Efficacy of immunotherapy in mismatch repair-deficient advanced colorectal cancer in routine clinical practice. An AGEO study

Background: Immunotherapy demonstrated remarkable efficacy in metastatic colorectal cancers (mCRCs) with mismatch repair deficiency (MMRd)/microsatellite instability (MSI). However, data regarding efficacy and safety of immunotherapy in the routine clinical practice are scarce. Patients and methods: This is a retrospective, multicenter study aiming to evaluate efficacy and safety of immunotherapy in routine clinical practice and to identify predictive markers for long-term benefit. Long-term benefit was defined as progression-free survival (PFS) exceeding 24 months. All patients who received immunotherapy for an MMRd/MSI mCRC were included. Patients who received immunotherapy in combination with another known effective therapeutic class agent (chemotherapy or tailored therapy) were excluded. Results: Overall, 284 patients across 19 tertiary cancer centers were included. After a median follow-up of 26.8 months, the median overall survival (mOS) was 65.4 months [95% confidence interval (CI) 53.8 months-not reached (NR)] and the median PFS (mPFS) was 37.9 months (95% CI 30.9 months-NR). There was no difference in terms of efficacy or toxicity between patients treated in the real-world or as part of a clinical trial. Overall, 46.6% of patients had long-term benefit. Independent markers associated with long-term benefit were Eastern Cooperative Oncology Group-performance status (ECOG-PS) 0 (P = 0.025) and absence of peritoneal metastases (P = 0.009). Conclusions: Our study confirms the efficacy and safety of immunotherapy in patients with advanced MMRd/MSI CRC in the routine clinical practice. ECOG-PS score and absence of peritoneal metastases provide simple markers that could help identify patients who benefit the most from this treatment.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

A multicenter study evaluating efficacy of immune checkpoint inhibitors in advanced non-colorectal digestive cancers with microsatellite instability

Background: One randomized phase III trial comparing chemotherapy (CT) with immune checkpoint inhibitors (ICI) has demonstrated significant efficacy of ICI in deficient DNA mismatch repair system/microsatellite instability-high (dMMR/MSI-H) metastatic colorectal cancer. However, few studies have compared ICI with CT in other advanced dMMR/MSI-H digestive tumors. Methods: In this multicenter study, we included patients with advanced dMMR/MSI-H non-colorectal digestive tumors treated with chemotherapy and/or ICIs. Patients were divided retrospectively into two groups, a CT group and an immunotherapy (IO) group. The primary endpoint was progression-free survival (PFS). A propensity score approach using the inverse probability of treatment weighting (IPTW) method was applied to deal with potential differences between the two groups. Results: 133 patients (45.1/27.1/27.8% with gastric/small bowel/other carcinomas) were included. The majority of patients received ICI in 1st (29.1%) or 2nd line (44.4%). The 24-month PFS rates were 7.9% in the CT group and 71.2% in the IO group. Using the IPTW method, IO treatment was associated with better PFS (HR=0.227; 95% CI 0.147–0.351; p < 0.0001). The overall response rate was 26.3% in the CT group versus 60.7% in the IO group (p < 0.001) with prolonged duration of disease control in the IO group (p < 0.001). In multivariable analysis, predictive factors of PFS for patients treated with IO were good performance status, absence of liver metastasis and prior primary tumor resection, whereas no association was found for the site of the primary tumor. Conclusions: In the absence of randomized trials, our study highlights the superior efficacy of ICI compared with standard-of-care therapy in patients with unresectable or metastatic dMMR/MSI-H non-colorectal digestive cancer, regardless of tumor type, with acceptable toxicity.SCOPUS: ar.jinfo:eu-repo/semantics/publishe