Unresectable Metastatic Colorectal Cancer Research Articles

XELOX (capecitabine plus oxaliplatin) plus bevacizumab (anti-VEGF-A antibody) with or without adoptive cell immunotherapy in the treatment of patients with previously untreated metastatic colorectal cancer: a multicenter, open-label, randomized, controlled, phase 3 trial

Fluoropyrimidine-based combination chemotherapy plus targeted therapy is the standard initial treatment for unresectable metastatic colorectal cancer (mCRC), but the prognosis remains poor. This phase 3 trial (ClinicalTrials.gov: NCT03950154) assessed the efficacy and adverse events (AEs) of the combination of PD-1 blockade-activated DC-CIK (PD1-T) cells with XELOX plus bevacizumab as a first-line therapy in patients with mCRC. A total of 202 participants were enrolled and randomly assigned in a 1:1 ratio to receive either first-line XELOX plus bevacizumab (the control group, n = 102) or the same regimen plus autologous PD1-T cell immunotherapy (the immunotherapy group, n = 100) every 21 days for up to 6 cycles, followed by maintenance treatment with capecitabine and bevacizumab. The main endpoint of the trial was progression-free survival (PFS). The median follow-up was 19.5 months. Median PFS was 14.8 months (95% CI, 11.6–18.0) for the immunotherapy group compared with 9.9 months (8.0–11.8) for the control group (hazard ratio [HR], 0.60 [95% CI, 0.40–0.88]; p = 0.009). Median overall survival (OS) was not reached for the immunotherapy group and 25.6 months (95% CI, 18.3–32.8) for the control group (HR, 0.57 [95% CI, 0.33–0.98]; p = 0.043). Grade 3 or higher AEs occurred in 20.0% of patients in the immunotherapy group and 23.5% in the control groups, with no toxicity-associated deaths reported. The addition of PD1-T cells to first-line XELOX plus bevacizumab demonstrates significant clinical improvement of PFS and OS with well tolerability in patients with previously untreated mCRC.

Patient experience of medication administration and development of a Patient Experience and Preference Questionnaire (PEPQ) for patients with advanced or metastatic cancer.

Introduction: A better understanding of patient experience of intravenous (IV) or subcutaneous (SC) routes of administration is fundamental to providing optimal administration of medical therapies to oncology patients. The objective of this study was to examine patient experiences of IV and SC treatment with nivolumab and confirm the relevance of item concepts in the Patient Experience and Preference Questionnaire (PEPQ). The PEPQ is a clinical outcomes' assessment instrument developed to obtain patient-centric data and understand the experience with IV and SC treatment administration. Methods: Embedded qualitative interviews were conducted with a subset of participants from three treatment cohorts with metastatic non-small-cell lung cancer (NSCLC), renal cell carcinoma (RCC), unresectable or advanced metastatic melanoma, hepatocellular carcinoma (HCC), or colorectal cancer (CRC) from the CA209-8KX clinical trial. Concept elicitation interviews were conducted within 14days of the initial treatment cycle and patient experiences with IV and SC treatment administration were assessed. Concepts from interviews were mapped to the PEPQ version 1.0 questions to assess relevance and convergence of concepts. Results: Interviews were conducted with 43 trial participants from clinical sites opting to participate from six countries (Argentina, France, the Netherlands, Poland, Spain, and New Zealand). The mean age of sub-study participants was 66 ± 11.3years (range 24-80years), and 67.4% (N = 29) were male. Sub-study participants with experience of SC most frequently reported symptoms or signs of injection-related redness (27.9%), itching (14.0%), and pain (of needle), and described the pain as pricking, stinging, or tingling (11.0% each). The amount of pain and time burden were widely endorsed as important factors for satisfaction and related to the route of medication administration. For 11 sub-study participants with experience with both IV and SC treatments, 10 (90.9%) preferred SC over IV treatment administration. Conclusion: This study summarizes the experience and satisfaction of receiving IV or SC treatment and confirms the relevance of the PEPQ in a subgroup of CA209-8KX clinical trial participants with metastatic NSCLC, RCC, melanoma, HCC, and CRC. Participant treatment experience and satisfaction with the route of medication mapped to the PEPQ question content support the relevance of PEPQ v2.0 in clinical trials as a self-report measure.

