Magnetic Fluorescent Bead-Based Dual-Reporter Flow Analysis of PDL1-Vaxx Peptide Vaccine-Induced Antibody Blockade of the PD-1/PD-L1 Interaction

The inhibition of checkpoint receptors (PD-1, PD-L1, and CTLA-4) with monoclonal antibodies has shown great benefit in clinical trials for treating cancer ...

The Ohio State University Wexner Medical Center

The James Comprehensive Cancer Center

The ErbB family (HER-1, HER-2, HER-3 and HER-4) of receptor tyrosine kinases has been the focus of cancer immunotherapeutic strategies while antiangiogenic therapies have focused on VEGF and its receptors VEGFR-1 and VEGFR-2. Agents targeting receptor tyrosine kinases in oncology include therapeutic antibodies to receptor tyrosine kinase ligands or the receptors themselves, and small-molecule inhibitors. Many of the US FDA-approved therapies targeting HER-2 and VEGF exhibit unacceptable toxicities, and show problems of efficacy, development of resistance and unacceptable safety profiles that continue to hamper their clinical progress. The combination of different peptide vaccines and peptidomimetics targeting specific molecular pathways that are dysregulated in tumors may potentiate anticancer immune responses, bypass immune tolerance and circumvent resistance mechanisms. The focus of this review is to discuss efforts in our laboratory spanning two decades of rationally developing peptide vaccines and therapeutics for breast cancer. This review highlights the prospective benefit of a new, untapped category of therapies biologically targeted to EGF receptor (HER-1), HER-2 and VEGF with potential peptide 'blockbusters' that could lay the foundation of a new paradigm in cancer immunotherapy by creating clinical breakthroughs for safe and efficacious cancer cures.

Peptide vaccines and targeting HER and VEGF proteins may offer a potentially new paradigm in cancer immunotherapy.

HER-2 and the vascular endothelial factor receptor (VEGF) represent validated targets for the therapy of multiple tumor types and inhibitors of these receptors have gained increasing importance in the clinic. In this context, novel bioactive agents associated with better therapeutic outcomes and improved safety profile are urgently required. Specifically engineered HER-2- and VEGF-derived peptides in combination with low-dose chemotherapy might provide a substantial impact on tumor metastasis and cancer progression. We tested the antitumor effects of HER-2 and VEGF peptide mimics in combination with metronomic paclitaxel in both PyMT and Balb/c murine model challenged with TUBO cells. The combination of low-dose paclitaxel and HER-2 or VEGF peptide mimics had greater inhibitory effects than either agent alone. Peptide treatment caused virtually no cardiotoxic effects, while paclitaxel and the anti-HER-2 antibody trastuzumab (Herceptin), exerted consistent cardiotoxicity. The combination regimen also promoted significant reductions in tumor burden and prolonged survival rates in both transgenic and transplantable tumor models. Tumor weights were significantly reduced in mice treated with HER-2 peptides alone, and even more in animals that received HER-2 peptide with low-dose paclitaxel, which alone had no significant effects on tumor growth in the transgenic model. Specifically engineered native peptide sequences from HER-2 and VEGF used in combination with metronomic paclitaxel demonstrate enhanced anticancer efficacy and an encouraging safety profile. This novel approach to targeted therapy may offer new avenues for the treatment of breast cancer and other solid tumors that overexpress HER-2 and VEGF.

Immunotherapy with HER-2 and VEGF peptide mimics plus metronomic paclitaxel causes superior antineoplastic effects in transplantable and transgenic mouse models of human breast cancer.

Bridging oncology and immunology: expanding horizons with innovative peptide vaccines and peptidomimetics.

