Wild-type Metastatic Colorectal Cancer Research Articles

CircHIF1A induces cetuximab resistance in colorectal cancer by promoting HIF1α-mediated glycometabolism alteration

Epidermal growth factor receptor (EGFR)-targeted therapy is an important treatment for RAS wild-type metastatic colorectal cancer (mCRC), but the resistance mechanism remains unclear. Here, the differential expression of circRNAs between Cetuximab sensitive and resistant cell lines was analyzed using whole-transcriptome sequencing. We identified that the expression of circHIF1A was significantly higher in LIM1215-R than in LIM1215. When treated with Cetuximab, downregulation of circHIF1A level weakened the proliferation and clonal formation ability of LIM1215-R, caused more cells to enter G0-G1 phase, and significantly reduced the basal respiration, ATP production, and maximal respiration, as well as the glycolytic capacity and glycolytic reserve. The response rate and prognosis of circHIF1A-positive patients were inferior to those of negative patients. Mechanistically, circHIF1A can upregulate the level of hypoxia-inducible factor 1 A (HIF1A) by competitively binding to miR-361-5p, inducing the overexpression of enzymes such as glucose transporter 1 (GLUT1) and lactate dehydrogenase A (LDHA). In a xenograft model, inhibition of circHIF1A expression increased the sensitivity to Cetuximab treatment. In conclusion, circHIF1A can promote HIF1α-mediated glycometabolism alteration to induce Cetuximab resistance in CRC. It has the potential to become a screening indicator for the Cetuximab beneficial population in mCRC and a new therapeutic target for enhancing treatment efficacy.

Chinese expert consensus on maintenance treatment with anti-EGFR monoclonal antibody for RAS wild-type metastatic colorectal cancer (2024 edition)

For patients with metastatic colorectal cancer (mCRC) who achieve disease control during first-line standard therapy, post-induction strategies should emphasize on quality of life improvement while maintaining disease control. Chemotherapy combined with anti-epidermal growth factor receptor (EGFR) monoclonal antibody is the standard first-line treatment for RAS wild-type mCRC patients. After anti-EGFR-based first-line induction therapy achieves at least stable disease, anti-EGFR-based maintenance treatment could maintain disease control while keeping a good safety profile. Based on research evidence and clinical practice, the Chinese expert consensus on anti-EGFR-based maintenance strategy for RAS wild-type mCRC aims to futher clarify the treatment timing, regimen options, adverse reaction management and follow-up strategy, providing standardized guidance to maximize the clinical benefit in RAS wild-type mCRC.

Sequential RAS mutations evaluation in cell-free DNA of patients with tissue RAS wild-type metastatic colorectal cancer: the PERSEIDA (Cohort 2) study.

RAS (KRAS/NRAS) mutational status on a tumor biopsy is mandatory to guide the best treatment in metastatic colorectal cancer (mCRC). Determining the RAS mutational status by tumor-tissue biopsy is essential in guiding the optimal treatment decision for mCRC. RAS mutations are negative predictive factors for the use of EGFR monoclonal antibodies. Cell-free DNA (cfDNA) analysis enables minimally invasive monitoring of tumor evolution. PERSEIDA was an observational, prospective study assessing cfDNA RAS, BRAF and EGFR mutations (using Idylla™) in first-line mCRC, RAS wild-type (baseline tumor-tissue biopsy) patients (cohort 2). Plasma samples were collected before first-line treatment, after 20 ± 2weeks, and at disease progression. 117 patients were included (103 received panitumumab + chemotherapy as first-line treatment). At baseline, 7 (6.8%) patients had RAS mutations, 4 (3.9%) BRAF mutations and no EGFR mutations were detected (cfDNA, panitumumab + chemotherapy subpopulation [panitumumab + Ch]). The baseline RAS mutational status concordance between tissue and liquid biopsies was 94.0% (93.2%, panitumumab + Ch). At 20weeks, only one patient in the study (included in the panitumumab + Ch) had an emerging cfDNA RAS mutation. No emerging BRAF or EGFR mutations were reported. At disease progression, 6 patients had emergent mutations not present at baseline (RAS conversion rate: 13.3% [6/45]; 15.0% [6/40], panitumumab + Ch). The concordance rate between liquid and solid biopsies at baseline was very high, as previously reported, while our results suggest a considerable emergence of RAS mutations during disease progression. Thus, the dynamics of the genomic landscape in ctDNA may provide relevant information for the management of mCRC patients.

Feasibility of implementation of the early tumor shrinkage as a potential predictive marker to daily clinical practice in patients with RAS wild type metastatic colorectal cancer, treated with cetuximab - a non-interventional observational study.

With the aim to show the feasibility of early tumor shrinkage (ETS) concept implementation into daily clinical practice in the Czech Republic, a non-interventional, multicentric, single arm, prospective study in real world set-up was performed. The study objectives were to explore the time interval from the treatment starting date to the date of the first radiographic control (TFRC) and evaluate the proportion of patients who achieved ≥ 20% tumor regression within the first 8 weeks of first-line therapy, in the real-world settings. The medians of TFRC in all individual participating centers were > 12 weeks (range 14.0-36.4 weeks). TFRC ≤ 8 weeks was reported for only 3% of patients in the cohort with first-line therapy, and there were only 3 patients (1%) who achieved tumor regression of ≥ 20% by day 60 (8.6 weeks). These findings indicate that the basic time parameter of ETS could not realistically be employed in routine oncology care of patients with metastatic colorectal cancer (mCRC) in the Czech Republic, unless there would be a strict request to perform TRFC by week 8 since the initiation of the therapy. In addition, the frequency of objective tumor response to first-line therapy with cetuximab + chemotherapy was evaluated. Based on the relative regression in the sum of diameters of measurable metastatic lesions, unconfirmed partial responses were achieved in 42.4 % and unconfirmed complete response in 8.6% of patients, altogether corresponding to the overall response rate of 51% with first-line therapy. The frequency of responses was higher among patients with left than right sided primary tumors. It seems that the regimen of cetuximab/FOLFOX might be more active in frontline therapy of right sided RAS wild type mCRC than cetuximab/FOLFIRI.

