The Prognostic Nutritional Index in patients with microsatellite instability-high metastatic gastric or gastroesophageal cancers receiving immune checkpoint inhibitors.

BACKGROUND: Microsatellite instability high (MSI-H) and/or mismatch repair deficient (dMMR) status is the strongest predictive factor for immune checkpoint inhibitors (ICIs) benefit in patients with metastatic gastroesophageal cancer (mGC). Primary resistance to ICIs is a relevant issue, but prognostic and predictive factors are lacking. MATERIALS AND METHODS: In this multinational, retrospective cohort of patients with MSI-H/dMMR mGC treated with ICIs without chemotherapy we collected baseline laboratory values to establish the prognostic nutritional index (PNI). We evaluated the association between baseline PNI with the activity and efficacy of ICIs. RESULTS: At a median follow-up of 31.6 months, median progression-free survival (PFS) and 2-year PFS rate were not reached and 73.6 % in the PNI-high subgroup versus 6.3 months and 38.3 % in the PNI-low one (HR 0.32, 95 % CI: 0.16-0.61, p < .001). Median overall survival (OS) and 2-year OS rate were not reached and 81.9 % in the PNI-high subgroup versus 24.4 months and 50.5 % in the PNI-low one (HR 0.26, 95 % CI: 0.12-0.56, p < .001). In multivariable models, high PNI was associated with longer PFS and OS (HR 0.30, 95 % CI: 0.15-0.61, p <0.001 and 0.37, 95 % CI: 0.15-0.91, p = .031). CONCLUSIONS: High PNI is associated with longer PFS and OS, in patients with MSI-H mGC receiving ICIs. Patients with low baseline PNI may benefit from intensive therapeutic approaches.

Prognostic and predictive impact of sex in locally advanced microsatellite instability high gastric or gastroesophageal junction cancer: An individual patient data pooled analysis of randomized clinical trials.

BACKGROUND: Surgery plus peri-operative/adjuvant chemotherapy is the standard of care for locally advanced GC/GEJC, though with unsatisfactory results. dMMR/MSI-high tumors have better prognosis and scant benefit from chemotherapy as compared to pMMR/MSS ones. The differential outcome of therapies in terms of safety and efficacy according to sex is still debated in GC/GEJC patients. METHODS: We previously performed an individual patient data pooled analysis of MAGIC, CLASSIC, ITACA-S, and ARTIST trials including GC/GEJC patients treated with surgery alone or surgery plus peri-operative/adjuvant chemotherapy to assess the value of MSI status. We performed a secondary analysis investigating the prognostic and predictive role of sex (female versus male) in the pooled analysis dataset in the overall population and patients stratified for MSI status (MSI-high versus MSS/MSI-low). Disease-free (DFS) and overall survival (OS) were calculated. RESULTS: Patients with MSI-high tumors had improved survival as compared to MSS/MSI-low ones irrespective of sex, whereas in those with MSS/MSI-low tumors, females had numerically longer OS and DFS (5-year OS was 63.2% versus 57.6%, HR 0.842; p = 0.058, and 5-year DFS was 55.8% versus 50.8%, HR 0.850; p = 0.0504 in female versus male patients). The numerical difference for the detrimental effect of chemotherapy in MSI-high GC was higher in females than males, while the significant benefit of chemotherapy over surgery alone was confirmed in MSS/MSI-low GC irrespective of sex. CONCLUSIONS: This pooled analysis including four randomized trials highlights a relevant impact of sex in the prognosis and treatment efficacy of MSI-high and MSS/MSI-low non-metastatic GC/GEJC.

Negative Hyperselection of Patients with HER2+ and RAS Wild-Type Metastatic Colorectal Cancer Receiving Dual HER2 Blockade: the PRESSING-HER2 Study.

PURPOSE: To demonstrate the negative prognostic impact of a panel of genomic alterations (PRESSING-HER2 panel) and lack of HER2 amplification by next-generation sequencing (NGS) in patients with HER2+, RAS wild-type metastatic colorectal cancer receiving dual HER2 blockade. EXPERIMENTAL DESIGN: The PRESSING-HER2 panel of HER2 mutations/rearrangements and RTK/MAPK mutations/amplifications was assessed by NGS. HER2 amplification was confirmed by NGS if copy-number variation (CNV) was ≥ 6. With a case-control design, hypothesizing 30% and 5% PRESSING-HER2 positivity in resistant [progression-free survival (PFS) <4 months and no RECIST response] versus sensitive cohorts, respectively, 35 patients were needed per group. RESULTS: PRESSING-HER2 alterations included HER2 mutations/rearrangements, EGFR amplification, and BRAF mutations and had a prevalence of 27% (9/33) and 3% (1/35) in resistant versus sensitive patients (P = 0.005) and 63% predictive accuracy. Overall, HER2 nonamplified status by NGS had 10% prevalence. Median PFS and overall survival (OS) were worse in PRESSING-HER2+ versus negative (2.2 vs. 5.3 months, P < 0.001; 5.4 vs. 14.9 months, P = 0.001) and in HER2 nonamplified versus amplified (1.6 vs. 5.2 months, P < 0.001; 7.4 vs. 12.4 months, P = 0.157). These results were confirmed in multivariable analyses [PRESSING-HER2 positivity: PFS HR = 3.06, 95% confidence interval (CI), 1.40-6.69, P = 0.005; OS HR = 2.93, 95% CI, 1.32-6.48, P = 0.007]. Combining PRESSING-HER2 and HER2 CNV increased the predictive accuracy to 75%. CONCLUSIONS: PRESSING-HER2 panel and HER2 nonamplified status by NGS warrant validation as potential predictive markers in this setting. See related commentary by Raghav et al., p. 260.

