Vididencel

Mendus AB ("Mendus" publ; IMMU. ST), a biopharmaceutical company focused on immunotherapies targeting tumor recurrence in life-threatening cancers, today announces a summary of the data presented at the 61st Annual American Society of Clinical Oncology conference (ASCO 2025) held from May 30 to June 3, 2025, in Chicago, Illinois, from the ongoing ALISON trial with Mendus’ lead product vididencel in ovarian cancer. The data demonstrate that stable disease is associated with the successful induction of tumor-directed immune responses following vididencel treatment in this indication. The Phase 1 ALISON trial evaluates safety, efficacy and immunogenicity of vididencel in patients with high-grade mutation agnostic serous ovarian cancer (HGSOC). Mendus and academic collaborators from the University Medical Center Groningen (UMCG) presented data at ASCO 2025 demonstrating that in the majority of patients vididencel treatment resulted in immune responses against one or more tumor antigens frequently upregulated in HGSOC and that these responses were associated with higher stable disease rates. Vididencel was found to be safe and effective, with the intradermal injection-site cutaneous reaction being the principal side effect and no adverse events above grade 2. At week 22 from start of vididencel treatment, 10 patients participating in the ALISON trial had stable disease and 7 had progressive disease, with all patients still alive. Stable disease rates were highest (67%) in patients with vididencel-induced immune responses (VIR) as compared to patients without VIR (40%). Updated survival data until March 2025 showed that 7 patients continued to have stable disease and 10 patients had developed progressive disease at a median follow-up of 19 months, with 10 patients still alive. Stable disease was associated with vididencel-induced immune responses, with VIR observed in 6 out of 7 of the patients with stable disease. Furthermore, two patients with VIR were reported to have stable disease for more than 3 years. “We are thankful for the collaboration with the UMCG investigators with a special interest in immune-oncology treatment strategies and appreciate the opportunity to present the ALISON trial data for the first time at ASCO,” said Mendus CMO Tariq Mughal. “High-grade serous ovarian cancer is associated with a poor prognosis and sadly remains difficult to be treated in the precision oncology era. Our current findings suggest that our active immunotherapy approach with vididencel improves tumor-directed immune responses in this high-risk cohort. Longer term follow-up data, in particular survival, will enhance our understanding of the disease and the potential benefit of vididencel treatment for women diagnosed with this hard-to-treat life-threatening malignancy.” “At the UMCG Department of Obstetrics and Gynecology, we are constantly seeking for more effective and safer methods to treat gynecological cancers” said Professor Marco de Bruyn, Head of the Immuno-oncology research group at UMCG. “The data presented at ASCO demonstrate that vididencel has the potential to induce immune responses against antigens previously shown to be relevant for HGSOC, combined with a strong safety profile. Together with Mendus we plan to further decipher the immune signatures, tumor characteristics and other potential mechanisms associated with improved clinical outcome following vididencel treatment.” Mendus and UMCG have engaged in a research and clinical development collaboration since 2019. The collaboration comprises the single-center Phase 1 ALISON trial with vididencel in HGSOC and a preclinical research program to develop novel immunotherapies for gynecological cancers, including therapies based on tumor-infiltrating lymphocytes. Enrolment and week 22 analysis has been completed for all 17 participants of the ALISON trial. Long-term follow-up to assess potential survival benefit of vididencel treatment is ongoing. A next read-out of the trial based on 2-year follow-up is anticipated in the fourth quarter of 2025. Please see below for details of the abstract presented at ASCO during the Gynecologic Cancer poster session on Sunday June 1, 2025, 9am-12pm CDT. Abstract title: Successful induction of tumor-directed immune responses in high gradeserous ovarian cancer patients after primary treatment using a whole tumor cell vaccine Authors: Annegé Vledder, Hester van Zeeburg, Koen Brummel, Anneke Eerkens, N. van Rooij, Annechien Plat, Jeroen Rovers, Marco de Bruyn, Hans Nijman Abstract Nr: 5566 For more information, please contact:Erik MantingChief Executive OfficerE-mail: ir@mendus.com About Mendus AB (publ) Mendus is dedicated to changing the course of cancer treatment by addressing tumor recurrence and improving long-term survival for cancer patients, while preserving health and quality of life. We leverage our understanding of dendritic cell biology to develop an advanced clinical pipeline of immunotherapies which combine clinical efficacy with a benign safety profile. Based in Sweden and The Netherlands, Mendus is publicly traded on the Nasdaq Stockholm under the ticker IMMU.ST. https://www.mendus.com/ AttachmentsALISON trial data presented at ASCO 2025

Mendus AB ("Mendus" publ; IMMU. ST), a biopharmaceutical company focused on immunotherapies targeting tumor recurrence, announces a summary of the data presented at the 2025 Cancer Immunotherapy Conference (CIMT), held May 12-14 in Mainz, Germany. The data demonstrate increased T cell diversity following treatment with Mendus’ lead product vididencel in acute myeloid leukemia (AML) and support the use of Mendus’ DCOne platform to expand tumor-infiltrating lymphocytes for the treatment of solid tumors. The first abstract with the title “Induction of multiple tumor specific T-cells in long-term surviving AML patients after treatment with a whole tumor cell vaccine” was presented during the poster session on May 12. Mendus had reported that at the latest data cut of the ADVANCE II Phase 2 trial, the majority of patients treated with Mendus’ lead product vididencel were alive at a median follow-up of 41.8 months. Long-term survival was associated with broad immune responses. The research presented at CIMT by Mendus and academic collaborators from Amsterdam UMC and Haukeland University Hospital Bergen focused on a detailed analysis of the T cell responses in long-term surviving patients of the ADVANCE II trial, including the detection of individual T cell receptors against tumor-associated antigens. Individual T cell receptors against WT-1 and other tumor antigens were detected and dynamics were followed over time during vididencel treatment. The study confirms the stimulation of broad tumor-specific immune responses following vididencel treatment, which contribute to the long-term immune control over residual disease in AML. A second abstract with the title “Robust ex vivo expansion of tumor-infiltrating lymphocytes from gynaecological cancer biopsies using dendritic cells derived from the leukemic cell line DCOne" was presented during a poster session on May 13. The data presented by Mendus and academic collaborators at the University Medical Center Groningen indicate that Mendus’ DCOne platform can be applied to optimize the production of tumor-infiltrating lymphocytes (TILs) for therapeutic purposes in gynaecological cancers. The therapeutic use of TILs has been demonstrated in a range of solid tumors, but their production process requires improvements to ensure reliability and reproducibility. Mendus’ DCOne platform provides off-the-shelf cells with a mature dendritic cell phenotype and these DCOne mDCs were shown to improve the expansion of TILs from ovarian and endometrial cancer tissue samples, supporting the development of improved production methods using the DCOne platform in these indications and potentially other solid tumors. For more information, please contact:Erik MantingChief Executive OfficerE-mail: ir@mendus.com About Mendus AB (publ) Mendus is dedicated to changing the course of cancer treatment by addressing tumor recurrence and improving long-term survival for cancer patients, while preserving health and quality of life. We leverage our understanding of dendritic cell biology to develop an advanced clinical pipeline of immunotherapies which combine clinical efficacy with a benign safety profile. Based in Sweden and The Netherlands, Mendus is publicly traded on the Nasdaq Stockholm under the ticker IMMU.ST. https://www.mendus.com/ AttachmentsMendus presents at CIMT