Table 1.
Characteristics of the included studies.
| Authors | Year | Cancer type | Study type | Biomarker type | Timing of biomarker | Biomarker detection method | Cutoff point | ICI | Outcome of interest | Results |
|---|---|---|---|---|---|---|---|---|---|---|
| Chen et al. | 2020 | Colorectal cancer | Prospective | bTMB | Pretreatment | NGS | ≥28 vs. <28 vts/Mb | Tremelimumab, durvalumab | OS | HR = 0.34, 90%CI = 0.18–0.63, p = 0.004 |
| Lee et al. | 2020 | Melanoma | Prospective | ctDNA | Pretreatment | PCR | Undetectable vs. detectable | Pembrolizumab, nivolumab, ipilimumab | OS | HR = 0.51, 95%CI = 0.28–0.94, p = 0.03 |
| Wang et al. | 2020 | NSCLC | Prospective | bTMB | Not mentioned | NGS | ≥6 vs.<6 vts/Mb | Atezolizumab, nivolumab, pembrolizumab, tislelizumab, toripalimab | OS | HR = 0.92, 95%CI = 0.46–1.82, p = 0.80 |
| Wang et al. | 2020 | NSCLC | Prospective | MSAF (ctDNA) | Not mentioned | NGS | Top 25% vs. bottom 75% | Atezolizumab, nivolumab, pembrolizumab, tislelizumab, toripalimab | OS | HR = 2.72, 95%CI = 1.33–5.59, p = 0.005 |
| Chen et al. | 2020 | Biliary tract cancer | Prospective | ctDNA | Posttreatment | NGS | Positive vs. negative | Camrelizumab | OS and PFS | OS: HR = 1.77, 95%CI = 0.78–3.99, p = 0.16 |
| PFS: HR = 2.83, 95%CI = 1.27–6.28, p = 0.007 | ||||||||||
| Chen et al | 2020 | Biliary tract cancer | Prospective | bTMB | Not mentioned | NGS | Top 25% vs. bottom 75% | Camrelizumab | OS and PFS | OS: HR = 1.05, 95%CI = 0.43–2.54, p = 0.92 |
| PFS: HR = 2.57, 95%CI = 1.08–6.12, p = 0.03 | ||||||||||
| Pedersen et al. | 2020 | Melanoma | Prospective | ctDNA | Posttreatment | PCR | Detectable vs. undetectable | Pembrolizumab, nivolumab, ipilimumab | PFS | HR = 7.89, 95%CI = 1.40–44.6, p = 0.019 |
| Marsavela et al. | 2020 | Melanoma | Prospective | ctDNA | Pretreatment | PCR | ≤20 vs. >20 copies/ml | Nivolumab, pembrolizumab, ipilimumab | PFS | HR = 0.42, 95%CI = 0.22–0.83, p = 0.006 |
| Anagnostou et al. | 2020 | NSCLC | Prospective | ctDNA | Clearance | NGS | No complete reduction vs. complete reduction | Unclear | OS and PFS | OS: HR = 6.91, 95%CI = 1.37–34.97, p = 0.02 |
| PFS: HR = 5.36, 95%CI = 1.57–18.35, p = 0.007 | ||||||||||
| Goldberg et al. | 2018 | NSCLC | Prospective | ctDNA | Clearance | NGS | >50% vs. ≤50% decrease in mutant allele fraction from baseline | Unclear | OS and PFS | OS: HR = 0.17, 95%CI = 0.05–0.62, p = 0.007 |
| PFS: HR = 0.29, 95%CI = 0.09–0.89, p = 0.03 | ||||||||||
| Cabel et al. | 2017 | NSCLC, etc. | Prospective | ctDNA | Posttreatment | NGS | Detectable vs. undetectable | Nivolumab, pembrolizumab | OS and PFS | OS: HR = 15, 95%CI = 2.5–94.9, p = 0.004 |
| PFS: HR = 10.2, 95%CI = 2.5–41, p < 0.001 | ||||||||||
| Herbreteau et al. | 2021 | Melanoma | Prospective | ctDNA | Clearance | PCR | Increase vs. decrease | Nivolumab/nivolumab + ipilimumab | OS and PFS | OS: HR = 7.49, 95%CI = 2.59–24.10, p = 0.0002 |
| PFS: HR = 12.74, 95%CI = 3.81–53.25, p < 0.0001 | ||||||||||
| Ricciuti et al. | 2021 | NSCLC | Retrospective | ctDNA | Clearance | NGS | Decrease vs. increase | Pembrolizumab | OS and PFS | OS: HR = 0.34, 95%CI = 0.15–0.75, p = 0.008 |
| PFS: HR = 0.29, 95%CI = 0.14–0.60, p = 0.0007 | ||||||||||
| Zhang et al. | 2020 | Advanced cancers | Prospective | ctDNA | Posttreatment | Not mentioned | Below median vs. above median | Durvalumab ± tremelimumab | OS and PFS | HR = 0.13, 95%CI = 0.05–0.34 |
| HR = 0.41, 95%CI = 0.25–0.68 | ||||||||||
| Powles et al. | 2021 | Urothelial carcinoma | Prospective | ctDNA | Clearance | PCR | Clear vs. not clear | Atezolizumab | OS | HR = 0.14, 95%CI = 0.03–0.59 |
vts/Mb, variations per megabase; ctDNA, circulating tumor DNA; bTMB, blood tumor mutation burden; ICI, immune checkpoint inhibitor; HR, hazard ratio; NSCLC, non-small-cell lung cancer; MSAF, maximum somatic allele frequency; NGS, next-generation sequencing; PCR, polymerase chain reaction; OS, overall survival; PFS, progression-free survival.