There is a recognizable and urgent need to speed the development and application of novel, more efficacious anti-cancer vaccine therapies that inhibit tumor progression and prevent acquisition of tumor resistance. We have created and established a portfolio of validated peptide epitopes against multiple receptor tyrosine kinases and we have identified the most biologically effective combinations of EGFR (HER-1), HER-2, HER-3, VEGF and IGF-1R peptide vaccines/mimics to selectively inhibit multiple receptors and signaling pathways. The strategy is based on the use of chimeric conformational B-cell epitope peptides incorporating "promiscuous" T-cell epitopes that afford the possibility of generating an enduring immune response, eliciting protein-reactive high-affinity anti-peptide antibodies as potential vaccines and peptide mimics that act as antagonists to receptor signaling that drive cancer metastasis. In this review we will summarize our ongoing studies based on the development of combinatorial immunotherapeutic strategies that act synergistically to enhance immune-mediated tumor killing aimed at addressing mechanisms of tumor resistance for several tumor types.

A paradigm shift: Cancer therapy with peptide-based B-cell epitopes and peptide immunotherapeutics targeting multiple solid tumor types: Emerging concepts and validation of combination immunotherapy.

Despite the promise of targeted therapies, there remains an urgent need for effective treatment for esophageal cancer (EC) and triple-negative breast cancer (TNBC). Current FDA-approved drugs have significant problems of toxicity, safety, selectivity, efficacy and development of resistance. In this manuscript, we demonstrate that rationally designed peptide vaccines/mimics are a viable therapeutic strategy for blocking aberrant molecular signaling pathways with high affinity, specificity, potency and safety. Specifically, we postulate that novel combination treatments targeting members of the EGFR family and IGF-1R will yield significant anti-tumor effects in in vitro models of EC and TNBC possibly overcoming mechanisms of resistance. We show that the combination of HER-1 and HER-2 or HER-1 and IGF-1R peptide mimics/vaccine antibodies exhibited enhanced antitumor properties with significant inhibition of tumorigenesis in OE19 EC and MDA-MB-231 TNBC cell lines. Our work elucidates the mechanisms of HER-1/IGF-1R and HER-1/HER-2 signaling in these cancer cell lines, and the promising results support the rationale for dual targeting with HER-1 and HER-2 or IGF-1R as an improved treatment regimen for advanced therapy tailored to difference types of cancer.

Anti-Tumor Effects of Peptide Therapeutic and Peptide Vaccine Antibody Co-targeting HER-1 and HER-2 in Esophageal Cancer (EC) and HER-1 and IGF-1R in Triple-Negative Breast Cancer (TNBC).

This first-in-human phase I study (NCT01417546) evaluated the safety profile, optimal immunologic/biological dose (OID/OBD), and immunogenicity of the combination of two peptide B-cell epitope vaccines engineered to represent the trastuzumab- and pertuzumab-binding sites. Although trastuzumab and pertuzumab have been approved for clinical use, patients often develop resistance to these therapies. We have advanced a new paradigm in immunotherapy that focuses on humoral responses based on conformational B-cell epitope vaccines.

Phase I Immunotherapy Trial with Two Chimeric HER-2 B-Cell Peptide Vaccines Emulsified in Montanide ISA 720VG and Nor-MDP Adjuvant in Patients with Advanced Solid Tumors.

We developed a PD-1 B-cell epitope vaccine (PD1-Vaxx) to rival nivolumab therapy which has received ethics approvals for a Phase 1 clinical trial in Australia. The US FDA granted Investigational New Drug approval to Imugene Ltd for clinical testing in NSCLC. We demonstrated synergistic vaccine combinations with an HER-2 targeted vaccine (B-Vaxx).

First prototype checkpoint inhibitor B-cell epitope vaccine (PD1-Vaxx) en route to human Phase 1 clinical trial in Australia and USA: exploiting future novel synergistic vaccine combinations.

