As Shingrix rivalry looms in the U.S., Merck's Zostavax yields share in Korea to SK’s Skyzoster

Merck blames marketing activities by SK Chemicals as its Zostavax quickly yields Korean market share to SK's newly launched Skyzoster. (SK Chemicals)

As Merck’s shingles shot Zostavax is challenged by GlaxoSmithKline’s Shingrix in the U.S., it's also quickly yielding market share in South Korea to SK Chemicals’ Skyzoster—and it is suspected that SK’s pricing and marketing tactics played an important part.

Some local clinics have lowered the price of shingles vaccines by 30,000 to 40,000 won ($28.20 to $37.60), saying they wanted to encourage more vaccinations. But the timing of those price cuts—they came on the heels of the Skyzoster launch—raised eyebrows at MSD Korea, according to Korea Biomedical Review.

It was reported that Merck suspected that clinics simply switched to cheaper Skyzoster under marketing influence from SK, because Merck itself hasn’t changed its Zostavax wholesale price. However, a media aide for Merck reached out to FiercePharma, saying that the drugmaker has not commented on the decrease of Zostavax sales or its relationship with marketing activities by SK.

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The price of Zostavax in Korea is reported at about 160,000 to 200,000 won per shot, whereas that of Skyzoster stands at 130,000 to140,000 won, according to the Korean publication.That's a difference of about $56.

SK says it's not involved in retail pricing decisions. “The company sets the supply price, which takes into account various factors such as facilities, R&D, and investment costs. We cannot intervene in clinics’ pricing of shingles vaccines at all,” said an official at SK, as quoted by Korea Biomedical Review.

After testing its shingles vaccine on a total of 842 adult patients over 50 years of age, SK Chemical gained approval for Skyzoster last October and rolled it out in late December to challenge Zostavax’s monopoly in the country since 2013.

Since then, Skyzoster has quickly eaten away Zostavax’s market share. SK recently said cumulative sales of the vaccine would exceed 8 billion won by the end of February. With that momentum, it aims to grab 50% of the country’s estimated 80 billion-won market by the end of 2018.

RELATED: Fresh off FDA approval, GlaxoSmithKline's Shingrix gets CDC panel vote over Merck shot

“There are more than 11 million potential patients in Korea alone who require a shingles vaccine,” said Jae-yong Ahn of SK Chemicals’ vaccine division in a recent statement. “We will contribute to the health of people nationwide through a stable supply of Skyzoster to the market, which has traditionally suffered from unsteady supply.”

The fight for the Korean shingles vaccine market comes as Merck is also prepping for intense competition in the U.S. and EU market from GSK's Shingrix.

In its recently revised immunization advisory, the CDC is already recommending Shingrix over Zostavax for adults 50 or older—even for those who’ve previously received Zostavax. Canada approved the GSK shot last October ahead of the FDA nod, and a positive decision from the European Commission is also expected by April as the EMA’s Committee for Medicinal Products for Human Use has also already recommended it. Analysts predicted that Shingrix could cross the blockbuster threshold by 2022.

SK, in its Skyzoster approval statement last October, said it also plans to expand into the global market.

Editor's Note: The story has been updated to include communication from a Merck representative, who denied the drugmaker has ever made comment on the issue.