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Purpose: KRASG12D mutation (mut) occurs in about 10%-12% of metastatic colorectal cancer (mCRC). Recently, novel KRASG12D inhibitors have been developed and are currently under investigation in phase I/II clinical trials in solid tumors including mCRC. We aimed at performing a comprehensive characterization of clinical, molecular, immunologic, and prognostic features of KRASG12D-mutated mCRC to inform the design and the interpretation of future trials., Methods: We performed a pooled analysis of phase III TRIBE and TRIBE2 studies comparing 5-fluorouracil, leucovorin, oxaliplatin, and irinotecan (FOLFOXIRI)/bevacizumab (bev) to doublets (5-fluorouracil, leucovorin, and oxaliplatin or 5-fluorouracil, leucovorin, and irinotecan)/bev., Results: One hundred and thirty-six (16%) of 854 patients with available KRASG12D mutational status were KRASG12D mutated. KRASG12D-mutated patients had more frequently right-sided primary tumor and were less likely to present liver-only metastases with respect to other RAS mutated and all-wild-type (wt) patients. Compared with the BRAFV600E-mutated group, KRASG12D-mutated patients had more frequently left-sided primary tumor, resected primary tumor at the time of diagnosis, and Eastern Cooperative Oncology Group performance status 0. KRASG12D-mutated patients had better prognosis than BRAFV600E-mutated and worse prognosis than all wt patients. No prognostic difference was evident between KRASG12D mut and other RAS mut patients overall or according to other specific KRAS or NRAS hotspot mutations. No interaction effect was observed between KRASG12D mut and the benefit provided by FOLFOXIRI/bev compared with doublets/bev. PIK3CA mut were reported more frequently among KRASG12D-mutated tumors compared with both other RAS mut and all wt., Conclusion: A detail estimation of KRASG12D mut mCRC patients' characteristics and expected outcomes may be useful when planning future studies in this subgroup. The high prevalence of PI3K/PTEN/Akt pathway activating alterations may affect the efficacy of targeted strategies.

Background: The PRODIGE-23 study showed a higher benefit for FOLFIRINOX (5-fluorouracil, irinotecan and oxaliplatin) as induction chemotherapy followed by long-course chemoradiotherapy (CTRT) respect to neoadjuvant CTRT alone both followed by total mesorectal excision (TME) in terms of disease-free survival (DFS) and overall survival (OS) in locally advanced rectal cancer (LARC). The added value of treatment intensification with irinotecan, over the doublet induction with fluoropyrimidine and oxaliplatin is still debated., Objective: To assess survival, pathological complete response (pCR) rate, and safety from phase II-III trials comparing triplet and doublet induction both followed by CTRT and TME in LARC., Methods: After a systematic literature review of PubMed, Embase, Cochrane, American Society of Clinical Oncology and European Society for Medical Oncology meetings' libraries, data from Kaplan-Meier (KM) curves were extracted from phase II-III clinical trials. Phase II-III trials including at least one treatment arm with doublet or triplet induction chemotherapy without biological agents administered for a minimum of 3 months followed by long-course CTRT and TME and with at least 48 months of follow-up were selected. When available, the neoadjuvant CTRT alone arms of the selected studies were included as a comparator reference treatment. Individual patient DFS and OS data were extracted from Kaplan-Meier plots of original trials through graphical reconstruction between April 10th and May 19th, 2024. A pooled analysis was conducted, and results were validated in a subsequent network meta-analysis (NMA). pCR rates and grade ≥ 3 adverse events rates were also collected. Primary endpoints were DFS and OS between triplet and doublet induction. Secondary endpoints were DFS and OS between neoadjuvant CTRT alone and triplet or doublet induction as well as pCR rates and safety profile among different arms., Results: Out of 674 patients enrolled in 3 trials, 231, 161 and 282 were treated with FOLFIRINOX or CAPOX (capecitabine and oxaliplatin) followed by CTRT or neoadjuvant CTRT alone, respectively. 