UPDATE 4-U.S. state lawsuits against Purdue Pharma over opioid epidemic mount

NEW YORK, May 15 (Reuters) - Litigation against OxyContin maker Purdue Pharma LP is intensifying as six more U.S. states on Tuesday announced lawsuits, accusing the company of fueling a national opioid epidemic by deceptively marketing its prescription painkillers to generate billions of dollars in sales.