GlaxoSmithKline's shingles vaccine has staying power. According to new data, Shingrix protects for at least four years, a claim that Merck's big-selling Zostavax can't make. With GSK now planning regulatory filings within a few months, the Merck shot may face trouble.
On Wednesday, GSK said Shingrix maintained its 90% efficacy in adults 70 and older for at least four years. If approved, the shot represents a “major” market disruptor, GSK vaccines head Moncef Slaoui previously told FiercePharma. That’s because it would see market share gains and also drive “uptake of the vaccine, which today is quite limited in the older population,” he said.
If the FDA notes Shingrix's long-lasting effects on its official label, GSK could use that advantage to grab market share from Zostavax. Currently the only shingles vaccine on the market, Zostavax posted lower efficacy numbers in its clinical trials, and the Merck shot's efficacy wanes within the first 5 years in people 60 and over, the CDC has said.
As GSK noted on Wednesday, in two Phase III trials, Shingrix showed 89% efficacy in preventing painful postherpetic neuralgia, the most common shingles complication, in people aged 70 and older. For people aged 50 and older, that number was 91%.
The only reliable way to compare two products is with head-to-head trials. But doctors and public health officials do consider trial-data differences. In its own studies, Zostavax showed a 64% reduction of herpes zoster in people aged 60 to 69, a number that fell to 41% in the 70-to-79 age range and 18% for those 80 and older.
Zostavax brought in $749 million in 2015 sales for Merck, and analysts cited by Bloomberg are looking for $842 million from Shingrix by 2020.
Dr. Emmanuel Hanon, SVP of vaccines R&D at the British pharma, said if approved, Shingrix “could be an important tool for the prevention of shingles and the pain associated with it, which would significantly impact the health and quality of life of so many people."
The vaccine’s success in the elderly population, according to Slaoui, is due to its adjuvant, which he previously said is "able to rejuvenate, in a way, the immune response to the vaccine antigen." By using the same formulation in other vaccines for the elderly, the company hopes to provide vaccines with efficacy "in the 90s rather than in the 50s and 60s,” he told FiercePharma.
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