Only a minority of clinical trials evaluating immunotherapeutic agents in 2019 used a biomarker to select patients for enrollment, a study found. The findings were reported at the virtual Society for Immunotherapy of Cancer 35th Anniversary Annual Meeting & Preconference Programs (SITC 2020).

Clinical trials evaluated were listed on ClinicalTrials.gov between January 1, 2019, and December 31, 2019, and identified using the search terms “nivolumab” and “pembrolizumab.”

A total of 413 trials were identified that had a planned collective enrollment of 57,853 patients. Of the 413 trials, only 37 trials (8.96%) used a biomarker to select patients for enrollment, meaning 89.3% of patients planned for enrollment were accrued without consideration of patient biomarkers. 

Further analysis of the subgroups of trials showed that a biomarker was used to select a fraction of patients planned for enrollment into trials evaluating a single-agent immunotherapy (4.6%), combination of 2 or more immunotherapies (5.9%), or combination of immunotherapy and chemotherapy (0.67%).


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Although trials evaluating a combination of immunotherapy and target therapy (27.1%) or other immunotherapy combinations (12.4%) had the highest percentage of patients selected using a biomarker, most patients were not selected this way.

An additional search was done for trials involving patients with glioblastoma multiforme or pancreatic cancer, revealing that a biomarker was used to select patients for only 8% of glioblastoma multiforme trials and 16% of pancreatic cancer trials.

“Precision oncology continues to struggle in the era of [immune checkpoint inhibitors] with an all-comers approach to patient selection and trial initiation,” the study authors wrote. “Selecting patients for trials based on biomarkers may help better identify responders to [immune checkpoint inhibitors].”

Reference

Adashek JJ, Goloubev A, Kato S, Kurzrock R. Immunotherapy trials lack a biomarker for inclusion: implications for drug development. Poster at: Society for Immunotherapy of Cancer 35th Anniversary Annual Meeting & Preconference Programs (SITC 2020); November 11-14, 2020. Abstract 179. J Immunother Cancer. 2020;8(Suppl 3):A656–A959.