5-year DFS rates were 73.1 % [95 %CI: 67.2 % - 79.0 %], 61.7 % [95 %CI: 53.9 % - 69.5 %] and 65.1 % [95 %CI: 59.4 % - 70.8 %] for triplet induction, doublet induction, and neoadjuvant CTRT alone, respectively. 5-year OS rates were 86.8 % [95 %CI: 82.3 % - 91.3 %], 74.7 % [95 %CI: 67.6 % - 81.8 %], and 79.6 % [95 %CI: 74.9 % - 84.3 %] for FOLFIRINOX, CAPOX, and neoadjuvant CTRT alone, respectively. Triplet induction showed longer DFS and OS respect to doublet induction (HR for DFS: 0.67 [95 % CI 0.47 - 0.96], p = 0.03; HR for OS: 0.49 [95 % CI 0.31 - 0.78], p = 0.003) with a trend for superiority when compared with neoadjuvant CTRT alone (HR for DFS: 0.77 [95 % CI 0.57 - 1.05], p = 0.10; HR for OS: 0.67 [95 % CI 0.45 - 1.01], p = 0.06). No difference was observed between the doublet induction and neoadjuvant CTRT groups. pCR rates were higher for patients treated with FOLFIRINOX (27.7 %) respect to subjects receiving CAPOX (19.7 %, p = 0.02) or neoadjuvant CTRT alone (12.5 %, p < 0.0001). Triplet was associated with higher rates of severe neutropenia (17 % vs 1 %, p < 0.0001) and nausea-vomiting (11 % vs 3 %, p = 0.02) respect to doublet induction., Conclusions: Induction with FOLFIRINOX showed better survival outcomes and pCR rates respect to CAPOX at the price of increased G3-4 neutropenia and nausea/vomiting. A randomized study comparing triplet and doublet chemotherapy in the frame of a total neoadjuvant treatment strategy is widely warranted., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. C.C. has received honoraria for speaker or advisory roles from Bayer, Roche, Merck Serono, Amgen, Servier, Mirati, Pierre Fabre, MSD, Nordic Pharma and Takeda; and research grants from Bayer, Servier, Merck and Amgen.G.M. has received payment or honoraria for lectures, presentations, speakers bureaux, manuscript writing or educational events from Roche, MSD, Eisai, Terumo, Amgen, Merck Serono; support for attending meetings and or travel from Roche, MSD, Eisai, Terumo, Amgen, Merck Serono; participation on a Data Safety Monitoring Board or Advisory Board from Roche,MSD, Eisai.R.M., G.V., M.C., P.C. declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported. We report 4-year results of the phase II randomized AtezoTRIBE study. Eligible patients with metastatic colorectal cancer (mCRC) received first-line fluorouracil, leucovorin, oxaliplatin, and irinotecan (FOLFOXIRI)/bevacizumab (control group, n = 73) or FOLFOXIRI/bevacizumab plus atezolizumab (experimental group, n = 145). We present overall survival (OS) and updated outcomes according to tumor immune-related biomarkers, both in the intention-to-treat (ITT) population and the cohort of patients with proficient mismatch repair (pMMR) tumors. Median follow-up was 45.2 months (IQR, 42.6-49.2). In the ITT population, median OS was 33.0 and 27.2 months for experimental and control groups, respectively (hazard ratio [HR], 0.78 [80% CI, 0.61 to 0.98]; P = .084). An interaction effect between Immunoscore Immune-Checkpoint (IC) and treatment arm was observed ( P int , .089), with higher benefit from atezolizumab in the Immunoscore IC-high group. In the pMMR cohort (N = 202), median OS was 30.8 and 29.2 months for experimental and control groups, respectively (HR, 0.80 [80% CI, 0.63 to 1.02]; P = .117). Interactions between treatment group and tumor mutational burden (TMB) and Immunoscore IC were reported ( P int , .043 and .092, respectively), with patients bearing TMB-high and Immunoscore IC-high tumors deriving higher benefit from the addition of atezolizumab. First-line FOLFOXIRI/bevacizumab plus atezolizumab improves OS in patients with mCRC. In the pMMR group, patients with Immunoscore IC-high and/or TMB-high tumors are identified as a subgroup of interest to further develop this treatment.

