GERCOR (France)

Background:Biliary tract cancers (BTC) are often diagnosed after the age of 70, when comorbidities and compromised performance status (PS) are more prevalent.Objectives:This study compared clinical and disease characteristics and outcomes in BTC patients aged ⩽70 and >70 years.Design and methods:PRONOBIL-ACABI is a cohort study including 1256 BTC patients treated across 16 French centers from January 2003 to June 2021. We analyzed demographics, clinical characteristics, treatment modalities, molecular profiles, overall survival (OS) as the primary endpoint, and progression-free survival (PFS).Results:Among the 1256 BTC patients (53% male; median age: 64.5), 31% were aged >70. Patients >70 exhibited poorer PS (PS ⩾2, 17% vs 8%; p < 0.0001), a higher rate of comorbidities (⩾1, 89% vs 78%; p < 0.0001), and were less often proposed a molecular profile (43% vs 65%; p < 0.0001) than those ⩽70. Patients with unresectable BTC aged >70 had significantly shorter OS compared to younger patients (median OS: 14.6 vs 17.4 months, p < 0.0001), despite similar PFS (median PFS: 6.6 vs 5.8 months, p = 0.61). They were also less likely to receive first-line chemotherapy (87% vs 97%, p < 0.0001). In resected BTC, survival outcomes were comparable across age groups, with a median OS of 47.0 months in patients >70 vs 48.8 months in those ⩽70.Conclusion:Patients aged >70 years with unresectable BTC had a significantly shorter OS compared to those aged ⩽70, despite similar first-line PFS. In resected BTC, elderly patients achieved OS and PFS outcomes comparable to those aged ⩽70.

Mismatch repair-deficient (dMMR) tumors displaying microsatellite instability (MSI) represent a paradigm for the success of immune checkpoint inhibitor (ICI)-based immunotherapy, particularly in patients with metastatic colorectal cancer (mCRC). However, a proportion of patients with dMMR/MSI mCRC exhibit resistance to ICI. Identification of tools predicting MSI mCRC patient response to ICI is required for the design of future strategies further improving this therapy. We combined high-throughput DNA and RNA sequencing of tumors from 116 patients with MSI mCRC treated with anti-programmed cell death protein 1 ± anti-cytotoxic T-lymphocyte-associated protein 4 of the NIPICOL phase II trial (C1, NCT03350126, discovery set) and the ImmunoMSI prospective cohort (C2, validation set). The DNA/RNA predictors whose status was significantly associated with ICI status of response in C1 were subsequently validated in C2. Primary endpoint was progression-free survival by immune RECIST (iRECIST) (iPFS). Analyses showed no impact of previously suggested DNA/RNA indicators of resistance to ICI, e.g. MSIsensor score, tumor mutational burden, or specific cellular and molecular tumoral contingents. By contrast, iPFS under ICI was shown in C1 and C2 to depend both on a multiplex MSI signature involving the mutations of 19 microsatellites hazard ratio cohort C2 (HRC2) = 3.63; 95% confidence interval (CI) 1.65-7.99; P= 1.4× 10-3] and the expression of a set of 182 RNA markers with a non-epithelial transforming growth factor beta (TGFB)-related desmoplastic orientation (HRC2= 1.75; 95% CI 1.03-2.98; P= 0.035). Both DNA and RNA signatures were independently predictive of iPFS. iPFS in patients with MSI mCRC can be predicted by simply analyzing the mutational status of DNA microsatellite-containing genes in epithelial tumor cells together with non-epithelial TGFB-related desmoplastic RNA markers.

BackgroundImmune checkpoint inhibitors (ICIs) are highly effective in patients with microsatellite instability/mismatch repair-deficient (MSI/dMMR) metastatic colorectal cancer (mCRC). Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria may underestimate response to ICIs due to the pseudoprogression phenomenon. The GERCOR NIPICOL phase II study aimed to evaluate the frequency of pseudoprogressions in patients with MSI/dMMR mCRC treated with nivolumab and ipilimumab.MethodsPatients with MSI/dMMR mCRC previously treated with fluoropyrimidines, oxaliplatin, and irinotecan with/without targeted therapies received nivolumab 3 mg/kg plus ipilimumab 1 mg/kg every 3 weeks for four cycles then nivolumab 3 mg/kg every 2 weeks until progression or a maximum of 20 cycles. Computed tomography scan tumor assessments were done every 6 weeks for 24 weeks and then every 12 weeks. The primary endpoint was disease control rate at 12 weeks according to RECIST 1.1 and iRECIST by central review.ResultsOf 57 patients included between December 2017 and November 2018, 48.0% received ≥3 prior lines of chemotherapy, 18.0% had BRAFV600E mutation, and 56.0% had Lynch syndrome-related cancer. Seven patients (12.0%) discontinued treatment due to adverse events; one died due to a treatment-related adverse event. The disease control rate (DCR) at 12 weeks was 86.0% with RECIST 1.1% and 87.7% with iRECIST. Two pseudoprogressions (3.5%) were observed, at week 6 and at week 36, representing 18% of patients with disease progression per RECIST 1.1 criteria. With a median follow-up of 18.4 months, median progression-free survival (PFS) and overall survival (OS) were not reached. The 12-month PFS rate was 72.9% with RECIST 1.1% and 76.5% with iRECIST. The 12-month OS rate was 84%. Overall response rate was 59.7% with both criteria. RAS/BRAF status, sidedness, Lynch syndrome, and other baseline parameters were not associated with PFS.ConclusionPseudoprogression is rare in patients with MSI/dMMR mCRC treated with nivolumab and ipilimumab. This combined ICI therapy confirms impressive DCR and survival outcomes in these patients.Trial registration numberNCT03350126.