Real-world treatment outcomes from nationwide Onco-colon Turkey registry in RAS wild-type patients treated with biologics second-line mCRC.

Colorectal cancer is one of the leading causes of mortality both globally and in our country. In Turkey, we conducted a multicenter investigation into the effectiveness of second-line treatments and real-life data for patients with RAS wild-type metastatic colorectal cancer (NCT04757311). In this retrospective analysis, records from 28 centers were collected, and histopathological, molecular, and clinical characteristics were documented. Patients were categorized into groups based on their second-line biological treatments: anti-EGFR (Group A and Group B, panitumumab and cetuximab) and anti-VEGF (Group C, bevacizumab and aflibercept). They were then compared within these groups. A total of 588 patients with documented RAS wild-type status were evaluated. The median OS was 15.7, 14.3 and 14.7 months in Group A, Group B and Group C, respectively (p = 0.764). The median PFS of the patients in second-line setting that received panitumumab, cetuximab and bevacizumab/aflibercept were 7.8, 6.6 and 7.4 months, respectively (p = 0.848). According to the results of our real-life data study, there is no significant difference in efficiency between the combination of biological agent and chemotherapy used in the second-line treatments.

Anti-EGFR Rechallenge in Patients With Refractory ctDNA RAS/BRAF wt Metastatic Colorectal Cancer

The available evidence regarding anti-epidermal growth factor receptor (EGFR) inhibitor rechallenge in patients with refractory circulating tumor DNA (ctDNA) RAS/BRAF wild-type (wt) metastatic colorectal cancer (mCRC) is derived from small retrospective and prospective studies. To evaluate the efficacy of anti-EGFR rechallenge in patients with refractory ctDNA RAS/BRAF wt mCRC. This nonrandomized controlled trial used a pooled analysis of individual patient data from patients with RAS/BRAF wt ctDNA mCRC enrolled in 4 Italian trials (CAVE, VELO, CRICKET, and CHRONOS) and treated with anti-EGFR rechallenge between 2015 and 2022 (median [IQR] follow-up, 28.1 [25.8-35.0] months). Patients received anti-EGFR rechallenge therapy, including cetuximab plus avelumab, trifluridine-tipiracil plus panitumumab, irinotecan plus cetuximab, or panitumumab monotherapy. Overall survival (OS), progression-free survival (PFS), overall response rate (ORR), and disease control rate (DCR) were calculated. Exploratory subgroup analysis evaluating several clinical variables was performed. Safety was reported. Overall, 114 patients with RAS/BRAF wt ctDNA mCRC (median [IQR] age, 61 [29-88] years; 66 men [57.9%]) who received anti-EGFR rechallenge as experimental therapy (48 received cetuximab plus avelumab, 26 received trifluridine-tipiracil plus panitumumab, 13 received irinotecan plus cetuximab, and 27 received panitumumab monotherapy) were included in the current analysis. Eighty-three patients (72.8%) had received 2 previous lines of therapy, and 31 patients (27.2%) had received 3 or more previous lines of therapy. The ORR was 17.5% (20 patients), and the DCR was 72.3% (82 patients). The median PFS was 4.0 months (95% CI, 3.2-4.7 months), and the median OS was 13.1 months (95% CI, 9.5-16.7 months). The subgroup of patients without liver involvement had better clinical outcomes. The median PFS was 5.7 months (95% CI, 4.8-6.7 months) in patients without liver metastasis compared with 3.6 months (95% CI, 3.3-3.9 months) in patients with liver metastasis (hazard ratio, 0.56; 95% CI, 0.37-0.83; P = .004). The median OS was 17.7 months (95% CI, 13-22.4 months) in patients without liver metastasis compared with 11.5 months (95% CI, 9.3-13.9 months) in patients with liver metastasis (hazard ratio, 0.63; 95% CI, 0.41-0.97; P = .04). Treatments showed manageable toxic effects. These findings suggest that anti-EGFR rechallenge therapy has promising antitumor activity in patients with refractory ctDNA RAS/BRAF wt mCRC. Within the limitation of a subgroup analysis, the absence of liver metastases was associated with significant improved survival. ClinicalTrials.gov Identifiers: NCT02296203; NCT04561336; NCT03227926; NCT05468892.

