Primary resistance to immunotherapy in patients with a dMMR/MSI metastatic gastrointestinal cancer: who is at risk? An AGEO real-world study.

BACKGROUND: The outstanding efficacy of immunotherapy in metastatic dMMR/MSI gastro-intestinal (GI) cancers has led to a rapid increase in the number of patients treated. However, 20-30% of patients experience primary resistance to immune checkpoint inhibitors (ICIPR) and need better characterization. METHODS: This AGEO real-world study retrospectively analyzed the efficacy and safety of ICIs and identified clinical variables associated with ICIPR in patients with metastatic dMMR/MSI GI cancers treated with immunotherapy between 2015 and 2022. RESULTS: 399 patients were included, 284 with colorectal cancer (CRC) and 115 with non-CRC, mostly treated by an anti-PD(L)1 (88.0%). PFS at 24 months was 55.8% (95CI [50.8-61.2]) and OS at 48 months was 59.1% (95CI [53.0-65.9]). ORR was 51.0%, and 25.1% of patients were ICIPR. There was no statistical difference in ORR, DCR, PFS, or OS between CRC and non-CRC groups. In multivariable analysis, ICIPR was associated with ECOG-PS ≥ 2 (OR = 3.36), liver metastases (OR = 2.19), peritoneal metastases (OR = 2.00), ≥1 previous line of treatment (OR = 1.83), and age≤50 years old (OR = 1.76). CONCLUSION: These five clinical factors associated with primary resistance to ICIs should be considered by physicians to guide treatment choice in GI dMMR/MSI metastatic cancer patients.

Relative dose intensity of first-line triplet chemotherapy in metastatic colorectal cancer.

PURPOSE: Relative dose intensity (RDI) is a measurement of chemotherapy (CT) dose defined as the actual dose received divided by the standard calculated dose during a set period. The study objective was to assess the impact of a RDI ≥ 80% on response and survival of patients treated in first line CT by FOLFOXIRI or FOLFIRINOX ± Bevacizumab (BV) for an unresectable metastatic colorectal cancer (mCRC). MATERIALS AND METHODS: It was a retrospective, non-interventional, multicenter study calculating RDI from the first cycles of CT to the first CT-scan evaluation (CT-scan1). Objective response and disease control rates (ORR and DCR), progression-free survival (PFS) and overall survival (OS) were compared between patients with RDI ≥ 80% and <80% and results were adjusted for age, gender, ECOG, tumor location, number of metastatic sites, RAS and BRAF status, the CT regimen, the use of BV, the delay from C1 to CT scan1. RESULTS: Among 152 screened patients, 100 met inclusion criteria, with a mean (± standard deviation) age at 59.0 (± 10.7) years. The ECOG performance status was 0-1 in 96 (96%) patients; metastases were synchronous in 95 (95%), RAS and BRAF were mutated in 60 (60%) and 22 (22%), respectively. ORR was observed in 51 (51%) at CT-scan1 with median PFS and OS of 10.5 and 21.9 months, respectively. A RDI ≥ 80% was observed in 44 (44%) patients without impact on ORR (ORa: 1.04, 95% CI: 0.37 to 2.89, p = 0.94) but was significantly associated to improved PFS and OS with HRa 0.50 (95%CI: 0.29 to 0.87, p = 0.013) and 0.52 (95% CI: 0.29 to 0.91, p = 0.023), respectively. CONCLUSION: Our results suggest a low level of FOLFOXIRI or FOLFIRINOX +/- BV exposure in first-line mCRC is associated with a significant trend on PFS and OS.

Postoperative circulating tumor DNA detection is associated with the risk of recurrence in patients resected for a stage II colorectal cancer.

Circulating tumor DNA (ctDNA) is reported to be promising in localized colorectal cancer (CRC). The present study aimed to retrospectively evaluate the impact of ctDNA in patients with a resected stage II CRC from the PROGIGE 13 trial with available paired tumor and blood samples. A group of recurrent patients were matched one-to-one with nonrecurrent patients according to sex, tumor location, treatment sequence, and blood collection timing. CtDNA was analyzed by digital PCR according to NGS of tumors. Disease-free survival (DFS) and overall survival (OS) were analyzed based on ctDNA, and the risks of recurrence and death were determined. A total of 134 patients were included, with 67 patients in each group. At least one alteration was identified in 115/134 tumors. Postoperative ctDNA was detected in 10/111 (9.0%) informative samples and was detected more frequently in the recurrent group (16.7% versus 1.8%; p = 0.02). The median DFS of ctDNA+ versus ctDNA- patients was 16.8 versus 54 months (p = 0.002), respectively, and the median OS was 51.3 versus 69.5 months (p = 0.03), respectively. CtDNA was associated with recurrence (ORa = 11.13, p = 0.03) and death (HRa = 3.15, p = 0.01). In conclusion, the presence of postoperative ctDNA is associated with both recurrence and survival in stage II CRC.