Predictive Impact of RNF43 Mutations in Patients With Proficient Mismatch Repair/Microsatellite Stable BRAFV600E-Mutated Metastatic Colorectal Cancer Treated With Target Therapy or Chemotherapy.

PURPOSE: Target therapy (TT) with encorafenib plus cetuximab is a standard option in patients with BRAFV600E-mutated (mut) pretreated metastatic colorectal cancer (mCRC). Recently, mutations in RNF43, encoding a negative regulator of the WNT pathway, were associated with longer progression-free survival (PFS) and overall survival (OS) in patients with proficient mismatch repair/microsatellite stable (pMMR/MSS) BRAFV600E-mut mCRC treated with TT. Here, we explored the effect of RNF43 mutations on the efficacy of second-line TT versus standard chemotherapy (CT). METHODS: A retrospective cohort of patients with pMMR/MSS BRAFV600E-mut tumors, available RNF43 mutational status, and treated with second-line TT or oxaliplatin- and/or irinotecan-based CT was analyzed. RESULTS: One hundred thirty-two patients with pMMR/MSS BRAFV600E-mut mCRC were included. RNF43 was found mut in 34 (26%) cases. Among RNF43 mutants, TT was associated with longer PFS (7.7 v 3.0 months; P = .002) and higher overall response rate (ORR; 45% v 0%; P = .009) compared with CT. Conversely, among RNF43 wild-type (wt) patients, only a trend for longer PFS (4.5 v 3.7 months; P = .064) favoring TT, with no differences in ORR (P = .14), was observed. After excluding 36 patients receiving TT in third line or beyond, a longer OS (19.4 v 10.1 months; P = .022) and a numerically OS advantage (10.6 v 6.6 months; P = .068) were reported for TT both in the RNF43-mut and in the RNF43 wt groups. However, no interaction effect was reported between RNF43 mutational status and treatment in ORR (Pinteraction = .96), PFS (Pinteraction = .13), and OS (Pinteraction = .44). CONCLUSION: Patients with pMMR/MSS BRAFV600E-mut mCRC achieve benefit from TT versus CT independently of RNF43 mutational status, although a higher magnitude of benefit from TT is observed in RNF43-mut tumors. These findings deserve confirmation in concluded and ongoing randomized trials.

Assessing the safety and activity of cabozantinib combined with lanreotide in gastroenteropancreatic and thoracic neuroendocrine tumors: rationale and protocol of the phase II LOLA trial.

BACKGROUND: Well-differentiated (WD) neuroendocrine tumors (NETs) are a group of rare neoplasms with limited therapeutic options. Cabozantinib is an inhibitor of multiple tyrosine kinases with a pivotal role in NET pathogenesis, including c-MET and Vascular Endothelial Growth Factor Receptor 2 (VEGFR2). LOLA is the first prospective phase II trial aiming to assess the safety and activity of cabozantinib combined with lanreotide in WD NETs of gastroenteropancreatic (GEP), thoracic and of unknown origin. METHODS: This is a multicenter, open-label, double-cohort, non comparative, non-randomized, three-stage phase II trial. Eligible patients have to meet the following inclusion criteria: diagnosis of advanced or metastatic, progressive, non-functioning WD thoracic NETs, GEP-NETs or NETs of unknown origin with Ki67 ≥ 10%; positive 68 Ga-PET uptake or somatostatin receptor 2 immunohistochemical (IHC) stain; maximum 1 prior systemic regimen for metastatic disease. Two cohorts will be considered: pNETs and carcinoids (typical or atypical lung and thymus NETs, gastro-intestinal NETs or NETs of unknown origin). In stage I, the primary objective is to find the optimal dose of cabozantinib in combination with lanreotide and to evaluate the safety of the combination (percentage of patients experiencing grade 3-5 toxicities according to NCI-CTCAE version 5.0). Starting dose of cabozantinib is 60 mg/day continuously, plus lanreotide 120 mg every 28 days. In stage II and III, co-primary endpoints are safety and overall response rate (ORR) according to RECIST version 1.1. The uninteresting antitumor activity is fixed in ORR ≤ 5%. Secondary endpoints are progression-free survival and overall survival. Exploratory objectives include the assessment of c-MET, AXL and VEGFR2 IHC expression, to identify predictive or prognostic tissue biomarkers. Enrolment started in July 2020, with an expected trial duration of 42 months comprehensive of accrual, treatment and follow-up. Considering a drop-out rate of 5%, the maximum number of enrolled patients will be 69. DISCUSSION: Supported by a solid rationale, the trial has the potential to generate milestone data about the synergistic effects of cabozantinib plus lanreotide in a group of NET patients with relatively aggressive disease and limited therapeutic options. TRIAL REGISTRATION: LOLA is registered at ClinicalTrials.gov (NCT04427787) and EudraCT (2019-004506-10).