Abstract CT126: A Phase 0 Study of EGF-Depleting Therapy CIMAvax-EGF in Combination With Standard Therapy for RAS- and BRAF Wild-Type Metastatic Colorectal Cancer

Abstract Background: Colorectal Cancer (CRC) is the 3rd most common cancer in the US and a leading cause of cancer-related death. The epidermal growth factor receptor (EGFR) is overexpressed by immunohistochemistry (IHC) in up to 60% of CRC and is a relevant target for treatment. Monoclonal antibodies targeting the EGFR (cetuximab, panitumumab) have been in clinical use since 2004 as single agents as well as in combination with chemotherapeutics for patients with metastatic CRC, however primary and secondary resistance is very common. CIMAvax-EGF® (CIMAvax) vaccinates against one of the main EGFR ligands: the epidermal growth factor (EGF) protein. The vaccine is based on active immunotherapy where an individual’s immune response is manipulated to release its own effector antibodies against circulating EGF. We hypothesize that adding CIMAvax-EGF to standard chemotherapy has the potential to elicit an immune response against EGF for RAS- and BRAF wild-type metastatic CRC. Methods: This is a phase 0 study to evaluate CIMAvax in combination with standard therapy for RAS- and BRAF wild-type metastatic CRC. Patients will be treated with chemotherapy/biologic agent plus CIMAvax 2.4 mg (DL 1); DL -1 is 1.2 mg. The starting dose is the dose currently established as recommended dose in combination with immunotherapy in patients with non-small cell lung cancer. Cohorts A, B1 and B2 will enroll each 6-12 patients. Based on the known CIMAvax safety profile, we expect to enroll 18-20 patients in these cohorts. Cohort C will enroll 4-6 patients. Cohort A will enroll patients who have not received prior therapy for advanced disease. Patients in Cohort A will be treated with mFOLFOX6/Bevacizumab/CIMAvax at present. Cohort B will enroll patients who have received at least one but no more than 2 prior therapies for advanced disease. Cohort B is comprised of 2 sub-Cohorts. The standard therapy backbone in Cohort B1 will be FOLFIRI/anti-EGFR therapy, and in Cohort B2 mFOLFOX6/anti-EGFR therapy. Cohort C will enroll patients who have not received prior therapy for advanced disease and are candidates for liver metastasectomy. Cohort C will start accruing after the safety run-in phase in Cohorts A, and B2 are completed. The primary objective of this study is to determine the immunogenicity of CIMAvax in the 1st and 2nd/3rd line setting. Secondary objectives include determining the safety and efficacy of these combinations in this patient population and PFS. Exploratory objectives include evaluation of immunomodulation in the tumor microenvironment in patients undergoing metastasectomy of liver metastases, predictive/prognostic role of EGFR ligands (such as EGF, epiregulin, and amphiregulin), somatic mutation profile, EGFR expression by IHC and EGFR copy number alterations/mRNA expression. This trial is currently open for accrual. Clinicaltrials.gov number NCT06011772 Citation Format: Deepak Vadehra, Cayla Janes, Rachel Frascati, Mary Reid, Tania C. Ramos, Sarbajit Mukherjee, Kalet L. Monzón, Patricia L. Alvárez, Orestes S. Morales, Circe M. Pardillo, Christos Fountzilas. A Phase 0 Study of EGF-Depleting Therapy CIMAvax-EGF in Combination With Standard Therapy for RAS- and BRAF Wild-Type Metastatic Colorectal Cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT126.

Switching from FOLFIRI plus cetuximab to FOLFIRI plus bevacizumab based on early tumor shrinkage in RAS wild-type metastatic colorectal cancer: A phase II trial (HYBRID).

Long-term anti-EGFR antibody treatment increases the risk of severe dermatologic toxicities. This single-arm, phase II trial aimed to investigate the strategy of switching from cetuximab to bevacizumab in combination with FOLFIRI based on early tumor shrinkage (ETS) in patients with RAS wild-type metastatic colorectal cancer (mCRC). Radiologic assessment was performed to evaluate ETS, defined as ≥20% reduction in the sum of the largest diameters of target lesions 8 weeks after the introduction of FOLFIRI plus cetuximab. ETS-negative patients switched to FOLFIRI plus bevacizumab, whereas ETS-positive patients continued FOLFIRI plus cetuximab for eight more weeks, with a switch to FOLFIRI plus bevacizumab thereafter. The primary endpoint was progression-free survival. This trial was prematurely terminated due to poor accrual after a total enrollment of 30 patients. In 29 eligible patients, 7 were ETS-negative and 22 were ETS-positive. Two ETS-negative patients and 17 ETS-positive patients switched to FOLFIRI plus bevacizumab 8 weeks and 16 weeks after initial FOLFIRI plus cetuximab, respectively. Median progression-free and overall survival durations were 13.4 and 34.7 months, respectively. Six (20%) patients experienced grade ≥3 paronychia, which improved to grade ≤2 by 18 weeks. Grade ≥3 acneiform rash, dry skin, and pruritus were not observed in any patients. Our novel treatment strategy delivered acceptable survival outcomes and reduced severe dermatologic toxicities.

Abstract 925: Continuing anti-EGFR treatment prolonged survival in mCRC patients receiving conversion liver resection

Abstract Introduction: Anti-EGFR monoclonal antibody plus doublet chemotherapy is the mainstay of first-line treatment of RAS/BRAF wild-type metastatic colorectal cancer (mCRC) patients. Some of these patients might undergo secondary resection. However, there is no standardized suggestion on whether colorectal cancer liver metastasis patients should keep target therapy after secondary resection. NCCN guidelines suggest chemotherapy only in patients receiving primary liver resection. Whether we could spare the use of target therapy after secondary resection is the main aim of our study. Methods: Using Taiwan's National Health Insurance Research Database, we established a cohort of KRAS wild-type mCRC patients treated with first-line anti-EGFR therapy plus doublet chemotherapy between 2013 and 2018. Secondary surgery was defined as either resection of liver metastases or radiofrequency ablation. Results: 5694 stage IV mCRC patients received anti-EGFR MAb plus doublet chemotherapy as a first-line treatment between 2013 and 2018. 174 patients were enrolled in the final analysis, with 153 continuing anti-EGFR MAb after secondary resection and 21 patients without anti-EGFR MAb. Compared with those who without anti-EGFR therapy after secondary resection, patients who continued anti-EGFR MAb exhibited significantly longer overall survival (OS; median, 43.8 vs. 31.9 months, p = 0.031) but not in time to treatment failure (TTF; median, 22.2 vs. 26.6 months, p = 0.841). The OS benefits of continuing anti-EGFR MAb remained regardless of left-sided or right-sided primary tumors (40.9 vs. 43.0 months, p = 0.980). The patient cohort from 2016 to 2018 showed more prolonged survival than from 2012 to 2015 (not reached vs. 40.450, p = 0.0305). TTF has no statistical difference when considering patient cohort or primary tumor location. In multivariate analyses, continuing first-line anti-EGFR MAb therapy after secondary resection remained an independent predictor of longer OS. Conclusion: For mCRC patients who received secondary resection after first-line anti-EGFR and doublet chemotherapy, continuing anti-EGFR MAb after resection was associated with significantly longer OS regardless of primary tumor sidedness. Citation Format: Yao-Yu Hsieh, Chin-Wen Tsai, T-CARE Group, Yi-Hsieh Liang. Continuing anti-EGFR treatment prolonged survival in mCRC patients receiving conversion liver resection [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 925.

