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Trastuzumab is the only approved targeted therapy in patients with HER2-amplified metastatic gastric cancer (GC). Regrettably, in clinical practice, only a fraction of them achieves long-term benefit from trastuzumab-based upfront strategy. To advance precision oncology, we investigated the therapeutic efficacy of different HER2-targeted strategies, in HER2 “hyper”-amplified (≥ 8 copies) tumors. We undertook a prospective evaluation of HER2 targeting with monoclonal antibodies, tyrosine kinase inhibitors and antibody–drug conjugates, in a selected subgroup of HER2 “hyper”-amplified gastric patient-derived xenografts (PDXs), through the design of ad hoc preclinical trials. Despite the high level of HER2 amplification, trastuzumab elicited a partial response only in 2 out of 8 PDX models. The dual-HER2 blockade with trastuzumab plus either pertuzumab or lapatinib led to complete and durable responses in 5 (62.5%) out of 8 models, including one tumor bearing a concomitant HER2 mutation. In a resistant PDX harboring KRAS amplification, the novel antibody–drug conjugate trastuzumab deruxtecan (but not trastuzumab emtansine) overcame KRAS-mediated resistance. We also identified a HGF-mediated non-cell-autonomous mechanism of secondary resistance to anti-HER2 drugs, responsive to MET co-targeting. These preclinical randomized trials clearly indicate that in HER2-driven gastric tumors, a boosted HER2 therapeutic blockade is required for optimal efficacy, leading to complete and durable responses in most of the cases. Our results suggest that a selected subpopulation of HER2-“hyper”-amplified GC patients could strongly benefit from this strategy. Despite the negative results of clinical trials, the dual blockade should be reconsidered for patients with clearly HER2-addicted cancers.

Liquid biopsy recently gained widespread attention as a noninvasive alternative/complementary technique to tissue biopsy in patients with cancer. As technological advances have improved both feasibility and turnaround time, liquid biopsy has expanded tumor molecular analysis with acknowledgement of both spatial and temporal heterogeneity, overcoming many limitations of traditional tissue biopsy. Because of its diagnostic, prognostic, and predictive value, liquid biopsy has been extensively studied also in metastatic colorectal cancer. Indeed, as personalized medicine establishes its role in cancer treatment, genetic biomarkers unveiling the emergence of early resistance are needed. Among the wide variety of tumor analytes amenable to collection, circulating DNA and circulating tumor cells are the most adopted approaches, and both carry clinical relevance in colorectal cancer. However, few studies focused on comparing feasibility between these two approaches. In this review, we discuss the potential implications of liquid biopsy in metastatic colorectal cancer, assessing the advantages and drawbacks of circulating DNA and circulating tumor cells, and highlighting the most relevant trials for clinical practice.

Purpose: Gastric and gastroesophageal adenocarcinomas represent the third leading cause of cancer mortality worldwide. Despite significant therapeutic improvement, the outcome of patients with advanced gastroesophageal adenocarcinoma is poor. Randomized clinical trials failed to show a significant survival benefit in molecularly unselected patients with advanced gastroesophageal adenocarcinoma treated with anti-EGFR agents. Experimental Design: We performed analyses on four cohorts: IRCC (570 patients), Foundation Medicine, Inc. (9,397 patients), COG (214 patients), and the Fondazione IRCCS Istituto Nazionale dei Tumori (206 patients). Preclinical trials were conducted in patient-derived xenografts (PDX). Results: The analysis of different gastroesophageal adenocarcinoma patient cohorts suggests that EGFR amplification drives aggressive behavior and poor prognosis. We also observed that EGFR inhibitors are active in patients with EGFR copy-number gain and that coamplification of other receptor tyrosine kinases or KRAS is associated with worse response. Preclinical trials performed on EGFR-amplified gastroesophageal adenocarcinoma PDX models revealed that the combination of an EGFR mAb and an EGFR tyrosine kinase inhibitor (TKI) was more effective than each monotherapy and resulted in a deeper and durable response. In a highly EGFR-amplified nonresponding PDX, where resistance to EGFR drugs was due to inactivation of the TSC2 tumor suppressor, cotreatment with the mTOR inhibitor everolimus restored sensitivity to EGFR inhibition. Conclusions: This study underscores EGFR as a potential therapeutic target in gastric cancer and identifies the combination of an EGFR TKI and a mAb as an effective therapeutic approach. Finally, it recognizes mTOR pathway activation as a novel mechanism of primary resistance that can be overcome by the combination of EGFR and mTOR inhibitors. See related commentary by Openshaw et al., p. 2964

Background Thymoma is an uncommon cancer often associated with myasthenia gravis, an autoimmune disorder of the neuromuscular junction characterized by muscular fatigability. In patients with advanced nonmetastatic thymoma, primary chemotherapy may be required to induce tumor shrinkage and to achieve radical resection. Cancer chemotherapy has been anecdotally reported as a trigger factor for worsening of myasthenia gravis in thymic epithelial cancers. The study of uncommon cases of chemotherapy-related myasthenic crisis is warranted to gain knowledge of clinical situations requiring intensive care support in the case of life-threatening respiratory failure. Case presentation We report a case of an 18-year-old Caucasian woman with advanced Masaoka-Koga stage III type B2 thymoma and myasthenia gravis on treatment with pyridostigmine, steroids and intravenous immunoglobulins, who developed a myasthenic crisis 2 hours after initiation of cyclophosphamide/doxorubicin/cisplatin primary chemotherapy. Because of severe acute respiratory failure, emergency tracheal intubation, mechanical ventilation, and temporary (2 hours) discontinuation of chemotherapy were needed. Considering the curative intent of the multimodal therapeutic program, we elected to resume primary chemotherapy administration while the patient remained on mechanical ventilation. After 24 hours, the recovery of adequate respiratory function allowed successful weaning from respiratory support, and no further adverse events occurred. After 3 weeks, upon plasma exchange initiation with amelioration of myasthenic symptoms, a second course of chemotherapy was given, and in week 6, having documented partial tumor remission, the patient underwent radical surgery (R0) and then consolidation radiation therapy with 50.4 Gy in 28 fractions in weeks 15–20. Conclusions This case report, together with the only four available in a review of the literature, highlights that chemotherapy may carry the risk of myasthenic crisis in patients affected by thymoma and myasthenia gravis. To our knowledge, this is the first reported case of chemotherapy continuation on mechanical ventilation in a patient with chemotherapy-induced myasthenic crisis requiring tracheal intubation. The lesson learned from the present case is that, in selected cases of advanced thymoma, the paradoxical worsening of myasthenia gravis during chemotherapy should not be considered an absolute contraindication for the continuation of primary chemotherapy with curative intent.

Background Radiomics is expected to improve the management of metastatic colorectal cancer (CRC). We aimed at evaluating the impact of liver lesion contouring as a source of variability on radiomic features (RFs). Methods After Ethics Committee approval, 70 liver metastases in 17 CRC patients were segmented on contrast-enhanced computed tomography scans by two residents and checked by experienced radiologists. RFs from grey level co-occurrence and run length matrices were extracted from three-dimensional (3D) regions of interest (ROIs) and the largest two-dimensional (2D) ROIs. Inter-reader variability was evaluated with Dice coefficient and Hausdorff distance, whilst its impact on RFs was assessed using mean relative change (MRC) and intraclass correlation coefficient (ICC). For the main lesion of each patient, one reader also segmented a circular ROI on the same image used for the 2D ROI. Results The best inter-reader contouring agreement was observed for 2D ROIs according to both Dice coefficient (median 0.85, interquartile range 0.78–0.89) and Hausdorff distance (0.21 mm, 0.14–0.31 mm). Comparing RF values, MRC ranged 0–752% for 2D and 0–1567% for 3D. For 24/32 RFs (75%), MRC was lower for 2D than for 3D. An ICC > 0.90 was observed for more RFs for 2D (53%) than for 3D (34%). Only 2/32 RFs (6%) showed a variability between 2D and circular ROIs higher than inter-reader variability. Conclusions A 2D contouring approach may help mitigate overall inter-reader variability, albeit stable RFs can be extracted from both 3D and 2D segmentations of CRC liver metastases.

Background Colorectal cancer (CRC) represents a major cause of cancer deaths worldwide. Although significant progress has been made by molecular and immune therapeutic approaches, prognosis of advanced stage disease is still dismal. Alterations in the DNA damage response (DDR) pathways are emerging as novel targets for treatment across different cancer types. However, even though preclinical studies have shown the potential exploitation of DDR alterations in CRC, systematic and comprehensive testing is lagging and clinical development is based on analogies with other solid tumors according to a tissue-agnostic paradigm. Recently, functional evidence from patient-derived xenografts and organoids have suggested that maintenance with PARP inhibitors might represent a therapeutic opportunity in CRC patients previously responsive to platinum-based treatment. Design and Results In this review, we highlight the most promising preclinical data and systematically summarize published clinical trials in which DDR inhibitors have been used for CRC and provide evidence that disappointing results have been mainly due to a lack of clinical and molecular selection. Conclusions Future preclinical and translational research will help in better understanding the role of DDR alterations in CRC and pave the way to novel strategies that might have a transformative impact on treatment by identifying new therapeutic options including tailored use of standard chemotherapy.

