Shares of GSK rose as much as 6.5% on Thursday after the British drugmaker agreed to pay up to $2.2 billion to settle lawsuits in the United States that claimed its discontinued heartburn drug Zantac caused cancer.

GSK Plc shares surged after the UK pharma company agreed to pay as much as $2.2 billion to resolve about 80,000 US court cases alleging that its old reflux medication Zantac was contaminated with a suspected carcinogen.

The British drugmaker reached a $2.2 billion settlement to resolve around 80,000 lawsuits over claims its Zantac heartburn remedy causes cancer