Venetoclax

TUS+VEN+AZA triplet frontline therapy demonstrates high rates of efficacy and MRD-negative remissions in newly diagnosed AML patients with diverse mutations Safety continues to be a notable hallmark of TUS-based therapies 100% response rate (CR/CRh) at the two higher dose levels (80 and 120 mg TUS dose) CR/CRh observed in FLT3 wildtype subjects, representing ~70% of AML patients CR/CRh observed in AML with TP53/complex karyotype, RAS, and MDS-related mutations SAN DIEGO and TORONTO, Dec. 06, 2025 (GLOBE NEWSWIRE) -- Aptose Biosciences Inc. (“Aptose” or the “Company”) (NASDAQ: APTO, TSX: APS), a clinical-stage precision oncology company developing highly differentiated targeted agents to treat hematologic malignancies, today featured clinical data for its lead compound tuspetinib (TUS) combined with standard dosing of venetoclax (VEN) and azacitidine (AZA) in a poster presentation at the 67th American Society of Hematology (ASH) Annual Meeting in Orlando, FL. Updated data from patients in the TUSCANY trial across all three cohorts, 40 mg, 80 mg or 120 mg TUS dose in TUS+VEN+AZA, reveal promising clinical safety and antileukemic activity and support the use of TUS in combination with standard of care treatment across a broad range of AML populations, including those with adverse mutations regardless of FLT3 mutation status. Poster title: “TUSCANY study demonstrates safety and efficacy of tuspetinib plus standard of care venetoclax and azacitidine in patients with newly diagnosed AML ineligible for induction chemotherapy” Key Findings and Messages: In newly diagnosed AML patients, TUS+VEN+AZA shows promising safety, tolerability and resilient efficacy, including MRD-negative remissions across a broad mutational spectrum High-quality clinical responses (CR/CRh): 90% across 40, 80 and 120 mg dose levels 100% at the higher 80 mg and 120 mg dose levels Observed in FLT3-WT, FLT3-ITD, and NPM1c genetic subgroups Observed in biallelic TP53/complex karyotype and RAS adverse genetic subgroups Observed in AML with MDS-related mutations MRD negativity: 78% by central flow cytometry in responding subjects TUS targets VEN resistance mechanisms; inhibits kinase-driven abnormal signaling Two subjects transitioned to stem cell transplantation and both returned for TUS maintenance TUS+VEN+AZA triplet therapy was well tolerated with no dose-limiting toxicities (DLTs) across all evaluable TUS dose levels No DLTs including no prolonged myelosuppression for subjects in remission in Cycle 1 No drug-related deaths, differentiation syndrome, QTc prolongation, or CPK elevation reported 8/10 evaluable subjects experienced red cell and platelet transfusion independence for > 8 weeks after their best response Febrile neutropenia was reported in 2 subjects (16.7%), with 1 subject related to TUS At the recently enrolled 160 mg dose level, preliminary findings show patients achieving early blast clearance with MRD-negativity and formal responses in the first few weeks of treatment (not included in poster data cut). 90% across 40, 80 and 120 mg dose levels 100% at the higher 80 mg and 120 mg dose levels Observed in FLT3-WT, FLT3-ITD, and NPM1c genetic subgroups Observed in biallelic TP53/complex karyotype and RAS adverse genetic subgroups Observed in AML with MDS-related mutations No DLTs including no prolonged myelosuppression for subjects in remission in Cycle 1 No drug-related deaths, differentiation syndrome, QTc prolongation, or CPK elevation reported 8/10 evaluable subjects experienced red cell and platelet transfusion independence for > 8 weeks after their best response Febrile neutropenia was reported in 2 subjects (16.7%), with 1 subject related to TUS “Tuspetinib, as part of a triple drug therapy, continues to perform well, achieving 100% clinical response in the two higher doses we have evaluated to date,” said Rafael Bejar, MD, PhD, Chief Medical Officer at Aptose. “We recently commenced treating patients at the highest dose level of 160 mg TUS and have already achieved early responses. With no dose-limiting toxicities and activity across diverse mutations, TUS+VEN+AZA targets AML’s greatest unmet needs and largest populations.” The ASH poster presentation is available here. About Tuspetinib Aptose’s lead compound tuspetinib is a convenient once daily oral agent that potently targets SYK, mutated and wild type forms of FLT3, mutated KIT, JAK1/2, and RSK2 kinases, while avoiding many typical toxicity concerns observed with other agents. The ongoing TUSCANY triplet Phase 1/2 study is designed to test various doses and schedules of TUS in combination with standard dosing of azacitidine and venetoclax in newly diagnosed patients with AML who are ineligible to receive