South Korea-based Hanmi Pharmaceutical Co., Ltd. has completed its acquisition of Aptose Biosciences Inc. (TSX: APS | OTC: APTOF), a clinical-stage oncology company developing a tuspetinib-based frontline triplet therapy for acute myeloid leukemia, through its wholly owned subsidiary HS North America Ltd. The deal gives Hanmi full ownership of Aptose's AML program and removes Aptose from public markets, with shares expected to delist from the Toronto Stock Exchange on or about July 3, 2026.
Under the plan of arrangement, Aptose shareholders received CAD 2.41 in cash per common share, representing a 28% premium over Aptose's 30-day volume-weighted average price of CAD 1.88 on the TSX for the period immediately preceding the arrangement agreement. No milestone payments, royalties, or contingent value rights were applicable; the transaction was a straightforward cash acquisition of all outstanding shares not already held by Hanmi or its affiliates. Shareholder approval was obtained at a special meeting on March 31, 2026, with 91.48% of voted shares approving the arrangement resolution, and final court approval was granted the same day. Closing was delayed from an initially targeted April 2026 date pending Korean regulatory approvals, which were subsequently obtained. The aggregate deal value was not explicitly disclosed in the closing announcement. Hanmi had provided Aptose with cumulative debt financing of more than USD 41 million over the prior 18 months to sustain the TUSCANY clinical trial during the arrangement process.
The strategic rationale centers on tuspetinib (TUS), an oral multikinase inhibitor being advanced in the Phase I/II TUSCANY trial as a triplet combination with venetoclax and azacitidine (TUS+VEN+AZA) for newly diagnosed AML patients ineligible for induction chemotherapy. Tuspetinib inhibits multiple kinase-driven signaling pathways implicated in AML cell survival and venetoclax resistance, including FLT3-wildtype and adverse-risk genotypes such as TP53-mutated and complex karyotype disease. At the European Hematology Association Congress in June 2026, Aptose reported a composite complete response rate of 86.2% across 29 evaluable patients at the 40 mg, 80 mg, 120 mg, and 160 mg dose levels, with MRD-negativity in 86.4% of CR/CRh responders — data that directly supported Hanmi's decision to close the transaction.
The competitive landscape for frontline AML is intensifying. The US FDA approval of decitabine/cedazuridine (Inqovi) with venetoclax established an all-oral frontline treatment option against which tuspetinib's triplet must demonstrate differentiated benefit, particularly in genetically adverse subgroups where existing regimens show limited durability. Separately, Yatiri Bio recently optioned global rights to Oscotec's denfivontinib, an oral FLT3/AXL inhibitor targeting the same AML population, underscoring continued deal-making interest in novel oral kinase inhibitors for the indication.