S. and the EU, but GlaxoSmithKline ($GSK) is one step closer to changing that. On Tuesday, the British pharma announced Phase III results for its shingles candidate, HZ/su, reporting an overall efficacy of 97.2% compared with placebo.

The clincher? HZ/su was tested in more than 16,000 adults aged 50 and older, and efficacy remained constant for people aged 50 to 70. This gives HZ/su an advantage over Zostavax, the efficacy of which declines in older people.

"We are extremely encouraged that the results may point out a health benefit in the prevention of shingles," Moncef Slaoui, GSK's Global Vaccines Chairman, said in a statement. "This disease can be painful and potentially debilitating for some people and older people are particularly at risk. We look forward to continuing the development of our Zoster program."

It's important to have a vaccine that maintains efficacy in older people as the risk for shingles "goes up really quite steeply as we age," Dr. Len Friedland, VP of scientific affairs and director of public health at GSK Vaccines, North America, told FierceVaccines. The vaccine not only prevents shingles disease, but also guards against complications from shingles, he said.

Moncef Slaoui

More trials are being conducted to assess the vaccine's efficacy in people aged 70 and older and also in adults with compromised immune systems.

After approval, HZ/su would be "well positioned to capture market share from Zostavax," wrote Cowen & Co. analysts in a note earlier this month. The analysts made sales forecasts for HZ/su of £10 million ($14.8 million) in 2017 and £75 million ($111 million) in 2020.

These revenues would help Glaxo protect its position as the top vaccine maker worldwide, a position it assumed after acquiring the bulk of Novartis' ($NVS) vaccine portfolio.

- here's the release (PDF)
- read FierceBiotech's take

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