Background: To date, only two studies have compared the outcomes of patients with liver-limited BRAF V600E-mutated colorectal liver metastases (CRLMs) managed with resection versus systemic therapy alone, and these have reported contradictory findings., Methods: In this observational, international, multicentre study, patients with liver-limited BRAF V600E-mutated CRLMs treated with resection or systemic therapy alone were identified from institutional databases. Patterns of recurrence/progression and overall survival were compared using multivariable analyses of the entire cohort and a propensity score-matched cohort., Results: Of 170 patients included, 119 underwent hepatectomy and 51 received systemic treatment. Surgically treated patients had a more favourable pattern of recurrence with most recurrences limited to a single site, whereas diffuse progression was more common among patients who received systemic treatment (19 versus 44%; P = 0.002). Surgically treated patients had longer median overall survival (35 versus 20 months; P < 0.001). Hepatectomy was independently associated with better OS than systemic treatment alone (HR 0.37, 95% c.i. 0.21 to 0.65). In the propensity score-matched cohort, surgically treated patients had longer median overall survival (28 versus 20 months; P < 0.001); hepatectomy was independently associated with better overall survival (HR 0.47, 0.25 to 0.88)., Conclusion: BRAF V600E mutation should not be considered a contraindication to surgery for patients with resectable, liver-only CRLMs., (© The Author(s) 2024. Published by Oxford University Press on behalf of BJS Foundation Ltd. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Trifluridine/tipiracil and regorafenib are indicated for metastatic colorectal cancer (mCRC) patients' refractory to standard chemotherapy. No prognostic or predictive biomarkers are available for these agents., Methods: We assessed messenger ribonucleic acid (mRNA) expression of four biomarkers implicated in the mechanism of action of trifluridine/tipiracil (TK-1 and TP) and regorafenib (Ang-2 and Tie-2) in baseline plasma-derived microvesicles of chemo-refractory mCRC patients treated with these agents (trifluridine/tipiracil cohort and regorafenib cohort), to explore their prognostic and predictive role., Results: Baseline characteristics of the two cohorts were not different. Ang-2 mRNA was not detectable. Only TK-1 expression measured as a continuous variable was associated with progression-free survival (HR=1.09, 95%CI: 0.99-1.21; p=0.07) and overall survival (HR=1.11, 95%CI: 1.00-1.22; p=0.04), confirmed at multivariate analysis for progression-free survival (p=0.02) with a positive trend for overall survival (p=0.08). Baseline mRNA levels of TK-1, TP and Tie-2 were not predictive of trifluridine/tipiracil and regorafenib benefit., Conclusion: Baseline mRNA levels of TK-1, TP and Tie-2 on plasma-derived microvesicles were not predictive of trifluridine/tipiracil and regorafenib benefit. Future studies should analyze the early modulation of these biomarkers to assess their potential predictive role.

Background . R0 minor parenchyma-sparing hepatectomy (PSH) is feasible for colorectal liver metastases (CRLM) in contact with hepatic veins (HV) at hepatocaval confluence since HV can be reconstructed, but in the case of contact with the first-order glissonean pedicle (GP), major hepatectomy is mandatory. To pursue an R0 parenchyma-sparing policy, we proposed vessel-guided mesohepatectomy for liver partition (MLP) and eventually combination with liver augmentation techniques for staged major PSH. Methods . We analyzed 15 consecutive vessel-guided MLPs for CRLM at the hepatocaval confluence. Patients had a median of 11 (range: 0-67) lesions with a median diameter of 3.5 cm (range: 0.0-8.0), bilateral in 73% of cases. Results . Grade IIIb or more complications occurred in 13%, median hospital stay was 14 (range: 6-62) days, 90-day mortality was 0%. After a median follow-up of 17.5 months, 1-year OS and RFS were 92% and 62%. In nine (64%) patients, MLP was combined with portal vein embolization (PVE) or ALPPS to perform staged R0 major PSH. Future liver remnant (FLR) volume increased from a median of 15% (range: 7-20%) up to 41% (range: 37-69%). Super-selective PVE was performed in three (33%) patients and enhanced ALPPS (e-ALPPS) in six (66%). In two e-ALPPS an intermediate stage of deportalized liver PSH was necessary to achieve adequate FLR volume. Conclusions . Vessel-guided MLP may transform the liver in a paired organ. In selected cases of multiple bilobar CRLM, to guarantee oncological radicality (R0), major PSH is feasible combining advanced surgical parenchyma sparing with liver augmentation techniques when FLR volume is insufficient.