Immunotherapy with monoclonal antibodies to checkpoint inhibitors against the PD-1/PD-L1 signaling pathway is a landmark achievement in cancer therapy. Some anti-PD-1 inhibitors such as nivolumab and pembrolizumab have shown clinical success, in a percentage of patients with prolonged survival rates. However, adverse effects accompany these benefits. In this case, strategies with lower toxicity and increased specificity are urgently required. Cancer vaccines have the ability to stimulate the native immune system and in particular, an engineered B-cell epitope can elicit high-affinity polyclonal antibodies with similar efficacy to PD-1 monoclonal antibodies in murine animal models. We have previously designed and synthesized a unique B-cell vaccine, PD1-Vaxx [MVF-PD-1(92-110)], and we have tested the immunogenicity and antitumor properties in CT26 colon cancer BALB/c syngeneic mice model. This manuscript provides results from comprehensive preclinical pharmacology studies encompassing primary and secondary pharmacodynamics, biodistribution, and safety studies. The results from these preclinical studies support the use of PD1-Vaxx in a first-in-human clinical trial in patients with non-small cell lung cancer (NSCLC). A phase I trial in patients with NSCLC has commenced.

Preclinical Studies of a Novel Human PD-1 B-Cell Peptide Cancer Vaccine PD1-Vaxx From BALB/c Mice to Beagle Dogs and to Non-Human Primates (Cynomolgus Monkeys).

Blockade of checkpoint receptors with monoclonal antibodies against CTLA-4, PD-1 and PD-L1 has shown great clinical success in several cancer subtypes, yielding unprecedented responses albeit a significant number of patients develop resistance and remain refractory. Both PD-1/PD-L1 and HER-2 signaling pathway inhibitors have limited efficacy and exhibits significant toxicities that limit their use. Ongoing clinical studies support the need for rationale combination of immuno-oncology agents to make a significant impact in the lives of cancer patients. We introduce the development of a novel chimeric PD-L1 B-cell peptide epitope vaccine (amino acid 130-147) linked to a "promiscuous" T cell measles virus fusion (MVF) peptide (MVF-PD-L1(130); PDL1-Vaxx) or linked to tetanus toxoid (TT3) TT3-PD-L1 (130) via a linker (GPSL). These vaccine constructs are highly immunogenic and antigenic in several syngeneic animal models. The PD-L1 vaccines elicited high titers of polyclonal antibodies that inhibit tumor growth in multiple syngeneic cancer models, eliciting antibodies of different subtypes IgG1, IgG2a, IgG2b and IgG3, induced PD-1/PD-L1 blockade, decreased proliferation, induced apoptosis and caused ADCC of tumor cells. The PDL1-Vaxx induces similar inhibition of tumor growth versus the standard anti-mouse PD-L1 antibody in both syngeneic BALB/c and C57BL/6J mouse models. The combination of PDL1-Vaxx with HER-2 vaccine B-Vaxx demonstrated synergistic tumor inhibition in D2F2/E2 carcinoma cell line. The anti-PDL1-Vaxx block PD-1/PD-L1 interaction and significantly prolonged anti-tumor responses in multiple syngeneic tumor models. The combination of HER-2 vaccine (B-Vaxx) with either PDL1-Vaxx or PD1-Vaxx demonstrated synergistic tumor inhibition. PDL1-Vaxx is a promising novel safe checkpoint inhibitor vaccine.

A newly discovered PD-L1 B-cell epitope peptide vaccine (PDL1-Vaxx) exhibits potent immune responses and effective anti-tumor immunity in multiple syngeneic mice models and (synergizes) in combination with a dual HER-2 B-cell vaccine (B-Vaxx).

Squamous cell carcinoma of the head and neck (HNSCC) is prevalent globally and in the US. Management, particularly after disease recurrence, can be challenging, and exploring additional treatment modalities, such as therapeutic cancer vaccines, may offer an opportunity to improve outcomes in this setting.

Pravin T. P. Kaumaya

Department of Obstetrics & Gynecology

The Ohio State University Wexner Medical Center

Magnetic Fluorescent Bead-Based Dual-Reporter Flow Analysis of PDL1-Vaxx Peptide Vaccine-Induced Antibody Blockade of the PD-1/PD-L1 Interaction

Pravin T. P. Kaumaya

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Obstetrics & Gynecology

The Ohio State University Wexner Medical Center

Magnetic Fluorescent Bead-Based Dual-Reporter Flow Analysis of PDL1-Vaxx Peptide Vaccine-Induced Antibody Blockade of the PD-1/PD-L1 Interaction

Department of Obstetrics & Gynecology