BackgroundHER2 amplification is detected in 3% of patients with colorectal cancer (CRC), making tumors in the metastatic setting vulnerable to double pharmacological HER2 blockade. Preclinical findings show that it also might impair response to anti-epidermal growth factor receptor (EGFR) treatment.Subjects and MethodsPatients with KRAS exon 2 wild-type metastatic CRC underwent molecular screening of HER2 positivity by HERACLES criteria (immunohistochemistry 3+ or 2+ in ≥50% of cells, confirmed by fluorescence in situ hybridization). A sample of consecutive HER2-negative patients was selected as control. A regression modeling strategy was applied to identify predictors explaining the bulk of HER2 positivity and the association with response to previous anti-EGFR treatment.ResultsFrom August 2012 to April 2018, a total of 100 HER2-positive metastatic CRC tumors were detected out of 1,485 KRAS exon 2 wild-type screened patients (6.7%). HER2-positive patients show more frequently lung metastases (odds ratio [OR], 2.04; 95% confidence interval [CI], 1.15–3.61; p = .014) and higher tumor burden (OR, 1.48; 95% CI, 1.10–2.01; p = .011), and tumors were more likely to be left sided (OR, 0.50; 95% CI, 0.22–1.11; p = .088). HER2-positive patients who received treatment with anti-EGFR agents (n = 79) showed poorer outcome (objective response rate, 31.2% vs. 46.9%, p = .031; progression-free survival, 5.7 months vs. 7 months, p = .087).ConclusionTesting for HER2 should be offered to all patients with metastatic CRC because the occurrence of this biomarker is unlikely to be predicted based on main clinicopathological features. Patients with HER2-amplified metastatic CRC are less likely to respond to anti-EGFR therapy.Implications for PracticePatients with HER2-amplified/overexpressed metastatic colorectal cancer (mCRC) harbor a driver actionable molecular alteration that has been shown in preclinical models to hamper efficacy of the anti-epidermal growth factor receptor (EGFR) targeted therapies. The present study confirmed that this molecular feature was associated with worse objective tumor response and shorter progression-free survival in response to previous anti-EGFR therapies. Moreover, it was found that the occurrence of this biomarker is unlikely to be predicted based on main clinicopathological features. Therefore, HER2 status assessment should be included in the molecular diagnostic workup of all mCRC for speedy referral to clinical trials encompassing HER2-targeted double blockade independently of previous anti-EGFR treatment.

An increasing number of patients with metastatic colorectal cancer (mCRC) are able to receive 3 or more lines of therapy. Treatments in this setting can include regorafenib (an oral multikinase inhibitor), trifluridine/tipiracil hydrochloride (TAS-102), antibodies that target epidermal growth factor receptor for patients with RAS wild-type tumors (if no prior exposure), and, where approved, anti-programmed cell death protein 1 inhibitors for patients with microsatellite instability-high mCRC. Although guidelines describe the available treatment options, few insights are provided to guide selection and sequencing. In this article, we share expert opinion from diverse geographic regions, to offer guidance for best practice when selecting and managing third-line treatment for mCRC. Various factors, including performance status, age, and tumor sidedness, can be used to guide treatment selection. Biomarkers, such as RAS, BRAF, and microsatellite instability, can be useful for treatment stratification. Management of adverse events, to maintain quality of life, is a key consideration and is crucial to best practice in this setting. Common toxicities associated with third-line treatments are hand-foot skin reaction, fatigue, diarrhea, and cytopenias. Patients who receive third-line and later-line treatments should be monitored for these events, especially during the first 2 cycles. Dose modifications can also be used to manage toxicities and to minimize the effect on quality of life, while maximizing treatment benefit. Clinical trials of emerging agents, new treatment combinations, and novel therapies continue the efforts to improve outcomes for patients with mCRC. Sharing expert opinions on best practice for treatment selection and management can ultimately improve outcomes for patients with mCRC.

The term liquid biopsy (LB) refers to the use of various biological fluids as a surrogate for neoplastic tissue to achieve information for diagnostic, prognostic and predictive purposes. In the current clinical practice, LB is used for the identification of driver mutations in circulating tumor DNA derived from both tumor tissue and circulating neoplastic cells. As suggested by a growing body of evidence, however, there are several clinical settings where biological samples other than tissue could be used in the routine practice to identify potentially predictive biomarkers of either response or resistance to targeted treatments. New applications are emerging as useful clinical tools, and other blood derivatives, such as circulating tumor cells, circulating tumor RNA, microRNAs, platelets, extracellular vesicles, as well as other biofluids such as urine and cerebrospinal fluid, may be adopted in the near future. Despite the evident advantages compared with tissue biopsy, LB still presents some limitations due to both biological and technological issues. In this context, the absence of harmonized procedures corresponds to an unmet clinical need, ultimately affecting the rapid implementation of LB in clinical practice. In this position paper, based on experts’ opinions, the AIOM–SIAPEC-IAP–SIBIOC–SIF Italian Scientific Societies critically discuss the most relevant technical issues of LB, the current and emerging evidences, with the aim to optimizing the applications of LB in the clinical setting., Highlights • In the current clinical practice LB is used for the identification of driver mutations in circulating tumor DNA (ctDNA). • New applications in tumors other than non-small-cell lung cancer (NSCLC) are emerging as useful clinical tools. • Other blood derivatives, together with other biofluids, are an active field of research and may be adopted in the near future. • Despite the evident advantages, liquid biopsy still presents limitations due to both biological and technological issues. • Standardization of the procedures needs to be addressed to ensure widespread implementation in clinical practice.

Simple Summary Small cell lung cancer (SCLC) is an aggressive tumor, which can occur either de novo or from the histologic transformation of non-small cell lung cancer. Liquid biopsy has demonstrated its capability to detect, characterize and monitor different cancers. The aim of this systematic review was to assess the potential added value of liquid biopsy, in terms of circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs), in the management of SCLC, either de novo or transformed. We found ctDNA analysis as the most valuable and feasible technology to be integrated into clinical for disease monitoring (response, relapse, transformation) or for genomic profiling of SCLC, with a potential use also for prognostic stratification. CTCs hold a strong prognostic significance, as confirmed by our meta-analysis (even if potentially biased), but the heterogeneity of available data, the lack of agreed cut-offs, and the less affordable technology make CTCs more difficult to be integrated into present clinical practice. Abstract Background: The potential added value of liquid biopsy (LB) is not well determined in the case of small cell lung cancer (SCLC), an aggressive tumor that can occur either de novo or from the histologic transformation of non-small cell lung cancer (NSCLC). Methods: A systematic review of studies adopting LB in patients with SCLC have been performed to assess the clinical utility of circulating tumor DNA (ctDNA) or circulating tumor cells (CTCs). Results: After a screening of 728 records, 62 studies (32 evaluating CTCs, 27 ctDNA, and 3 both) met predetermined eligibility criteria. Only four studies evaluated LB in the diagnostic setting for SCLC, while its prognostic significance was evaluated in 38 studies and prominently supported by both ctDNA and CTCs. A meta-analysis of 11 studies as for CTCs enumeration showed an HR for overall survival of 2.63 (1.71–4.05), with a potential publication bias. The feasibility of tumor genomic profiling and the predictive role of LB in terms of response/resistance to chemotherapy was assessed in 11 and 24 studies, respectively, with greater consistency for those regarding ctDNA. Intriguingly, several case reports suggest that LB can indirectly capture the transition to SCLC in NSCLC treated with EGFR tyrosine kinase inhibitors. Conclusions: While dedicated trials are needed, LB holds potential clinical roles in both de novo and transformed SCLC. CtDNA analysis appears the most valuable and practicable tool for both disease monitoring and genomic profiling.

Summary Background HER2 amplification has been identified in 2–3% of patients with colorectal cancer, although there are currently no approved HER2-targeted therapies for colorectal cancer. We aimed to study the antitumour activity and safety of trastuzumab deruxtecan (an antibody–drug conjugate of humanised anti-HER2 antibody with topoisomerase I inhibitor payloads) in patients with HER2-expressing metastatic colorectal cancer. Methods DESTINY-CRC01 is an open-label, phase 2 study that recruited patients from 25 clinics and hospitals in Italy, Japan, Spain, the UK, and the USA. Eligible patients had centrally confirmed HER2-expressing metastatic colorectal cancer that had progressed on two or more previous regimens (HER2-targeted therapies other than trastuzumab deruxtecan permitted), were aged 18 years or older (≥20 years in Japan), had an Eastern Cooperative Oncology Group score of 0 or 1, and had RAS and BRAFV600E wild-type tumours. Patients were enrolled into one of three cohorts by HER2 expression level: cohort A (HER2-positive, immunohistochemistry [IHC] 3+ or IHC2+ and in-situ hybridisation [ISH]-positive), cohort B (IHC2+ and ISH-negative), or cohort C (IHC1+). Patients received 6·4 mg/kg trastuzumab deruxtecan intravenously every 3 weeks until disease progression, unacceptable adverse events, withdrawal of consent, or death. The primary endpoint was confirmed objective response rate in cohort A by independent central review which was assessed in the full analysis set and safety was assessed in the safety analysis set. Both the full analysis set and the safety analysis set included all patients who received one or more doses of trastuzumab deruxtecan. This ongoing trial is registered with ClinicalTrials.gov , number NCT03384940 . Findings Between Feb 23, 2018, and July 3, 2019, 78 patients were enrolled in the study (53 in cohort A, seven in cohort B, and 18 in cohort C), all of whom received at least one dose of study drug. For the 53 (68%) patients with HER2-positive tumours (cohort A), a confirmed objective response was reported in 24 (45·3%, 95% CI 31·6–59·6) patients after a median follow-up of 27·1 weeks (IQR 19·3–40·1). Grade 3 or worse treatment-emergent adverse events that occurred in at least 10% of all participants were decreased neutrophil count (17 [22%] of 78) and anaemia (11 [14%]). Five patients (6%) had adjudicated interstitial lung disease or pneumonitis (two grade 2; one grade 3; two grade 5, the only treatment-related deaths). Interpretation Trastuzumab deruxtecan showed promising and durable activity in HER2-positive metastatic colorectal cancer refractory to standard treatment, with a safety profile consistent with that reported in previous trastuzumab deruxtecan trials. Interstitial lung disease and pneumonitis are important risks requiring careful monitoring and prompt intervention. Funding Daiichi Sankyo.