Abstract 3700: Genomic alterations on first-line panitumumab plus FOLFIRI in metastatic colorectal cancer

Abstract Background: IMPROVE is a randomized, non-comparative multicenter, phase 2 study evaluating continuous or intermittent FOLFIRI/PANI, in first-line in patients (pts) with unresectable RAS/BRAF wild-type metastatic colorectal cancer (mCRC). In this trial intermittent FOLFIRI/PANI strategy produced a longer progression-free survival (PFS) on treatment, 17.6 months (mts) vs 11.3 mts, a reduced skin severe toxicity, 18% vs 30%, without any detrimental effect on overall survival (OS), 36.2 mts vs 36.2 mts. The trial also included a prospective genomic alterations (GAs) analysis on circulating tumor DNA with the aim to explore emergence of GAs under the selective pressure of FOLFIRI/PANI. Methods: We analyzed paired plasma samples (basal and PD) by a commercially available NGS panel enabled to simultaneously analyze KRAS, NRAS, BRAF and PIK3CA hotspot mutations from blood samples. Among them, inspecting default calling parameters on proprietary analysis software (Ion Reporter software 5.2.0), only variants with ⩾5X allele coverage and a quality score ⩾20, within an amplicon that covered at least 1000X alleles was considered. As clonality, the threshold of 0.5% of variant allele frequency (VAF) was established to classify mutations as clonal (VAF⩾0.5%) or subclonal (VAF<0.5%). Results: Of the 137 pts enrolled in the trial, GAs basal analyses were available for 84 pts. Among these, in 55 (65.5%) no GAs were detected (ND). In the remaining cases, the analysis relieved the presence of mutations for PIK3CA (N=14), KRAS (N=12), NRAS (N=2) and BRAF (N=1). According to the clonality threshold, these GAs were classified as subclonal (SC) in 12 cases (14.3%) and clonal (CL) in 17 (20.2%) cases. Survival analysis according to basal GAs clonality showed a median PFS of 16.6 mts (95% IC 13.0-20.2), 12 mts (95% IC 9.1-14.9) and 25.8 mts (95% IC 17.2-34.5) for ND, CL and SC group, respectively. Median OS was 47.7 mts for ND group (95% IC 34.9-60.5), 26.8 mts for CL (95% IC 25.8-27.8) and not reached for SC group. Moreover, we performed GAs analysis on 61 cases of which basal and PD samples were available. Forty-two cases (68.9%) resulted ND, 7 (11.5%) with SC and 12 (19.7%) with CL GAs.At PD, among 42 ND basal cases, 29 remained ND (69%), 8 (19%) and 5 cases (11.9%) developed SC and CL GAs, respectively. In the SC group, 1 kept SC (14.3%), 4 (57.1%) and 2 (28.6%) cases became ND and CL GAs, respectively. In the CL group, 10 (83.3%) kept CL GAs, 1 (8.3%) case became ND and 1 (8.3%) CL. Conclusions: These findings suggest that classical GAs associated with anti-EGFR resistance are infrequent with up-front use of anti-EGFR/chemotherapy. Moreover, our data show that basal SC GAs rarely evolve to CL GAs at progression disease and do not affect survival of pts with anti-EGFR/chemotherapy treatment. An update will be provided at the congress. NCT04425239 Citation Format: Antonio Avallone, Francesco Giuliani, Guglielmo Nasti, Vincenzo Montesarchio, Giuseppe Santabarbara, Silvana Leo, Umberto Malapelle, Gerardo Rosati, Claudio Lotesoriere, Emiliano Tamburini, Alfredo Colombo, Francesco Pepe, Claudia Cardone, Alessandra Leone, Carlo Vitagliano, Gianluca Russo, Giancarlo Troncone, Diana Giannarelli, Alfonso De Stefano, Alfredo Budillon. Genomic alterations on first-line panitumumab plus FOLFIRI in metastatic colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3700.

