INB03

We have demonstrated that TNF induces trastuzumab resistance through mucin 4 (MUC4) upregulation and it is an independent biomarker of poor response to therapy in HER2+ breast cancer...TNF blockade was achieved with etanercept (E), which blocks the soluble (sTNF) and transmembrane isoform of TNF, or with the dominant negative protein INB03 (DN) which neutralizes only sTNF...MUC4 is associated with poorly-infiltrated TNBC, and sTNF blockade downregulates its expression decreasing MTS when combined with anti-PD-1. We propose the TNF as a new target for the treatment of TNBC, and MUC4 as a predictive biomarker to guide a combined treatment of TNF blockers with immunotherapy.

In preclinical models of de novo trastuzumab-resistant tumors, combination of a sTNF blocking agent INB03, (DN), with T-DXd decreases tumor growth compared to T-DXd alone...Methods Nude mice bearing HER2+MUC4+ JIMT-1 tumor, primary resistant to trastuzumab, pertuzumab and lapatinib, were treated with IgG 5 mg/kg, T-DXd 5 mg/kg (T-DXd 5), 2.5 mg/kg (T-DXd 2.5) or 1.25 mg/kg (T-DXd 1.25), DN 10 mg/kg or the combined therapies...Combination of DN with T-DXd in MUC4 expressing HER2+ BC improves response to T-DXd alone by increasing T-DXd internalization and improving anti-tumor innate immune responses in the TME without increasing toxicity. The results suggest this combination should be investigated in clinical trials in patients who have MUC4 expressing tumors when T-DXd is started or become resistant to T-DXd therapy.

We have demonstrated that the proinflammatory cytokine TNFα induces trastuzumab resistance through Mucin4 (MUC4) upregulation and it is an independent biomarker of poor response to therapy in HER2+ breast cancer...TNFα blockade was achieved using etanercept (E), which blocks the soluble (sTNFα) and transmembrane isoforms of TNFα, or dominant negative protein INB03 (DN) which only neutralizes sTNFα...MUC4 is an independent biomarker of poor overall survival, it is associated with an increased risk of metastasis and immune desert tumors. We propose TNFα as a new target for the treatment of TNBC, and MUC4 as a predictive marker to guide a combined treatment of TNFα blockers with chemotherapy or immunotherapy.

Here, we study whether sTNFα blockade with INB03 (DN) plays a role in regulation of innate immunity to enhance T-DXd antitumor effects in a multiple HER2-targeted therapy-resistant model. Nude mice bearing HER2+MUC4+ JIMT-1 tumor, primary resistant to trastuzumab, pertuzumab and lapatinib, were treated with IgG 5 mg/kg, T-DXd 5 mg/kg (T-DXd 5), 2.5 mg/kg (T-DXd 2.5) or 1.25 mg/kg (T-DXd 1.25), DN 10 mg/kg or the combined therapies...Adding DN allows to lower T-DXd doses to induce a reinforced antitumor innate immune response, reduced tumor cell mitosis and achieve similar tumor inhibition. Since sTNFα and MUC4 expression proved to be important variables in the response to T-DXd, neutralizing this cytokine may open new therapeutic strategies to treat patients with MUC4 expressing tumors or have progression on T-DXd therapy.

In preclinical models of de novo trastuzumab-resistant tumors, we proved that administration of the sTNFα blocking agent INB03 (DN) together with trastuzumab inhibited tumor growth and induced an innate immune response in the tumor microenvironment (TME)...Methods JIMT-1 is a HER2- positive BC cell line resistant to trastuzumab, pertuzumab and lapatinib, which expresses MUC4...This finding highlights that sTNFα and MUC4 expression are important variables in the response to T-DXd. Neutralization of sTNFα may open new therapeutic strategies for treatment of patients who present with MUC4 expression or have progression on T-DXd therapy.

BC patients are treated with chemotherapy (CT) and/or radiotherapy (RT), and HER2+ BC patients also receive targeted therapies, such as trastuzumab (Tz)...In preclinical models of de no5vo Tz-resistant tumors, administration of the sTNF blocking agent INB03 (DN) together with Tz inhibited tumor growth...Conclusion Our results suggest that i) MUC4 expression is associated with immunologically “cold” HER2+ and TNBC, inducing an immunosuppressive TME that reflects in poor DFS/OS, and it confers resistance to Tz in HER2+ BC; ii) elimination of MUC4 expression reverses resistance to Tz; iii) tumor infiltrating macrophages are critical to the anti-tumor response in HER2+ BC. Patients with MUC4+ HER2+ or MUC4+ TNBC should benefit from sTNF blockade treatment leading to MUC4 downregulation and higher TILs, which would result in a better response to Tz and probably to immune checkpoint inhibitors.

TNFα blockade can be achieved by monoclonal antibodies (such as infliximab, adalimumab, etc.), fusion proteins (etanercept) and dominant negative proteins (INB03). Here we address the different effects of each compound and also analyze the use of potential biomarkers in the selection of patients who would benefit from a combination of TNFα blocking agents with HER2-targeted treatments to prevent or overcome therapy resistance in breast cancer.