Phase II study evaluating the efficacy of PDS0301 in combination with hepatic artery infusion pump (HAIP) and systemic therapy for patients with metastatic colorectal cancer or intrahepatic cholangiocarcinoma.

TPS586 Background: Treatment of advanced liver tumors continues to pose significant challenges. Despite advances in immunotherapies, including immune checkpoint blockade, responses in colorectal liver metastases and biliary tract cancers remain suboptimal. The lack of robust clinical efficacy is likely myriad, including immunosuppression by the tumor microenvironment and poor susceptibility of these tumors to immune infiltration and surveillance. Interleukin-12 (IL-12) is a pro-inflammatory cytokine with extensive anti-tumor properties, but therapeutic development of recombinant human IL-12 (rhIL-12) was halted due to significant systemic toxicities. PDS0301 (formerly M9241) is a novel human monoclonal antibody (NHS76) fused to two IL-12 heterodimers. The NHS76 antibody specifically targets histone/DNA complexes in regions of cellular necrosis resulting in accumulation within tumors. Importantly, recent Phase I trials have shown PDS0301 monotherapy to be well tolerated. We hypothesize that synchronization of PDS0301 administration with tumor cell death induced by locoregional and systemic chemotherapies will demonstrate increased efficacy over standard of care therapy. Methods: This is a single center, non-randomized Phase II study to determine the safety and efficacy of PDS0301 in combination with floxuridine (FUDR) administered by hepatic artery infusion pump (HAIP) and systemic chemotherapies in patients with either unresectable metastatic colorectal cancer (mCRC) or intrahepatic cholangiocarcinoma (ICC). Eligibility criteria include histologically or cytologically confirmed colorectal adenocarcinoma metastatic to the liver (Cohort 1) or unresectable intrahepatic cholangiocarcinoma with no evidence of extrahepatic metastases (Cohort 2). Patients will receive HAIP-administered (FUDR) plus PDS0301 at a starting dose of 12mcg/kg in 28-day cycles. Beginning in cycle 2, systemic chemotherapy with FOLFOX (Leucovorin, 5-Fluorouracil [5-FU], and Oxaliplatin) or FOLFIRI (Leucovorin, 5-FU and Irinotecan) for mCRC or GemOx (Gemcitabine and Oxaliplatin) for ICC will be introduced. Patients will be evaluated for response at eight-week intervals. The primary endpoint is overall response rates to PDS0301 and HAIP/systemic combination therapy. Secondary objectives include hepatic progression-free survival (PFS), extra-hepatic PFS, overall survival, and safety. Scientific objectives include determination of microenvironment alterations through pre-and post-treatment biopsies as well as evaluation of peripheral immune subsets and cytokines. To date, we have enrolled 8 of 23 patients in Cohort 1. Clinical trial information: NCT05286814 .

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 .

Clinical Phase I Study of TAS102/Irinotecan/Bevacizumab Combination Therapy in Japanese Patients With Unresectable Metastatic Colorectal Cancer (mCRC).

