The billionaire Sackler family, owners of OxyContin maker Purdue Pharma, said it would abandon a pledge to pay a $4.5 billion settlement to help communities that have been devastated by the opioid epidemic, unless they’re granted immunity for all current and future lawsuits. David Sackler, a former Purdue board member and the grandson of one of the founders, made the remarks as he testified at a hearing in federal bankruptcy court Tuesday.