Sheller P.C. managing partner Brian J. McCormick Jr., whose practice is heavily focused on pharmaceutical mass torts and whistleblower litigation, is leaving the firm to join Ross Feller Casey, both firms confirmed Friday.

Ross Feller principals Matthew A. Casey and Joel Feller said McCormick will be directing the firm’s new mass tort and whistleblower department along with Mark A. Hoffman, who joined the firm from Kline & Specter in February.

Meanwhile, Sheller P.C. and Kline & Specter also confirmed Friday that they are now co-counsel in the litigation over the antipsychotic drug Risperdal.

Kline & Specter principal Tom Kline said Sheller’s clients have been notified and he and his firm have entered their appearance as trial counsel in more than 250 Risperdal cases.

Kline said his firm will work alongside Sheller P.C.’s lawyers, including firm head Stephen Sheller, in the litigation.

“We are going to work on the cases collaboratively and I expect to be at the helm, with Steve along with me,” Kline said, noting that several cases are scheduled for trial in July and August.

Though McCormick has been very involved in the Risperdal suits, serving as plaintiffs liaison counsel in the litigation, Sheller said he had been planning to bring in an outside attorney as trial counsel in the litigation even before McCormick announced his departure.

“That was going to occur whether Brian left or stayed,” Sheller said, noting that his firm previously teamed up with Robert Hilliard of Corpus Christi, Texas-based Hilliard Munoz Gonzales as trial counsel in the first Risperdal trial in October 2012.

Sheller said that, because of the number of Risperdal cases his firm is currently handling and with trials coming up this summer and more scheduled for fall, he thought his firm would need assistance.

According to Sheller, he first began talking to Kline & Specter about partnering on the case a few months ago but finalized the agreement about two weeks ago.

Kline & Specter is a good fit, he said, because of the firm’s extensive experience with pharmaceutical litigation.

According to Sheller, while the firms have referred work to each other over the years, they’ve never before co-counseled a case.

But Sheller stressed that his firm will work closely with Kline & Specter on the Risperdal litigation.

“This is not a case of us referring it,” Sheller said, noting that his firm has been developing the Risperdal litigation for about 10 years. “They need us and we need them.”

Kline agreed.

“I am expecting to work the cases along with the team Sheller has in place,” Kline said, adding, “Steve and his firm singlehandedly, in the nation, were pioneers in the Risperdal litigation and developed an extensive work product. I’ve now reviewed a significant portion of it and it is excellent and I believe the case is strong.”

McCormick, meanwhile, said he plans to remain involved in the Risperdal litigation, noting that Ross Feller currently has some Risperdal cases the firm’s investigating and preparing to file.

McCormick said it’s up to Philadelphia Court of Common Pleas Judge Arnold L. New, the coordinating judge of the court’s Complex Litigation Center, whether he remains liaison counsel in the case, but he is optimistic he will continue in that role.

“I am confident that Judge New knows I am capable of performing my duties as liaison going forward wherever I work and that I am committed to helping the court and all parties conduct this litigation efficiently and effectively,” McCormick said in an email follow-up to a phone interview. “I also believe that the other plaintiff firms involved understand that my knowledge and history with the Risperdal mass tort litigations, both in New Jersey and here in Philadelphia, will be of benefit to them as the litigation proceeds.”

Casey said his firm has previous experience in pharmaceutical mass tort litigation, but has now decided to form a dedicated mass torts department.

McCormick added that part of what enticed him about joining the firm was the opportunity to build up a new practice.

Casey said that, in addition to the Risperdal cases it’s working on, the firm expects McCormick will also be heavily involved in litigation related to testosterone therapy products designed to treat low testosterone levels, or “low T,” in men.

The firm filed the first case earlier this month in the Philadelphia Court of Common Pleas against Auxilium Pharmaceuticals Inc. and GlaxoSmithKline, the maker and co-promoter, respectively, of testosterone therapy drug Testim, which is alleged to have caused a stroke in the plaintiff.

The firm said it has since filed two more cases.

Casey said that, in addition to his drug product litigation experience, McCormick’s whistleblower practice was also part of what attracted the firm to him.

McCormick said that, while he has traditionally divided his practice about evenly between pharmaceutical litigation and qui tam litigation, it remains to be seen whether that 50/50 split will continue.

“I’m going to a firm where they have so much work, no matter what I do, my plate’s going to be full,” McCormick said.

With McCormick leaving, Sheller said that, for the time being, he and his daughter, Sheller P.C. of counsel Jamie L. Sheller, are handling the firm’s management duties until they can appoint a permanent replacement.

Sheller also said his firm and McCormick are still in the process of determining what work McCormick will be taking with him.

“We’re working things out and I think we’ll be working things out comfortably,” Sheller said.

McCormick’s departure comes on the heels of Sheller P.C. losing another key partner: Claudine Q. Homolash left the firm in December to start her own firm.

When asked Friday whether those moves and the decision to bring co-counsel aboard in the Risperdal litigation were any indication that he was considering winding down Sheller P.C., Sheller said they weren’t but admitted he has thought about closing down his long-running shop.

“It does cross my mind,” Sheller said, but added that he feels there’s still work to be done.

With the Risperdal litigation picking up steam and the firm’s involvement in the recently filed litigation against General Motors Co. over deaths alleged related to an ignition switch problem in Chevrolet Cobalts, Sheller P.C. is not slowing down any time soon, Sheller said.

“I enjoy this,” Sheller said.

Zack Needles can be contacted at 215-557-2493 or Follow him on Twitter @ZNeedlesTLI.