SAN DIEGO and TORONTO — October 16, 2025 — Leads & Copy — Aptose Biosciences Inc. (OTC: APTOF, TSX: APS) presented data from the TUSCANY trial of tuspetinib in combination with venetoclax and azacitidine (TUS+VEN+AZA) at the European School of Haematology (ESH) 7th International Conference on Acute Myeloid Leukemia. The data, from 10 patients across three cohorts (40 mg, 80 mg, or 120 mg TUS dose), showed promising clinical safety and antileukemic activity, supporting the use of TUS with standard of care treatment across a broad range of AML populations, including those carrying adverse mutations regardless of FLT3 mutation status.
The TUS+VEN+AZA triplet is being developed as a safe, mutation-agnostic frontline therapy for newly diagnosed AML patients ineligible for induction chemotherapy. No significant safety concerns or dose-limiting toxicities (DLTs) have been observed in the TUSCANY trial across all dose cohorts, including no prolonged myelosuppression, drug-related QTc prolongation, differentiation syndrome (DS), CPK elevation, or treatment-related deaths. Dosing has begun at the 160 mg TUS dose level.
Rafael Bejar, M.D., Ph.D., Chief Medical Officer of Aptose, noted that TUS can be safely added to VEN+AZA without reducing the dose of these standard-of-care drugs. He added that the activity observed with the TUS triplet in the first 10 patients exceeded expectations, with 9 achieving complete remissions and 7 demonstrating MRD-negativity. These remissions occurred in diverse genetic subtypes, making this a mutation-agnostic therapy.
Data highlights:
- TUS in combination with VEN+AZA has been well tolerated with no DLT, treatment-related deaths, differentiation syndrome, QTc prolongation, prolonged myelosuppression after remission in Cycle 1, and no CPK elevations reported at any dose levels.
- Addition of TUS to VEN+AZA achieved CR/CRh responses in 6/6 (100%) patients treated at the higher dose levels of 80 mg and 120 mg TUS, exceeding the 66% rate expected from VEN+AZA alone.
- Overall, TUS+VEN+AZA CR/CRh responses were observed in 9/10 (90%) patients.
- 7 of 8 (88%) CR/CRh responses in FLT3 wildtype AML, representing 70% of AML population.
- TUS+VEN+AZA MRD-negativity noted in 7/9 (78%) responding patients by central flow cytometry.
- CR/CRh responses achieved across diverse mutational subtypes including: unmutated FLT3, FLT3-ITD, NPM1c, biallelic TP53 with complex karyotype, RAS, and myelodysplasia related mutations.
- Dosing at the TUS 160 mg dose level is now ongoing.
The tuspetinib-based TUS+VEN+AZA triplet therapy is being advanced in the TUSCANY Phase 1/2 trial to create an improved frontline therapy for newly diagnosed AML patients. The study is being conducted at 10 leading U.S. clinical sites and is designed to test various doses and schedules of TUS in combination with standard dosing of AZA and VEN for patients with AML who are ineligible to receive induction chemotherapy.
Aptose Biosciences Inc. is a clinical-stage biotechnology company focused on developing precision medicines for oncology, with an initial focus on hematology. The Company’s lead clinical-stage, oral kinase inhibitor tuspetinib (TUS) has demonstrated activity as a monotherapy and in combination therapy in patients with relapsed or refractory acute myeloid leukemia (AML) and is being developed as a frontline triplet therapy in newly diagnosed AML.
For further information, please contact:
Susan Pietropaolo
Corporate Communications & Investor Relations
201-923-2049
spietropaolo@aptose.com
Source: Aptose Biosciences Inc.
