A risk stratification model for toxicities in phase 1 immunotherapy trials.

INTRODUCTION: Despite the increased number of novel immunotherapy (IO) agents under current development, their toxicity profile remains to be fully elucidated. METHODS: An IO risk stratification model was developed based on 5 different variables: treatment-related deaths; rate of grade ≥3 treatment-related adverse events or treatment-emergent adverse events; grade ≥2 encephalopathy or central nervous system toxicity; grade ≥2 cytokine release syndrome; and the number and type of dose-limiting toxicity. Phase 1 IO trials published from January 2014 to December 2020 were reviewed and categorised based on our risk stratification model into three categories: low-, intermediate- and high-risk. Clinical trial variables were associated with the high-risk category. To review the quality of reporting across phase 1 IO trials, a subset of studies was further examined by the use of the ASCO/SITC Trial Reporting in Immuno-Oncology (TRIO) standards. RESULTS: Different IO compounds demonstrated diverse risk profiles. In multivariable analysis, combination versus IO single agent treatment, and testing IO agents different from anti-programmed death-1/programmed death ligand-1 (anti-PD1/L1), anti-cytotoxic t-lymphocyte antigen-4 (anti-CTLA4) antibodies and anti-cancer vaccines were associated with a higher toxicity risk. None of the studies examined in our dataset reported all the items included in the TRIO standards. CONCLUSIONS: Our results have important implications for future clinical trial design. Additionally, standards for reporting are urgently needed.

Impact of pharmacodynamic biomarkers in immuno-oncology phase 1 clinical trials.

BACKGROUND: Phase 1 immuno-oncology (IO) trials frequently involve pharmacodynamic (PD) biomarker assessments involving tumour biopsies and/or blood collection, with increasing use of molecular imaging. PD biomarkers are set to play a fundamental role in early drug development of immuno-oncology (IO) agents. In the IO era, the impact of PD biomarkers for confirmation of biologic activity and their role in subsequent drug development have not been investigated. METHODS: Phase 1 studies published between January 2014 and December 2020 were reviewed. Studies that reported on-treatment PD biomarkers [tissue-derived (tissue-PD), blood-based (blood-PD) and imaging-based (imaging-PD)] were analysed. PD biomarker results and their correlation with clinical activity endpoints were evaluated. Authors' statements on the influence of PD biomarkers on further drug development decisions, and subsequent citations of PD biomarker study results were recorded. RESULTS: Among 386 trials, the most frequent IO agent classes evaluated were vaccines (32%) and PD-(L)1 inhibitors (25%). No PD biomarker assessments were reported in 100 trials (26%). Of the remaining 286, blood-PD, tissue-PD, and imaging-PD data were reported in 270 (94%), 94 (33%), and 12 (4%) trials, respectively. Assessments of more than one PD biomarker type were reported in 82 studies (29%). Similar proportions of blood-PD (9%), tissue-PD (7%), and imaging-PD studies (8%) had positive results that correlated with clinical activity. Results of 22 PD biomarker studies (8%) were referenced in subsequent clinical trials. CONCLUSIONS: Most phase 1 IO studies performed PD biomarker assessments. Overall, positive PD biomarker results were infrequently correlated with clinical activity or cited in subsequent trials, suggesting a limited impact on subsequent drug development. With emerging health regulatory emphasis on optimal dose selection based on PD activity, more informative and integrative multiplexed assays that capture the complexity of tumour-host immunity interactions are warranted to improve phase 1 IO trial methodology.