SQZ Biotechnologies Presents New eAPC Preclinical Data Demonstrating That Multiplexed mRNA Engineering of Immune Cells Increases Killer T Cell Activity In Vivo
WATERTOWN, Mass.–(BUSINESS WIRE)– SQZ Biotechnologies (NYSE: SQZ), focused on unlocking the full potential of cell therapies for multiple therapeutic areas, today shared enhanced antigen presenting cell (eAPC) preclinical data demonstrating that delivery of multiple mRNAs encoding for disease-specific antigens together with immune stimulators (CD86 costimulatory factor and membrane bound IL-2 and IL-12 cytokines) had a synergistic effect that substantially increased killer T cells in humanized mouse models. The preclinical data, presented at the American Association for Cancer Research (AACR) 2022 Annual Meeting, showed this in vivo enhancement can be seen with a variety of disease antigen mRNAs across a range of HLA types. The findings indicate the potential of the company’s eAPC platform to induce a robust killer T cell response against specific diseases, and the opportunity to increase the number of patients who could potentially benefit from eAPC therapeutic candidates.
The company’s first eAPC therapeutic candidate, SQZ-eAPC-HPV, is in a Phase 1/2 clinical trial (COMMANDER-001) in patients who have human papillomavirus positive (HPV16+) solid tumors. SQZ-eAPC-HPV delivers mRNA for HPV-specific E6 and E7 antigens, CD86 costimulatory factor, and membrane-bound IL-2 and IL-12 cytokines. This new platform represents sophisticated engineering that we believe to be an advancement over the company’s APC platform candidate, which has demonstrated promising preliminary monotherapy clinical activity in a patient with HPV16+ solid tumors.
“Our eAPC preclinical data, both in vitro and in vivo, demonstrate the synergistic potential of our multiple mRNA delivery approach on activating CD8+T cells,” said Howard Bernstein, M.D., Ph.D., Chief Scientific Officer at SQZ Biotechnologies. “The inclusion of disease-specific antigens, costimulatory factor, and cytokines into a single cell therapy offers tremendous opportunity for patient impact. With the capability to engineer all three T cell activating signals simultaneously, we can pursue additional preclinical activities that could extend our eAPC platform to additional indications.”
In addition to the eAPC preclinical data, a Trial in Progress poster presentation of the ENVOY-001 Phase 1/2 clinical trial will be delivered by Victoria Villaflor, M.D., City of Hope Medical Center. The presentation will summarize the ENVOY-001 study design of SQZ-AAC-HPV, the company’s first engineered red blood cell clinical candidate being investigated in patients with HPV16+ recurrent, locally advanced, or metastatic solid tumors.
AACR EAPC MRNA HIGHLIGHTS IN HUMANIZED MOUSE MODEL
Synergistic Impact of Multiple mRNA T cell Stimulators
- Mice treated with human eAPCs including mRNA for CMV antigen, CD86 costimulatory factor, and membrane-bound IL-2 and IL-12 cytokines were shown to have a dramatic increase in killer T cells compared to APCs with mRNA for antigen alone
- Mice treated with human eAPCs including mRNA for influenza (Flu) antigen, CD86 costimulatory factor, and membrane-bound IL-2 and IL-12 cytokines were shown to have a three-fold increase in killer T cell compared to APCs with mRNA for antigen alone
Strong T Cell Responses Across Multiple HLA Types
- Mice treated with human eAPCs including mRNA for CMV antigen, CD86 costimulatory factor, and membrane-bound IL-2 and IL-12 cytokines were shown to have higher killer T cells responses across a range of HLA types (A*01, A*02, A*11, A*24, B*07, B*35) compared to those squeezed with CMV peptide alone
AACR mRNA HIGHLIGHTS IN HUMAN PBMCs (B cell, T cell, NK cell, Monocytes)
Expansion of CD8 T Cells & Cytokine Signaling
- Human PBMCs with antigen-encoding mRNA for CMV, Flu, HPV16 E6, HPV16 E7 and KRAS G12V substantially increased activation of antigen-specific T cells in vitro compared to untreated PBMCs
- Membrane-bound IL-2 and IL-12 mRNA delivery in PBMC subsets led to surface expression of the cytokines and functional signaling
AACR eAPC Poster Presentation
Title: Co-delivery of antigen-encoding mRNA and signal 2/3 mRNAs to PBMCs by CellSqueeze® technology generates SQZ® eAPCs that prime CD8 T cells in humanized mouse model
Presenter: Scott Loughhead, PhD, SQZ Biotechnologies
Session Date and Time: Tuesday, Apr 12, 2022 9:00 AM – 12:30 PM ET
Poster Board Number: 19
Abstract Number: 2853
AACR Trial in Progress Presentation
Title: ENVOY-001: A phase 1, multicenter, open-label study of SQZ-AAC-HPV as monotherapy and in combination with immune checkpoint inhibitors in HLA-A*02+ patients with HPV16+ recurrent, locally advanced, or metastatic solid tumors
Presenter: Victoria M. Villaflor, MD, City of Hope Medical Center
Session Date and Time: Wednesday, April 13, 2022 9:00 AM – 12:30 PM ET
Poster Section: 35
Abstract Number: 7645
SQZ® Activating Antigen Carriers (AACs), derived from engineered red blood cells (RBCs), are designed to transport tumor-specific antigens and adjuvant to a patient’s own professional antigen presenting cells (APCs). The APCs would then activate CD8 killer T cells that travel to tumor sites and attack specific diseased cells. SQZ-AAC-HPV is the company’s first AAC clinical candidate, and it is being evaluated in a Phase 1/2 clinical trial (ENVOY-001 or SQZ-AAC-HPV-101) for the treatment of HPV16+ advanced or metastatic solid tumors. The investigational candidate is being studied as a monotherapy and in combination with immune checkpoint inhibitors.
ENVOY-001 Trial Design
SQZ-AAC-HPV is being evaluated in a Phase 1/2 clinical trial (ENVOY-001) for the treatment of HPV16+ advanced or metastatic solid tumors. The investigational candidate, which targets E6 and E7 oncoproteins, is being studied as a monotherapy and in combination with immune checkpoint inhibitors. The study consists of two parts. The first part is designed to assess the safety and tolerability of multiple doses of SQZ-AAC-HPV monotherapy in treatment-experienced patients. The second part of the study will assess safety and tolerability of SQZ-AAC-HPV in combination with nivolumab and/or ipilimumab.