Currently, there is limited real-world data examining association of TMB levels with clinical and healthcare utilization (HCRU) outcomes.
Patients ≥18 years, diagnosed with advanced or metastatic solid tumours between 1/1/2015 and 1/31/2019, and had ≥1 numeric TMB result were selected. They were divided into “low-TMB” (TMB <10 mut/Mb) and “high-TMB” groups (TMB ≥10 mut/Mb). Data were abstracted from medical records of community oncology practices maintained in the Vector Oncology Data Warehouse. Kaplan-Meier analysis was used to evaluate overall survival (OS) and progression-free survival (PFS) from the start of first-line (1L) treatment. HCRU and costs during 1L were analyzed using descriptive methods.
Of 202 eligible patients, median age was 62.5 years, 52.0% were male and 71.3% white. There were no significant differences for age, sex and race between the low (N=170) and high-TMB (N=32) groups. The distribution of tumour type differed between groups. For example, more high-TMB patients vs. low-TMB had lung cancer (37.5% vs. 2.4%; p<0.0001). More high-TMB patients had ≥1 comorbid condition (59.4% vs 37.6%; p=0.0219). Of low-TMB patients, 161 (94.7%) received systemic anti-cancer treatment compared to 24 (75.0%) high-TMB. Median OS was 18.3 months (95% CI 15.5-24.8) for low-TMB patients compared to 13.6 (95% CI 10.2-21.8) for the high-TMB group. Median PFS was 9.3 months (95% CI 7.7-10.8) for low-TMB patients and 7.4 months (95% CI 5.0-13.1) for the high-TMB group. HCRU and cost results during 1L treatment are summarized below. Table: 2007P
|Utilization||Low (N=161)||High (N=24)|
|Hospitalization, n (%)||33 (20.5%)||4 (16.7%)|
|Emergency department visit, n (%)||17 (10.6%)||5 (20.8%)|
|Monthly office visit, mean (SD)||1.6 (1.34)||2.2 (2.20)|
|Cost of care|
In this real-world analysis, only about 1 of 6 cases had a high-TMB score. There were some notable differences in clinical characteristics between low and high-TMB groups. Despite the limited sample size, the results indicate some correlation between TMB level and clinical and HCRU outcomes among those using systemic therapy. Future studies with larger sample size are required to confirm these results and further address confounding.
Clinical trial identification
Legal entity responsible for the study
Merck & Co., Inc.
Merck & Co., Inc.
R. DeClue: 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.. S. Gautam: 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: The University of Washington; Advisory/Consultancy: Merck & Co., Inc..