Abstract 2355: SGN-EGFRd2 binding and activity are agnostic to common EGFR extracellular resistance mutations acquired in response to anti-EGFR targeted antibody therapies

Abstract SGN-EGFRd2 is an investigational bispecific antibody comprised of two camelid-derived humanized variable heavy chain only (VHH) domains, one targeting Vγ9Vδ2 (gamma delta) T cells and the other targeting the epidermal growth factor receptor (EGFR). Selective antitumor activity occurs when two conditions are met: 1) the molecule engages both EGFR-expressing tumor cells and gamma delta T cells and 2) butyrophilins, in complex with phosphoantigens (pAgs), are expressed by EGFR-positive tumor cells, resulting in gamma delta T cell directed tumor cell killing by activation, degranulation and secretion of cytolytic molecules. The tumor specific proximity of gamma delta T cells and expression of the butyrophilins/pAgs complex results in the killing of EGFR-expressing tumor cells but not EGFR-expressing normal cells. EGFR is an oncogenic receptor tyrosine kinase and target of several classes of therapeutic modalities, including antibodies. Two antibodies are currently approved for the treatment of EGFR-expressing, KRAS wild-type metastatic colorectal cancer (mCRC): cetuximab (CET) and panitumumab (PAN). Although these anti-EGFR therapies provide significant survival benefits to patients, the duration of response is transient, and most patients progress and develop secondary resistance [1]. One such escape mechanism is the acquisition of mutations in the extracellular domain (ECD) of EGFR, which prevent binding of therapeutic antibodies [2]. Because SGN-EGFRd2 will be tested on patients previously exposed to anti-EGFR therapeutic antibodies, it is paramount to assess its binding to EGFR ECD mutations identified in antibody resistant mCRC patients. EGFR-negative A2058 cells were transduced to express wild type EGFR and a panel of EGFR ECD resistance mutations (N=16). The binding specificity and kinetics of SGN-EGFRd2 were compared to CET and PAN by flow cytometry on engineered cell lines and biolayer interferometry, respectively. Results indicated SGN-EGFRd2 maintained the ability to bind to all tested EGFR ECD mutants, whereas CET and PAN were unable to bind several ECD mutants, as previously described [3,4]. SGN-EGFRd2 binding to EGFR ECD mutant cell lines induced the production of interferon gamma and expression of cell surface CD107a on gamma delta T cells, confirming functional engagement. In contrast to current anti-EGFR therapeutic antibodies, SGN-EGFRd2 binding and activity was unaffected by commonly identified EGFR ECD mutations. These findings highlight SGN-EGFRd2 as a novel molecule targeting wild-type EGFR and common EGFR ECD mutations identified in the mCRC setting. Citation Format: Liem Nguyen, Chun-Shu Wong, Serena Wo, Bryan Grogan, Daniel Diolaiti, Maria Corinna Palanca-Wessels, Astrid Clarke. SGN-EGFRd2 binding and activity are agnostic to common EGFR extracellular resistance mutations acquired in response to anti-EGFR targeted antibody therapies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2355.

Dynamic ctDNA-based analysis of drug-resistant gene alterations at RAS/BRAF wild-type metastatic colorectal cancer patients after cetuximab plus chemotherapy as the first-line treatment

BackgroundThe purpose of this study was to explore the dynamic changes of genomic mutations and their correlations with the efficacy in metastatic colorectal cancer (mCRC) patients treated with cetuximab plus mFOLFOX as the first-line treatment. MethodsWe included mCRC patients from January 2018 to October 2020 as a studied cohort which were treated with cetuximab plus mFOLFOX as first line therapy. Blood samples were collected for circulating tumor DNA (ctDNA) test at three timepoints: before the first-line therapy(baseline), at the time of first-line progression and at the time of second-line progression. Progression-free survival was considered as the primary endpoint while objective response rate and overall survival were determined as the secondary endpoints. ResultsTotally 39 patients received first-line treatment, of which 25 patients entered the second-line treatment, while 10 patients entered the third-line treatment. The median follow-up time was 16.4 months (95 %CI, 14.8–19.3). Along the treatment from first-line progress disease (PD) to second-line PD, proportions of TP53 (12/18, 67 %), APC (10/18, 56 %), FBXW7 (3/18, 17 %), and AMER1 (2/18, 11 %) were gradually increased according to results of single nucleotide variation (SNV). ConclusionsResistant gene mutations caused by anti-EGFR drugs in RAS/BRAF wild-type mCRC patients can be observed by dynamic ctDNA analysis. TP53 and AMER1 mutations, tumor mutational burden (TMB) levels, and TP53/AMER1 co-mutation may predict the efficacy of the first-line cetuximab-contained treatment. Situations of genetic mutations were differentiated from first-line PD to second-line PD, which indicated that mutation detection may contribute to predict prognosis of mCRC patients.

Efficacy and Safety of Maintenance Therapy Using Cetuximab in Patients with Metastatic Colorectal Cancer: Retrospective Study.

Cetuximab (CET) combined with chemotherapy significantly improved the survival in RAS and RAF wild-type metastatic colorectal cancer (mCRC) patients, while clinical evidence was lacking on the use of maintenance therapy (MT). The study aimed to explore the role of maintenance therapy following Cetuximab + chemotherapy and the optimal Cetuximab-based maintenance therapy regimen. We retrospectively reviewed data on the efficacy and safety of CET-based MT in patients with mCRC who achieved diseasecontrolafter induction therapy. Eighty-one patients with mCRC who achieved disease control after CET + chemotherapy induction were enrolled. Overall median progression-free survival (PFS) was 10.5 (95% CI = 8.8-12.2) months and median maintenance/observation PFS (mnPFS) was 6.0 (95% CI = 5.0-7.0) months. Among these 81 patients, 61 patients were prescribed MT (CET alone for 21 patients and CET + chemotherapy for 40 patients). Median PFS and mnPFS in the MT group were significantly longer than those for the non-MT group. Different MT regimens did not affect PFS and mnPFS significantly. Univariate and multivariate analysis demonstrated MT, complete response/partial response during induction therapy, and absence of peritoneal metastasis to be positively associated with longer PFS and mnPFS. Treatment-related adverse events (AEs) were tolerable during MT, and AE-related deaths were not observed. MT with CET or CET + chemotherapy was an appropriate option following initial induction chemotherapy for patients with RAS and RAF wild-type mCRC. This strategy endowed survival benefits and a tolerable safety profile.