Mismatch Repair system protein deficiency as a resistance factor for locally advanced rectal adenocarcinoma patients receiving neoadjuvant chemo-radiotherapy.

BACKGROUND: Available data on Mismatch Repair system (MMR) deficiency are conflicting and derived from small studies. Our study aimed to evaluate the therapeutic implications of MMR status in patients with locally advanced rectal cancer (LARC). METHODS: We retrospectively collected data from 318 patients affected by LARC treated in Italy at the Medical Oncology Units of the University Hospital of Cagliari, Istituto Nazionale dei Tumori Milan, and AOU Ospedali Riuniti Ancona. All patients underwent neoadjuvant chemoradiotherapy. The primary objective was major TRG while secondary objectives were pathological complete response, disease-free survival (DFS) and overall survival (OS). RESULTS: One hundred sixty patients (148 pMMR and 12 dMMR) were included in the exploratory cohort and 158 (146 pMMR and 12 dMMR) were included in the validation cohort. A major TRG has been shown in 42.6% and 43.1% patients with pMMR in exploratory and validation cohort, respectively; while no major TRG have been shown in dMMR patients in both cohorts. Exploratory and validation cohorts showed a statistically significant higher mDFS in pMMR patients compared to dMMR: NR vs. 14 months and NR vs. 17 months, respectively. CONCLUSION: Our results indicated an association between dMMR and poor response to preoperative chemoradiotherapy and they represent a hypothesis-generating data for new neoadjuvant strategies.

Mytomicin-C, Metronomic Capecitabine, and Bevacizumab in Patients With Unresectable or Relapsed Pseudomyxoma Peritonei of Appendiceal Origin.

INTRODUCTION: Pseudomyxoma peritonei (PMP) is a rare, slow growing tumor, traditionally considered chemoresistant. The only curative approach is cytoreductive surgery (CRS) followed by hyperthermic intraperitoneal chemotherapy (HIPEC). At disease relapse, or in patients with inoperable disease at diagnosis, no standard treatment has been defined, though nonrandomized series showed promising results with fluoropyrimidine-based regimens. PATIENTS AND METHODS: We conducted a prospective study in patients with relapsed or unresectable PMP and confirmed disease progression at baseline. Patients received MMC (7 mg/m2 every 6 weeks, up to a maximum of 4 cycles) plus metronomic capecitabine (625 mg/sqm/day b.i.d.) and bevacizumab (7.5 mg/kg every 3 weeks) until disease progression, unacceptable toxicity, or consent withdrawal. Primary endpoint was progression-free survival (PFS); secondary endpoints were overall survival (OS), overall response rate according to RECIST v1.1 criteria, serum markers response and safety. RESULTS: Fifteen patients were included. At a median follow-up of 26.1 months (IQR, 17.7-49.6), median PFS was 17.9 months (95% CI, 11.0-NE), with 1-year PFS and OS rates of 73% and 87%. Safety profile was manageable, with only 13% G3/G4 treatment-related adverse events. CONCLUSION: Metronomic capecitabine, bevacizumab, and MMC are an active regimen in advanced and progressive PMP and favorably compares with historical series.

Towards Multiomics-Based Dissection of Anti-EGFR Sensitivity in Colorectal Cancer.

Overexpression of the EGFR ligands amphiregulin (AREG)/epiregulin (EREG) may be a surrogate of EGFR dependency regardless of sidedness in metastatic colorectal cancer. High AREG/EREG may be coupled with negative hyper-selection (i.e., lack of genomic drivers of primary resistance beyond RAS and BRAF) to identify patients with right-sided tumors and potential sensitivity to EGFR blockade. See related article by Williams et al., p. 4153.

Optimal maintenance strategy following FOLFOX plus anti-EGFR induction therapy in patients with RAS wild type metastatic colorectal cancer: An individual patient data pooled analysis of randomised clinical trials.

