Mayne Pharma has surged to the top of the ASX leaderboard in early trade, jumping 24% to $5.96, after the Takeovers Panel handed down a significant ruling in its long-running dispute with reluctant US bidder Cosette Pharmaceuticals.
The two companies have been locked in a legal and regulatory battle since Cosette attempted to walk away from its agreed $670 million scheme of arrangement, signed in February. The buyer has issued multiple termination notices citing a “material adverse change”, while Mayne has challenged those notices in the NSW Supreme Court.
A key hurdle for the deal remains approval from the Foreign Investment Review Board, which continues to assess national-interest implications amid concerns that Cosette may shut Mayne’s Salisbury manufacturing plant in Adelaide. Treasurer Jim Chalmers has previously identified the potential closure — which would affect more than 200 jobs — as a central concern.
Earlier this month The Australian's DataRoom revealed that Indonesian pharmaceutical company Pyridam Farma had expressed interest in acquiring the Salisbury site.
Takeovers Panel final orders
After the market closed on Wednesday, Mayne notified investors that the Takeovers Panel had issued final orders compelling Cosette to comply with any conditions the Treasurer reasonably requires as part of FIRB approval. These include conditions aimed at preventing or restraining closure of the Salisbury facility, provided they do not contradict Cosette’s previously stated intentions in the scheme booklet.
The Panel found that Cosette had changed its intentions for the Salisbury site as early as June 24, 2025, advising FIRB that it now intended to “seek to dispose of or close” the facility — a significant departure from its earlier commitment to continue Mayne’s operations and retain staff.
However, the market was not informed of this shift until 8 September 2025, following media reports that the South Australian Premier had intervened in the FIRB process. The Panel ruled that this lack of disclosure meant the market for control of Mayne Pharma had not proceeded in a way consistent with an “efficient, competitive and informed market” under the Corporations Act.
Court setback for Cosette
The decision follows last week’s ruling by the NSW Supreme Court that no material adverse change had occurred, rendering Cosette’s termination attempts invalid and keeping the original scheme implementation deed in force.
The Takeovers Panel also expressed broader policy concerns, warning that allowing bidders to use last-minute intention changes to derail agreed transactions could undermine confidence in Australian control transactions.
Additional transparency requirements
As part of its orders, the Panel directed both sides to share all correspondence with FIRB relating to Cosette’s application, subject to limited redactions for privileged or competitively sensitive information. It also extended the scheme’s end date to November 24, 2025.
What happens next
The Treasurer is yet to make a final ruling on national-interest grounds, leaving the future of the takeover — and the fate of the Salisbury site — unresolved. But with the Panel’s orders now binding, Cosette faces stricter conditions and reduced flexibility as FIRB weighs the proposal.
Mayne’s shares rallied sharply as investors assessed the strengthened protections surrounding the plant and the clearer pathway for the scheme to proceed.