Adaptation of the Immune Related Response Criteria: Irrecist

ABSTRACT Aim: The immune related response criteria were published in November 2009, based on results and clinical findings of the ipilimumab® program. RECIST as published in 2000 had its shortcomings for targeted immunotherapy in oncology and still has with its successor version RECIST 1.1. Investigators may declare progressive disease (PD) too early, when the treatment effect is not yet fully evident. With this paper we introduce irRECIST to further clarify and reduce assessment criteria ambiguity and minimize discordance between sites and independently read results. Methods: The adaptations from RECIST 1.1 and/or irRC, as applicable in an immunotherapy clinical study, are documented in the irRECIST Modifications and Clarifications column in a comparative table format within the charter for Blinded Independent Central Review (BICR). However, typically these independent review details and specifications are not available for investigators at sites. The modifications we introduce represent adaptations of the published criteria based on current radiology practice and clinical trial experience and with that aim to provide more objective and reproducible response assessments for investigators and also central independent image review. Results: Bearing industry demands and RECIST shortcomings in mind we introduce a modification of the irRC to better address patients' treatment, investigators' patient management and sponsors' analysis needs for targeted immunotherapy developments in oncology with irRECIST, based on adaptation of unidimensional measurements aligned with RECIST 1.1. irRECIST will reduce site:central discordance in patient assessment and contains guidance for ambiguous cases and also describes how to evaluate patients with non-measurable non target disease only. Conclusions: RECIST published in 2000 and its successor version RECIST 1.1 from 2009 has its shortcomings for targeted immunotherapy in oncology. With these adapted irRECIST criteria we introduce the needed adjustment to the irRC criteria to allow for treatment evaluations and assessments that better meets both investigators' and patients' needs and with that better reflects sponsors' demands for more reliable and reproducible study data analyses. Disclosure: All authors have declared no conflicts of interest.