A&O Shearman advises Mallinckrodt plc on international aspects of its merger with Endo, Inc.

This transformative transaction brings together two major players in the specialty and generic pharmaceuticals sector, creating a more diversified and resilient business with a combined focus on specialty pharmaceuticals, specialty generics and hospital products.

The merger, signed on March 13, 2025, and completed on July 31, 2025, involved complex cross-border legal, regulatory and financial arrangements, reflecting the international footprint of both companies. The combined company will have a robust operating presence, primarily in the United States, supported by capabilities in Europe, India, Australia and Japan, with 17 manufacturing facilities, 30 distribution centers and approximately 5,700 employees at closing.

The A&O Shearman team was led out of London by corporate partner Gillian Holgate and associates Khin Hsu Myat, Kemilia Ogunmuyiwa and Noel Low. Specialist advice was provided by the A&O Shearman Antitrust/FDI, Employment and Tax teams. A&O Shearman offices in Luxembourg, Netherlands, and Germany advised on corporate and financing matters.

Gillian Holgate, partner at A&O Shearman, commented: “We are delighted to have assisted Mallinckrodt on this landmark merger with Endo, which marks a significant milestone for both companies and the wider pharmaceuticals sector. This transaction, coming directly on the heels of the successful carve-out sale of the Therakos business last year, further demonstrates Mallinckrodt’s strategic vision and our ability to support them on their most complex and transformative matters. We hugely value our longstanding relationship with Mallinckrodt and look forward to supporting them as they embark on this next phase of growth.”