Mayne Pharma wins dismissal of Cosette appeal over abandoned takeover
The court awarded appeal costs; the A$7.40-a-share deal was terminated in December 2025, and Mayne is pursuing damages.
Adrian Kessler
An appeal over termination rights in an abandoned A$7.40-a-share takeover was dismissed on Wednesday as Mayne Pharma Group Limited ASXMYX reported that the New South Wales Court of Appeal rejected Cosette's challenge.
The Oct. 14 announcement says the court dismissed every appeal ground and awarded Mayne its appeal costs. The ruling preserves Mayne's earlier legal victory, while its board says it will continue pursuing damages claims arising from the failed transaction.
Mayne is an Australian specialty pharmaceutical company focused on U.S. dermatology and women's health, with a contract development and manufacturing business.
Mayne shares rose 6.3 per cent to A$2.70 on the ASX as of 3:07 p.m. AEDT on Wednesday, according to Google Finance's ASXMYX quote. Cosette has until Nov. 11 to consider seeking special leave to appeal to the High Court, Mayne said.
Both Parties Already Issued Termination Notices
The ruling concerns the grounds Cosette advanced against the earlier judgment, rather than an acquisition now approaching completion. Privately held Cosette Pharmaceuticals, Inc. said on Dec. 11, 2025 that it served a termination notice on Dec. 9 and Mayne served its own notice on Dec. 11.
Cosette's account says both notices followed the Australian Treasurer's decision blocking the transaction and the expiry of the agreement's end date in November. The original cash consideration therefore describes the abandoned proposal, rather than a payment now scheduled for shareholders.
The Takeovers Panel's reasons record that the parties signed the scheme implementation deed on Feb. 20, 2025. The proposal covered all Mayne shares at A$7.40 each, conditional on requirements including the Treasurer's foreign investment approval and the absence of a defined material adverse change.
That approval was a separate requirement from the disputed termination grounds. The parties' subsequent termination notices mean Wednesday's announcement provides no remaining closing timetable for that proposal.
The court's appeal submissions page records Cosette's Jan. 15, 2026 notice of appeal. The dispute included whether Mayne's sales performance permitted termination and whether it had made a misleading representation about expected earnings.
Mayne's Oct. 14 release says the appeal court affirmed findings that no defined material adverse change occurred and that Mayne did not engage in misleading conduct regarding its financial performance. It also says Cosette had elected to affirm the deed through its conduct at the first scheme hearing.
"We are delighted that the Court of Appeal has upheld the decision of the Supreme Court at first instance and rejected Cosette's attempts to assert it had any right to terminate the deal."
Mayne board chair Professor Bruce Robinson said this in Wednesday's announcement. The account of the appellate findings here comes from that release; the appellate judgment itself was not reviewed.
Costs And Damages Remain Separate
Mayne said approximately A$14.4 million in earlier proceeding costs had already been paid, as disclosed on May 22, 2026. Wednesday's decision leaves that payment unaffected, while the newly awarded appeal costs remain to be determined.
Cosette's December statement rejected Mayne's allegations of contractual breach and said it had complied with its obligations. Mayne's current announcement gives no damages award or amount for the claims its board says it will pursue.
A separate pharmaceutical litigation outcome came from Liquidia Corporation NASDAQLQDA, which announced a net US$380.7 million settlement on Oct. 13. That agreement specifies payments, unlike Mayne's continuing damages claims.
Read more: Liquidia Corporation agrees to US$380.7M litigation settlement
Among specialty pharmaceutical peers, ANI Pharmaceuticals, Inc. NASDAQANIP reported second-quarter generic drug revenue of US$99.1 million on Aug. 7. New launches helped drive growth of 9.7 per cent, providing an operating comparison alongside the legal developments. Its portfolio also includes the ophthalmology medicine ILUVIEN.
Read more: ANI Pharmaceuticals reports Phase 4 eye-implant trial met both endpoints
The broader State Street SPDR S&P Biotech ETF NYSEARCAXBI traded at US$146.80 as of 8:00 p.m. EDT on Oct. 13, according to its Google Finance quote.
The next dated step is Nov. 11, 2026, the date until which Mayne says Cosette can consider seeking special leave. Any such request would ask the High Court to hear a further challenge to the appellate decision.
