Cosette Pharmaceuticals, Inc. entered into a definitive agreement to acquire Mayne Pharma Group Limited (ASX:MYX) from Viburnum Funds Pty Ltd, Bruce Mathieson and others for approximately AUD 600 million on February 20, 2025. A cash consideration of AUD 601.22 million valued at AUD 7.4 per share will be paid by Cosette Pharmaceuticals, Inc. As part of consideration, AUD 601.22 million is paid towards common equity of Mayne Pharma Group Limited. The transaction is subject to approval by regulatory board / committee, approval of merger agreement by target board, approval of offer by target shareholders and subject to court approval. The deal has been unanimously approved by the board. The expected completion of the transaction is May 21, 2025 to June 10, 2025. On May 17, 2025 Mayne Pharma received correspondence from Cosette purportedly in accordance with the terms of the SID. The Cosette Notice asserted that a Mayne Material Adverse Change had occurred. As of June 4, 2025 Mayne Pharma advises that the 10 business day consultation period asserted by Cosette in the Cosette Notice has now expired and that Mayne Pharma has not received any notice of termination for the purposes of the SID, Mayne Pharma intends to reject the Cosette Termination Notice as invalid and reiterates its position that no Mayne Material Adverse Change has been triggered such that there is no lawful basis for Cosette to terminate the SID. The Mayne Pharma Directors continue to unanimously recommend that you vote in favor of the Scheme Resolution at the Scheme Meeting. As of June 18, 2025, the transaction has been approved by shareholders of Mayne Pharma Group Limited. As on August 5, 2025 Mayne Pharma intends to reject any termination notice received as a result of the Cosette August 5, Notice as invalid and reiterates its position that there is no lawful basis for Cosette to terminate the SID. As on October 16, 2025 It is noted that transaction will be effective on October 23, 2025. As on October 31, 2025. FIRB has requested an extension to the statutory deadline to December 1, 2025. As this timeframe is after the End Date under the SID, Mayne Pharma has engaged with Cosette to urge Cosette to comply with its obligations under the SID and seek to shorten this statutory extension. As of November 7, 2025, Mayne Pharma announced that the Foreign Investment Review Board (FIRB) had unilaterally extended the statutory deadline for FIRB approval to November 14, 2025 and the Court hearing to approve the Scheme has been rescheduled to take place on November 18, 2025. The Scheme Implementation Date will be December 1, 2025. Mayne Pharma has received an extension from the Australian Securities and Investments Commission (ASIC) to hold its 2025 Annual General Meeting (AGM). The deadline for the AGM has been moved from on or before November 28, 2025, to on or before January 30, 2026. As of November 13, 2025, Mayne Pharma was notified that FIRB had unilaterally extended the statutory deadline for FIRB approval to November 17, 2025. As of November 18, 2025, Mayne Pharma was notified that FIRB had unilaterally extended the statutory deadline for FIRB approval to November 20, 2025. As of November 20, 2025, Mayne Pharma was notified that FIRB had unilaterally extended the statutory deadline for FIRB approval to November 21, 2025. As of December 3, 2025 Mayne Pharma issued a notice to Cosette pursuant to clause 15.1 of the SID in relation to Cosette?s material breaches of the SID which Mayne Pharma considers were wilful and intentional. Mayne Pharma may terminate the SID if the relevant circumstances set out in the notice of
intention to terminate continue to exist for five Business Days, being to 10 December 2025.

Jefferies Pty Ltd acted as financial advisor for Mayne Pharma Group Limited. Derek Stoldt, Tracy A. Belton, Debbie Feinstein, Sheryl Gittlitz, Peter G. Danias of Arnold & Porter Kaye Scholer LLP acted as legal advisor for Mayne Pharma Group Limited. Adam Laura, Nirangjan Nagarajah of Gilbert and Tobin acted as legal advisor for Mayne Pharma Group Limited. Sam Levitt, Jackie Cohen, David Blittner, Arek Maczka, Jacqueline Grise, Lisa Kaltenbrunner, Jane E. Willis, Laura G. Hoey, Brendan C. Hanifin, Benjamin Rogers, David H. Saltzman, Megan Bisk, Pascal Mayer, Deborah L. Gersh, Margaux J. Hall, Kellie B. Combs, Jordan Altman, Peter A. Alpert, David Kaye, Lincoln Tsang of Ropes & Gray LLP and Ropes & Gray International LLP acted as legal advisor for Cosette Pharmaceuticals, Inc. Sandy Mak, Shabarika Ajitkumar and Russell Philip of Corrs Chambers Westgarth acted as legal advisor for Cosette Pharmaceuticals, Inc. UBS Securities LLC acted as financial advisor for Cosette Pharmaceuticals, Inc. Santander US Capital Markets LLC acted as financial advisor for Cosette Pharmaceuticals, Inc.

Cosette Pharmaceuticals, Inc. cancelled the acquisition of Mayne Pharma Group Limited (ASX:MYX) from Viburnum Funds Pty Ltd, Bruce Mathieson and others on December 9, 2025. On December 11, 2025, Mayne Pharma Group Limited issued its own notice of termination.