Molecular screening with liquid biopsy for anti-EGFR retreatment in metastatic colorectal cancer: preliminary data from the randomized phase 2 PARERE trial.

Retreatment with anti-EGFR monoclonal antibodies is a promising strategy in patients with RAS/BRAF wild-type (wt) metastatic colorectal cancer (mCRC) who achieved benefit from previous anti-EGFR exposure upon exclusion of mutations in RAS/BRAF genes according to circulating tumor DNA (ctDNA) analysis by means of liquid biopsy (LB). This treatment approach is now being investigated in the randomized phase II trial PARERE (NCT04787341). We here present preliminary findings of molecular screening. Patients with RAS/BRAFV600E wt mCRC according to tissue genotyping who benefited from previous anti-EGFR-based treatment (fluoropyrimidines, oxaliplatin, irinotecan, and antiangiogenics) and then experienced disease progression to EGFR targeting were eligible for screening in the PARERE trial. The next-generation sequencing (NGS) panel Oncomine™ was employed for ctDNA testing. A total of 218 patients underwent LB, and ctDNA sequencing was successful in 201 of them (92%). RAS/BRAFV600E mutations were found in 68 (34%) patients and were mainly subclonal (median variant allele fraction [VAF] for KRAS, NRAS, and BRAF mutant clones: 0.52%, 0.62%, and 0.12%, respectively; p = 0.01), with KRASQ61H being the most frequently detected (31%). Anti-EGFR-free intervals did not predict ctDNA molecular status (p = 0.12). Among the 133 patients with RAS/BRAFV600E wt tumors according to LB, 40 (30%) harbored a mutation in at least another gene potentially implied in anti-EGFR resistance, mainly with subclonal expression (median VAF, 0.56%). In detail, alterations in PIK3CA, FBXW7, GNAS, MAP2K, ERBB2, BRAF (class I and II non-BRAFV600E), SMAD, EGFR, AKT1, and CTNNB1 occurred in 13%, 8%, 7%, 3%, 2%, 2%, 1%, 1%, 1%, and 1% cases, respectively. Co-mutations were detected in 13 (33%) out of 40 patients. This is the largest prospective cohort of mCRC patients screened with LB for anti-EGFR retreatment in a randomized study. ctDNA genotyping reveals that at least one out of three patients candidate for retreatment should be excluded from this therapy, and other potential drivers of anti-EGFR resistance are found in approximately one out of three patients with RAS/BRAFV600E wt ctDNA.

Updated survival results of ALTER-C002: Anlotinib combined with CAPEOX as first-line treatment in RAS/BRAF wild-type unresectable metastatic colorectal cancer.

131 Background: Anlotinib is an oral multi-target tyrosine kinase inhibitor, mainly targeting VEGFR 1-3, FGFR 1-4, PDGFR a/b and c-kit. Previous trial had demonstrated that anlotinib monotherapy was effective and safe in advanced colorectal cancer. ALTER-C002 trial is an open-label, single-arm, phase II study, aimed to evaluate the efficacy and safety of anlotinib plus CAPEOX as first-line therapy in patients with RAS/ BRAF wild-type unresectable metastatic colorectal cancer (mCRC). The progression-free survival has been reported, preliminary results demonstrated significant antitumor activity and manageable toxicity, here we reported the overall survival results at the data cutoff of May 29, 2023. Methods: RAS/BRAF wild-type unresectable mCRC patients with no prior systemic treatment received anlotinib (12 mg p.o. qd, d1-d14, q3w), capecitabine (850 mg/m2 p.o., bid, d1-d14, q3w) and oxaliplatin (130 mg/m2 i.v., d1, q3w) for 6 cycles followed by anlotinib and capecitabine as maintenance therapy until disease progression. Tumor response was assessed every 6 weeks according to RECIST v1.1 by investigator. The primary endpoint was ORR, and secondary endpoints included safety, DCR, DOR and PFS. Results: From Nov 2019 to February 2021, 30 eligible patients were enrolled, of whom, median age was 60y (range, 32-72y), 26 (86.7%) had left colon or rectal cancer, and 25 (83.3%) had liver metastases. In previous reports, ORR, DCR, and median PFS were 76.7%, 93.3%, and 11.3 months, respectively. At a Median follow-up of 31.7 months (95% CI, 27.8-35.6), the median OS was 29.7 months (95% CI, 21.2-38.2), the 24-month OS rate was 55.0% (95%CI, 35.4-70.9%) and the 30-month OS rate was 40.6% (95%CI:21.6-58.9%). Conclusions: Anlotinib combined with oxaliplatin and capecitabine achieved considerable OS and showed potential efficacy as first-line therapy for mCRC with manageable toxicity profiles. Clinical trial information: NCT04080843 .

Genome-wide DNA methylation status to predict the efficacy of modified (m)-FOLFOXIRI plus cetuximab as initial treatment for RAS wild-type metastatic colorectal cancer: A biomarker study of the DEEPER trial (JACCRO CC-13AR).

