Ann-Cathrine Siefen ^1,2 Melina S. Kurte ^1,2 Florian Jakobs ³ Marcel Teichert ³ Bastian Von Tresckow ⁴ Hans C. Reinhardt ³ Udo Holtick ⁵ Johannes Atta ⁶ Christian Jehn ⁷ Elisa Sala ⁸ Anke Warnecke ⁹ Mathias Hänel ¹⁰ Christof Scheid ⁵ Florian Kron ^11,2,5*

• ¹ Faculty of Medicine, University of Duisburg-Essen, Duisburg, North Rhine-Westphalia, Germany
• ² VITIS Healthcare Group, Cologne, Germany
• ³ Department of Hematology and Stem Cell Transplantation, Faculty of Medicine and University Hospital Essen, University of Duisburg-Essen, Essen, Germany
• ⁴ Department of Hematology and Stem Cell Transplantation, West German Cancer Center and German Cancer consortium (DKTK partner site Essen), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
• ⁵ Department I of Internal Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
• ⁶ Department of Hematology, Giessen & Marburg University Hospital, Giessen, Germany
• ⁷ Department of Hematology/Oncology and Stem-cell transplantation, St Georg, Asklepios Hamburg, Hamburg, Germany
• ⁸ Department of Internal Medicine III, University Hospital of Ulm, Ulm, Germany
• ⁹ Department of Hematology and Medical Oncology, Division for stem cell transplantation and cellular therapy, University Hospital Göttingen, Goettingen, Germany
• ¹⁰ Department of Internal Medicine III, Klinikum Chemnitz, Chemnitz, Germany
• ¹¹ FOM University of Applied Sciences for Economics and Management, Essen, North Rhine-Westphalia, Germany

Introduction: Treatment with chimeric antigen receptor T (CAR-T) cells involves a large number of interdisciplinary stakeholders and is associated with complex processes ranging from patient-specific production to follow-up care. Due to the complexity, maximum process optimization is required in order to avoid efficiency losses. This study aimed at systematically determining the preconditions for a frictionless flow of the CAR-T process by surveying the stakeholders involved.Methods: A Group Concept Mapping (GCM) analysis, a mixed-methods participatory research, was conducted. CAR-T experts from different professional backgrounds went through three steps: 1) Brainstorming relevant aspects (statements) for a frictionless process, 2) Sorting the collected statements based on their similarity, and 3) Rating the importance and feasibility of each statement. A cluster map reflecting the overarching topics was derived, and mean ratings per statement and cluster were calculated.Results: Overall, 20 CAR-T experts participated. A total of 80 statements were collected, resulting in a map of the following 10 clusters (mean importance/feasibility): Information for patients and physicians (4.16/3.77), Supportive network (4.03/3.53), Eligibility of patients (4.41/3.63), Evidence, transparency and communication (4.01/3.33), Paperwork (4.1/2.52), Interface with pharmaceutical manufacturer (4.03/2.85), Reimbursement (4.29/2.31), Quality Management (4.17/3.18), Infrastructure of CAR-T clinics (4.1/2.93), and Patient-oriented processes (4.46/3.32).Discussion: The 80 statements underlined the complex and manifold nature of the CAR-T treatment process. Our results reflect the first step in overcoming hurdles: identifying potential hurdles and required preconditions. Decision-makers and stakeholders can use the results to derive strategies and measures to further promote a frictionless process.