Mark S. Cheffo
Partner | New York
Mark S. Cheffo

Mark S. Cheffo, co-chair of Dechert’s global litigation practice, 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.

Mr. Cheffo has taken part in several trial teams in high-profile pharmaceutical litigation, managing all stages of a dispute from negotiation, through pre-trial proceedings to trial. In addition to defending expert and company witness depositions, Mr. Cheffo has briefed and conducted numerous Daubert and Frye challenges. He has also briefed and argued dispositive motions and appeals in state and federal courts throughout the United States. Mr. Cheffo also has considerable experience conducting arbitrations and mediations relating to disputes.

Widely recognized as a leader in the field, Mr. Cheffo holds a Band 1 ranking from Chambers USA and is acknowledged as a top lawyer by The Legal 500 U.S. for product liability and mass torts matters. He earned the title of "Litigator of the Week" from The American Lawyer for representing GSK and Saint- Gobain. In 2024, Who’s Who Legal: Life Sciences recognized Mr. Cheffo as a Recommended Individual for Product Liability. In 2023, he was named a Global Elite Thought Leader for Life Sciences - Product Liability by Who's Who Legal and received the Life Sciences Lawyer of the Year award at the Who's Who Legal Awards 2020. BTI Consulting Group listed Mr. Cheffo as a Client Service All-Star and Product Liability Attorney of the Year by LMG Life Sciences in 2022. He was chosen as one of Law360's MVPs of the Year in the Product Liability category in 2019 and 2020. Mr. Cheffo is part of a product liability team that has garnered numerous accolades over the past two decades, including Law360's Practice Group of the Year for Product Liability in 2018 and 2019, and New York Law Journal's Litigation Department of the Year for Product Liability in 2019, 2020, 2021, and 2022.

Mr. Cheffo maintains an active pro bono practice, assisting clients in a variety of matters. Most notably, he obtained a judgment of more than US$1.7 million for liability and legal fees on behalf of 11 restaurant workers in New York’s Chinatown. He also obtained a jury verdict in a defamation case and obtained a directed verdict in a case brought by three plaintiffs who had been shot while in prison.

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. 

Includes matters handled at Dechert or prior to joining the firm.

  • Lawdragon 500 Leading Litigators in America – Lawdragon
  • Client Service All Star – BTI Consulting Group 2022 (View Video)
Services Industries
    • Stony Brook University, B.A., with Honors, 1987
    • Boston University School of Law, J.D., 1990, Paul J. Liacos Scholar
    • New York
    • United States Court of Appeals for the First Circuit
    • United States Court of Appeals for the Second Circuit
    • United States Court of Appeals for the Fourth Circuit
    • United States Court of Appeals for the Sixth Circuit
    • United States Court of Appeals for the Ninth Circuit
    • United States District Court for the Eastern District of New York
    • United States District Court for the Southern District of New York
    • New York City Bar Association
    • International Association of Defense Counsel