Metastatic Colorectal Cancer Vaccine Candidate Delivers Positive Results

A London-based immuno-oncology company reported positive interim results from its first-in-man, Phase 1/2 clinical study of its precision cancer vaccine with maintenance therapy in patients with metastatic colorectal cancer (mCRC). 

This is good news since the 5-year relative survival rate for patients with mCRC is just 14 percent. 

This small Phase 1/2 study is evaluating the subcutaneous injection of the PolyPEPI1018 CRC vaccine as an add-on immunotherapy to the standard-of-care. 

PolyPEPI1018 is an off-the-shelf, long peptide vaccine comprised of 12 unique epitopes derived from 7 conserved cancer testis antigens (CTAs) frequently expressed in mCRC. 

PolyPEPI1018 was designed to induce polyvalent T cell responses in a large subpopulation of CRC patients using its PEPI TestTM platform which identifies Personal EPItopes (PEPIs) that are likely to induce antigen-specific T cell responses in a subject.

Analysis of the first part of this clinical study revealed that 100 percent of patients exhibited PolyPEPI1018-specific immune responses, 90 percent of them (10) had both CD8+ and CD4+T cell responses. 

And, the detailed immunogenicity analysis for the first 4 subjects showed unprecedented immunological activity after a single dose of vaccine:

• polyfunctional CD8+ T cell responses were detected against up to five vaccine antigens per patient
• both CD8+ and CD4+ T cell responses were detectable ex vivo

The PEPI TestTM correctly predicted the subjects’ antigen-specific T cell responses based on their complete HLA class I genotype determined from a saliva sample, 71% agreement with measured T cell responses. 

Joleen M. Hubbard M.D., the principal investigator of the OBERTO trial conducted at the Mayo Clinic, said in a press release, “Based on these encouraging results, we amended the trial to administer 3 doses of PolyPEPI1018 given 12 weeks apart. We plan to share updated data from this study later this year.” 

Recent colon cancer news:

• Colon Cancer Vaccine Candidate Produced Antibody Responses in 10% of Patients
• Cancer Vaccine Model Suggests Optimism for Lynch Syndrome Patients

Colorectal cancer is the third most common cancer worldwide, accounting for one-third of the cancer incidence and mortality burden worldwide. 

The full abstract, along with three others related to Treos’ PEPI TestTM platform technology are available at Treosbio and the poster presentation will be available at Treosbiom on 3 June 2019 at 12.00 CDT.

Treos Bio Limited is headquartered in London, with operational subsidiaries in Budapest, Hungary, and San Francisco, CA.