- Significant clinical improvements, including partial remissions and complete metabolic responses, observed in cancers resistant to PD-1/PD-L1 therapies
- A novel, first-in-class multi-checkpoint inhibitor demonstrating strong effectiveness and a favorable safety profile
- The combination study arm involving pembrolizumab (Keytruda®) in Australia is expected to conclude by the end of 2025
Schlieren, Switzerland, October 20, 2025 – , a clinical-stage biopharmaceutical company that utilizes its unique HLA-based technology platform to develop pioneering treatments for cancer and inflammatory diseases, today released encouraging preliminary data from its ongoing Phase I clinical trial assessing IOS-1002 in patients suffering from advanced solid tumors.
So far, 47 patients have been enrolled in the Australia-based multicenter study. Nineteen patients were given IOS-1002 as a standalone treatment, while 28 patients are receiving IOS-1002 alongside MSD’s (Merck & Co., Inc., Rahway, NJ, USA) anti-PD-1 therapy, pembrolizumab (Keytruda®). The monotherapy group has finished enrollment, and the combination group is presently enrolling patients for the highest dose level, with the last dose group anticipated to be completed by December 2025.
Within the monotherapy arm, 6 of 19 patients (32%) reached Stable Disease, indicating a positive rate of disease control. In the combination therapy group, 15 out of 21 assessable patients (71%) achieved Disease Control. Overall, 13 patients (61%) have so far achieved Stable Disease, with 10 of these patients still receiving treatment. An additional 2 patients (10%) have shown Partial Responses, including one patient who had a complete metabolic response confirmed via PET imaging.
This patient remains in follow-up past week 40. In addition to offering very encouraging clinical benefits for patients, IOS-1002 exhibits an excellent safety and tolerability profile, with no anti-drug antibodies detected.
“These initial indicators of clinical activity, particularly in a patient who achieved a lasting complete metabolic response, underscore IOS-1002’s distinct mechanism of action and its capacity to conquer PD-1/PD-L1 resistance,” stated Dr. Christoph Renner, Chief Medical Officer at ImmunOs. “We are heartened by the compound’s effectiveness in patients who are resistant to PD-1/PD-L1 blockade.”
IOS-1002 is a new, pioneering stabilized HLA-B57 ‘open format’ fusion protein designed to target three critical immune checkpoints: LILRB1, LILRB2, and KIR3DL1, while concurrently interacting with CD64 to stimulate macrophage activation. This multi-pronged strategy activates NK cells, macrophages, and T cells at the same time, consequently boosting both innate and adaptive anti-tumor responses.
Clinical findings, including a promising biomarker strategy for Phase Ib, were recently presented at the European Society for Medical Oncology (ESMO) meeting on October 19, 2025. Furthermore, a peer-reviewed article in Cancers () showcased IOS-1002’s preclinical effectiveness across various tumor models and detailed its mechanism of action, which involves suppressing immunosuppressive signaling and amplifying phagocytic and cytotoxic activity.
The identified biomarkers and patient response characteristics will inform patient selection for the forthcoming Phase Ib clinical trial, which is expected to commence in the latter half of 2026. Further details concerning the Phase Ib study’s design and goals will be announced before the trial begins.
“These data highlight IOS-1002’s potential to reshape our approach to targeting immune evasion in solid tumors,” added Dr. Reinhard Ambros, Chairman of the Board of Directors at ImmunOs. “We eagerly anticipate progressing this program into more advanced clinical development and investigating strategic partnerships.”
The trial is being conducted in compliance with ICH-GCP guidelines and is listed on clinicaltrials.gov. Subsequent updates will be given after the completion of the combination dose escalation phase and will be shared at future scientific conferences.
KEYTRUDA® is a registered trademark owned by Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.
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About ImmunOs Therapeutics AG
ImmunOs Therapeutics AG utilizes its distinctive HLA-based technology platform, which modulates the immune system, to develop pioneering therapeutics for managing cancer and inflammatory conditions. ImmunOs’ primary program involves a multi-functional HLA-fusion protein that targets specific LILRB (leukocyte immunoglobulin-like) and KIR (killer cell immunoglobulin-like) receptors, capable of stimulating both the innate and adaptive immune systems in cancer patients to eradicate tumor cells. ImmunOs is also working on various approaches to activate receptors for immune system modulation in inflammatory diseases.
The Company receives support from prominent international investors and is situated in Schlieren, Switzerland. For further details, please visit .
Company Contact
ImmunOs Therapeutics AG
Wagistrasse 18
8952 Schlieren (Zurich Area), Switzerland
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