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LONDON, Nov. 07, 2019 (GLOBE NEWSWIRE) -- Treos Bio has developed a unique approach to create cancer vaccines by focusing not just on the vaccine targets but also on delivering antigen targets to which each patient’s immune system can specifically respond. Its proprietary class-leading platform, the Personal Antigen Selection Calculator (PASCal), addresses both patient and tumor heterogeneity. PAScal enabled the development of two families of effective shared antigen-based cancer vaccines (“off-the-shelf” and “personalized”) that target 19 cancer indications and are commercially scalable, without need for tumor biopsy and on-demand manufacturing.
The results will be presented on November 8, 2019 from 7:00 a.m. to 8:00 p.m. ET at the Society for Immunotherapy of Cancer's 34th annual meeting (SITC 2019) in National Harbor, MD poster session, entitled
P329 PolyPEPI1018 off-the-shelf vaccine as an add-on to maintenance therapy achieved durable treatment responses in patients with microsatellite-stable metastatic colorectal cancer patients (MSS mCRC);
P677 Warehouse approach for the development of personalized cancer vaccines by using Personal Antigen Selection Calculator (PASCal) without the need for tumor biopsy.
Treos Bio uses a knowledgebase and algorithm embedded in its proprietary PASCal tool to develop cancer vaccines. The knowledgebase contains a comprehensive taxonomy of immunological information linking the HLA genetics of 26,000 subjects to tumor-specific antigens derived from over 96,000 tumor biopsies, resulting in 10^8 true HLA-epitope pairs (both HLA class I and class II molecules). PASCal has a unique, validated algorithm for the selection of Personal EPItopes (PEPIs) that are likely to induce antigen-specific T cell responses in a subject based on the patients’ complete HLA-genotype.
The PolyPEPI1018 “off-the-shelf” cancer vaccine achieved unprecedented immune and tumor responses in MSS mCRC patients as an add-on to maintenance therapy in a Phase 1/2 clinical trial (OBERTO), interim results of which were presented at ASCO 2019 and ESMO 2019. The results to be presented at SITC 2019 demonstrated improvements in progression-free survival (PFS) that compare favorably to those observed with the first-line maintenance therapy alone, based on historical benchmark data.
“At nine months median follow-up, the median PFS was not reached with three of six patients controlling their disease for at least ten months, thereby delaying the need for 2nd line treatment” – said Joleen M. Hubbard M.D., principal investigator of the OBERTO trial at the Mayo Clinic.
The improvements in clinical benefit were consistent with the immunological responses observed at both peripheral and tumor level. Specifically, HalioDx proprietary assay Immunoscore® CR TL (CD3/CD8) revealed that vaccination-induced recruitment of tumor-infiltrating lymphocytes (TILs) to both the invasive margin and core tumor area for three out of four patients’ biopsies tested. For two patients experiencing tumor regression and prolonged control of the disease, CD3+ and CD8+ cytotoxic T cells accumulated in the core tumor post-vaccination, turning them into inflamed, immunologically “hot” tumors.
“These clinical results, together with the unprecedented autologous HLA-dependent vaccine antigen-specific immune responses observed at both peripheral and tumor level, provide the sequence of evidences for the vaccine’s mode of action against the tumor, in vivo,” said Dr. Eniko R. Toke, Chief Scientific Officer of Treos Bio.
For the development and production of off-the-shelf personalized vaccines, Treos Bio has designed the PEPI Panel, a library of vaccine peptides that contains almost 3,300 immunogenic peptides derived from 184 frequently expressed, shared tumor antigens associated with and shared between 19 cancer indications. PASCal selects the patient-specific immunogenic vaccine peptides based on the patients’ complete HLA-set, frequently expressed antigens specific to the patient’s tumor with no tumor biopsy required from the patient, only a saliva sample. Personalized vaccines administered to three HLA-genotyped metastatic cancer patients (with ovarian-, breast- and colorectal cancer) induced CD8+ T-cell responses against an average of 12 different vaccine antigens, from the 12-13 vaccine peptides administered for each patient. Long-lasting CD8+ T-cell responses were also detected 14 months after the last vaccination. The vaccinations boosted the pre-existing T-cell reactivities against multiple antigens, demonstrating their presence in the patients’ tumor and confirming the success of the vaccine design strategy, which aims to induce polyclonal T-cell responses against at least three antigens expressed by the tumor.
“These results are very promising. Treos is the first in the immunotherapy field to generate positive data for classically cold tumors: MSS mCRC, ovarian cancer and breast cancer,” said Christopher C. Gallen, MD, PhD, and Chairman of Treos Bio. “Our vaccines have the potential to overcome the limitations of other vaccines and unlike other approaches to personalized cancer vaccination, there is no need for tumor biopsy. Moreover, the proposed treatment process is highly efficient and commercially scalable.”
More detailed scientific and clinical data will be presented at the meeting.
The full abstracts are available at
The presentations will be available at www.treosbio.com on November 11, 2019 at 13.00 CET.
About Colorectal Cancer
Colorectal cancer is the third most common cancer worldwide, accounting for one-third of the cancer incidence and mortality burden worldwide together with lung and breast cancers with nearly 881,000 deaths in 2018 from colorectal cancer worldwide, according to GLOBOCAN. While improvements in cancer care have boosted survival rates for all stages of colorectal cancer in the past two decades, the prognosis for patients with metastatic colorectal cancer remains grim. The five-year relative survival rate for patients with metastatic colon cancer is just 14 percent. For patients with metastatic rectal cancer, the five-year relative survival rate is just 15 percent, according to the American Cancer Society.
About Treos Bio Limited
Treos Bio, headquartered in London, with operational subsidiaries in Hungary and the USA, uses data science and proprietary biomarkers to develop its precision cancer vaccines, with substantially shortened development timelines and at lower costs. Treos Bio’s off-the-shelf cancer vaccines are designed to exclude autoimmunity and induce tumor-specific immune responses allowing them to be safer and more effective in patients who cannot benefit from current immunotherapies. Treos Bio’s novel biomarkers will support the development of in vitro companion diagnostic tests to identify patients who are most likely to respond to treatment.
Treos Bio has completed preclinical development of additional members of the PolyPEPI cancer vaccine family with companion diagnostics to select likely responders. These off-the-shelf vaccines are designed for a general population of patients with ovarian-, breast-, lung cancers, glioma, melanoma, and leukemia. Treos Bio patient-focused vaccine design also supports the development of vaccines for single individuals and a population of individuals with a specific genetic background, including specific vaccines most effective in ethnic populations.
More information can be found at www.treosbio.com.
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