Background Although sorafenib is the global standard first-line systemic treatment for unresectable hepatocellular carcinoma (HCC), it does not have reliable predictive or prognostic biomarkers. Circulating cell-free DNA (cfDNA) has shown promise as a biomarker for various cancers. We investigated the use of cfDNA to predict clinical outcomes in HCC patients treated with sorafenib. Methods This prospective biomarker study analyzed plasma cfDNA from 151 HCC patients who received first-line sorafenib and 14 healthy controls. The concentration and VEGFA-to-EIF2C1 ratios (the VEGFA ratio) of cfDNA were measured. Low depth whole-genome sequencing of cfDNA was used to identify genome-wide copy number alteration (CNA), and the I-score was developed to express genomic instability. The I-score was defined as the sum of absolute Z-scores of sequenced reads on each chromosome. The primary aim of this study was to develop cfDNA biomarkers predicting treatment outcomes of sorafenib, and the primary study outcome was the association between biomarkers with treatment efficacy including disease control rate (DCR), time to progression (TTP) and overall survival (OS) in these patients. Results The cfDNA concentrations were significantly higher in HCC patients than in healthy controls (0.71 vs. 0.34 ng/μL; P < 0.0001). Patients who did not achieve disease control with sorafenib had significantly higher cfDNA levels (0.82 vs. 0.63 ng/μL; P = 0.006) and I-scores (3405 vs. 1024; P = 0.0017) than those achieving disease control. The cfDNA-high group had significantly worse TTP (2.2 vs. 4.1 months; HR = 1.71; P = 0.002) and OS (4.1 vs. 14.8 months; HR = 3.50; P < 0.0001) than the cfDNA-low group. The I-score-high group had poorer TTP (2.2 vs. 4.1 months; HR = 2.09; P < 0.0001) and OS (4.6 vs. 14.8 months; HR = 3.35; P < 0.0001). In the multivariable analyses, the cfDNA remained an independent prognostic factor for OS ( P < 0.0001), and the I-score for both TTP ( P = 0.011) and OS ( P = 0.010). The VEGFA ratio was not significantly associated with treatment outcomes. Conclusion Pretreatment cfDNA concentration and genome-wide CNA in cfDNA are potential biomarkers predicting outcomes in advanced HCC patients receiving first-line sorafenib. Electronic supplementary material The online version of this article (10.1186/s12885-019-5483-x) contains supplementary material, which is available to authorized users.

The aim of our study is to evaluate the clinical efficacy of durvalumab in patients with microsatellite instability‐high/mismatch repair‐deficient (MSI‐H/dMMR) or polymerase epsilon (POLE)‐mutated metastatic or unresectable colorectal cancer (mCRC) who had disease progression after standard chemotherapy. This prospective, open‐label, multicenter, phase II study enrolled patients with mCRC harboring MSI‐H/dMMR or POLE mutations treated with at least one prior line of therapy. The participants received durvalumab (1500 mg) every 4 weeks intravenously. The primary endpoint was the objective response rate (ORR). Of the 33 patients, 30 had MSI‐H/dMMR and 3 had POLE‐mutated microsatellite stable (MSS) CRC. With a median follow‐up duration of 11.2 months (95% confidence interval [CI]: 7.3‐15.0), the ORR was 42.4% (95% CI: 25.5‐60.8). Among three patients with POLE‐mutated CRC, one patient who had an exonuclease domain mutation (EDM) achieved an objective response, but the others with mutations in the non‐exonuclease domain had progressive disease. Overall, the median duration of response was not reached and 85.7% of the responses were ongoing at data cutoff. The progression‐free survival rate of 12 months was 58.2% (95% CI: 39.0‐73.1) and the 12‐month overall survival rate was 68.3% (95% CI: 48.8‐81.7). Grade 3 treatment‐related adverse events occurred in 36.4% of the patients and were manageable. In conclusion, durvalumab showed promising clinical activity with encouraging response rates and satisfactory survival outcomes in mCRC patients with MSI‐H/dMMR or POLE EDM. In patients with POLE‐mutated mCRC, clinical response to durvalumab may be restricted to those with EDM.