Aptose Biosciences Inc.

What they do

Aptose is a science-driven clinical-stage biotechnology company developing small molecule cancer therapeutics focused on hematology. Its lead program is tuspetinib (TUS), being studied in the Phase 1/2 TUSCANY trial as a triplet combination with venetoclax and azacitidine for newly diagnosed acute myeloid leukemia (AML) patients ineligible for induction chemotherapy. The company returned the license rights to luxeptinib (CG-806) to CGI Invites Co., Ltd. and is winding down that program. Aptose has executive offices in San Diego, California and a head office in Toronto, Canada.

Revenue drivers

• Tuspetinib (TUS) program — No product revenue; the company's lead asset is in clinical development as a frontline triplet therapy for AML, with program costs of $2.9 million in Q1 2026.
• Luxeptinib (LUX) program — No revenue; license rights were returned to CGI, and program costs decreased to a $(5) thousand credit in Q1 2026 as the trial winds down.
• No commercial products — Aptose has reported $0 revenue annually from 2021 through 2025 and $0 in each recent quarter; all funding comes from financing activities.

Recent performance

For the three months ended March 31, 2026, Aptose reported a net loss of $7.6 million, or $2.99 per share, compared to a net loss of $5.5 million, or $2.61 per share, in the prior-year period. Research and development expenses rose to $3.6 million from $2.4 million, driven by higher tuspetinib program costs of $2.9 million associated with the TUSCANY study. General and administrative expenses increased to $3.6 million from $3.1 million, primarily due to higher professional fees and regulatory filing costs. The company reported $0 revenue in the quarter and in each of the prior four quarters.

Strategy

Aptose is advancing tuspetinib as a mutation-agnostic frontline therapy for newly diagnosed AML patients ineligible for induction chemotherapy, with updated TUSCANY trial data presented at EHA 2026. The company is simultaneously pursuing a plan of arrangement under which Hanmi Pharmaceutical and its subsidiary will acquire all outstanding common shares for C$2.41 in cash per share. The arrangement closing was delayed pending certain Korean regulatory approvals. Aptose returned luxeptinib license rights to CGI to focus resources on tuspetinib.

Risks

• Going concern and liquidity — As of March 31, 2026, Aptose had total assets of $10.7 million, total liabilities of $45.4 million, and shareholder equity of negative $34.7 million, with no revenue.
• Clinical development risk — Tuspetinib is still in Phase 1/2 testing, and there is no guarantee the TUSCANY trial will produce positive results or lead to regulatory approval.
• Acquisition closing uncertainty — The pending acquisition by Hanmi Pharmaceutical was delayed as of April 30, 2026, pending Korean regulatory approvals, and may not close on the expected timeline or at all.
• Reliance on external financing — With no product revenue, Aptose funds operations through equity or other financings, which may be dilutive or unavailable on acceptable terms.

Outlook

Management expects the acquisition by Hanmi Pharmaceutical to close, targeting the month of May 2026, and continues to work toward completing the arrangement pending Korean regulatory approvals. Aptose expects to present updated TUSCANY trial data, including new 160 mg dose data, at the EHA 2026 Congress in June. The company will provide a further update on the acquisition when available.