BACKGROUND: Anti-EGFR antibodies plus doublet chemotherapy is the standard of care in RAS/BRAF wild-type metastatic colorectal cancer (mCRC). No phase-3 level of evidence is available to guide treatment de-escalation after anti-EGFR-based first-line. Several randomised clinical trials investigated de-intensification strategies with 5-fluorouracil/leucovorin (5-FU/LV) and/or anti-EGFR. METHODS: We performed an individual patient data pooled analysis of Valentino, Panama, MACRO-2, COIN-B trials including RAS wild-type mCRC patients who received first-line therapy with FOLFOX plus panitumumab or cetuximab followed by pre-specified maintenance strategy. Only patients who started maintenance according to the assigned arm were included. Patients were categorised by type of maintenance (i.e. 5-FU/LV, anti-EGFR or 5-FU/LV + anti-EGFR). Progression-free survival (PFS) and overall survival (OS) were calculated from the start of maintenance; toxicity was evaluated for the maintenance treatment period. RESULTS: A total of 518 patients were included in the pooled analysis. Overall, 123, 185 and 210 patients received maintenance with 5-FU/LV, anti-EGFR, 5-FU/LV + anti-EGFR, respectively. Median PFS was 5.6, 6.0 and 9.0 (P = 0.009) and OS was 25.7, 24.0 and 28.0 months (P = 0.134) in 5-FU/LV, anti-EGFR and 5-FU/LV + anti-EGFR arms, respectively. Monotherapy maintenance (either 5-FU/LV or anti-EGFR) was inferior to combination in terms of PFS (hazard ratios [HR] 1.26, P = 0.016) and non-significantly trending also in OS (HR 1.20, P = 0.111). An increase of overall any grade and grade ≥ 3 AEs and selected AEs was reported in combination compared to either 5-FU/LV or anti-EGFR arms. CONCLUSIONS: This pooled analysis including four randomised phase II supports the use of 5-FU/LV plus anti-EGFR as the preferred maintenance regimen. Data provide rational for a more individualised maintenance treatment approach based on tumour and patients features.

Outcomes and a prognostic classifier in patients with microsatellite instability-high metastatic gastric cancer receiving PD-1 blockade.

BACKGROUND: Subgroup analyses of randomized trials suggest the superiority of immune checkpoint inhibitor-based therapy over chemotherapy in patients with mismatch-repair deficient (dMMR) and/or microsatellite instability-high (MSI-high) advanced gastric or gastroesophageal junction adenocarcinoma. However, these subgroups are small and studies examining prognostic features within dMMR/MSI-high patients are lacking. METHODS: We conducted an international cohort study at tertiary cancer centers and collected baseline clinicopathologic features of patients with dMMR/MSI-high metastatic or unresectable gastric cancer treated with anti-programmed cell death protein-1 (PD-1)-based therapies. The adjusted HRs of variables significantly associated with overall survival (OS) were used to develop a prognostic score. RESULTS: One hundred and thirty patients were included. At a median follow-up of 25.1 months, the median progression-free survival (PFS) was 30.3 months (95% CI: 20.4 to NA) and 2-year PFS rate was 56% (95% CI: 48% to 66%). Median OS was of 62.5 months (95% CI: 28.4 to NA) and 2-year OS rate was 63% (95% CI: 55% to 73%). Among the 103 Response Evaluation Criteria in Solid Tumors-evaluable patients, objective response rate was 66% and disease control rate 87% across lines of therapy. In the multivariable models, Eastern Cooperative Oncology Group Performance Status of 1 or 2, non-resected primary tumor, presence of bone metastases and malignant ascites were independently associated with poorer PFS and OS. These four clinical variables were used to build a three-category (ie, good, intermediate, and poor risk) prognostic score. Compared with patients with good risk, patients with intermediate risk score had numerically inferior PFS and OS (2-year PFS rate: 54.3% versus 74.5%, HR 1.90, 95% CI: 0.99 to 3.66; 2-year OS rate: 66.8% versus 81.2%, HR 1.86, 95% CI: 0.87 to 3.98), whereas patients with poor risk score had significantly inferior PFS and OS (2-year PFS rate: 10.6%, HR 9.65, 95% CI: 4.67 to 19.92; 2-year OS rate: 13.3%, HR 11.93, 95% CI: 5.42 to 26.23). CONCLUSIONS: Overall outcomes with anti-PD-1-based therapies are favorable in MSI-high gastroesophageal adenocarcinomas. However, within this overall favorable subgroup a more accurate prognostication using baseline clinical characteristics might identify patients at higher risk of rapid disease progression who may deserve intensified immunotherapy combination strategies.

Tumour mutational burden as a biomarker in patients with mismatch repair deficient/microsatellite instability-high metastatic colorectal cancer treated with immune checkpoint inhibitors.