The definition of oligometastatic colorectal cancer (CRC) identifies a peculiar subpopulation of patients characterized by a limited metastatic spread of disease.1 Oligometastatic disease is defined as the involvement of up to two or occasionally three sites with five or sometimes more metastases that for their anatomic localization is amenable to local ablative therapies, thus rendering the patient free of disease.1-3 Thus, this subgroup is wide and has a significant cohort of patients with CRC. Among patients with oligometastatic CRC, those with liver-limited disease represent a more refined subset and should always be discussed in multidisciplinary teams since they appear to more likely benefit from multimodal approaches with curative intent.2,4-6 A perioperative systemic treatment integrated with surgical liver metastasectomy should be regarded as the best multimodal approach.2,7 However, the best drug regimen to be adopted for this subset of patients with CRC is still debatable and should be tailored case-by-case. Considering left-sided microsatellite stable, RAS and BRAF wild-type CRC, doublet cytotoxic regimens (FOLFIRI or FOLFOX) plus an anti-epidermal growth factor receptor (EGFR) drug can represent the best option on the basis of significant response rate (RR).8-10 However, triplet cytotoxic regimens FOLFOXIRI plus bevacizumab or anti-EGFR drug demonstrate an impressive RR up to 87%, which are increasingly regarded as potential novel neoadjuvant standard strategies.5,11 However, severe treatment-related toxicities have been reported in up to 80% of patients.11,12 Hence, both doublet or triplet combinations and anti-EGFR or antivascular endothelial growth factor are feasible options in this subset of patients. The generation of preclinical models such as patient-derived organoids (PDOs), recapitulating patient tumor histology and genetics, is emerging as a tool to predict treatment efficacy in oncology.13,14 Although genomics has already improved treatment choice in patients with CRC, especially for those carrying RAS/BRAF wild type, coclinical trials are becoming more and more important to directly test different treatment options in patient-derived tumors.15 Here, we present a proof-of-concept case report about the potential role of drug sensitivity testing in PDOs in the clinical decision making of oligometastatic CRC.

Simple Summary The BRAFV600E mutation accounts for 8–10% of metastatic colorectal cancer (mCRC) patients and it is an established prognostic factor. Median overall survival of this subset of patients is indeed so poor that it is similar to first line PFS of patients without this molecular alteration. An exception is represented by patients displaying concomitant MSI-H status who can benefit from immunotherapy with checkpoint inhibitors (CPIs). Recently, a targeted therapy with the combination of encorafenib and cetuximab provided for the first time a survival gain and thus translation in the clinic, even though acquired resistance limits the possibility of more than an incremental benefit. Many studies exploiting other different strategies are ongoing. In this review we present current therapies specifically headed to BRAFV600E mutant mCRC and systematically review ongoing clinical trials identifying different approaches under investigations: targeting MAPK pathway (monotherapy or combinations), targeting MAPK pathway combined with cytotoxic agents, intensive cytotoxic regimen combinations, targeted agents combined with CPIs, oxidative stress induction, and cytotoxic agents combined with antiangiogenic drugs and CPIs. Abstract The BRAFV600E mutation is found in 8–10% of metastatic colorectal cancer (mCRC) patients and it is recognized as a poor prognostic factor with a median overall survival inferior to 20 months. At present, besides immune checkpoint inhibitors (CPIs) for those tumors with concomitant MSI-H status, recommended treatment options include cytotoxic chemotherapy + anti-VEGF in the first line setting, and a combination of EGFR and a BRAF inhibitor (cetuximab plus encorafenib) in second line. However, even with the latter targeted approach, acquired resistance limits the possibility of more than an incremental benefit and survival is still dismal. In this review, we discuss current treatment options for this subset of patients and perform a systematic review of ongoing clinical trials. Overall, we identified six emerging strategies: targeting MAPK pathway (monotherapy or combinations), targeting MAPK pathway combined with cytotoxic agents, intensive cytotoxic regimen combinations, targeted agents combined with CPIs, oxidative stress induction, and cytotoxic agents combined with antiangiogenic drugs and CPIs. In the future, the integration of new therapeutic strategies targeting key players in the BRAFV600E oncogenic pathways with current treatment approach based on cytotoxic chemotherapy and surgery is likely to redefine the treatment landscape of these CRC patients.

Takmaz et al. enrolled 39 women where the fundal pressure maneuver was applied and 47 women who delivered spontaneously without the maneuver. The authors found that the Kristeller maneuver is associated with a higher risk of levator ani muscle defects, and in particular a significantly higher anteroposterior hiatal diameter during rest, Valsalva maneuver, and pelvic floor muscle contraction. In 2012, we published an article that evaluated the effects of uterine fundal pressure on pelvic floor function 3 months after vaginal delivery. We enrolled 522 primiparous women divided into two groups: 297 women received the Kristeller maneuver with different indications (fetal distress, failure to progress, mother exhaustion), and 225 women constituted the control group. We did not find significant differences in terms of urinary or anal incontinence, genital prolapse, and pelvic floor strength, whereas mediolateral episiotomies, dyspareunia, and perineal pain were significantly higher in the Kristeller group. These data seem to confirm the role of episiotomies in developing perineal pain in the puerperium.

Purpose: The routine use of liquid biopsy is not recommended for the choice of initial treatment for patients with metastatic colorectal cancer (mCRC). Experimental Design: We included patients with left-sided, RAS/BRAF wild-type, HER2-negative, and microsatellite stable mCRC, treated with upfront panitumumab/FOLFOX-4 in the Valentino study. We performed amplicon-based genomic profiling of 14 genes in baseline plasma samples and compared these data with tumor tissue ultra-deep sequencing results. Specific gene mutations in circulating tumor DNA (ctDNA) and their clonality were associated with progression-free survival (PFS), overall survival (OS), and radiological dynamics. Results: Ten and 15 of 120 patients had a mutation of RAS and PIK3CA in ctDNA, with a positive concordance with tissue deep sequencing of only 31.3% and 47.1%, respectively. Presence of RAS or PIK3CA mutations in baseline ctDNA was associated with worse median PFS [8 vs. 12.8 months; HR, 2.49; 95% confidence interval (CI), 1.28–4.81; P = 0.007 and 8.5 vs. 12.9 months; HR, 2.86; 95% CI, 1.63–5.04; P < 0.001] and median OS (17.1 vs. 36.5 months; HR, 2.26; 95% CI, 1.03–4.96; P = 0.042 and 21.1 vs. 38.9 months; HR, 2.18; 95% CI, 1.16–4.07; P = 0.015). RAS mutations in ctDNA were associated with worse RECIST response, early tumor shrinkage, and depth of response, while PIK3CA mutations were not. Patients with higher levels of RAS/PIK3CA variant allele fraction (VAF) in ctDNA had the worst outcomes (VAF ≥ 5% vs. all wild-type: median PFS, 7.7 vs. 13.1 months; HR, 4.02; 95% CI, 2.03–7.95; P < 0.001 and median OS, 18.8 vs. 38.9 months; HR, 4.07; 95% CI, 2.04–8.12; P < 0.001). Conclusions: Baseline ctDNA profiling may add value to tumor tissue testing to refine the molecular hyperselection of patients with mCRC for upfront anti-EGFR–based strategies.

open 25 no Background HER2 is a therapeutic target for metastatic colorectal cancer (mCRC), as demonstrated in the pivotal HERACLES-A (HER2 Amplification for Colo-rectaL cancer Enhanced Stratification) trial with trastuzumab and lapatinib. The aim of HERACLES-B trial is to assess the efficacy of the combination of pertuzumab and trastuzumab-emtansine (T-DM1) in this setting. Methods HERACLES-B was a single-arm, phase II trial, in patients with histologically confirmed RAS/BRAF wild-type and HER2+ mCRC refractory to standard treatments. HER2 positivity was assessed by immunohistochemistry and in situ hybridisation according to HERACLES criteria. Patients were treated with pertuzumab (840 mg intravenous load followed by 420 mg intravenous every 3 weeks) and T-DM1 (3.6 mg/kg every 3 weeks) until disease progression or toxicity. Primary and secondary end points were objective response rate (ORR) and progression-free survival (PFS). With a Fleming/Hern design (H0=ORR 10%; α=0.05; power=0.85), 7/30 responses were required to demonstrate an ORR ≥30% (H1). Results Thirty-one patients, 48% with ≥4 lines of previous therapies, were treated and evaluable. ORR was 9.7% (95% CI: 0 to 28) and stable disease (SD) 67.7% (95% CI: 50 to 85). OR/SD ≥4 months was associated with higher HER2 immunohistochemistry score (3+ vs 2+) (p = 0.03). Median PFS was 4.1 months (95% CI: 3.6 to 5.9). Drug-related grade (G) 3 adverse events were observed in two patients (thrombocytopaenia); G≤2 AE in 84% of cycles (n = 296), mainly nausea and fatigue. Conclusions HERACLES-B trial did not reach its primary end point of ORR; however, based on high disease control, PFS similar to other anti-HER2 regimens, and low toxicity, pertuzumab in combination with T-DM1 can be considered for HER2+mCRC as a potential therapeutic resource. open Sartore-Bianchi A.; Lonardi S.; Martino C.; Fenocchio E.; Tosi F.; Ghezzi S.; Leone F.; Bergamo F.; Zagonel V.; Ciardiello F.; Ardizzoni A.; Amatu A.; Bencardino K.; Valtorta E.; Grassi E.; Torri V.; Bonoldi E.; Sapino A.; Vanzulli A.; Regge D.; Cappello G.; Bardelli A.; Trusolino L.; Marsoni S.; Siena S. Sartore-Bianchi A.; Lonardi S.; Martino C.; Fenocchio E.; Tosi F.; Ghezzi S.; Leone F.; Bergamo F.; Zagonel V.; Ciardiello F.; Ardizzoni A.; Amatu A.; Bencardino K.; Valtorta E.; Grassi E.; Torri V.; Bonoldi E.; Sapino A.; Vanzulli A.; Regge D.; Cappello G.; Bardelli A.; Trusolino L.; Marsoni S.; Siena S.

