Pilot study on the feasibility, safety and immunogenicity of a personalized neoantigen-targeted immunotherapy (NeoPepVac) in combination with anti-PD-1 or anti-PD-L1 in advanced solid tumors

The majority of neoantigens arise from unique mutations which are not shared between individual patients. Thus, neoantigen-directed immunotherapy is a fully personalized treatment. Novel technical advances in next-generation sequencing and artificial intelligence (AI) allow fast and systematic prediction of cancer neoantigens for each individual patient.

In this study, the proprietary AI platform PIONEERTM is used for fast and accurate identification of tumor-derived neoantigens to be included in an immunotherapy (NeoPepVac), tailored to each individual patient. NeoPepVac immunotherapy, consisting of 5-15 predicted neoantigens as synthetic peptides, is formulated with a novel cationic liposomal adjuvant (CAF09b) to strengthen CD8+ T-cell immunity towards cancer.

Immune checkpoint inhibitors, targeting PD-1 or PD-L1, are administered before, during and after neoantigen-targeted immunotherapy to augment the activity of induced immune responses. The study is designed as an open phase I/IIa trial. Patients with either unresectable or metastatic melanoma, non-small cell lung cancer (NSCLC) or bladder (urothelial) cancer who meet the criteria for treatment with anti-PD-1 or anti-PD-L1 are included.

The NeoPepVac immunotherapy is given every second week, for a total of 6 immunizations. Blood samples are collected before, during and after NeoPepVac treatment to monitor the induction of a neoantigen-specific immune response and immune-related changes. Four patients have been included and treated with personalized NeoPepVac immunotherapy.

So far, only CTCAE Grade 1 mild flu-like symptoms have been observed as NeoPepVac-related AEs at the first dose level (500 mg total peptide). At least 50% of the neoantigens are generating a specific T-cell response as determined by IFN-γ ELISPOT analyses of patient PBMCs. So far the vaccine is well tolerated and safe.

Neoantigen prediction and immunotherapy manufacturing is feasible within 6 weeks of patient enrolment using the PIONEERTM platform. Preliminary analyses indicate induction of NeoPepVac-specific immune responses. EudraCT: 2018-002892-16. Inge Marie Svane. Innovations fonden. J.V. Kringelum: Full / Part-time employment, PhD, Director, Genomic Immuno-Oncology: Evaxion.

T. Bogenrieder: Full / Part-time employment, CMO at Evaxion: Evaxion. B. Rønø: Full / Part-time employment, PhD, Director, Cancer Vaccines: Evaxion. A.B. Sorensen: Full / Part-time employment, Project Manager, Personalized Immuno-oncology: Evaxion. N.V. Petersen: Full / Part-time employment: Evaxion.

L.V. Andreasen: Leadership role: SSI. D. Christensen: Leadership role, Full / Part-time employment: SSI. P.L. Andersen: Leadership role, Full / Part-time employment: SSI. All other authors have declared no conflicts of interest.