Mayne Pharma acquisition hits FIRB roadblock

Mayne Pharma Group Limited announced on November 21, 2025, that its proposed acquisition by Cosette Pharmaceuticals, Inc., via a scheme of arrangement, is unlikely to proceed. Cosette received written notice from the Foreign Investment Review Board (FIRB) stating that the Treasurer has objected to the proposed scheme, meaning the FIRB condition precedent will not be satisfied.

The Second Court Hearing, previously scheduled for November 23, 2025, has been vacated. Mayne Pharma also received a notice from Cosette under the Scheme Implementation Deed (SID) dated February 20, 2025, informing them of the FIRB condition failure and requesting good faith consultation on available alternatives. Mayne Pharma is currently evaluating its options and next steps and will keep the market informed.