Background: Carcinomas of unknown primary (CUP) account for 3-5% of all malignancy and, despite a reduction in incidence, the overall survival has not improved over the last decade. Chemotherapy regimens have not provided encouraging results. New diagnostic technologies, such as next generation sequencing (NGS), could represent a chance to identify potentially targetable genomic alterations in order to personalize treatment of CUP and provide insights into tumor biology. Methods: A systematic review of studies of patients with CUP, whose tumor specimen was evaluated through a NGS panel, has been performed on June 10th, 2019 according to PRISMA criteria from PubMed, ASCO meeting library and Clinicaltrial.gov. We have identified potentially targetable alterations for which approved/off-label/in clinical trials drugs are available. Moreover, we have included case reports about CUP patients treated with targeted therapies driven by NGS results in order to explore the clinical role of NGS in this setting. Results: We have evaluated 15 publications of which eleven studies (9 full-text articles and 2 abstracts) have analyzed the genomic profiling of CUPs through NGS technology, with different platforms and with different patients cohorts, ranging from 16 to 1,806 patients. Among all these studies, 85% of patients demonstrated at least one molecular alteration, the most frequent involving TP53 (41.88%), KRAS (18.81%), CDKN2A (8.8%), and PIK3CA (9.3%). A mean of 47.3% of patients harbored a potentially targetable alteration for which approved/off-label/in clinical trials drugs were available. Furthermore, we have identified 4 case reports in order to evaluate the clinical relevance of a specific targeted therapy identified through NGS. Conclusions: NGS may represent a tool to improve diagnosis and treatment of CUP by identifying therapeutically actionable alterations and providing insights into tumor biology.

Introduction: Gene fusions are strong driver alterations in various cancers, increasingly diagnosed with multiple testing techniques. ROS1 fusions can be found in 1-2% of non-small cell lung cancer...

Entrectinib, a potent oral inhibitor of the tyrosine kinases TRKA/B/C, ROS1, and ALK, was evaluated in two phase I studies in patients with advanced or metastatic solid tumors, including patients with active central nervous system (CNS) disease. Here, we summarize the overall safety and report the antitumor activity of entrectinib in a cohort of patients with tumors harboring NTRK1/2/3, ROS1, or ALK gene fusions, naïve to prior TKI treatment targeting the specific gene, and who were treated at doses that achieved therapeutic exposures consistent with the recommended phase II dose. Entrectinib was well tolerated, with predominantly Grades 1/2 adverse events that were reversible with dose modification. Responses were observed in non–small cell lung cancer, colorectal cancer, mammary analogue secretory carcinoma, melanoma, and renal cell carcinoma, as early as 4 weeks after starting treatment and lasting as long as >2 years. Notably, a complete CNS response was achieved in a patient with SQSTM1–NTRK1-rearranged lung cancer.Significance: Gene fusions of NTRK1/2/3, ROS1, and ALK (encoding TRKA/B/C, ROS1, and ALK, respectively) lead to constitutive activation of oncogenic pathways. Entrectinib was shown to be well tolerated and active against those gene fusions in solid tumors, including in patients with primary or secondary CNS disease. Cancer Discov; 7(4); 400–9. ©2017 AACR.This article is highlighted in the In This Issue feature, p. 339

Background Oxaliplatin represents a main component of cytotoxic treatment regimens in colorectal cancer (CRC). Given its efficacy, oxaliplatin is frequently re-administered in the context of the continuum of care in metastatic CRC (mCRC). However, efficacy and tolerability of this therapeutic strategy has not been comprehensively assessed. Methods We performed a systematic review of the literature on September 19th 2020, according to PRISMA criteria 2009. The research was performed on PubMed, ASCO Meeting Library, ESMO library and ClinicalTrials.gov for citations or ongoing trials. Results 64 records were retrieved and 13 included in the systematic review: 8 full-text articles, 4 abstracts and 1 ongoing clinical trial. According to readministration timing, studies were classified as rechallenge/reintroduction (n = 8) or stop & go/intermittent therapeutic strategies (n = 4). The studies presented wide heterogeneity in terms of efficacy (Response Rate 6–31%; Disease Control Rate 39–79%; median Progression-Free Survival 3.1–7 months). Those patients who received retreatment after prior adjuvant oxaliplatin or exploiting a stop-&-go strategy appeared to achieve better outcomes. However, no formal comparisons on treatment outcomes were feasible. The most frequent grade 3 or higher adverse events were hematologic toxicities (5–27%), peripheral neuropathy (5–14%) and hypersensitivity reactions (5–20%). Conclusions Retreatment with oxaliplatin for mCRC is practiced based on scarce and heterogeneous data indicating efficacy and manageable toxicity. The best strategy to exploit this approach remains to be defined, and the most promising research avenue to improve therapeutic index of oxaliplatin is represented by selection of responder patients whose tumors harbor molecular defects in the DNA damage repair pathway.

Purpose: Defects in the homologous recombination (HR) repair pathway are of clinical interest due to sensitivity of HR-deficient cells to PARP inhibitors. We were interested in defining PARP vulnerability in patients with metastatic colorectal cancer (mCRC) carrying KRAS and BRAF mutations who display poor prognosis, have limited therapeutic options, and represent an unmet clinical need. Experimental Design: We tested colorectal cancer cell lines, patient-derived organoids (PDO), and patient-derived xenografts (PDX) enriched for KRAS and BRAF mutations for sensitivity to the PARP inhibitor olaparib, and the chemotherapeutic agents oxaliplatin and 5-fluorouracil (5-FU). Genomic profiles and DNA repair proficiency of colorectal cancer models were compared with pharmacologic response. Results: Thirteen of 99 (around 13%) colorectal cancer cell lines were highly sensitive to clinically active concentrations of olaparib and displayed functional deficiency in HR. Response to PARP blockade was positively correlated with sensitivity to oxaliplatin in colorectal cancer cell lines as well as patient-derived organoids. Treatment of PDXs with olaparib impaired tumor growth and maintenance therapy with PARP blockade after initial oxaliplatin response delayed disease progression in mice. Conclusions: These results indicate that a colorectal cancer subset characterized by poor prognosis and limited therapeutic options is vulnerable to PARP inhibition and suggest that PDO-based drug-screening assays can be used to identify patients with colorectal cancer likely to benefit from olaparib. As patients with mCRC almost invariably receive therapies based on oxaliplatin, “maintenance” treatment with PARP inhibitors warrants further clinical investigation.

Background Immune-inflammatory biomarkers (IIBs) showed a prognostic relevance in patients with metastatic CRC (mCRC). We aimed at evaluating the prognostic power of a new comprehensive biomarker, the Pan-Immune-Inflammation Value (PIV), in patients with mCRC receiving first-line therapy. Methods In the present pooled-analysis, we included patients enrolled in the Valentino and TRIBE trials. PIV was calculated as: (neutrophil count × platelet count × monocyte count)/lymphocyte count. A cut-off was determined using the maximally selected rank statistics method. Generalised boosted regression (GBR), the Kaplan–Meier method and Cox hazards regression models were used for survival analyses. Results A total of 438 patients were included. Overall, 208 patients (47%) had a low-baseline PIV and 230 (53%) had a high-baseline PIV. Patients with high PIV experienced a worse PFS (HR, 1.66; 95% CI, 1.36–2.03, P P Conclusion PIV is a strong predictor of survival outcomes with better performance than other well-known IIBs in patients with mCRC treated with first-line therapy. PIV should be prospectively validated to better stratify mCRC patients undergoing first-line therapy.

Background Quality of life (QoL) patient-reported outcomes (PROs) data from pivotal first-line trials in metastatic colorectal cancer (mCRC) are poor. The Valentino study showed that de-escalation to single-agent panitumumab after 4-month induction with panitumumab-FOLFOX is inferior to panitumumab-5-FU/LV in patients with RAS wild-type mCRC, although slightly reducing toxicity. We report QoL, a secondary end-point. Methods PROs were assessed by European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire – Core 30 (QLQ-C30), EORTC QLQ-CR29, EuroQol EQ-5D questionnaires, at baseline and every 8 weeks until disease progression. First two evaluations correspond to induction treatment (identical in both arms), while subsequent to maintenance. To describe QoL changes over time, mean changes from baseline at each time point were calculated in overall population. To compare maintenance between two arms, mean changes and proportion of improved/stable/worse patients versus baseline were compared for each item. Results In arm A/B, 91.5%/92.0% of enrolled patients completed questionnaires at baseline. No significant differences in the two arms were reported in compliance, baseline scores and mean changes versus baseline for the three questionnaires during maintenance (24/32/40 weeks). Overall, mean changes versus baseline showed an early deterioration during induction with partial recovering during maintenance for global QoL, functional scales and several symptoms/items of QLQ-C30 (fatigue, nausea/vomiting, appetite loss, diarrhoea) and QLQ-CR29 (body image, dry mouth, hair loss, taste, faecal incontinence, sore skin), and EQ-5D Visual Analogue Scale (VAS) score. Conclusion In patients with RAS wild-type mCRC, induction with oxaliplatin-containing chemotherapy plus anti-EGFRs induces a transient significant QoL deterioration. After induction phase, treatment deintensification determines an overall recovery of health-related QoL, besides the expected prevention of oxaliplatin-related neurotoxicity.

