GSK’s first quarter, under CEO Luke Miels, saw its flagship shingles vaccine Shingrix set a new quarterly sales record, while its hot new asthma product Exdenser showed “early signs” of commercial progress despite recent trial failures.
Shingrix sales in the U.S. rebounded from a 17% decline in full-year 2025, reaching 12% growth in the first quarter at constant currency, due to inventory increases related to the launch of new, easier-to-use prefilled syringes.
Thanks to tailwinds from the U.S. market, as well as strong demand in Europe, Shingrix’s global sales reached 1.03 billion pounds ($1.39 billion) in the first quarter, setting a new quarterly record, Nina Mohas, GSK’s president of global product strategy, said on a conference call with investors on Wednesday.
Shingrix’s rapid growth comes as a surprise as the entire vaccine industry grapples with a hostile U.S. policy environment. Sales exceeded Wall Street expectations by 20%.
In the U.S., cumulative vaccination rates for shingles increased by 3.5 percentage points from a year ago to reach 45% of eligible adults, Miels said.
“If you look at the remaining efforts, about 70 million people over the age of 50 have not been vaccinated. About a third of them intend to get vaccinated,” Miels said on the conference call, citing market research. “We are focusing on a comorbid subpopulation that is more motivated, and whose physicians and pharmacists are also more engaged.”
Meanwhile, demand in China also appears to be improving as the number of doses increases, but this is not reflected in GSK’s sales numbers, at least for the majority of the year, as the doses are sourced from partner Chongqing Jifei Biologicals’ existing stockpiles, Mojas said.
China’s self-administered vaccine market has shrunk in recent years, affecting major products such as Shingrix, also sold by Zhifei, and Merck & Co.’s HPV blockbuster Gardasil.
However, Mojas warned that year-on-year comparisons of vaccines in Europe and Japan will be difficult for the rest of the year.
“About 11% of the eligible population has been vaccinated in the top 10 markets outside the U.S., and there remains opportunity for further uptake,” she said.
Shingrix led GSK’s first-quarter sales growth, but the numbers for respiratory syncytial virus vaccine Arexvy don’t look quite as rosy. Sales of the shot fell 18% to 65 million pounds, 13% below analyst consensus, due to unseasonably low uptake as U.S. sales continued to decline due to slowing market demand.
Boot progress
During a conference call Wednesday, GSK management touted momentum on several new product launches. Among these, the bi-annual IL-5 drug Exdensur is one of the most important developments, with peak annual sales across several respiratory diseases estimated at around £3bn, according to GSK.
Exdensur, which was approved by the FDA in December to treat severe asthma, had sales of just £11 million in the first quarter. Mojas noted that access to the drug in the United States is currently limited to about 20% of commercial patients, ahead of the assignment of a permanent J code for reimbursement expected in July.
“Unaided awareness is above the benchmark, and usage intent is right in line with the benchmark,” Miels said of Exdensur. “And the main driver is the question of access, and that’s what we expect, especially if you’re buying six-monthly treatments.”
To convince investors that Exdenshul and its long-acting dosing are “key value drivers,” Mojas noted that 65% of patients discontinued short-acting biologics within the first 12 months. She noted that in its early days, about 70% of Exdensur users came from other biologics.
Compliance with biologics is the main reason for discontinuation, Mojas said, as some patients end up going back to inhalers.
However, GSK recently hit a snag with plans to convince patients that they can switch from existing short-acting biologics to Exdensur, which provides similar benefits. The Phase 3a Nimble trial compared Exdensur with GSK’s proprietary monthly Nucala or AstraZeneca’s bimonthly Fasenra, but failed to meet statistical non-inferiority. The annual rate of clinically significant exacerbations over 52 weeks was 0.57 for the GSK drug versus 0.49 for the comparison group. Although the rate ratio was 1.16, the study failed to meet its primary endpoint because the upper limit of the 95% confidence interval reached 1.38, exceeding the predefined non-inferiority bar of 1.28.
Dr Tony Wood, GSK’s head of research and development, said in an earnings call that Nimble was a well-controlled study, so the overall exacerbation rate was low. He noted that the absolute difference in annual exacerbation rates between the two groups was 0.08, meaning that patients on treatment would need 12.5 years to achieve one additional exacerbation.
“You put it in the context of beneficial compliance associated with long-acting drugs. I think you understand the importance of (Exdensur) as a long-acting drug in that population,” Wood said.
In well-controlled studies, patients are closely followed and treatment adherence is usually good compared to real-world experience.
Mojas also pointed out that about 30% of asthma patients are taking biologics. She suggested that if Exdensur receives a J code, it could use its convenience to capture some patients who are not receiving biologics.
Exdensur is undergoing three Phase 3 clinical trials (Endura-1, -2 and Vigilant) in moderate to severe chronic obstructive pulmonary disease, which drove Nucala’s first quarter growth of 12% at constant exchange rates to £484m.
Overall, GSK’s first quarter sales were $7.6 billion, up 5% year over year on a constant currency basis and meeting analyst consensus. The British pharmaceutical company has confirmed its full-year outlook for 2026, which includes a 3% to 5% increase in sales.