Objective: To investigate the clinical implications of BRAF -mutated (mut BRAF ) colorectal liver metastases (CRLMs)., Background: The clinical implications of mut BRAF status in CRLMs are largely unknown., Methods: Patients undergoing resection for mut BRAF CRLM were identified from prospectively maintained registries of the collaborating institutions. Overall survival (OS) and recurrence-free survival (RFS) were compared among patients with V600E versus non-V600E mutations, KRAS/BRAF comutation versus mut BRAF alone, microsatellite stability status (Microsatellite Stable (MSS) vs instable (MSI-high)), upfront resectable versus converted tumors, extrahepatic versus liver-limited disease, and intrahepatic recurrence treated with repeat hepatectomy versus nonoperative management., Results: A total of 240 patients harboring BRAF -mutated tumors were included. BRAF V600E mutation was associated with shorter OS (30.6 vs 144 mo, P =0.004), but not RFS compared with non-V600E mutations. KRAS/BRAF comutation did not affect outcomes. MSS tumors were associated with shorter RFS (9.1 vs 26 mo, P <0.001) but not OS (33.5 vs 41 mo, P =0.3) compared with MSI-high tumors, whereas patients with resected converted disease had slightly worse RFS (8 vs 11 mo, P =0.01) and similar OS (30 vs 40 mo, P =0.4) compared with those with upfront resectable disease. Patients with extrahepatic disease had worse OS compared with those with liver-limited disease (8.8 vs 40 mo, P <0.001). Repeat hepatectomy after intrahepatic recurrence was associated with improved OS compared with nonoperative management (41 vs 18.7 mo, P =0.004). All results continued to hold true in the multivariable OS analysis., Conclusions: Although surgery may be futile in patients with BRAF -mutated CRLM and concurrent extrahepatic disease, resection of converted disease resulted in encouraging survival in the absence of extrahepatic spread. Importantly, second hepatectomy in select patients with recurrence was associated with improved outcomes. Finally, MSI-high status identifies a better prognostic group, with regard to RFS while patients with non-V600E mutations have excellent prognosis., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

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 ( P interaction = .96), PFS ( P interaction = .13), and OS ( P interaction = .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.

Background: In patients with locally advanced rectal cancer (LARC) treated with preoperative (chemo) radiotherapy and surgery, adjuvant chemotherapy is poorly feasible and its benefit is questionable. In the last years, several total neoadjuvant treatment (TNT) strategies, moving the adjuvant chemotherapy to the neoadjuvant setting, have been investigated with the aim of improving compliance to systemic chemotherapy, treating micrometastases earlier and then reducing distant recurrence., Patients and Methods: ShorTrip (NTC05253846) is a prospective, multicentre, single-arm phase II trial where 63 patients with LARC will be treated with short-course radiotherapy followed by intensified consolidation chemotherapy with FOLFOXIRI regimen and surgery. Primary endpoint is pCR. Among the first 11 patients who started consolidation chemotherapy, a preliminary safety analysis showed a high rate of grade 3 to 4 neutropenia (N = 7, 64%) during the first cycle of FOLFOXIRI. Therefore, the protocol has been emended with the recommendation to omit irinotecan during the first cycle of consolidation chemotherapy. After amendment, in a subsequent safety analysis focused on the first 9 patients treated with FOLFOX as first cycle and then with FOLFOXIRI, grade 3 to 4 neutropenia was reported in only one case during the second cycle., Aim of the Study: The aim of this study is to assess the safety and activity of a TNT strategy including SCRT, intensified consolidation treatment with FOLFOXIRI and delayed surgery. After protocol amendment, the treatment seems feasible without safety concern. Results are expected at the end of 2024., Competing Interests: Disclosure The authors have stated that they have no conflicts of interest., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The multimodal approach with total mesorectal excision preceded by neoadjuvant (chemo)radiotherapy represented the mainstay treatment for locally advanced rectal cancer (LARC) for a long time. However, the benefit of adjuvant chemotherapy in terms of distant relapse reduction is limited. Recently, chemotherapy regimens administered before surgery and incorporated with (chemo)radiotherapy in total neoadjuvant treatment protocols have