The aim of this study was to develop and validate a machine learning algorithm to predict response of individual HER2-amplified colorectal cancer liver metastases (lmCRC) undergoing dual HER2-targeted therapy. Twenty-four radiomics features were extracted following 3D manual segmentation of 141 lmCRC on pre-treatment portal CT scans of a cohort including 38 HER2-amplified patients; feature selection was then performed using genetic algorithms. lmCRC were classified as non-responders (R-), if their largest diameter increased more than 10% at a CT scan performed following 3 months of treatment, responders (R+) otherwise. Sensitivity, specificity, negative (NPV) and positive (PPV) predictive values in correctly classifying individual lesion and overall patient response were assessed on a training dataset and then validated on a second dataset using a Gaussian naive bayesian classifier. Per-lesion sensitivity, specificity, NPV and PPV were 89%, 85%, 93%, 78% and 90%, 42%, 73%, 71% respectively in the testing and validation datasets. Per-patient sensitivity and specificity were 92% and 86%. Heterogeneous response was observed in 9 of 38 patients (24%). Five of the 9 patients were carriers of non-responder lesions correctly classified as such by our radiomics signature, including 4 of 7 harboring only one non-responder lesion. The developed method has been proven effective in predicting behavior of individual metastases to targeted treatment in a cohort of HER2 amplified patients. The model accurately detects responder lesions and identifies non-responder lesions in patients with heterogeneous response, potentially paving the way to multimodal treatment in selected patients. Further validation will be needed to confirm our findings. This article is protected by copyright. All rights reserved.

This secondary analysis of data from the HERACLES-A clinical trial examines long-term outcomes in 32 patients with colorectal cancer treated with trastuzumab and lapatinib.

Purpose: To determine whether second-line therapy with capecitabine and temozolomide was superior to irinotecan, leucovorin, and fluorouracil (FOLFIRI) in patients with RAS-mutated, methyl-guanine methyltransferase (MGMT)-methylated metastatic colorectal cancer (mCRC). Patients and Methods: In this randomized, phase II trial, we enrolled patients with RAS-mutated, MGMT-methylated mCRC after failure of oxaliplatin-based regimen. Patients with centrally confirmed MGMT methylation were stratified by first-line progression-free survival (PFS) and prior bevacizumab and randomized to either capecitabine plus temozolomide (arm A, CAPTEM) or FOLFIRI (arm B). The primary endpoint was PFS analyzed on intention-to-treat basis, with 90% power and one-sided significance level of 0.05 to detect an increase of median time from 2 months in arm B to 4 months in arm A. Results: Between November 2014 and May 2019, 86 patients were randomly assigned to arm A (n = 43) or arm B (n = 43). After a median follow-up of 30.5 months (interquartile range, 12.2–36.3), 79 disease progression or death events occurred. Superiority of arm A was not demonstrated (one-sided P = 0.223). Progression-free survival and overall survival were 3.5 (2.0–5.0) and 9.5 (8.2–25.8) in arm A versus 3.5 (2.3–6.1) and 10.6 (8.5–20.8) in arm B [HR = 1.19 (0.82–1.72) and HR = 0.97 (0.58–1.61)], respectively. Grade ≥3 treatment-related adverse events had higher incidence in arm B versus A (47.6% vs 16.3%), and quality of life was significantly worse in arm B. Patients with positive MGMT expression by IHC did not benefit from CAPTEM. Conclusions: Temozolomide-based therapy warrants further investigation in molecularly hyperselected subgroups.

Palbociclib, ribociclib, and abemaciclib belong to the third generation of cyclin-dependent kinases inhibitors (CDKis), an established therapeutic class for advanced and metastatic breast cancer. Interindividual variability in the therapeutic response of CDKis has been reported and some individuals may experience increased and unexpected toxicity. This narrative review aims at identifying the factors potentially concurring at this variability for driving the most appropriate and tailored use of CDKis in the clinic. Specifically, concomitant medications, pharmacogenetic profile, and pathophysiological conditions could influence absorption, distribution, metabolism, and elimination pharmacokinetics. A personalized therapeutic approach taking into consideration all factors potentially contributing to an altered pharmacokinetic/pharmacodynamic profile could better drive safe and effective clinical use.

Background The management of locally advanced rectal cancer (RC) is an evolving clinical field where the multidisciplinary approach can reach its best, and liquid biopsy for obtaining tumor-derived component such as circulating tumor DNA (ctDNA) might provide complementary informations. Methods A systematic review of studies available in literature of liquid biopsy in non-metastatic RC has been performed according to PRISMA criteria to assess the role of ctDNA as a diagnostic, predictive and prognostic biomarker in this setting. Results Twenty-five publications have been retrieved, of which 8 full-text articles, 7 abstracts and 10 clinical trials. Results have been categorized into three groups: diagnostic, predictive and prognostic. Few but promising data are available about the use of liquid biopsy for early diagnosis of RC, with the main limitation of sensitivity due to low concentrations of ctDNA in this setting. In terms of prediction of response to chemoradiation, still inconclusive data are available about the utility of a pre-treatment liquid biopsy, whereas some studies report a positive correlation with a dynamic (pre/post-treatment) monitoring. The presence of minimal residual disease by ctDNA was consistently associated with worse prognosis across studies. Conclusions The use of liquid biopsy for monitoring response to chemoradiation and assess the risk of disease recurrence are the most advanced potential applications for liquid biopsy in RC, with implications also in the context of non-operative management strategies.

The approval of targeted therapies for metastatic colorectal cancer (mCRC) has led to important improvements in patient outcomes. However, it is still necessary to increase individualisation of treatments based on tumour genetic profiles to optimise efficacy, while minimising toxicity. As such, there is currently great focus on the discovery and validation of further biomarkers in mCRC, with many new potential prognostic and predictive markers being identified alongside developments in patient molecular profiling technologies. Here, we review data for validated and emerging biomarkers impacting treatment strategies in mCRC. We completed a structured literature search of the PubMed database to identify relevant publications, limiting for English-language publications published between 1 January 2014 and 11 July 2018. In addition, we performed a manual search of the key general oncology and CRC-focused congresses to identify abstracts reporting emerging mCRC biomarker data, and of ClinicalTrials.gov to identify ongoing clinical trials investigating emerging biomarkers in mCRC and/or molecular-guided clinical trials. There is solid evidence supporting the use of BRAF status as a prognostic biomarker and DYPD, UGT1A1, RAS, and microsatellite instability as predictive biomarkers in mCRC. There are a number of emerging biomarkers that may prove to be clinically relevant in the future to have prognostic (HPP1 methylation), predictive (HER3, microRNAs, anti-angiogenic markers, and CRC intrinsic subtypes), or both prognostic and predictive values (HER2, CpG island methylator phenotype, tumour mutational load, gene fusions, and consensus molecular subtypes). As such, new biomarker-led treatment strategies in addition to anti-epidermal growth factor receptor and anti-angiogenetic treatments are being explored. Biomarkers that are not recommended to be tested in clinical practice or are unlikely to be imminently clinically relevant for mCRC include thymidylate transferase, ERCC1, PIK3CA, and PTEN. We highlight the clinical utility of existing and emerging biomarkers in mCRC and provide recommended treatment strategies according to the biomarker status. An update on ongoing molecular-guided clinical trials is also provided.

Background: Regorafenib improves progression free survival (PFS) in a subset of metastatic colorectal cancer (mCRC) patients, although no biomarkers of efficacy are available. Circulating methylated DNA (cmDNA) assessed by a five-gene panel was previously associated with outcome in chemotherapy treated mCRC patients. We hypothesized that cmDNA could be used to identify cases most likely to benefit from regorafenib (i.e., patients with PFS longer than 4 months).Methods: Plasma samples from mCRC patients were collected prior to (baseline samples N = 60) and/or during regorafenib treatment (N = 62) for the assessment of cmDNA and total amount of cell free DNA (cfDNA).Results: In almost all patients, treatment with regorafenib increased the total cfDNA, but decreased cmDNA warranting the normalization of cmDNA to the total amount of circulating DNA (i.e., cmDNA/ml). We report that cmDNA/ml dynamics reflects clinical response with an increase in cmDNA/ml associated with higher risk of progression (HR for progression = 1.78 [95%CI: 1.01–3.13], p = 0.028). Taken individually, high baseline cmDNA/ml (above median) was associated with worst prognosis (HR for death = 3.471 [95%CI: 1.83–6.57], p < 0.0001) and also predicted shorter PFS (

The RAS oncogene is among the most commonly mutated in cancer. RAS mutations are identified in about half of patients diagnosed with metastatic colorectal cancer (mCRC), conferring poor prognosis and lack of response to anti-epidermal growth factor receptor (EGFR) antibodies. In the last decades, several investigational attempts failed in directly targeting RAS mutations, thus RAS was historically regarded as ‘undruggable’. Recently, novel specific KRASG12C inhibitors showed promising results in different solid tumors, including mCRC, renewing interest in this biomarker as a target. In this review, we discuss different strategies of RAS targeting in mCRC, according to literature data in both clinical and preclinical settings. We recognized five main strategies focusing on those more promising: direct RAS targeting, targeting the mitogen-activated protein kinase (MAPK) pathway, harnessing RAS through immunotherapy combinations, RAS targeting through metabolic pathways, and finally other miscellaneous approaches. Direct KRASG12C inhibition is emerging as the most promising strategy in mCRC as well as in other solid malignancies. However, despite good disease control rates, tumor response and duration of response are still limited in mCRC. At this regard, combinational approaches with anti-epidermal growth factor receptor drugs or checkpoint inhibitors have been proposed to enhance treatment efficacy, based on encouraging results achieved in preclinical studies. Besides, concomitant therapies increasing metabolic stress are currently under evaluation and expected to also provide remarkable results in RAS codon mutations apart from KRASG12C. In conclusion, based on hereby reported efforts of translational research, RAS mutations should no longer be regarded as ‘undruggable’ and future avenues are now opening for translation in the clinic in mCRC., Highlights • RAS mutations were historically considered ‘undruggable’ despite their high prevalence in colorectal cancer. • Many strategies targeting RAS mutations were attempted in the past with poor results across all histologies. • Novel inhibitors of the KRASG12C mutation recently obtained encouraging results in early-phase clinical trials. • Combining KRASG12C inhibition with anti-EGFR drugs or immunotherapy may provide further opportunities in colorectal cancer.

