The majority of metastatic cancers remain incurable since the current methods of treatment often fail to target the heterogeneous nature of each individual patient's tumor. Personalized approaches targeting each individual patient's tumor may therefore bring significant improvements. The Mutanome Engineered RNA Immuno-Therapy (MERIT) consortium will clinically validate a pioneering RNA-based immunotherapy concept for the treatment of triple negative breast cancer (TNBC) by targeting shared tumor antigens and individual neo-antigens in TNBC patients.

MERIT combines two personalized treatment concepts: (i) treatment with vaccines containing “off-the-shelf” mRNAs selected from a pre-synthesized mRNA vaccine warehouse (MERIT WAREHOUSE) that encode shared breast cancer tumor antigens expressed in the respective patient's tumor; (ii) treatment with mRNAs engineered on-demand that encode patient-specific mutated neo-antigens identified by next generation sequencing (NGS) and ranked according to the predicted immunogenicity (MERIT MUTANOME). The mRNAs are administered intravenously as a nanoparticulate lipoplex formulation, which specifically targets APCs and consequently induces antigen-specific T cell responses.

MERIT is a multi-center phase I trial (NCT02316457) conducted in four European countries to assess the feasibility, safety and biological efficacy of this personalized immunotherapy. TNBC patients (pT1cN0M0 - anyTanyNM0) after surgery and adjuvant chemotherapy will be allocated to one of two study arms. Patients in ARM1 will receive eight vaccination cycles with a personalized set of shared tumor antigens selected from the WAREHOUSE that correspond to the patient tumor's antigen-expression profile. Patients in ARM2 will be first treated with the personalized WAREHOUSE vaccine approach followed by six vaccination cycles of on-demand manufactured MUTANOME vaccine targeting the unique mutation signature of the individual patient. During the clinical trial, patients will receive the individualized combination of the RNAs in parallel to standard radiotherapy. The clinical trial is approved and the study start is planned for Q1 2016.

The consortium has built a multi-disciplinary clinical workflow and trial design tailored to this unique therapeutic concept, which covers the whole individualized drug development cycle from target discovery, validation to GMP manufacturing and drug release for each individual patient. We will present the therapeutic concept and study protocol as well as the methodologies required for this highly innovative phase I trial.

The personalized immunotherapy overcomes the current limitations of fixed, off-the-shelf therapeutics and thus might increase the clinical benefit for TNBC patients.

This project is a collaborative effort of five partners from academia and industry funded by the European Commission's FP7 and led by BioNTech AG.

Citation Format: Sandra Heesch, Valesca Bukur, Janina Buck, Jan Diekmann, Mustafa Diken, Kerstin Ewen, Heinrich Haas, Alexandra Kemmer-Brueck, Björn-Philipp Kloke, Sebastian Kreiter, Andreas N. Kuhn, Klaus Kuehlcke, Martin Loewer, Anna Paruzynski, Kathrin Schultheiß, Doreen Schwarck, Marcus Schmidt, Fabrice André, Jacques De Greve, Thomas Kuendig, Henrik Lindman, Steve Pascolo, Tobias Sjöblom, Kris Thielemans, Laurence Zitvogel, Özlem Türeci, Ugur Sahin. MERIT: introducing individualized cancer vaccines for the treatment of TNBC - a phase I trial. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr CT020.