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Mark Cheffo

Dechert LLP

Mark S. Cheffo is co-chair of Dechert’s product liability and mass torts practice and has extensive experience serving as national coordinating and trial counsel in complex product liability, insurance and mass torts litigation. He acts for corporations and individuals in the pharmaceutical, medical device manufacturing, bioengineering, insurance and industrial products industries, amongst others. Mr. Cheffo has also handled numerous toxic and environmental exposure suits. Prior to joining Dechert, Mr. Cheffo was co-chair of Quinn Emanuel Urquhart & Sullivan’s global product liability and mass torts practice.


  • A major pharmaceutical company as national counsel in an MDL involving over 3,000 plaintiffs and allegations that one of the company’s medications caused women to develop diabetes. Successfully excluded plaintiffs’ causation experts and won summary judgment in all MDL cases; argued the appeal in the U.S. Court of Appeals for the Fourth Circuit, which unanimously affirmed.
  • A major pharmaceutical company as national counsel in an MDL and related state cases involving allegations that in utero exposure to an antidepressant medication caused children to develop birth defects. Successfully excluded the MDL plaintiffs’ general causation experts and obtained summary judgment for all MDL cases; argued the appeal before the U.S. Court of Appeals for the Third Circuit, which unanimously affirmed.
  • Several pharmaceutical companies in securing a complete dismissal in multidistrict litigation in connection with personal injury claims arising from the manufacturing and distribution of generic prescription medications containing propoxyphene.
  • A client in successfully arguing a motion to dismiss a consolidated nationwide consumer fraud class action complaint in an MDL and also argued the appeal in the Ninth Circuit, where the district court’s decision was affirmed.
  • A major biotechnology company in multidistrict litigation involving a nationwide consumer fraud action.
  • Several major pharmaceutical companies in connection with the development of risk management initiatives, labelling advice and document management.
  • One of the world’s largest computer manufacturers in class actions challenging alleged product defects.
  • Individual and corporate property owners in connection with more than 70 cases alleging pediatric brain injuries from exposure to environmental toxins.


  • Holds a Band 1 ranking from Chambers USA.
  • Acknowledged as a top lawyer by The Legal 500 U.S. for product liability and mass torts matters.
  • In 2023, he was named a Global Elite Thought Leader for Life Sciences – Product Liability by Who’s Who Legal


  • Stony Brook University, B.A., with Honors, 1987
  • Boston University School of Law, J.D., 1990, Paul J. Liacos Scholar