Simple Summary A subset of colorectal cancers (CRCs) is characterized by a mismatch repair deficiency that is frequently associated with microsatellite instability (MSI). The compromised DNA repair machinery leads to the accumulation of tumor neoantigens affecting the sensitivity of MSI metastatic CRC to immune checkpoint inhibitors (CPIs), both upfront and in later lines of treatment. However, up to 30% of MSI CRCs exhibit primary resistance to frontline immune based therapy, and an additional subset develops acquired resistance. Here, we first discuss the clinical and molecular features of MSI CRCs and then we review how the loss of antigenicity, immunogenicity, and a hostile tumor microenvironment could influence primary and acquired resistance to CPIs. Finally, we describe strategies to improve the outcome of MSI CRC patients upon CPI treatment. Abstract Immune checkpoint inhibitors (CPIs) represent an effective therapeutic strategy for several different types of solid tumors and are remarkably effective in mismatch repair deficient (MMRd) tumors, including colorectal cancer (CRC). The prevalent view is that the elevated and dynamic neoantigen burden associated with the mutator phenotype of MMRd fosters enhanced immune surveillance of these cancers. In addition, recent findings suggest that MMRd tumors have increased cytosolic DNA, which triggers the cGAS STING pathway, leading to interferon-mediated immune response. Unfortunately, approximately 30% of MMRd CRC exhibit primary resistance to CPIs, while a substantial fraction of tumors acquires resistance after an initial benefit. Profiling of clinical samples and preclinical studies suggests that alterations in the Wnt and the JAK-STAT signaling pathways are associated with refractoriness to CPIs. Intriguingly, mutations in the antigen presentation machinery, such as loss of MHC or Beta-2 microglobulin (B2M), are implicated in initial immune evasion but do not impair response to CPIs. In this review, we outline how understanding the mechanistic basis of immune evasion and CPI resistance in MMRd CRC provides the rationale for innovative strategies to increase the subset of patients benefiting from CPIs.

3506 Background: Despite advances in molecular segmentation of metastatic colorectal cancer (mCRC), beyond RAS status therapeutic actionability remains confined to the limited subgroups of ERBB2 amplified, BRAF mutated and MSI-H patients. Optimization of available treatments is therefore warranted. Rechallenge with anti-EGFR monoclonal antibodies is often empirically used with some benefit as late-line therapy. We previously found that mutant RAS and EGFR ectodomain clones, which emerge in blood during EGFR blockade, decline upon antibody withdrawal leading to regain drug sensitivity. Based on this rationale, we designed CHRONOS, a multicenter phase II trial of anti-EGFR therapy rechallenge guided by monitoring of the mutational status of RAS, BRAF and EGFR in circulating tumor DNA (ctDNA). To our knowledge, this is the first interventional clinical trial of liquid biopsy for driving anti-EGFR rechallenge therapy in mCRC. Methods: Eligible patients were PS ECOG 0-2 RAS/BRAF WT mCRC having first achieved an objective response and then progression in any treatment line with an anti-EGFR antibody containing regimen, displaying RAS, BRAF and EGFR ectodomain WT status in ctDNA at molecular screening after progression to the last anti-EGFR-free regimen. Clonal evolution in ctDNA was analyzed by ddPCR and next generation sequencing. Panitumumab 6 mg/kg was administered IV every two weeks until progression. The primary endpoint was objective response rate (ORR) by RECIST version 1.1 with independent central review. 27 total patients and 6 responses were required to declare the study positive (power = 85%, type I error = 0.05). Results: Between Aug 19, 2019 and Nov 6, 2020 52 patients were screened by liquid biopsy and 36 (69%) were negative in ctDNA for RAS/BRAF/EGFR mutations. Of these, 27 patients were enrolled in 4 centers. Median age was 64 years (range: 42-80). PS ECOG was 0/50%, 1/46%, 2/4%. Previous anti-EGFR was administered in 1st line in 63%, 2nd in 15% and > 2nd in 22%. Median number of previous treatments was 3. The primary endpoint was met, with 8/27 partial responses (PR) observed (2 unconfirmed) (ORR = 30%, 95% CI: 12-47%). Stable disease (SD) was obtained in 11/27 (40%, 95% CI: 24-59%), lasting > 4 months in 8/11. Disease control rate (PR plus SD > 4 months) was therefore obtained in 16/27 (59%, 95% CI: 41-78%). Median progression-free survival was 16 weeks. Median duration of response was 17 weeks (1 ongoing). Maximal grade toxicity was G3, limited to dermatological and occurring in 19% of patients. ctDNA dynamics were studied in all patients. Conclusions: Liquid biopsy-driven rechallenge with anti-EGFR antibodies leads to further objective responses in one third of patients. Genotyping tumor DNA in the blood to direct therapy can be effectively incorporated in the management of advanced CRCs. Clinical trial information: 2016-002597-12.

Oxaliplatin immune-induced syndrome (OIIS) is an uncommon, potentially life-threatening, side effect associated with oxaliplatin-based chemotherapy. The present study reports 5 original cases of OIIS and systematically reviewed the available published cases. We retrospectively analyzed the clinical archives of the Niguarda Cancer Center from 2009 to 2015 and conducted a search for OIIS using the PubMed database, followed by deeper investigation of the references of the recorded studies. We pooled our series with other reported cases for systematic review in accordance with the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement using only English language as the selection criterion. A total of 61 OIIS cases were analyzed, the largest series reported to date. Of the 61 patients, 56 (91.8%) had received oxaliplatin for metastatic colorectal cancer. In 32 of the 61 patients (52.5%), OIIS was associated with grade 4 thrombocytopenia and in 4 (6.6%) with grade 4 anemia. OIIS was fatal in 4 patients. In 49 patients, oxaliplatin-induced immune system activation was tested using the Coombs test or by detection of antiplatelet antibodies and was positive in 87.7% of the patients. The average number of oxaliplatin cycles until the onset of OIIS was 16.7, and the number was significantly lower when oxaliplatin was administered as a rechallenge after a period of vacancy of treatment with this agent (4.6 cycles as rechallenge vs. 13.6 as first-time exposure; P < .00001). OIIS is triggered by cumulative administration of oxaliplatin, characteristically with a threefold earlier onset when the drug is administered as a rechallenge. Prompt identification of OIIS can be expected to reduce the risk of iatrogenic morbidity and mortality.

Although recent clinical trials of BRAF inhibitor combinations have demonstrated improved efficacy in BRAF-mutant colorectal cancer, emergence of acquired resistance limits clinical benefit. Here, we undertook a comprehensive effort to define mechanisms underlying drug resistance with the goal of guiding development of therapeutic strategies to overcome this limitation. We generated a broad panel of BRAF-mutant resistant cell line models across seven different clinically relevant drug combinations. Combinatorial drug treatments were able to abrogate ERK1/2 phosphorylation in parental-sensitive cells, but not in their resistant counterparts, indicating that resistant cells escaped drug treatments through one or more mechanisms leading to biochemical reactivation of the MAPK signaling pathway. Genotyping of resistant cells identified gene amplification of EGFR, KRAS, and mutant BRAF, as well as acquired mutations in KRAS, EGFR, and MAP2K1. These mechanisms were clinically relevant, as we identified emergence of a KRAS G12C mutation and increase of mutant BRAF V600E allele frequency in the circulating tumor DNA of a patient at relapse from combined treatment with BRAF and MEK inhibitors. To identify therapeutic combinations capable of overcoming drug resistance, we performed a systematic assessment of candidate therapies across the panel of resistant cell lines. Independent of the molecular alteration acquired upon drug pressure, most resistant cells retained sensitivity to vertical MAPK pathway suppression when combinations of ERK, BRAF, and EGFR inhibitors were applied. These therapeutic combinations represent promising strategies for future clinical trials in BRAF-mutant colorectal cancer. Cancer Res; 76(15); 4504–15. ©2016 AACR.

SummaryWhat is known and objective Hypertriglyceridaemia (HTG) is a potentially serious side effect of everolimus therapy. We here report a case of severe HTG in an everolimus-treated patient and provide recommendations for its management. Case summary The patient was a 70-year-old woman, being treated with everolimus for a pancreatic neuroendocrine tumour (pNET). She developed severe HTG to a maximum of 969 mg/dL after 22 months of therapy. Treatment with fenofibrate rapidly normalized triglyceride (TG) levels. What is new and conclusion Severe HTG may occur in everolimus-treated patients. Prescription of the appropriate therapy can allow patients to continue this medication.

