Cosette Pharmaceuticals, Inc. has announced a definitive agreement to acquire Mayne Pharma Group Limited for approximately USD $430 million, at AUD$7.40 per share. The acquisition, which has been approved by both companies’ Boards of Directors, is expected to finalize in the second quarter of 2025. Mayne Pharma’s Board of Directors has unanimously recommended that shareholders approve the transaction.

Apurva Saraf, President and CEO of Cosette Pharma, stated that the acquisition is a transformative step for Cosette, solidifying its leadership in women’s health in the U.S. and expanding its global reach. Shawn Patrick O’Brien, CEO of Mayne Pharma, sees the merger as a unique opportunity for employees, customers, and patients to extend the reach of therapies, drive innovation, and improve patient access.

The acquisition will combine Cosette’s portfolio with Mayne Pharma’s commercial expertise. Cosette Pharmaceuticals is being advised by Santander US Capital Markets LLC and UBS Investment Bank as financial advisers and Ropes & Gray LLP and Corrs Chambers Westgarth as legal advisers. Mayne Pharma is being advised by Jefferies Australia as financial adviser and Gilbert + Tobin and Arnold & Porter as legal advisers.

Cosette Pharmaceuticals’ acquisition of Mayne Pharma is set to create a leading U.S. pharmaceutical company focused on women’s health and dermatology, with a significant international presence.

By combining the strengths of both companies, the merger aims to drive innovation and broaden access to women’s health therapies. Cosette will leverage its commercial and operational capabilities, supported by its team of over 350 employees and a strong product portfolio, alongside Mayne Pharma’s expertise in these specialty areas. Mayne Pharma contributes an additional 480+ employees, including successful sales and marketing teams. The combined company will operate two FDA-approved manufacturing sites in Lincolnton, North Carolina, and Salisbury, South Australia, to serve patients worldwide.