By Amber Murray Pharmaceutical giant GSK has reported a drop in profit due to charges related to the Zantac lawsuits but has reaffirmed guidance and said its core outlook remained unchanged. Operating profit fell by 86 per cent, and earnings per share slumped due to a settlement charge of £1.8bn related to the Zantac lawsuits. The lawsuits arose after recipients of GSK’s heartburn drug Zantac claimed it caused cancer. Chief executive Emma Walmsey said the move to settle around 80,000 lawsuits across the US – covering about 93 per cent of the claims – was “to remove uncertainty… so we can focus…