Background: Moving stage III Colon Cancer (CC) into the precision medicine space is a priority in view of the lack of molecular markers driving adjuvant treatment. Retrospective studies have demonstrated the tremendous prognostic impact of circulating tumor DNA (ctDNA) analysis after curative intent surgery, and suggested that lack of conversion of ctDNA from detectable to undetectable after adjuvant chemotherapy reflects treatment failure. With these premises, we have designed the PEGASUS trial (EudraCT 2019-002074-32) to prove the feasibility of using liquid biopsy to guide the post-surgical and post-adjuvant clinical management of early colon cancer patients. Methods: PEGASUS is a prospective multicentric vanguard study designed to test the feasibility of performing serial interventional liquid biopsies (LB) for ctDNA determination in 140 microsatellite stable Stage-III and T4N0 Stage-II CC patients. The LUNAR1 (Guardant Health, Redwood City, CA, USA) will be used for ctDNA determination. For the efficacy analysis, the PEGASUS cohort will be compared with a cohort of 420 patients from the TOSCA trial (NCT00646607) population matched 3:1 for all known prognostic phenotypes. A post-surgical LB executed 2-4 weeks after surgery will guide a “Molecular Adjuvant” treatment as follows: i) ctDNA+ patients will receive CAPOX for 3 months and ii) ctDNA- patients will receive capecitabine (CAPE) for 6 months but will be retested after 1 cycle, and if found ctDNA+ will be switched to CAPOX treatment. Immediately after the end of “Molecular Adjuvant” treatment a further LB will be performed and instruct subsequent treatment. Positive patients (ctDNA+/+ and ctDNA-/+) will receive an up-scaled “Molecular Metastatic” systemic treatment for 6 months or until radiological progression or toxicity as follows: i) ctDNA+/+ patients will be treated with FOLFIRI; ii) ctDNA-/+ patients with CAPOX. These patients will be subjected to a LB after 3 months and at the end of treatment and in case of positivity will be switched to FOLFIRI. Patients experiencing ctDNA conversion to negative (ctDNA+/-) will receive a de-escalated treatment with CAPE for 3 months. 3 LB will be performed within 3 months and in case of positivity the patient will be switched to FOLFIRI. Patients with ctDNA-/- will be subjected to an interventional follow-up comprising 2 further LB and in case of positivity they will be switched to CAPOX treatment. PEGASUS is piggybacked to AlfaOmega (NCT04120935), a Master Observational Protocol that will follow patients from diagnosis to 5 years or recurrence/death (whichever comes first), collecting clinical data, radio images and biological samples. AlfaOmega provides a clinical and logistic ecosystem for the seamless integration of PEGASUS clinical results with the biological underpinning of colon cancer. Citation Format: Elena Elez, Filippo Pietrantonio, Andrea Sartore-Bianchi, Clara Montagut, Andres Cervantes, Stefania Sciallero, Maria Giulia Zampino, Stefania Mosconi, Valter Torri, Noelia Tarazona, Luca Lazzari, Paolo Luraghi, Susana Muñoz, Matteo Fassan, Enzo Medico, Livio Trusolino, Maria Rescigno, Salvatore Siena, Alberto Sobrero, Roberto Labianca, Josep Tabernero, Alberto Bardelli, Sara Lonardi, Silvia Marsoni. Post-surgical liquid biopsy-guided treatment of stage III and high-risk stage II colon cancer patients: The PEGASUS trial [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT263.

Background: The analysis of circulating free tumor DNA (ctDNA) in blood, commonly referred to as liquid biopsy, is being used to characterize patients with solid cancers. Tumor-specific genetic variants can also be present in DNA isolated from other body fluids such as urine. Unlike blood, urine sampling is noninvasive, can be self-performed, and allows recurrent longitudinal monitoring. The features of tumor DNA that clears from the glomerular filtration barrier (transrenal tumor DNA, hereafter trtDNA) are largely unexplored. Patients and Methods: Specimens were collected from 24 patients with KRAS or BRAF mutant metastatic colorectal cancer (mCRC). Driver mutations were assessed by droplet digital PCR (ddPCR) in ctDNA from plasma and trtDNA from urine. Whole-exome sequencing (WES) was performed in DNA isolated from tissue, plasma, and urine. Results: Out of the 24 CRC cases, only four had sufficient DNA to allow WES analyses in urine and plasma. We found that tumor alterations reside primarily in low-molecular-weight fragments. In patients where trtDNA was more than 2.69% of the urine-derived DNA, cancer-specific molecular alterations, mutational signatures, and copy number profiles identified in urine DNA are comparable with those detected in plasma ctDNA. Conclusions: With current technologies, WES analysis of trtDNA is feasible in a small fraction of mCRC patients. Tumor-related genetic information is mainly present in shorter DNA fragments. Although the limited amounts of trtDNA pose analytical challenges, enrichment of low-molecular-weight DNA and optimized computational tools improve detection of tumor-specific genetic information in urine. Citation Format: Giovanni Crisafulli, Benedetta Mussolin, Andrea Cassingena, Monica Montone, Alice Bartolini, Ludovic Barault, Antonio Martinetti, Federica Morano, Filippo Pietrantonio, Andrea Sartore-Bianchi, Salvatore Siena, Federica Di Nicolatonio, Silvia Marsoni, Alberto Bardelli, Giulia Siravegna. Whole-exome sequencing analysis of urine transrenal tumor DNA in metastatic colorectal cancer patients [abstract]. In: Proceedings of the AACR Special Conference on Advances in Liquid Biopsies; Jan 13-16, 2020; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(11_Suppl):Abstract nr B11.

TPS4124 Background: Moving stage III Colon Cancer (CC) into the precision medicine space is a priority in view of the lack of molecular markers driving adjuvant treatment. Retrospective studies have demonstrated the tremendous prognostic impact of circulating tumor DNA (ctDNA) analysis after curative intent surgery, and suggested that lack of conversion of ctDNA from detectable to undetectable after adjuvant chemotherapy reflects treatment failure. With these premises, we have designed the PEGASUS trial (NCT04259944). Methods: PEGASUS is a prospective multicentric study designed to prove the feasibility of using liquid biopsy (LB) to guide the post-surgical and post-adjuvant clinical management in 140 microsatellite stable Stage-III and T4N0 Stage-II CC patients. The LUNAR1 test (Guardant Health, Redwood City, CA, USA) will be used for ctDNA determination. For the efficacy analysis, the PEGASUS cohort will be compared with a 3:1 matched cohort of 420 patients from the TOSCA trial (NCT00646607). A LB executed 2-4 weeks post-surgery will guide a “Molecular Adjuvant” treatment: i) ctDNA+ patients will receive CAPOX for 3 months and ii) ctDNA- patients will receive capecitabine (CAPE) for 6 months but will be retested after 1 cycle, and if found ctDNA+ will be switched to CAPOX treatment. At the end of the “Molecular Adjuvant” treatment a further LB will be performed and instruct subsequent treatment. Positive patients (ctDNA+/+ and ctDNA-/+) will receive an up-scaled “Molecular Metastatic” systemic treatment for 6 months or until radiological progression or toxicity: i) ctDNA+/+ patients will be treated with FOLFIRI; ii) ctDNA-/+ patients with CAPOX. These patients will be subjected to a LB after 3 months and at the end of treatment: in case of positivity will be switched to FOLFIRI. ctDNA+/- patientswill receive a de-escalated treatment with CAPE for 3 months. 3 LB will be performed within 3 months and in case of positivity the patient will be switched to FOLFIRI. Patients with ctDNA-/- will be subjected to an interventional follow-up comprising 2 further LB and in case of positivity they will be switched to CAPOX treatment. PEGASUS is piggybacked to AlfaOmega (NCT04120935), a Master Observational Protocol that will follow patients from diagnosis to 5 years or recurrence/death (whichever comes first), collecting clinical data, radio-images and biological samples. AlfaOmega provides a clinical and logistic ecosystem for the seamless integration of PEGASUS clinical results with the biological underpinning of colon cancer. Clinical trial information: NCT04259944 .

Background The analysis of circulating free tumour DNA (ctDNA) in blood, commonly referred as liquid biopsy, is being used to characterise patients with solid cancers. Tumour-specific genetic variants can also be present in DNA isolated from other body fluids, such as urine. Unlike blood, urine sampling is non-invasive, can be self-performed, and allows recurrent longitudinal monitoring. The features of tumour DNA that clears from the glomerular filtration barrier, named trans-renal tumour DNA (trtDNA), are largely unexplored. Patients and methods Specimens were collected from 24 patients with KRAS or BRAF mutant metastatic colorectal cancer (mCRC). Driver mutations were assessed by droplet digital PCR (ddPCR) in ctDNA from plasma and trtDNA from urine. Whole exome sequencing (WES) was performed in DNA isolated from tissue, plasma and urine. Results Out of the 24 CRC cases, only four had sufficient DNA to allow WES analyses in urine and plasma. We found that tumour alterations primarily reside in low molecular weight fragments (less than 112 bp). In patients whose trtDNA was more than 2.69% of the urine derived DNA, cancer-specific molecular alterations, mutational signatures and copy number profiles identified in urine DNA are comparable with those detected in plasma ctDNA. Conclusions With current technologies, WES analysis of trtDNA is feasible in a small fraction of mCRC patients. Tumour-related genetic information is mainly present in low molecular weight DNA fragments. Although the limited amounts of trtDNA poses analytical challenges, enrichment of low molecular weight DNAs and optimised computational tools can improve the detection of tumour-specific genetic information in urine.