been established as new options in the management of LARC. Meanwhile, patients with clinical complete response to neoadjuvant treatment can benefit from organ preservation strategies, aimed at sparing surgery and long-term post-operative morbidities, while preserving an adequate disease control. However, the introduction of a non-operative management in clinical practice is a matter of debate with some concerns regarding the risk of local recurrence and long-term outcomes. In this review, we discuss how these recent advances are reshaping the multimodal management of localized rectal cancer and propose an algorithm to place them in the clinical practice., Competing Interests: Declaration of Competing Interest CC, Honoraria: Roche, Amgen, Bayer, Servier, MSD, Merck, Pierre Fabre. Organon Consulting or Advisory Role: Roche, Bayer, Amgen, MSD, Pierre Fabre Speakers’ Bureau: Servier, Merck Research Funding: Merck, Bayer, Roche, Servier. GM, Received speakers’ fees - Merck, Amgen. All the other authors declared no conflicts of interest., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: Retrospective subgroup analyses of previous trials in the first-line therapy of RAS wt metastatic colorectal cancer (mCRC) suggested a predictive impact of primary tumour side on the efficacy of anti-epidermal growth factor receptor (EGFR) agents. Recently, new head-to-head trials of doublets/bevacizumab versus doublets/anti-EGFR, PARADIGM and CAIRO5 were presented., Patients and Methods: We searched for phase II and III trials comparing doublet chemotherapy plus an anti-EGFR or bevacizumab as the first-line treatment for RAS wt mCRC patients. Overall survival (OS), progression-free survival (PFS), overall response rate (ORR) and radical resection rate result in the overall study populations and, according to the primary side, were pooled together in a two-stage analysis with random effects and fixed effect models. The interaction between sidedness and treatment effect was then analysed., Results: We identified five trials (PEAK, CALGB/SWOG 80405, FIRE-3, PARADIGM and CAIRO5), including 2739 patients, 77% left- and 23% right-sided. Among patients with left-sided mCRC, the use of anti-EGFRs was associated with higher ORR (74% versus 62%, OR = 1.77 [95% confidence interval {CI} 1.39-2.26-0.88], p < 0.0001), longer OS (hazard ratio [HR] = 0.77 [95% CI 0.68-0.88], p < 0.0001) and not significantly longer PFS (HR = 0.92, p = 0.19). Among patients with right-sided mCRC, the use of bevacizumab was associated with longer PFS (HR = 1.36 [95% CI 1.12-1.65], p = 0.002) and not significantly longer OS (HR = 1.17, p = 0.14). A subgroup analysis confirmed a significant interaction effect between the primary tumour side and treatment arm in terms of ORR (p = 0.02), PFS (p = 0.0004) and OS (p = 0.001). No differences in the radical resection rate were found according to treatment and sidedness., Conclusions: Our updated metanalysis corroborates the role of the primary tumour location in the choice of the upfront therapy for RAS wt mCRC patients, leading to strongly recommend anti-EGFRs in left-sided tumours and to prefer bevacizumab in the right-sided., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

We aimed to evaluate the outcome of the disappearance or small remnants of colorectal liver metastases during first-line chemotherapy assessed by hepatobiliary contrast-enhanced and diffusion-weighted MR imaging (DW-MRI). Consecutive patients with at least one disappearing liver metastasis (DLM) or small residual liver metastases (≤10 mm) assessed by hepatobiliary contrast-enhanced and DW-MRI during first-line chemotherapy were included. Liver lesions were categorized into three groups: DLM; residual tiny liver metastases (RTLM) when ≤5 mm; small residual liver metastases (SRLM) when >5mm and ≤10 mm. The outcome of resected liver metastases was assessed in terms of pathological response, whereas lesions left in situ were evaluated in terms of local relapse or progression. Fifty-two outpatients with 265 liver lesions were radiologically reviewed; 185 metastases fulfilled the inclusion criteria: 40 DLM, 82 RTLM and 60 SRLM. We observed a pCR rate of 75% (3/4) in resected DLM and 33% (12/36) of local relapse for DLM left in situ. We observed a risk of relapse of 29% and 57% for RTLM and SRLM left in situ, respectively, and a pCR rate of about 40% overall for resected lesions. DLM assessed via hepatobiliary contrast-enhanced and DW-MRI very probably indicates a complete response. The surgical removal of small remnants of liver metastases should always be advocated whenever technically possible.

