• Most (78%) patients experienced disease control (stable disease), including heavily pretreated individuals with HER2-positive breast and gastric cancers

• A favorable clinical safety profile and early signs of efficacy further support the potential of FcγRIIB-blocking monoclonal antibodies in multiple solid tumors

• BioInvent remains focused on BI-1206, its lead FcγRIIB‑blocking antibody, and BI-1808, its anti-TNFR2 antibody, and the BI‑1607 program is currently paused

Lund, Sweden – November 18, 2025 – BioInvent International AB (“BioInvent”) (Nasdaq Stockholm: BINV), a biotech company focused on the discovery and development of novel and first-in-class immune-modulatory antibodies for cancer immunotherapy, today announced that preclinical data and early clinical results from its first‑in-human study of BI‑1607, a novel FcγRIIB-blocking monoclonal antibody, have been published in the peer-reviewed journal Clinical Cancer Research, a journal of the American Association for Cancer Research.

The publication, entitled “A First-in-Class Monoclonal Antibody (BI-1607) Targeting FcRIIB: Preclinical Data and First-in-Human Studies in Patients with HER2-Positive Advanced Solid Tumors,” highlights the preclinical rationale and early clinical findings from the Phase 1 dose-escalation study (NCT05555251). While the BI-1607 program is currently on pause as BioInvent prioritizes its more advanced clinical-stage programs BI‑1206 and BI-1808, the Company remains encouraged by the scientific and clinical insights generated from this study.[1]

"The publication of our BI-1607 study in Clinical Cancer Research underscores the potential of FcγRIIB blockade as a novel strategy to enhance the efficacy of tumor-targeting antibodies,” said Martin Welschof, Chief Executive Officer of BioInvent. “While we have paused this program to focus on our lead clinical candidates, the data further validate tailored FcyR-blockade to enhance antibody immunotherapy. Our lead FcγRIIB blocking antibody, BI-1206, is developed to enhance efficacy and overcome rituximab resistance in NHL, as well as to enhance anti-PD-1 in solid cancers."

"BI-1607 was well-tolerated and showed encouraging disease control in a heavily pretreated population,” said Andres McAllister, Chief Medical Officer at BioInvent. “The ability to safely achieve full receptor saturation opens the door to future studies combining BI-1607 with other therapeutic antibodies”.

In this first-in-human study, data demonstrate that BI-1607 can be safely administered and combined with trastuzumab (anti-HER2) at doses achieving sustained and complete FcγRIIB saturation. Given its mode of action, BI-1607 is not expected to have single agent activity. The choice of trastuzumab as the combination agent in this trial was based on promising preclinical studies and a recognized need for additional options for those patients who fail to respond or stop responding to trastuzumab. Ultimately, if shown to be safe and effective in combination with trastuzumab, BI-1607 can also be used in combination with other cytotoxic or immunomodulatory antibodies for cancer treatment.

The full article is available here: A First-in-Class mAb (BI-1607) Targeting FcγRIIB: Preclinical Data and First-in-Human Studies in Patients with HER2-Positive Advanced Solid Tumors | Clinical Cancer Research | American Association for Cancer Research

Key findings in summary:
Early signs of clinical efficacy

• A majority of the evaluable patients (78%) experienced disease control (stable disease), including heavily pretreated individuals with HER2-positive breast and gastric cancers, with the longest duration of 6 months
• Tumor progression in target lesions was observed in 2 subjects, both from the low dose groups

BI-1607 showed excellent drugability

• BI-1607 was well-tolerated across the dose range, and maximum tolerated dose could not be identified
• The pharmacokinetic and pharmacodynamic profile in humans were very favorable, and sustained target saturation could be achieved with every three weeks dosing.

About BI-1607
Like BI-1206, BioInvent’s lead FcyRIIB antibody, BI-1607 is intended to enhance the efficacy and overcome resistance to existing cancer treatments such as trastuzumab. Trastuzumab alone or in combination with chemotherapy significantly improves overall survival of HER2 postive breast cancer patients. However, many patients remain uncured and develop resistance to trastuzumab resulting in relapse or progression of the disease. BI-1607 differs from BI-1206 in that BI-1607 has been engineered for reduced Fc-binding to FcyRs. This alteration generates a major differentiating factor between the two antibodies, and specifically with respect to the best combination partners.

About BioInvent
BioInvent International AB (Nasdaq Stockholm: BINV) is a clinical-stage biotech company that discovers and develops novel and first-in-class immuno-modulatory antibodies for cancer therapy, with drug candidates in ongoing clinical programs in Phase 1/2 trials for the treatment of hematological cancer and solid tumors. The Company's validated, proprietary F.I.R.S.T™ technology platform identifies both targets and the antibodies that bind to them, generating many promising new immune-modulatory candidates to fuel the Company's own clinical development pipeline and providing licensing and partnering opportunities.

The Company generates revenues from research collaborations and license agreements with multiple top-tier pharmaceutical companies, as well as from producing antibodies for third parties in the Company's fully integrated manufacturing unit. More information is available at www.bioinvent.com.

For further information, please contact:
Cecilia Hofvander, VP Investor Relations
Phone: +46 (0)46 286 85 50
Email: cecilia.hofvander@bioinvent.com

BioInvent International AB (publ)
Co. Reg. No.: 556537-7263
Visiting address: Ideongatan 1
Mailing address: 223 70 LUND
Phone: +46 (0)46 286 85 50
www.bioinvent.com

The press release contains statements about the future, consisting of subjective assumptions and forecasts for future scenarios. Predictions for the future only apply as the date they are made and are, by their very nature, in the same way as research and development work in the biotech segment, associated with risk and uncertainty. With this in mind, the actual outcome may deviate significantly from the scenarios described in this press release.

[1] As announced in August of this year (more details here), following a comprehensive strategic review, BioInvent will concentrate resources on advancing BI-1808, its first-in-class anti-TNFR2 antibody, currently in Phase 2a clinical development in solid cancer and cutaneous T-cell lymphoma (CTCL), as well as BI-1206, an FcyRIIB-blocking antibody, currently in Phase 2a in non-Hodgkin’s lymphoma (NHL), and starting a Phase 2a trial in the first-line treatment of patients with metastatic non-small cell lung cancer (NSCLC). As part of this strategy, BioInvent has paused the development of Phase 1 programs for BI-1910 and BI-1607.