induction chemotherapy. Data from the first three dose cohorts demonstrate safety, CRs and minimal residual disease (MRD) negativity across patients with diverse mutations. The early data showed that 9 out of 10 patients responded to the TUS triplet therapy, with 100% complete remission (CR/CRh) achieved in the 80mg and 120mg cohorts. Notably, patients with difficult-to-treat mutations in TP53, RAS and FLT3 genes also achieved a 100% CR/CRh rate. About Aptose Aptose Biosciences is a clinical-stage biotechnology company committed to developing precision medicines addressing unmet medical needs in oncology, with an initial focus on hematology. The Company's small molecule cancer therapeutics pipeline includes products designed to provide single agent efficacy and to enhance the efficacy of other anti-cancer therapies without overlapping toxicities. The Company’s lead clinical-stage compound tuspetinib (TUS), is an oral kinase inhibitor that has demonstrated activity as 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 more information, please visit www.aptose.com. Forward Looking Statements This press release may contain forward-looking statements within the meaning of Canadian and U.S. securities laws, including, but not limited to, statements relating to the therapeutic potential of tuspetinib, its clinical development and safety profile including its tolerability and resilient efficacy, as well as statements relating to the Company’s plans, objectives, expectations and intentions and other statements including words such as “continue”, “expect”, “intend”, “will”, “should”, “would”, “may”, and other similar expressions. Such statements reflect our current views with respect to future events and are subject to risks and uncertainties and are necessarily based upon a number of estimates and assumptions that, while considered reasonable by us are inherently subject to significant business, economic, competitive, political and social uncertainties and contingencies. Many factors could cause our actual results, performance or achievements to be materially different from any future results, performance or achievements described in this press release. Such factors could include, among others: our ability to obtain the capital required for research and operations and to continue as a going concern; the inherent risks in early stage drug development including demonstrating efficacy; development time/cost and the regulatory approval process; the progress of our clinical trials; our ability to find and enter into agreements with potential partners; our ability to attract and retain key personnel; changing market conditions; inability of new manufacturers to produce acceptable batches of GMP in sufficient quantities; unexpected manufacturing defects; and other risks detailed from time-to-time in our ongoing quarterly filings, annual information forms, annual reports and annual filings with Canadian securities regulators and the United States Securities and Exchange Commission. Should one or more of these risks or uncertainties materialize, or should the assumptions set out in the section entitled "Risk Factors" in our filings with Canadian securities regulators and the United States Securities and Exchange Commission underlying those forward-looking statements prove incorrect, actual results may vary materially from those described herein. These forward-looking statements are made as of the date of this press release and we do not intend, and do not assume any obligation, to update these forward-looking statements, except as required by law. We cannot assure you that such statements will prove to be accurate as actual results and future events could differ materially from those anticipated in such statements. Investors are cautioned that forward-looking statements are not guarantees of future performance and accordingly investors are cautioned not to put undue reliance on forward-looking statements due to the inherent uncertainty therein. For further information, please contact: Aptose Biosciences Inc. Susan Pietropaolo Corporate Communications & Investor Relations 201-923-2049 spietropaolo@aptose.com Released December 6, 2025