BACKGROUND: Immune checkpoint inhibitors (ICIs) are the standard treatment in patients with mismatch repair deficient (dMMR)/microsatellite instability-high (MSI-H) metastatic colorectal cancer (mCRC). Tumour mutational burden (TMB) is a promising biomarker for the prediction of treatment outcomes. PATIENTS AND METHODS: We screened 203 patients with dMMR/MSI-H mCRC treated with an anti-PD-(L)1 (anti-Programmed-Death-(Ligand)1) plus or minus an anti-Cytotoxic T-Lymphocyte Antigen 4 (anti-CTLA-4) agent at three Italian Academic Centers. TMB was tested by Foundation One Next Generation Sequencing assay and correlated with clinical outcomes, in the overall population and according to ICI regimen. RESULTS: We included 110 patients with dMMR/MSI-H mCRC. Eighty patients received anti-PD-(L)1 monotherapy and 30 received anti-CTLA-4 combinations. Median TMB was 49 mut/Mb (range: 8-251 mut/Mb). The optimal prognostic cut-off for progression-free survival (PFS) stratification was 23 mut/Mb. Patients with TMB ≤23 mut/Mb had significantly worse PFS (adjusted Hazard Ratio [aHR] = 4.26, 95% confidence interval [CI]:1.85-9.82, p = 0.001) and overall survival (OS) (aHR = 5.14, 95% CI: 1.76-14.98, p = 0.003). Using a cut-off optimised for predicting treatment outcome, anti-CTLA-4 combination was associated with a significant PFS/OS benefit versus anti-PD-(L)1 monotherapy in patients with TMB>40 mut/Mb (2-year PFS: 100.0% versus 70.7%, p = 0.002; 2-year OS: 100.0% versus 76.0%, p = 0.025), but not in those with TMB ≤40 mut/Mb (2-year PFS: 59.7% versus 68.6%, p = 0.888; 2-year OS: 80.0% versus 81.0%, p = 0.949). CONCLUSION: Patients with dMMR/MSI-H mCRC and relatively lower TMB value displayed early disease progression when receiving ICIs, whereas patients with the highest TMB values may obtain the maximal benefit from intensified anti-CTLA-4/PD-1 combination.

RNF43 mutations predict response to anti-BRAF/EGFR combinatory therapies in BRAFV600E metastatic colorectal cancer.

Anti-BRAF/EGFR therapy was recently approved for the treatment of metastatic BRAFV600E colorectal cancer (mCRCBRAF-V600E). However, a large fraction of patients do not respond, underscoring the need to identify molecular determinants of treatment response. Using whole-exome sequencing in a discovery cohort of patients with mCRCBRAF-V600E treated with anti-BRAF/EGFR therapy, we found that inactivating mutations in RNF43, a negative regulator of WNT, predict improved response rates and survival outcomes in patients with microsatellite-stable (MSS) tumors. Analysis of an independent validation cohort confirmed the relevance of RNF43 mutations to predicting clinical benefit (72.7% versus 30.8%; P = 0.03), as well as longer progression-free survival (hazard ratio (HR), 0.30; 95% confidence interval (CI), 0.12-0.75; P = 0.01) and overall survival (HR, 0.26; 95% CI, 0.10-0.71; P = 0.008), in patients with MSS-RNF43mutated versus MSS-RNF43wild-type tumors. Microsatellite-instable tumors invariably carried a wild-type-like RNF43 genotype encoding p.G659fs and presented an intermediate response profile. We found no association of RNF43 mutations with patient outcomes in a control cohort of patients with MSS-mCRCBRAF-V600E tumors not exposed to anti-BRAF targeted therapies. Overall, our findings suggest a cross-talk between the MAPK and WNT pathways that may modulate the antitumor activity of anti-BRAF/EGFR therapy and uncover predictive biomarkers to optimize the clinical management of these patients.

Early onset metastatic colorectal cancer in patients receiving panitumumab-based upfront strategy: Overall and sex-specific outcomes in the Valentino trial.

Anti-EGFRs plus doublet chemotherapy is considered the optimal upfront option for RAS/BRAF wild-type left-sided metastatic colorectal cancer (mCRC). Early-onset (EO) mCRC has an increasing incidence and its prognostic/predictive role and management is debatable. We performed a post hoc analysis of Valentino study, that randomized RAS wild-type mCRC patients to two panitumumab-based maintenance regimens after FOLFOX/panitumumab induction. We assessed the safety and efficacy outcomes in patients stratified for age (<50/≥50 years old). We assessed progression-free survival (PFS), overall survival (OS), response rate (ORR), rate of treatment-related and panitumumab-related adverse events (AEs) and quality of life (QoL). In 229 patients enrolled, 35 (15%) had EO mCRC, with a higher rate of female sex (P = .020) and lower rate of primary tumor resection (P = .001). Median PFS and OS were 10.9 vs 10.8 months (P = .593) and 28.1 vs 27.5 months (P = .865) in patients <50 and ≥50 years old, respectively, with no significant impact of maintenance arm. ORR and disease control rate were 74% vs 65% (P = .337) and 97% vs 81% (P = .013) in patients <50 or ≥50 years old. In younger patients, a trend for increased chemotherapy-related AEs (peculiarly anemia) was shown, while significantly decreased EGFR-related hypomagnesemia and increased skin rash were reported. No significant differences in treatment intensity or QoL were observed. In patients with EO mCRC and RAS wild-type status, we found no differences in terms of survival outcomes based on age when selecting maintenance strategies. Management of treatment-related AEs should consider the differential toxicity profile of age and sex.