101 Background: Immune checkpoint inhibitors (ICKi) are highly effective for MSI/dMMR mCRC pts. RECIST1.1 criteria are reported to underestimate response to ICKi. The GERCOR NIPICOL phase II study aimed to evaluate disease control rate (DCR) using RECIST1.1 and iRECIST for MSI/dMMR mCRC pts treated with nivolumab (NIVO) and ipilimumab (IPI). Methods: MSI/dMMR mCRC pts previously treated with fluoropyrimidines (FP), oxaliplatin (OX) and irinotecan (IRI) ± targeted therapies received NIVO 3 mg/kg + IPI 1 mg/kg Q3W for 4 cycles then NIVO 3 mg/kg Q2W until progression or a maximum of 20 cycles. CT-scan tumor assessments were done every 6 weeks during 24 weeks and then every 12 weeks. Primary objective was DCR at 12 weeks (12wDCR) according to RECIST1.1 and iRECIST by central review. Response rates and progression-free survival (PFS) by central review were secondary objectives. A one-stage Fleming design was used with a targeted improvement of 12wDCR from 70% to 85%. Results: Of 57 pts included between Dec 2017 and Nov 2018, 43.9% had received ≥ 3 prior lines including FP (100%), OX (100%), IRI (95.5%), antiangiogenics (57.9%) and anti-EGFRs (45.6%). 17.5% of pts had BRAF mutation and 27.5% Lynch syndrome. Grade 3-4 treatment-related adverse events were reported in 49.1% of pts, mainly hepatitis (12.3%). 12wDCR was 86.0% and 87.7% using RECIST1.1 and iRECIST respectively, with only 1 pseudo-progression (1.8%) observed during the first 12 weeks, and one later. Kappa coefficient between RECIST and iRECIST 12wDCR was 0.92 (95%CI 0.77-1.0). Best observed responses with RECIST1.1/iRECIST were: 2/2 complete responses (3.5/3.5%), 19/19 partial responses (33.3/33.3%), 30/31 stable diseases (52.6/54.4%) and 3/2 disease progressions (5.3/3.5%), with 3 pts not evaluable (cancer-related deaths before first evaluation). Conclusions: Combination of NIVO and IPI in MSI/dMMR mCRC is associated with a low frequency of pseudo-progression and high DCR rate. PFS will be evaluated in Dec 2019, with all pts having completed the predefined 1-year of ICKi therapy. Clinical trial information: NCT033501260.

3121 Background: TEXCAN, a prospective phase II GERCOR study of treatment with REGO in chemorefractory metastatic colorectal cancer (mCRC) patients (NCT02699073) included a prospective pharmacokinetic (PK) ancillary study aiming to investigate correlations between OS and concentrations (C) of REGO and its active metabolites M-2 and M-5. Methods: 55 patients were included, with the same inclusion/exclusion criteria as CORRECT (NCT01103323), and treated orally with 160 mg REGO daily for 3 weeks on and 1 week off. 34 patients had PK samples at C1D15 and 26 at C2D15 for Cmin. REGO, M-2 and M-5 Cmin were measured by LC-MS/MS. PK analyses studied the link between OS and PK parameters: Cmin of REGO, M-2 and M-5 at C1 and accumulation of pharmacological active metabolites between C1 and C2, assessed by the C2/C1 ratio of M-2 or M-5 Cmin concentrations. Results: REGO, M-2 and M-5 Cmin [median (Q1-Q3)] were respectively 1.99 (1.03-2.73), 1.44 (0.89-2.49) and 1.61 (0.79-2.37) mg/L at C1D15 and 1.90 (1.10-2.76), 1.29 (0.77-2.24) and 1.17 (0.45-2.42) mg/L at C2D15. C2/C1 M-2 ratio and M-5 ratio medians were 0.82 (0.50-1.78) and 0.75 (0.41-1.93), respectively. Univariate analyses showed a major OS benefit in patients with C2/C1 M-2 ratio ≥median vs &lt; median (12.6 vs 4.0 months respectively, hazard ratio = 0.35, 95% confidence interval 0.14-0.86, p-value = 0.023) but not for C2/C1 M-5 ratio ≥median. Multivariate analyses, including the CORRECT REGOSCORE groups, showedan independent 66% reduction in death risk in the group of patients with C2/C1 M-2 ratio ≥median. The C2/C1 M-2 ratio correlated with C1 REGO+M-2+M-5 (Csum) (0.53, p-value = 0.006). Restricted Cubic spline analysis showed an increased OS benefit as the C2/C1 M-2 ratio rises and when C1 Csum ranged between 2.5 and 5.5 mg/L. PK parameters were not associated with toxicities. Conclusions: M-2 accumulation between C1 and C2 is independently associated with improved OS in mCRC patients treated by REGO. M-2 accumulates and OS is favorable when C1 REGO+M-2+M-5 sum ranged between 2.5 and 5.5 mg/L. These results may lead to develop individual REGO dosage modification strategies based on PK monitoring. Clinical trial information: NCT02699073.