On April 16, 2026 INmune Bio Inc. (NASDAQ: INMB) (the "Company"), a clinical-stage biotechnology company focused on developing therapies that harness the patient’s innate immune system, reported new preclinical data for INB03 (XPro1595 for oncology). The data will be presented at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting 2026 in San Diego on April 17-22.

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The poster, titled, "Soluble TNF blockade overcomes tyrosine kinase inhibitors resistance in HER2-positive breast cancer," details how INB03 ("XPro"), a first-in-class dominant-negative soluble TNF (sTNF) inhibitor, significantly enhances the anti-tumor activity of the tyrosine kinase inhibitors (TKIs) lapatinib and tucatinib while reducing metastatic spread to the brain, lungs, and liver in HER2-positive breast cancer models. It was authored by collaborators from the Instituto de Biología y Medicina Experimental (IBYME-CONICET) in Buenos Aires, Argentina.

Key Scientific Findings:

Overcoming Resistance in Vitro: The combination of INB03 (10 µg/mL) with either lapatinib (1 µM) or tucatinib (10 µM) produced statistically superior inhibition of cell proliferation and migration in both HER2+ JIMT-1 and brain-metastatic JIMT-1 Br3-luc cell lines compared to TKIs alone (p < 0.05 to p < 0.0001).
Enhanced Tumor Control In Vivo: In female nude mice bearing JIMT-1 or JIMT-1 Br3-luc tumors, INB03 + TKI combinations markedly slowed tumor growth compared to TKIs alone.
Reduction of Metastatic Spread: The addition of INB03 significantly reduced the incidence of metastases to brain, lung, and liver (quantified by ex-vivo IVIS luminescence imaging). Notably, it further enhanced tucatinib’s effect on lung metastases (p < 0.05 to p < 0.0001).
Mechanism of Action: These results support prior research showing that selective sTNF neutralization with INB03 down-regulates MUC4, a protein that shields the HER2 molecule and prevents therapies from binding effectively.
"These results build on our prior work showing that selective sTNF neutralization with INB03 down-regulates MUC4, restoring sensitivity to HER2-targeted therapies," said Roxana Schillaci, Ph.D., lead investigator. "The ability of INB03 to overcome TKI resistance and limit metastatic dissemination, including to the brain, highlights its potential to address key unmet needs in advanced HER2-positive breast cancer."

David Moss, CEO of INmune Bio, added, "INB03 continues to demonstrate broad therapeutic potential across solid tumors by targeting the soluble TNF pathway. These AACR (Free AACR Whitepaper) data reinforce our confidence in advancing INB03 combinations in the clinic for patients who have developed resistance to standard TKIs or who are at high risk for brain metastases."

The poster will be available for viewing during the AACR (Free AACR Whitepaper) 2026 meeting on April 21st.

About XPro (INB03)

XPro is a next-generation inhibitor of tumor necrosis factor (TNF) that is currently in clinical trial and acts differently than currently available TNF inhibitors in that it neutralizes soluble TNF (sTNF), without affecting trans-membrane TNF (tmTNF) or TNF receptors. XPro could have potential substantial beneficial effects in patients with neurologic disease by decreasing neuroinflammation. For more information about the importance of targeting neuroinflammation in the brain to improve cognitive function and restore neuronal communication visit this section of INmune Bio’s website.

(Press release, INmune Bio, APR 16, 2026, View Source [SID1234664458])