Cosette’s Mayne Pharma Acquisition Faces FIRB Deadline Extension to December

National Interest Concerns Stall Acquisition

Mayne Pharma Group Limited (ASX – MYX) has provided a critical update on the status of its proposed acquisition by Cosette Pharmaceuticals, Inc., revealing that the Australian Treasurer has expressed a preliminary view that the deal may be contrary to the national interest. The Treasurer’s concerns hinge on the potential negative impact on the Australian economy and community, specifically highlighting Cosette’s intention to dispose of or close Mayne Pharma’s manufacturing site in Adelaide.

This development marks a significant regulatory hurdle for the acquisition, which has already faced legal challenges, including Cosette’s unsuccessful attempts to terminate the scheme as ruled by the NSW Supreme Court. The Treasurer’s letter underscores the strategic importance of the Adelaide facility, which holds both TGA and FDA approvals and has recently benefited from an $18 million investment by Mayne Pharma, supported by a $4.8 million Commonwealth Government grant.

Mayne Pharma Pushes Back on Closure Claims

Mayne Pharma strongly contests the notion that closing the Adelaide site would be commercially rational. The company emphasizes the site’s role as a trusted partner to global pharmaceutical firms, underpinning its innovation and manufacturing capabilities. Since Cosette’s stated change of intention in June 2025, Mayne Pharma has consistently communicated its position that the site’s closure would be detrimental and illogical from a business perspective.

Despite these concerns, Mayne Pharma has been unable to engage directly with the Foreign Investment Review Board (FIRB) or the Treasurer, as Cosette has withheld consent for such communications. This lack of direct dialogue complicates efforts to address the Treasurer’s concerns and move the acquisition forward.

Regulatory Timelines and Next Steps

The FIRB has requested an extension to the statutory deadline for approval until 1 December 2025, which exceeds the scheme’s End Date under the Scheme Implementation Deed (SID). Mayne Pharma is pressing Cosette to comply with its obligations under the SID and to seek a shortened timeframe. Cosette has indicated it will request a final decision by 7 November 2025, aiming to finalise the scheme before the 20 November End Date.

Meanwhile, Mayne Pharma has postponed the second court hearing related to the scheme pending resolution of these regulatory issues. The company remains committed to enforcing the SID provisions and keeping shareholders informed of all material developments.

Broader Implications for Australian Pharmaceutical Manufacturing

This episode highlights the Australian government’s increasing scrutiny of foreign acquisitions in strategic sectors, particularly where critical manufacturing infrastructure and jobs are at stake. The Treasurer’s intervention signals a willingness to prioritize national economic and community interests over foreign investment deals, especially when there is a risk of losing key domestic capabilities.

For Mayne Pharma, the outcome will not only determine ownership but also the future of its Adelaide manufacturing hub, a linchpin in its global operations. Investors will be watching closely as the FIRB process unfolds and as Cosette responds to the Treasurer’s concerns.