The densities of CD3+ and CD8+ tumor-infiltrating lymphocytes (TILs), combined with tumor–node–metastasis (TNM) staging, have prognostic value for patients with nonmetastatic colorectal cancer. We compared the prognostic value of CD3+ and FoxP3+ TILs at the invasive front, TNM classifiers, and microsatellite (MS) status in a trial set of patients with stage II and III colorectal cancer (n = 413), by recursive partitioning with a classification and regression tree (CART). Significant prognostic factors and interactions were reassessed by logistic regression and Cox proportional-hazards modeling in the trial and a validation set (n = 215) of patients with stage II colorectal cancer. In the trial set, CART indicated that TIL numbers were of value only in predicting recurrence risk for stage II cancers, where low densities of FoxP3+ TILs ranked first and low densities of CD3+ TILs further stratifying risk. Multivariate analysis showed that TILs interacted with tumor stage (FoxP3+, P = 0.06; CD3+, P = 0.02) and MS instability (MSI; FoxP3+; P = 0.02). In stage II MS-stable cancers, concomitant low densities of both FoxP3+ and CD3+ TILs identified patients with the highest progression risk in the trial [HR 7.24; 95% confidence interval (CI), 3.41–15.4; P < 0.001] and the validation (HR 15.16; 95% CI, 3.43–66.9; P < 0.001) sets. FoxP3+ and CD3+ TIL load in colorectal cancer was more informative than other prognostic factors before the cancer progressed to lymph nodes. This prognostic information about TILs, including FoxP3+ cells, suggests that randomized controlled trials might be refined to include interactions between TNM status, molecular classifiers, and postsurgical treatments.

Importance Few studies are available on the role of maintenance strategies after induction treatment regimens based on anti–epidermal growth factor receptors, and the optimal regimen for an anti–epidermal growth factor receptors–based maintenance treatment in patients withRASwild-type metastatic colorectal cancer is still to be defined. Objective To determine whether maintenance therapy with single-agent panitumumab was noninferior to panitumumab plus fluorouracil and leucovorin after a 4-month induction treatment regimen. Design, Setting, and Participants This open-label, randomized phase 2 noninferiority trial was conducted from July 7, 2015, through October 27, 2017, at multiple Italian centers. Patients withRASwild-type, unresectable metastatic colorectal adenocarcinoma who had not received previous treatment for metastatic disease were eligible. Induction therapy consisted of panitumumab plus FOLFOX-4 (panitumumab, 6 mg/kg, oxaliplatin, 85 mg/m2at day 1, leucovorin calcium, 200 mg/m2, and fluorouracil, 400-mg/m2bolus, followed by 600-mg/m2continuous 24-hour infusion at days 1 and 2, every 2 weeks). Cutoff date for analyses was July 30, 2018. Interventions Patients were randomized (1:1) to first-line panitumumab plus FOLFOX-4 for 8 cycles followed by maintenance therapy with panitumumab plus fluorouracil-leucovorin (arm A) or panitumumab (arm B) until progressive disease, unacceptable toxic effects, or consent withdrawal. The minimization method was used to stratify randomization by previous adjuvant treatment and number of metastatic sites. Main Outcomes and Measures The prespecified primary end point was 10-month progression-free survival (PFS) analyzed on an intention-to-treat basis with a noninferiority margin of 1.515 for the upper limit of the 1-sided 90% CI of the hazard ratio (HR) of arm B vs A. Results Overall, 229 patients (153 male [66.8%]; median age, 64 years [interquartile range (IQR), 56-70 years]) were randomly assigned to arm A (n = 117) or arm B (n = 112). At a median follow-up of 18.0 months (IQR, 13.1-23.3 months]), a total of 169 disease progression or death events occurred. Arm B was inferior (upper limit of 1-sided 90% CI of the HR, 1.857). Ten-month PFS was 59.9% (95% CI, 51.5%-69.8%) in arm A vs 49.0% (95% CI, 40.5%-59.4%) in arm B (HR, 1.51; 95% CI, 1.11-2.07;P = .01). During maintenance, arm A had a higher incidence of grade 3 or greater treatment-related adverse events (36 [42.4%] vs 16 [20.3%]) and panitumumab-related adverse events (27 [31.8%] vs 13 [16.4%]), compared with arm B. Conclusions and Relevance In patients withRASwild-type metastatic colorectal cancer, maintenance therapy with single-agent panitumumab was inferior in terms of PFS compared with panitumumab plus fluorouracil-leucovorin, which slightly increased the treatment toxic effects. Trial Registration ClinicalTrials.gov identifier:NCT02476045

Purpose: ERBB2 (HER2) amplification is an emerging biomarker in colon cancer, conferring sensitivity to combination anti-HER2 therapy. Measurement of HER2 copy number is typically performed using surgical specimens, but cell-free circulating tumor DNA (ctDNA) analysis may be a noninvasive alternative. We determined the sensitivity of plasma copy number (pCN) for detecting ERBB2 amplifications and whether pCN correlated with tissue-detected copy number. We also assessed response to HER2-targeted therapy based on pCN and suggest a pCN threshold predictive of response. Experimental Design: Forty-eight pretreatment and progression plasma samples from 29 HER2-positive patients in the HERACLES A clinical trial were tested using the Guardant360 cfDNA assay. We correlated ERRB2 pCN with progression-free survival (PFS) and best objective response (BOR) and applied an adjustment method based on tumor DNA shedding using the maximum mutant allele fraction as a surrogate for tumor content to accurately determine the pCN threshold predictive of response. Results: Forty-seven of 48 samples had detectable ctDNA, and 46 of 47 samples were ERBB2-amplified on the basis of cfDNA [2.55–122 copies; 97.9% sensitivity (95% confidence interval, 87.2%–99.8%)]. An adjusted ERBB2 pCN of ≥25.82 copies correlated with BOR and PFS (P = 0.0347). Conclusions: cfDNA is a viable alternative to tissue-based genotyping in the metastatic setting. The cfDNA platform utilized correctly identified 28 of 29 (96.6%) of pretreatment samples as ERBB2-amplified and predicted benefit from HER2-targeted therapy. In this study, an observed pCN of 2.4 and an adjusted pCN of 25.82 copies of ERBB2 are proposed to select patients who will benefit from HER2-targeted therapy.

PURPOSE We assessed the prognostic/predictive role of primary tumor sidedness and uncommon alterations of anti–epidermal growth factor receptor (EGFR) primary resistance (primary resistance in RAS and BRAF wild-type metastatic colorectal cancer patients treated with anti-EGFR monoclonal antibodies [PRESSING] panel) in patients with RAS/ BRAF wild-type (wt) metastatic colorectal cancer (mCRC) who were randomly assigned to panitumumab plus fluorouracil, leucovorin, and oxaliplatin (FOLFOX-4) induction followed by maintenance with panitumumab with or without fluorouracil (FU) plus leucovorin (LV); Valentino trial (ClinicalTrials.gov identifier: NCT02476045 ). PATIENTS AND METHODS This prespecified retrospective analysis included 199 evaluable patients with RAS/ BRAF wt. The PRESSING panel included the following: immunohistochemistry (IHC) and in situ hybridization for HER2/MET amplification, IHC with or without RNA sequencing for ALK/ROS1/NTRKs/RET fusions, next-generation sequencing for HER2/ PIK3CAex.20/PTEN/ AKT1 and RAS mutations with low mutant allele fraction, and multiplex polymerase chain reaction for microsatellite instability. PRESSING status (any positive biomarker v all negative) and sidedness were correlated with overall response rate (ORR), progression-free survival (PFS), and overall survival (OS) in the study population and by treatment arm. RESULTS Overall, left- and right-sided tumors were 85.4% and 14.6%, respectively, and PRESSING-negative and -positive tumors were 75.4% and 24.6%, respectively. At a median follow-up of 26 months, inferior outcomes were consistently observed in right- versus left-sided tumors for ORR (55.2% v 74.1%; P = .037), PFS (8.4 v 11.5 months; P = .026), and OS (2-year rate: 50.2% v 65.1%; P = .062). Similar results were observed in the PRESSING-positive versus PRESSING-negative subgroup for ORR (59.2% v 75.3%; P = .030), PFS (7.7 v 12.1 months; P < .001), and OS (2-year rate: 48.1% v 68.1%; P = .021). The PFS benefit of FU plus LV added to panitumumab maintenance, reported in the study, was independent from sidedness and PRESSING status (interaction for PFS P = .293 and .127, respectively). However, outcomes were extremely poor in patients who received single-agent panitumumab and had right-sided tumors (median PFS, 7.7 months; 2-year OS, 38.5%) or PRESSING-positive tumors (median PFS, 7.4 months; 2-year OS, 47.0%). CONCLUSION The combined assessment of sidedness and molecular alterations of anti-EGFR primary resistance identified a consistent proportion of patients with RAS/ BRAF–wt mCRC who had inferior benefit from initial anti-EGFR–based regimens, particularly after maintenance with single-agent anti-EGFRs.

Background Despite the well-known negative prognostic value of the V600EBRAF mutation in patients with metastatic colorectal cancer (mCRC), its outcome is quite heterogeneous, and the basis for this prognostic heterogeneity should be better defined. Methods Two large retrospective series of V600EBRAF-mutated mCRC from 22 institutions served as an exploratory and validation set to develop a prognostic score. The model was internally and externally validated. Results A total of 395 V600EBRAF-mutated mCRCs were included in the exploratory set. Performance status, CA19.9, lactate dehydrogenase, neutrophil/lymphocyte ratio, grading and liver, lung and nodal involvement emerged as independent prognostic factors for overall survival (OS). Two different scoring systems were built: a ‘complete’ score (0–16) including all significant covariates and a ‘simplified’ score (0–9), based only on clinicopathological covariates, and excluding laboratory values. Adopting the complete score, proportions of patients with a low (0–4), intermediate (5–8) and high (9–16) score were 44.7%, 42.6% and 12.6%, respectively. The median OS was 29.6, 15.5 (hazard ratio [HR] for intermediate vs low risk: 2.16, 95% confidence interval [CI]: 1.44–3.22, p Conclusions These scoring systems are based on easy-to-collect data and defined specific subgroups with relevant differences in their life expectancy. These tools could be useful in clinical practice, would allow better stratification of patients in clinical trials and may be adopted for proper adjustments in exploratory translational analyses.