Abstract OT2-06-01: Highly innovative personalized RNA-immunotherapy for patients with triple negative breast cancer

Background: The treatment of triple negative breast cancer (TNBC) is hampered by the lack of established therapeutic targets such as hormone receptors or HER-2. Chemotherapy and radiotherapy is the standard of care, yet survival rates in TNBC remain poor. Approaches tailored to the patient9s individual tumor signature may lead to improved therapeutic outcome. We have set up a clinical workflow covering drug development (from target discovery to manufacturing) and drug release providing a custom-made investigational medicinal product (IMP) for each individual patient. Trial Design: A phase I/II trial assesses the feasibility, safety and biological efficacy of this personalized immunotherapy in three clinical sites in Germany and Sweden. TNBC patients (pT1cN0M0 – TxNxM0) after completion of initial standard of care therapy will be allocated to one of two study arms. Patients in ARM1 receive 8 vaccination cycles with a personalized combination of shared tumor-associated antigens, selected based on each patient tumor9s antigen-expression profile out of a WAREHOUSE of pre-manufactured mRNA vaccine. Patients in ARM2 receive the personalized mRNA WAREHOUSE vaccine followed by 8 vaccination cycles of an on-demand manufactured mRNA MUTANOME vaccine encoding up to twenty unique neo-epitopes of the individual patient identified by next generation sequencing. The mRNAs are administered intravenously as a nanoparticulate lipoplex formulation, which protects RNA from degradation, activates innate immunity, transfects APCs and consequently induces highly potent antigen-specific T-cell responses. The treatment of 12 patients in ARM1 is completed and enrolment of patients for ARM2 has started. Preliminary data show that the RNA-WAREHOUSE approach is feasible and can be applied safely. Biomarker analysis is ongoing. This approach is promising as it addresses the heterogeneity of TNBC. The TNBC-MERIT trial was initially funded by the EU Commission9s FP7 and led by BioNTech AG. Citation Format: Schmidt M, Bolte S, Frenzel K, Heesen L, Derhovanessian E, Bukur V, Diken M, Gruetzner J, Kreiter S, Klein A, Kuhn A, Langer D, Loewer M, Lindman H, Schneeweiss A, Tuereci O, Sahin U. Highly innovative personalized RNA-immunotherapy for patients with triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT2-06-01.