152 Background: Genome-wide DNA methylation status (GWMS) has been shown to be a predictor of therapeutic response to anti-EGFR antibody therapies. This study investigated the association between GWMS and clinical outcomes of first-line chemotherapy with anti-EGFR or anti-VEGF antibody agents for metastatic colorectal cancer (mCRC). Methods: Tumor tissues of mCRC patients registered in the JACCRO CC-13AR (clinical trial number: UMIN000018412) were analyzed for GWMS and were classified into low-methylated colorectal cancer (LMCC) and high-methylated colorectal cancer (HMCC). Clinical data were obtained from the randomized phase II trial, DEEPER trial (JACCRO CC-13) [NCT02515734], in which patients were randomly assigned to m-FOLFOXIRI plus cetuximab (CET) arm and m-FOLFOXIRI plus bevacizumab (BEV) arm for treatment. Progression-free survival (PFS), overall survival (OS), depth of response (DpR), and response rate (RR) were analyzed according to GWMS for each treatment arm. Results: One hundred thirty-seven out of 227 patients enrolled in the JACCRO CC-13AR were analyzed. Of these, 122 (89.1%) and 15 (10.9%) were classified in the LMCC and HMCC, respectively; 66 were assigned to the CET arm including 7 HMCCs, and 54 were assigned to the BEV arm including 8 HMCCs. In the CET arm, PFS and OS of the LMCC were significantly longer than those of the HMCC (median PFS 14.3 vs. 4.0 months, hazard ratio [HR] 0.11, 95% CI: 0.05–0.29, P<0.01; median OS 42.7 vs. 13.6 months, HR 0.04, 95% CI: 0.01–0.13, P<0.01). There were no differences in DpR and RR between the LMCC and the HMCC (median DpR 58.1% vs. 46.7%, P=0.45), although RR of the LMCC was numerically higher than that of the HMCC (71.2% vs. 42.9%, P=0.13). In contrast, in the BEV arm, there were no differences in PFS, DpR, and RR between the two groups (median PFS 16.1 vs. 12.2 months, P=0.08; median DpR 48.3% vs. 53.9%, P=0.99; RR 73.0% vs. 75.0%, P=0.91). However, OS of the LMCC was significantly longer than that of the HMCC (median OS 48.9 vs. 24.2 months, HR 0.39, 95% CI: 0.16–0.95, P=0.03). Conclusions: This study showed that GWMS may be a prognostic marker for initial treatment in RAS wild-type mCRC. Also, GWMS correlates to the survival outcomes of m-FOLFOXIRI plus CET as initial treatment for RAS wild-type mCRC. Clinical trial information: 000018412 .

Refining first-line treatment decision in RAS wildtype (RAS-WT) metastatic colorectal cancer (mCRC) by combining clinical biomarkers: Results of the randomized phase 3 trial FIRE-3 (AIO KRK0306).

13 Background: Optimal patient selection for first-line treatment targeting epithelial growth factor receptor (EGFR) in RAS-WT mCRC is based on primary tumor sidedness (PTS) with anti-EGFR being the preferred option for patients with left-sided mCRC (LC). Right-sided mCRCs (RC) are preferentially treated in combination with bevacizumab targeting vascular endothelial growth factor (VEGF). Here, improvement in patient selection was evaluated by combining clinical biomarkers beyond PTS using the randomized phase III trial FIRE-3. Methods: FIRE-3 evaluated first-line FOLFIRI (folinic acid, fluorouracil and irinotecan) plus cetuximab (FOLFIRI/Cet) versus FOLFIRI plus bevacizumab (FOLFIRI/Bev) in patients with RAS-WT mCRC. Besides PTS, further clinical biomarkers were evaluated in pairwise combinations using Cox regression models and model-based recursive partitioning with Weibull models to predict treatment benefit of either treatment arm regarding overall survival (OS): age, sex, liver-limited disease status (LLD) and baseline carcinoembryonic antigen serum level (CEA). The resulting P-values of second-order interactions were adjusted using Holm-Bonferroni correction. The model with the best test statistics and P-value was chosen for further evaluations. Results: In 400 patients with RAS-WT mCRC, a model combining PTS and LLD status best predicted treatment outcome of either treatment arm (c-index = 0.603, p=0.005). Here, a significant survival benefit of FOLFIRI/Cet over FOLFIRI/Bev was evident in patients with LC/non-LLD (HR 0.62, p=0.02) compared to LC/LLD (HR 0.83, p=0.40). In patients with RC, FOLFIRI/Bev was significantly associated with increased OS compared to FOLFIRI/Cet when patients suffered from non-LLD (HR 2.09, p=0.010). However, patients with RC/LLD rather had a benefit from FOLFIRI/Cet compared to FOLFIRI/Bev (HR 0.59, p=0.218). Conclusions: Combining clinical biomarkers PTS and LLD status might improve optimal patient selection for targeted first-line treatment in RAS-WT mCRC. Validation in further data sets is warranted. Clinical trial information: NCT00433927 .

Efficacy, safety and genomic analysis of SCT200, an anti-EGFR monoclonal antibody, in patients with fluorouracil, irinotecan and oxaliplatin refractory RAS and BRAF wild-type metastatic colorectal cancer: a phase Ⅱ study

