GlaxoSmithKline's shingles vaccine gets a leg up on Merck's rival with a PhIII win

GlaxoSmithKline's ($GSK) in-development shingles vaccine successfully staved off the virus in a massive Phase III study--and, in contrast with its top competitor, the shot's effects didn't wane among elderly patients.

The vaccine, HZ/su, reduced the risk of shingles by 97.2% compared with placebo in a study involving more than 16,000 patients, GSK said, maintaining its efficacy across all age groups. That latter point is particularly important, as Merck's ($MRK) Zostavax, the only approved shingles vaccine, tends to lose steam as patients approach 70.

Analysts with eyes on the shingles race have long pointed to elderly efficacy as the key catalyst that could vault HZ/su over Zostavax, and the Phase III success could rocket GSK's candidate to more than $1 billion in annual sales once it's approved. That'll likely come at the expense of Merck, which grossed $765 million from Zostavax last year.

In the meantime, GSK is running two more trials focusing on patients over 70 and those with compromised immune systems, evaluating how well the vaccine can prevent shingles-related complications including neuropathic pain. GSK's global Phase III effort for HZ/su involves more than 37,000 patients.

GSK Vaccines chief Moncef Slaoui

Unlike Zostavax, HZ/su is not a live shingles vaccine but rather uses a protein found in the virus to train the immune system and prevent infection. The shot charted a similar side-effect profile to placebo in the latest study, GSK said, with the most common complaints being muscle pain, fatigue and headache.

GSK had disclosed top-line data from the trial back in December but saved its age-group analysis for a presentation and simultaneous New England Journal of Medicine publication today.

"We are extremely encouraged that the results may point out a health benefit in the prevention of shingles," GSK Vaccines chief Moncef Slaoui said in a statement. "This disease can be painful and potentially debilitating for some people and older people are particularly at risk."

- read the results

Read more on