About 1.6% of counties and other governments across the country have opted out of a class action designed to reach a global settlement over the opioid crisis—a turnout that one lead lawyer called a "landslide endorsement."

According to a report filed late Monday, 541 out of 34,000 governments as of Nov. 27 had opted out of the novel class, approved by U.S. District Judge Dan Polster of the Northern District of Ohio in September.  In response, co-lead counsel have labeled the class notice program a success that "has provided more than adequate notice to members of the negotiation class," according to Monday's filing.

"We're just thrilled. It's a landslide endorsement," said Jayne Conroy, one of two interim co-leads appointed for the class. "What we now have from the plaintiffs' perspective is an enormous group of sophisticated and active decision-makers who have all made a decision to remain in a negotiation class, and we have a way to reach out to them and discuss any potential settlement offers that would come our way. We have a very active, sophisticated and participating group of municipalities, government entities, counties and cities, who can now act as one."

Last month, ahead of a Nov. 22 deadline, Conroy predicted that there would be few opt-outs, even though some large counties, such as Harris County in Texas and Florida's Palm Beach County, announced plans to do so.

The unprecedented "negotiation" class is a master case designed to resolve all opioid lawsuits against drug companies and pharmacies. Polster certified the class Sept. 11 as part of a multidistrict litigation proceeding involving 2,400 opioid lawsuits, but more than 34,000 governments could participate in the class, even if they have not filed opioid lawsuits. If they do not opt out, cities and counties would be part of the class.

Although no settlement exists, lawyers for the class used a hypothetical $1 billion settlement to calculate an estimated dollar figure for each government.

"We had significant discussions with many, many government entities who decided to stay in, and they're all suffering from the opioid epidemic and anxious for anything to alleviate some of the pain. We heard that overwhelmingly again and again," said Conroy, who said she was on calls with hundreds of individuals from counties and cities across the country.

Class counsel expected additional opt-outs through this week but "the vast bulk of the exclusion requests likely have been received at this point," according to Monday's filing.

Deborah Hensler, a professor at Stanford Law School, called the opt-out rate typical for class actions, "which in this very atypical class procedure is notable."

"Where we see class actions with large numbers of opt-outs there are usually one or a few lawyers who have representation agreements with those class members, are very knowledgeable about the litigation, believe strongly that their clients will secure better outcomes through litigation or settlement outside the class action and therefore advise them to opt out," she wrote in an email. "That the opt-out rate here is so low suggests to me that there aren't many lawyers out there who believe that is the case here."

The 49 class representatives in the master case include major cities such as Atlanta, Chicago, Denver, Los Angeles and San Francisco. Conroy, of New York's Simmons Hanly Conroy, also noted that the city of New York and Cook County, Illinois, which includes Chicago, are staying in the class.

The "negotiation" class is novel because it comes prior to any settlement but, also, is not for pursuing litigation. In most cases, judges certify class actions under those two circumstances, but lead plaintiffs lawyers in the opioid multidistrict litigation insisted that the proposal fits within the confines of the Federal Rule 23 of Civil Procedure, which governs class actions.

The idea has faced criticism—most notably, from the drug companies and pharmacies that are defendants in the lawsuits. The defendants, and six Ohio cities, separately petitioned the U.S. Court of Appeals for the Sixth Circuit to reverse certification of the class. The Sixth Circuit agreed to take up the interlocutory appeal last month.

The "negotiation" class also excludes states, many of which opposed the idea. More than a month ago, a potential $48 billion global settlement fell apart after lead counsel in the multidistrict litigation, most of whom represent cities and counties, would not agree to the deal, hammered out by attorneys general in the states of North Carolina, Pennsylvania, Tennessee and Texas.

Conroy said settlement talks are ongoing.

"The endorsement of the class has nothing to do with the endorsement of an unknown settlement offer," she said. "But it tells me if we ever do receive a settlement offer to bring to the class, we have a very involved and active group of class members that will be anxious to vote on such an offer."