Upfront Modified Fluorouracil, Leucovorin, Oxaliplatin, and Irinotecan Plus Panitumumab Versus Fluorouracil, Leucovorin, and Oxaliplatin Plus Panitumumab for Patients With RAS/BRAF Wild-Type Metastatic Colorectal Cancer: The Phase III TRIPLETE Study by GONO.

PURPOSE: To verify whether the intensification of the upfront chemotherapy backbone with a modified schedule of modified fluorouracil, leucovorin, oxaliplatin, and irinotecan (mFOLFOXIRI) increases the activity of fluorouracil, leucovorin, and oxaliplatin when both regimens are combined with panitumumab as initial treatment for RAS and BRAF wild-type (wt) metastatic colorectal cancer (mCRC). METHODS: TRIPLETE was a prospective, open-label, phase III trial in which previously untreated patients with unresectable RAS and BRAF wt mCRC were randomly assigned 1:1 to modified FOLFOX/panitumumab (control group) or mFOLFOXIRI/panitumumab (experimental group) up to 12 cycles, followed by fluorouracil/-leucovorin/panitumumab until disease progression. The primary end point was objective response rate (ORR) according to RECIST 1.1. Hypothesizing an ORR of 60% in the control group, 432 cases provided 90% power to a two-sided chi-square test for heterogeneity with a two-sided alpha error of .05 to detect ≥ 15% differences between arms (ClinicalTrials.gov identifier: NCT03231722). RESULTS: From September 2017 to September 2021, 435 patients were enrolled (control group/experimental group: 217/218) in 57 Italian sites. One hundred sixty (73%) patients treated with mFOLFOXIRI plus panitumumab and 165 (76%) patients treated with modified FOLFOX plus panitumumab achieved RECIST response (odds ratio 0.87, 95% CI, 0.56 to 1.34, P = .526). No differences in early tumor shrinkage rate (57%/58%, P = .878) and deepness of response (median: 48%/47%, P = .845) were reported, nor in R0 resection rate (25%/29%, P = .317). No significant difference between arms was reported in terms of progression-free survival (median progression-free survival: 12.7 in the experimental group v 12.3 months in the control group, hazard ratio: 0.88, 95% CI, 0.70 to 1.11, P = .277). CONCLUSION: The intensification of the upfront chemotherapy backbone in combination with panitumumab does not provide additional benefit in terms of treatment activity at the price of increased gastrointestinal toxicity in patients with RAS and BRAF wt mCRC.

Negative Ultraselection of Patients With RAS/BRAF Wild-Type, Microsatellite-Stable Metastatic Colorectal Cancer Receiving Anti-EGFR-Based Therapy.

PURPOSE: Several uncommon genomic alterations beyond RAS and BRAFV600E mutations drive primary resistance to anti-epidermal growth factor receptors (EGFRs) in metastatic colorectal cancer (mCRC). Our PRESSING panel (including PIK3CA exon 20/AKT1/PTEN mutations, ERBB2/MET amplifications, gene fusions, and microsatellite instability-high status) represented a paradigm of negative hyperselection with more precise tailoring of EGFR blockade. However, a modest proportion of hyperselected mCRC has intrinsic resistance potentially driven by even rarer genomic alterations. MATERIALS AND METHODS: A prospective data set at three Italian Academic Hospitals included 650 patients with mCRC with comprehensive genomic profiling by FoundationOne CDx and treated with anti-EGFRs. PRESSING2 panel alterations were selected on the basis of previous clinico-biologic studies and included NTRKs, ERBB3, NF1, MAP2K1/2/4, AKT2 pathogenic mutations; PTEN/NF1 loss; ERBB3, FGFR2, IGF1R, KRAS, ARAF, and AKT1-2 amplification; and EGFR rearrangements. These were collectively associated with outcomes in patients with hyperselected disease, ie, RAS/BRAF wild-type, PRESSING-negative, and microsatellite stable. RESULTS: Among 162 hyperselected patients, 24 (15%) had PRESSING2 alterations, which were mutually exclusive except in two samples and were numerically higher in right-sided versus left-sided cancers (28% v 13%; P = .149). Independently of sidedness and other factors, patients with PRESSING2-positive status had significantly worse progression-free survival and overall survival compared with PRESSING2-negative ones (median progression-free survival 6.4 v 12.8 months, adjusted hazard ratio 4.19 [95% CI, 2.58 to 6.79]; median overall survival: 22.6 v 49.9 months, adjusted hazard ratio 2.98 [95% CI, 1.49 to 5.96]). The combined analysis of primary tumor sidedness and PRESSING2 status allowed us to better stratify outcomes. CONCLUSION: Negative ultraselection warrants further investigation with the aim of maximizing the benefit of EGFR blockade strategies in patients with RAS and BRAF wild-type, microsatellite stable mCRC.