Limited therapeutic options are available for metastatic colorectal cancer (mCRC) patients after failure of first- and second-line therapies, representing an unmet medical need for novel therapies. This is an open-label, single arm, multicenter, phase Ⅱ study aiming to perform the efficacy, safety and genomic analysis of SCT200, a noval fully humanized IgG1 anti-epidermal growth factor receptor (EGFR) monoclonal antibody, in patients with fluorouracil, irinotecan and oxaliplatin refractory RAS and BRAF wild-type mCRC. SCT200 (6mg/kg) was given weekly for the first six weeks, followed by a higher dose of 8mg/kg every two weeks until disease progression or unacceptable toxicity. Primary endpoint was independent review committee (IRC)-assessed objective response rate (ORR) and secondary endpoints included ORR in patients with left-sided tumor, disease control rate (DCR), duration of response (DoR), time to response (TTR), progression-free survival (PFS), overall survival (OS) and safety. From February 12, 2018 to December 1, 2019, a total of 110 patients aged between 26 and 77 years (median: 55; interquartile range [IQR]: 47-63) with fluorouracil, oxaliplatin, and irinotecan refractory RAS and BRAF wild-type mCRC were enrolled from 22 hospitals in China. As the data cut-off date on May 15, 2020, the IRC-assessed ORR and DCR was 31% (34/110, 95% confidence interval [CI] 22-40%) and 75% (82/110, 95% CI 65-82%), respectively. Thirty one percent (34/110) patients achieved confirmed partial response (PR). The median PFS and median OS were 5.1 months (95% CI 3.4-5.2) and 16.2 months (95% CI 11.1-not available [NA]), respectively. The most common≥grade 3 treatment-related adverse events (TRAEs) were hypomagnesemia (17%, 19/110) and acneiform dermatitis (11%, 12/110). No deaths occurred. Genomic analysis suggested positive association between MYC amplification and patients' response (P=0.0058). RAS/RAF mutation and MET amplification were the most frequently detected resistance mechanisms. Patients with high circulating tumor DNA (ctDNA) at baseline or without ctDNA clearance at the 7th week after the first dose of SCT200 administration before receiving SCT200 had worse PFS and OS. SCT200 exhibited promising clinical efficacy and manageable safety profiles in RAS and BRAF wild-type mCRC patients progressed on fluorouracil, irinotecan and oxaliplatin treatment. The baseline ctDNA and ctDNA clearance status at the 7th week after the first dose of SCT200 administration before receiving SCT200 could be a potential prognostic biomarker for RAS and BRAF wild-type mCRC patients with SCT200 therapy. This study was sponsored by Sinocelltech Ltd., Beijing, China and partly supported by the National Science and Technology Major Project for Key New Drug Development (2019ZX09732001-006, 2017ZX09304015).

Triplet chemotherapy plus cetuximab as first-line treatment in extended RAS wild-type metastatic colorectal cancer patients

BackgroundTriplet chemotherapy plus cetuximab showed promising results in phase II trials in unsystematically selected RAS population. We evaluated FOLFIRINOX+cetuximab efficacy as first-line treatment in extended RAS wild-type metastatic colorectal cancer (mCRC) patients. MethodsWe retrospectively analyzed patients treated with FOLFIRINOX+cetuximab, using data from clinical trials and real-life practice. Extended mutation analysis was performed when RAS/BRAF status was unavailable. The primary endpoint was progression-free survival (PFS). ResultsSeventy patients (61.4 % male, median age 58.7 years) were analyzed. Eighty percent had left-sided mCRC and 97.1 % had liver metastases. Median PFS and overall survival (OS) were 13.3 and 48.5 months, respectively. The objective response rate was 85.7 %, with 20 % complete response. Primary tumor location did not affect OS and PFS. BRAF wild-type patients (n = 65) had longer PFS (13.3 vs. 6.0 months; p = 0.005) and OS (50.1 vs. 21.2 months; p = 0.007) than BRAF mutated patients (n = 5, including four BRAFV600E). Median OS was significantly longer in resected patients (n = 39, 55.1 vs. 30.7 months; p = 0.030). Main toxicities were diarrhea (31.4 %) and neutropenia (21.4 %). ConclusionFOLFIRINOX+cetuximab provides good PFS, high response rate and prolonged disease control in initially unresectable extended RAS wild-type mCRC. This combination is particularly interesting for selected patients with liver-limited disease eligible to secondary resection.

Potential Efficacy of Shiunko for Anti-Epidermal Growth Factor Receptor (EGFR) Monoclonal Antibody-Induced Skin Fissure: A Single Institutional Case Series.

Anti-epidermal growth factor receptor monoclonal antibody (anti-EGFR mAb) is the key drug for RAS/BRAF V600E wild-type metastatic colorectal cancer (mCRC). However, anti-EGFR mAb-induced skin fissures often affect a patient's quality of life. Shiunko, a traditional Japanese topical herbal medicine, is used for burns and dermatitis and may potentially have wound-healing effects. Herein, we report cases of patients with mCRC who were treated with Shiunko for anti-EGFR mAb-induced skin fissure. We retrospectively reviewed consecutive patients with mCRC who received an anti-EGFR mAb-containing regimen and were treated with Shiunko twice a day for skin fissures at the National Cancer Center Hospital East between March 2022 and December 2022. Skin fissures were assessed at baseline and at every visit until 28 days after Shiunko initiation according to CTCAE v5.0. Among the 11 patients, 5 patients were female; the median age was 61 (range, 43-79) years. The median treatment duration with anti-EGFR mAb before Shiunko initiation was 13.1 (range, 6-52) weeks. Skin moisturizer and topical steroids were applied for skin fissures in 11 and 5 patients, respectively. All patients had grade 2 skin fissures at baseline of Shiunko initiation. Two weeks after Shiunko initiation, complete recovery was noted in 4 patients and improvement to grade 1 was noted in 6 patients. There were no Shiunko-related adverse events. Ten patients continued anti-EGFR mAb treatment until disease progression, while 1 patient discontinued anti-EGFR mAb treatment due to severe eruptions. Shiunko could be a treatment option for anti-EGFR mAb-induced skin fissure. Further studies are warranted to investigate the efficacy and safety of Shiunko for anti-EGFR mAb-induced skin fissure.