Background: Tumor immune cells influence the efficacy of immune-checkpoint inhibitors (ICIs) and many efforts aim at identifying features of tumor immune microenvironment able to predict benefit from ICIs in proficient mismatch repair (pMMR)/microsatellite stable (MSS) metastatic colorectal cancer (mCRC)., Methods: We characterized tumor immune cell infiltrate, by assessing tumor-infiltrating lymphocytes (TILs), Immunoscore, Immunoscore-IC, and programmed death ligand-1 (PD-L1) expression in tumor samples of patients with mCRC enrolled in the AtezoTRIBE study, a phase II randomized trial comparing FOLFOXIRI/bevacizumab/atezolizumab to FOLFOXIRI/bevacizumab, with the aim of evaluating the prognostic and predictive value of these features., Results: Out of 218 patients enrolled, 181 (83%), 77 (35%), 157 (72%) and 162 (74%) specimens were successfully tested for TILs, Immunoscore, Immunoscore-IC and PD-L1 expression, respectively, and 69 (38%), 45 (58%), 50 (32%) and 21 (13%) tumors were classified as TILs-high, Immunoscore-high, Immunoscore-IC-high and PD-L1-high, respectively. A poor agreement was observed between TILs and Immunoscore or Immunoscore-IC (K of Cohen <0.20). In the pMMR population, longer progression-free survival (PFS) was reported for Immunoscore-high and Immunoscore-IC-high groups compared with Immunoscore-low (16.4 vs 12.2 months; HR: 0.55, 95% CI: 0.30 to 0.99; p=0.049) and Immunoscore-IC-low (14.8 vs 11.5 months; HR: 0.55, 95% CI: 0.35 to 0.85; p=0.007), respectively, with a significant interaction effect between treatment arms and Immunoscore-IC (p for interaction: 0.006) and a trend for Immunoscore (p for interaction: 0.13). No PFS difference was shown according to TILs and PD-L1 expression. Consistent results were reported in the overall population., Conclusions: The digital evaluation of tumor immune cell infiltrate by means of Immunoscore-IC or Immunoscore identifies the subset of patients with pMMR mCRC achieving more benefit from the addition of the anti-PD-L1 to the upfront treatment. Immunoscore-IC stands as the most promising predictor of benefit from ICIs., Competing Interests: Competing interests: AC, AK, JF: are Veracyte employees. JG: has patents associated with the immune prognostic and predictive biomarkers, is co-founder of HalioDx, a Veracyte company. SL: has a consulting or an advisory role for Amgen, Merck Serono, Lilly, AstraZeneca, Incyte, Daiichi-Sankyo, BMS, Servier, and MSD; has received research funding from Amgen, Merck Serono, Bayer, Roche, Lilly, AstraZeneca, and BMS; and has received speakers’ fees from Roche, Lilly, BMS, Servier, Merck Serono, Pierre-Fabre, GlaxoSmithKline, and Amgen. FP: honoraria from Amgen, Bayer, Servier, Merck-Serono, Lilly, MSD, Organon, BMS, AstraZeneca, Pierre-Fabre; research grants from Bristol-Myers Squibb, AstraZeneca, Agenus and Incyte. LS: speakers’ and consultant’s fee from MSD, AstraZeneca, Servier, Bayer, Merck, Amgen, Pierre-Fabre. GM: received speakers’ fees—Merck, Amgen. CC: honoraria—Amgen, Bayer, Merck, Roche and Servier. Consulting or advisory role—Amgen, Bayer, MSD, Roche. Speakers’ Bureau—Servier. Research funding—Bayer, Merck, Servier. Travel, accommodations and expenses—Roche and Servier. All other authors have declared no conflicts of interest., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Trop-2 and Nectin-4 are transmembrane proteins overexpressed in many tumours and targets of antibody-drug conjugates (ADC). In metastatic colorectal cancer (mCRC), the role of Trop-2 and Nectin-4 has been poorly investigated., Methods: Tumour samples of patients randomised in the phase III TRIBE2 were assessed for Trop-2 and Nectin-4 expression., Results: Three hundred eighty-six tumours were assessed for Trop-2 expression. 90 (23%), 115 (30%) and 181 (47%) were Trop-2 high, medium and low, respectively. Patients with low Trop-2 tumours achieved longer PFS (12 versus 9.9 months, p = 0.047) and OS (27.3 versus 21.3 months, p = 0.015) than those with high/medium Trop-2 tumours. These findings were confirmed in multivariate analysis (p = 0.022 and p = 0.023, respectively). A greater OS benefit from treatment intensification with FOLFOXIRI/bevacizumab was observed in patients with high/medium Trop-2 tumours (p-for-interaction = 0.041). Two hundred fifty-one tumours were assessed for Nectin-4 expression. Fourteen (5%), 67 (27%) and 170 (68%) were high, medium and low, respectively. No prognostic impact was observed based on Nectin-4 expression and no interaction effect was reported between Nectin-4 expression groups and treatment arm., Conclusions: In mCRC, expression levels of Trop-2 and Nectin-4 are heterogeneous, suggesting a target-driven development of anti-Trop2 and anti-Nectin-4 ADCs. Medium/high Trop-2 expression is associated with worse prognosis and higher benefit from chemotherapy intensification., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)