Treatments after second progression in metastatic colorectal cancer: A pooled analysis of the TRIBE and TRIBE2 studies.

BACKGROUND: The availability of new drugs in the chemo-refractory setting opened the way to the concepts of treatment sequencing in mCRC. However, the impact of later line options in the therapeutic route of metastatic colorectal cancer (mCRC) patients and the attrition rate across subsequent lines of therapy are not well established. METHODS: We performed a pooled analysis of treatments administered after the 2nd disease progression in 1187 mCRC patients enrolled in the randomized phase III TRIBE and TRIBE2 studies, where upfront FOLFOXIRI/bev was compared with FOLFOX or FOLFIRI/bev. Per each line, we assessed the attrition rate, treatment choices and clinical outcomes. RESULTS: 625 (53%), 326 (27%) and 136 (11%) patients received a systemic treatment after the 2nd, 3rd and 4th disease progression, respectively. PFS and objective response rate decreased along each line. RAS/BRAF wild-type patients received more likely a 3rd line (75%) compared with RAS (66%, p = 0.005) and BRAF (66%, p = 0.11) mutants. In 3rd line, 67% of RAS/BRAF wild-type patients received anti-EGFRs, achieving longer PFS with respect to other therapies (6.4 vs 3.9 months, p = 0.02). A trend towards longer 3rd line OS was observed in TRIBE patients (9.9 vs 7.2 months, p = 0.05). CONCLUSIONS: A relevant attrition rate across subsequent lines of therapy is evident, and more pronounced in RAS and BRAF mutated patients, thus highlighting the relevance of the choice of the upfront treatment. The efficacy of anti-EGFR agents among RAS/BRAF wild-type patients unexposed to anti-EGFRs is higher than other options. The reintroduction of chemotherapy remains frequent in clinical practice. TRIAL REGISTRATION: Clinicaltrials. gov Identifiers NCT00719797, NCT02339116.

ALK Inhibitors in Patients With ALK Fusion-Positive GI Cancers: An International Data Set and a Molecular Case Series.

PURPOSE: In GI cancers, anaplastic lymphoma kinase (ALK) rearrangements are extremely less frequent than in non-small-cell lung cancer but may be important to offer personalized strategies of treatment in selected patients. Data about the activity and efficacy of ALK inhibitors (ALKi) in GI cancers are scarce. MATERIALS AND METHODS: We assembled a clinical and molecular international data set of pretreated patients with metastatic or nonresectable cancers of GI primary tumor origin with documented ALK rearrangement treated with at least one line of ALKi. Measurable disease as per RECIST 1.1 was required for response analysis. RESULTS: Primary tumor sites were distributed as follows: 5 (38%) pancreas, 3 (23%) right colon, and 1 (8%) for each one of gastric, duodenal, rectal, left colon, and biliary tract sites. Seven patients (54%) were treated with alectinib, 5 (38%) with crizotinib, and 1 (8%) with entrectinib. After disease progression, five patients (38%) received a subsequent ALKi treatment line, and at the time of data cutoff date, treatment was still ongoing in two patients. Five of 12 evaluable patients (41%) achieved a partial response to first-line ALKi, five patients (41%) had stable disease, and 2 (17%) had progressive disease. No complete responses were registered. At a median follow-up of 39.6 months (interquartile range: 19.8-59.5), the median progression-free survival was 5.0 months (95% CI, 3.68 to no response) and the median overall survival was 9.3 months (95% CI, 5.46 to no response). CONCLUSION: Treatment with ALKi provides remarkable responses and clinical benefit in pretreated patients with ALK fusion-positive GI malignancies. Despite the rarity, ALK rearrangements represent an important therapeutic target in individual pretreated patients with GI solid tumors. Further work providing prospective clinical validation of this target is needed.

Temozolomide Followed by Combination With Low-Dose Ipilimumab and Nivolumab in Patients With Microsatellite-Stable, O6-Methylguanine-DNA Methyltransferase-Silenced Metastatic Colorectal Cancer: The MAYA Trial.

