Members of the Sackler family who own Purdue Pharma LP. are nearing an agreement to boost their more than $4 billion offer to resolve sprawling opioid litigation after negotiating with states that had objected to terms of the OxyContin maker’s bankruptcy reorganization, according to a court filing. Sackler family members and states objecting to terms of Purdue’s bankruptcy reorganization are “close to an agreement in principle” to contribute additional cash beyond the $4.325 billion they had pledged to settle opioid litigation, according to a mediator’s interim report filed on Monday. An agreement involving members of the Sackler family and several state attorneys general could potentially end a legal challenge that has prevented Purdue from exiting bankruptcy, and clear the way for a plan aimed at helping to abate the opioid crisis. The mediation kicked off in January among Sackler family members and several states after a U.S. district judge overturned …