Most of the information about the use and results of tumour mutational burden (TMB) has been collected in the context of randomized clinical trials. There is limited information about the use of TMB in real-world settings. This study aimed to address this gap by comparing the differences in clinical and demographic characteristics of patients receiving the test to those not receiving it.
Patients ≥18 years old and diagnosed with advanced or metastatic solid tumour carcinoma between 1/1/2015 and 1/31/2019 were identified. Patients with ≥1 numeric TMB test result were randomly selected into the “TMB cohort”. We selected a comparison cohort of patients who did not have a record for TMB testing (non-TMB) representing the tumour mix of the TMB cohort using stratified random sampling. Data were abstracted from electronic medical records from a network of community oncology practices maintained in the Vector Oncology Data Warehouse.
Patients in the TMB cohort (n=202) were significantly younger than those in the non-TMB cohort (n=212) (mean age 62.1 vs. 65.6; p=0.0045). The distribution of race between the two groups was significantly different (p=0.0041). For instance, there were 21.3% Black or African American patients in the TMB cohort compared to 11.8% in the non-TMB cohort. The clinical characteristics were comparable between the two cohorts. A higher proportion of patients in the TMB cohort received systemic anti-cancer treatment compared to the non-TMB cohort (91.6% vs. 77.8%). Out of 202 patients in TMB cohort, 32 had a high TMB score (TMB ≥10 mut/Mb). Patients with high TMB scores were likely to have ≥1 comorbid condition (59.4% vs. 37.6%; p=0.0219). There were 161 patients (94.7%) who received systemic anti-cancer treatment in low-TMB group as compared to 24 (75.0%) in the high-TMB group.
In this analysis of an advanced solid pan-tumour population, we found that patients who received TMB test were comparatively younger and were more likely to receive systemic treatment than those who do not receive the test. Among TMB tested patients, only about 1 out of 6 cases had a high TMB score. These data provide a benchmark/historical perspective for future research focusing on the real-world effectiveness outcomes associated with TMB.
Clinical trial identification
Legal entity responsible for the study
Merck & Co., Inc.
Merck & Co., Inc.
S. Gautam: Full/Part-time employment: Concerto HealthAI; Research grant/Funding (institution): Merck & Co., Inc.. S. Kachroo: Shareholder/Stockholder/Stock options, Full/Part-time employment: Merck & Co., Inc.. R. DeClue: Full/Part-time employment: Concerto HealthAI; Research grant/Funding (institution): Merck & Co., Inc.. M.D. Fisher: Full/Part-time employment: Concerto HealthAI; Research grant/Funding (institution): Merck & Co., Inc.. A. Basu: Full/Part-time employment: University of Washington; Advisory/Consultancy: Merck & Co, Inc..