Immune-modified Response Criteria in Cancer Immunotherapy Clinical Trials
Thursday, Nov. 8, 2018
2 – 6 p.m.
This free workshop was intended to identify best practices for design, conduct, data collection, and analysis of clinical trials evaluating tumor measurement based efficacy endpoints for cancer immunotherapeutics and to engage with leaders in academia, industry, international regulatory, and patient groups. Numerous studies have been reported in the literature in an effort to improve upon conventional response criteria for tumor measurement based efficacy endpoints for cancer immunotherapeutics as conventional response criteria may not fully capture the benefit of this product class. This workshop evaluated current practices and identified opportunities to advance strategies that can provide rigorous tumor measurement-based endpoint data—accounting for the unique mechanism of action of cancer immunotherapeutics—suitable to support regulatory, payer, clinician, and patient decision making.
Based on greater understanding of the molecular underpinnings of cancer and the host immune response to cancer, immunotherapeutics are now demonstrating efficacy across a wide breadth of cancer types. In oncology, improvements in overall survival remains a gold standard for demonstrating the efficacy of drugs; however, tumor measurement-based endpoints, e.g., response rate and progression-free survival, facilitate assessment of direct effects of treatment on the cancer. Trials evaluating tumor assessment based endpoints can inform benefit-risk assessments of a drug earlier than a trial evaluating treatment effects on mortality. Based on a unique mechanism of action, conventional tumor response criteria do not appear to fully capture the benefit of immunotherapeutics. For example, treatment with immune checkpoint inhibitors (anti-CTLA-4 monoclonal antibody (mAb), anti-PD-1 mAb, and anti-PD-L1 mAb) may result in an atypical response pattern characterized by initial progression of disease based on appearance of new lesions or an increase in the size of existing tumors followed by either subsequent stable disease or regression of overall tumor burden. Tumor response criteria for cancer immunotherapeutics containing modifications to conventional criteria that account for this atypical pattern of response exist but pose unique challenges for use in clinical trials intended to support marketing approval. The purpose of this workshop was to provide an open public forum for a broad representation of stakeholders (1) to explore methods for analysis, presentation, and interpretation of tumor measurement-based efficacy endpoints and (2) to discuss considerations for use of immune-modified response criteria in development programs of cancer immunotherapeutics intended to support marketing approval.