Sales of shingles vaccines boosted GlaxoSmithKline's profits in the final quarter of 2018, allaying investor concerns about Britain's biggest drugmaker's prospects beyond its blockbuster Advair asthma drug.
However, the drugmaker cautioned that full-year earnings for 2019 would decline between 5 percent and 9 percent because of fresh competition for Advair from Mylan's generic treatment, which won approval from U.S. regulators last month, and the impact of its $5.1 billion Tesaro acquisition.
Sales of Shingrix, the company's Shingles vaccine launched in 2017, more than doubled in the quarter to 221 million pounds, while Advair sales fell 20 percent to 647 million pounds, although that was still more than the 592 million pounds expected by analysts.
GSK shares reversed earlier losses to trade marginally higher at 1527.6 pence by 1 p.m. GMT.
GSK has been streamlining operations and spinning off or selling units, including its consumer health division, in order to focus on expanding its drug pipeline and developing vaccines.
The moves come as British companies face the many unknowns related to the UK's impending exit the European Union.
GSK, which is heavily dependent on international markets, said that there was "considerable uncertainty" about Brexit and warned that leaving the bloc without a exit deal would be a bad outcome.
Britain is due to leave the EU on March 29, and with Prime Minister Theresa May still battling to get parliamentary approval for her exit plan, businesses are spending millions of pounds to prepare for a "no-deal" exit.
GSK reported adjusted earnings per share of 31.2 pence on sales of about 8.20 billion pounds ($10.62 billion) in the three months to Dec. 31.
Analysts had expected earnings of 27.7 pence and sales of 7.95 billion pounds, according to a company-provided consensus of 11 analysts.
Brokerage Jefferies said it believed the initial 2019 earnings target of between 5 percent and 9 percent lower should be well received, given widespread concern of up to a double-digit decline.