ImCheck Announces Oral Presentation of ICT01 First-Line AML Data at the 67th ASH Annual Meeting Marseille, France, December 5, 2025 05:00 a.m. ET / 11:00 a.m. CET– ImCheck Therapeutics announced today an oral presentation at the upcoming American Society of Hematology (ASH) Annual Meeting 2025, taking place from December 6 to December 9, in Orlando, FL, USA. The presentation will highlight the high remission rates and overall survival observed in EVICTION, ImCheck’s open-label, randomized Phase I/II study evaluating ICT01, a first-in-class γ9δ2 T-cell activator, in combination with azacitidine and venetoclax in older or unfit patients with newly diagnosed acute myeloid leukemia (AML). Details of the oral presentation at ASH 2025 are: Abstract Title: “γ9δ2 T-cell (γ9δ2TC) activation with ICT01 and azacitidine-venetoclax (Aza-Ven) induces high rates of remission and overall survival in patients with newly diagnosed (ND) acute myeloid leukemia (AML): Results from the phase 1/2 study eviction”Presenter: Sylvain GRACIAZ, MD, PhD, Institut Paoli-Calmettes, Marseille, FranceSession: 616. Acute Myeloid Leukemias: Investigational Drug and Cellular Therapies: Immunotherapy and chemotherapy combinations in AMLRoom: OCCC - Chapin Theater (320)Date: Sunday, December 7, 2025Time: 5:15 p.m.- 5:30 p.m. ET The ASH presentation will be available on ImCheck’s corporate website after the presentation has been held. *** About the EVICTION Study EVICTION is a first-in-human, dose-escalation (Part 1) and cohort-expansion (Part 2) clinical study of ICT01 in patients with various advanced relapsed or refractory solid or hematologic cancers that have exhausted standard-of-care treatment options. Part 1 (Phase I) is designed to characterize the preliminary safety, tolerability, and pharmacodynamic activity of increasing doses of ICT01 as monotherapy (Group A: solid tumors; Group B: hematologic tumors) and in combination with pembrolizumab (Group C: solid tumors). Part 2 comprises randomized dose-optimizing and efficacy estimating expansion cohorts of monotherapy (Group D: ovarian cancer; Group E: prostate cancer) and combination treatment of patients with AML (Group F), melanoma (Group G), urothelial cell carcinoma (Group H), or head-and-neck squamous cell carcinoma (Group I). More information on the EVICTION study can be found at clinicaltrials.gov (NCT04243499). About ICT01 ICT01 is a humanized, anti-BTN3A (also known as CD277) monoclonal antibody that selectively activates γ9δ2 T cells, which are responsible for immunosurveillance of malignancy and infections. The three isoforms of BTN3A targeted by ICT01 are overexpressed on many solid tumors (e.g., melanoma, urothelial cell, colorectal, ovarian, pancreatic, and lung cancer) and hematologic malignancies (e.g., leukemia and lymphomas) and also expressed on the surface of innate (e.g., γδ T cells and NK cells) and adaptive immune cells (T cells and B cells). BTN3A is essential for the activation of the anti-tumor immune response of γ9δ2 T cells. As demonstrated by data presented at past AACR, ASCO, ASH, ESMO and SITC conferences, ICT01 selectively activates circulating γ9δ2 T cells leading to migration of γ9δ2 T cells out of the circulation and into the tumor tissue and triggers a downstream immunological cascade through secretion of pro-inflammatory cytokines, including but not limited to IFNγ and TNFα, further augmenting the anti-tumor immune response. Anti-tumor activity and efficacy of ICT01 have been shown in patients across several cancer indications. About IMCHECK THERAPEUTICS ImCheck Therapeutics is developing a new generation of immunotherapeutic antibodies targeting butyrophilins, a novel superfamily of immunomodulators. By unlocking the power of γ9δ2 T cells, ImCheck’s innovative approach has the potential to transform treatments across oncology, autoimmune, and infectious diseases. The lead clinical-stage program, ICT01, has been advancing to late-stage trials, demonstrating a unique mechanism of action that modulates both innate and adaptive immunity. These “first-in-class” activating antibodies may deliver superior clinical outcomes compared to first-generation immunotherapy approaches, in particular in rationale combinations with immune checkpoint inhibitors and immunomodulatory anti-cancer drugs. Additionally, ImCheck’s pipeline compounds are progressing toward clinical development for autoimmune and infectious diseases.The company benefits from the pioneering research of Prof. Daniel Olive (INSERM, CNRS, Institut Paoli Calmettes, Aix-Marseille University), a global leader in γ9δ2 T cells and butyrophilins, as well as the expertise of a seasoned management team and the commitment of leading U.S. and European investors. As announced on October 22, Ipsen (Euronext: IPN; ADR: IPSEY) and ImCheck have entered into a definitive share purchase agreement in which Ipsen will acquire all issued and outstanding shares of ImCheck, with the transaction close anticipated by the end of Q1 2026. For further information: https://www.imchecktherapeutics.com/ Press contacts: US and EU Trophic CommunicationsGretchen Schweitzer +49 (0) 172 861 8540imcheck@trophic.eu FranceATCG PARTNERSCéline Voisin+33 (0)6 62 12 53 39imcheck@atcg-partners.com Attachment PR in english