(Bloomberg) -- GSK Plc raised its profit forecast for the year as it predicts higher-than-expected sales from HIV, infectious diseases and respiratory drugs.

It now expects core earnings per share to rise as much as 10%, up one percentage point at the top end of its previous range.

The British pharmaceutical company saw sales increases for several of its products across the portfolio, including its HIV drug Tivicay, asthma medicine Trelegy and its cancer product Zejula.

The biggest seller was its shingles vaccine. GSK’s new vaccine for respiratory syncytial virus, Arexvy, posted lower than expected sales, but the drugmaker still has the leading market share, even with strong competition from Pfizer. It will soon also have to vie with Moderna Inc, which is awaiting approval for its own RSV vaccine.

The lower sales for Arexvy “reflects the seasonality that was expected to start playing out for this vaccine,” said Shore Capital’s Sean Conroy.

The big issue is what happens when the RSV season gets going again, according to Chief Executive Officer Emma Walmsley, who also said an extra 15 million American patients could get access to the treatment if it’s approved for the 50 to 59 year-old age group. “There is plenty of room for growth,” she said on a call with reporters. 

GSK also said Wednesday that core earnings per share were 43.1 pence ($0.51) in the first quarter, beating expectations. The drug maker’s share price rose about 1.5% in morning trading, and is up nearly 17% since a year ago.

GSK increased its long-term sales forecast in January and has seen several analysts upgrade their ratings.

“GSK’s minor guidance increase looks conservative and gives it the ability to raise later in the year,” said Bloomberg Intelligence analyst John Murphy.

Still, litigation over the heartburn medication Zantac continues to loom. Former Zantac users who have sued GSK and other producers claim the drug’s active ingredient, ranitidine, degraded and turned into a potential carcinogen called NDMA under some conditions. The companies deny these claims.

Read More: Zantac’s Maker Kept Quiet About Cancer Risks for 40 Years

--With assistance from Lisa Pham.

(Updates with comments from CEO in sixth paragraph.)

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