PURPOSE: This is a multicenter, single-arm phase II trial evaluating the efficacy and safety of an immune-sensitizing strategy with temozolomide priming followed by a combination of low-dose ipilimumab and nivolumab in patients with microsatellite-stable (MSS) and O6-methylguanine-DNA methyltransferase (MGMT)-silenced metastatic colorectal cancer (mCRC). PATIENTS AND METHODS: Patients with pretreated mCRC were centrally prescreened for MSS status and MGMT silencing (ie, lack of MGMT expression by immunohistochemistry plus MGMT methylation by pyrosequencing). Eligible patients received two priming cycles of oral temozolomide 150 mg/sqm once daily, days 1-5, once every 4 weeks (first treatment part) followed, in absence of progression, by its combination with ipilimumab 1 mg/kg once every 8 weeks and nivolumab 480 mg once every 4 weeks (second treatment part). The primary end point was the 8-month progression-free survival (PFS) rate calculated from enrollment in patients who started the second treatment part, with ≥ 4 out of 27 subjects progression-free by the 8-month time point as decision rule. RESULTS: Among 716 prescreened patients, 204 (29%) were molecularly eligible and 135 started the first treatment part. Among these, 102 (76%) were discontinued because of death or disease progression on temozolomide priming, whereas 33 patients (24%) who achieved disease control started the second treatment part and represented the final study population. After a median follow-up of 23.1 months (interquartile range, 14.9-24.6 months), 8-month PFS rate was 36%. Median PFS and overall survival were 7.0 and 18.4 months, respectively, and overall response rate was 45%. Grade 3-4 immune-related adverse events were skin rash (6%), colitis (3%), and hypophysitis (3%). No unexpected adverse events or treatment-related deaths were reported. CONCLUSION: The MAYA study provided proof-of-concept that a sequence of temozolomide priming followed by a combination of low-dose ipilimumab and nivolumab may induce durable clinical benefit in MSS and MGMT-silenced mCRC.

Ascites and resistance to immune checkpoint inhibition in dMMR/MSI-H metastatic colorectal and gastric cancers.

BACKGROUND: Despite unprecedented benefit from immune checkpoint inhibitors (ICIs) in patients with mismatch repair deficient (dMMR)/microsatellite instability high (MSI-H) advanced gastrointestinal cancers, a relevant proportion of patients shows primary resistance or short-term disease control. Since malignant effusions represent an immune-suppressed niche, we investigated whether peritoneal involvement with or without ascites is a poor prognostic factor in patients with dMMR/MSI-H metastatic colorectal cancer (mCRC) and gastric cancer (mGC) receiving ICIs. METHODS: We conducted a global multicohort study at Tertiary Cancer Centers and collected clinic-pathological data from a cohort of patients with dMMR/MSI-H mCRC treated with anti-PD-(L)1 ±anti-CTLA-4 agents at 12 institutions (developing set). A cohort of patients with dMMR/MSI-high mGC treated with anti-PD-1 agents±chemotherapy at five institutions was used as validating dataset. RESULTS: The mCRC cohort included 502 patients. After a median follow-up of 31.2 months, patients without peritoneal metastases and those with peritoneal metastases and no ascites had similar outcomes (adjusted HR (aHR) 1.15, 95% CI 0.85 to 1.56 for progression-free survival (PFS); aHR 0.96, 95% CI 0.65 to 1.42 for overall survival (OS)), whereas inferior outcomes were observed in patients with peritoneal metastases and ascites (aHR 2.90, 95% CI 1.70 to 4.94; aHR 3.33, 95% CI 1.88 to 5.91) compared with patients without peritoneal involvement. The mGC cohort included 59 patients. After a median follow-up of 17.4 months, inferior PFS and OS were reported in patients with peritoneal metastases and ascites (aHR 3.83, 95% CI 1.68 to 8.72; aHR 3.44, 95% CI 1.39 to 8.53, respectively), but not in patients with only peritoneal metastases (aHR 1.87, 95% CI 0.64 to 5.46; aHR 2.15, 95% CI 0.64 to 7.27) when compared with patients without peritoneal involvement. CONCLUSIONS: Patients with dMMR/MSI-H gastrointestinal cancers with peritoneal metastases and ascites should be considered as a peculiar subgroup with highly unfavorable outcomes to current ICI-based therapies. Novel strategies to target the immune-suppressive niche in malignant effusions should be investigated, as well as next-generation ICIs or intraperitoneal approaches.

Biomarker Landscape in Neuroendocrine Tumors With High-Grade Features: Current Knowledge and Future Perspective.

Neuroendocrine tumors (NETs) are classified based on morphology and are graded based on their proliferation rate as either well-differentiated low-grade (G1) to intermediate (G2-G3) or poorly differentiated high-grade neuroendocrine carcinomas (NEC G3). Recently, in gastroenteropancreatic (GEP) NETs, a new subgroup of well-differentiated high-grade tumors (NET G3) has been divided from NEC by WHO due to its different clinical-pathologic features. Although several mutational analyses have been performed, a molecular classification of NET is an unmet need in particular for G3, which tends to be more aggressive and have less benefit to the available therapies. Specifically, new possible prognostic and, above all, predictive factors are highly awaited, giving the basis for new treatments. Alteration of KRAS, TP53, and RB1 is mainly reported, but also druggable alterations, including BRAF and high microsatellite instability (MSI-H), have been documented in subsets of patients. In addition, PD-L1 demonstrated to be highly expressed in G3 NETs, probably becoming a new biomarker for G3 neuroendocrine neoplasm (NEN) discrimination and a predictive one for immunotherapy response. In this review, we describe the current knowledge available on a high-grade NET molecular landscape with a specific focus on those harboring potentially therapeutic targets in the advanced setting.