In this phase I study, we aimed to examine the safety of a triple combination (TAS-102/irinotecan/bevacizumab) therapy in patients with previously treated metastatic colorectal cancer (mCRC). In the TAS-102 dose-escalation phase, we determined dose-limiting toxicity (DLT), estimated the maximum tolerated dose (MTD), and determined the recommended dose (RD); in the expansion phase, we evaluated safety. The RD was administered in advance for 10 patients. The TAS-102 dose was increased to 25-35 mg/m2 and administered orally twice on days 1-5 and 8-12. Irinotecan (100 mg/m2) and bevacizumab (5 mg/m2) were administered on days 1 and 15 of the treatment, respectively. Fifteen patients were enrolled in dose-escalation Levels 1-3, and ten in the expansion phase. A 30 mg/m2 TAS-102 dose at Level 2 was administered to three patients, with one presenting grade 4 neutropenia. A 35 mg/m2 TAS-102 dose at Level 3 was administered to five patients, with three patients presenting grade 4 neutropenia and grade 3 DLTs. We added three patients at Level 2 and set the MTD at 30 mg/m2, with no DLTs. The RD was fixed at 25 mg/m2, with no DLTs (N = 10) or treatment-related deaths. One patient showed complete response at Level 2, four presented partial response, and eleven individuals maintained stable disease for over four months. The median progression-free survival duration was 7.6 months, while the median overall survival period was 16.9 months. The TAS-102/irinotecan/bevacizumab combination therapy was safe, effective, and well-tolerated in patients previously treated with mCRC.

Triplet‐drug chemotherapy combined with anti‐EGFR antibody as an effective therapy for patients with initially unresectable metastatic colorectal cancer: a meta-analysis

The meta-analysis aimed to assess the clinical efficacy of chemotherapeutic triplet‐drug regimen combined with anti‐EGFR antibody in patients with initially unresectable metastatic colorectal cancer (mCRC). A systematic literature search was performed in PubMed Publisher. Studies evaluating FOLFOXIRI combine with panitumumab or cetuximab as the therapy for initially unresectable mCRC were included. The primary outcome was objective response rate (ORR) and rate of R0 resections. The secondary outcomes included overall survival (OS), progression-free survival (PFS), and grades 3 or 4 adverse events. R software (version 4.0.2) and RevMan (version 5.3) were used to analyze the extracted data. The studies included were published between 2010 and 2021, involving four single-arm phase II trials and two randomized phase II trials. A total of 6 studies with 282 patients were included. The data showed a significant benefit for the FOLFOXIRI + anti-EGFR antibody arm compared with FOLFOXIRI arm (RR 1.33; 95% CI, 1.13–1.58; I2 = 0%, P < 0.05). The pooled ORR and pooled rate of R0 resection in patients who receiving FOLFOXIRI + anti-EGFR antibody were 85% (95% CI, 0.78–0.91; I2 = 58%) and 42% (95% CI, 0.32–0.53; I2 = 62%), respectively. The range of median PFS between all the six studies was 9.5–15.5 months, with weighted pooled median PFS mean 11.7 months. The range of median OS between all the four studies was 24.7–37 months, with weighted pooled median PFS mean 31.9 months. The common grades 3 and 4 adverse events were diarrhea and neutropenia. Our findings show that triplet-drug chemotherapy (FOLFOXIRI) combined with anti-EGFR antibody (panitumumab or cetuximab) represents a very effective therapeutic combination associated with a significant ORR and R0 rection rate for patients with molecularly unselected and surgically unresectable metastatic CRC.

110P The correlation between multi-dimensional characteristics of circulating tumor cells (CTC) and treatment response in patients with initially unresectable metastatic colorectal cancer

110P The correlation between multi-dimensional characteristics of circulating tumor cells (CTC) and treatment response in patients with initially unresectable metastatic colorectal cancer

Clinical Outcomes of Upfront Primary Tumor Resection in Synchronous Unresectable Metastatic Colorectal Cancer.

The role of upfront primary tumor resection (PTR) in patients with unresectable metastatic colorectal cancer without severe symptoms remains controversial. We retrospectively analyzed the role of PTR in overall survival (OS) in this population. Among the 205 patients who enrolled, the PTR group (n = 42) showed better performance (p = 0.061), had higher frequencies of right-sided origin (p = 0.058), the T4 stage (p = 0.003), the M1a stage (p = 0.012), and <2 organ metastases (p = 0.002), and received fewer targeted agents (p = 0.011) than the chemotherapy group (n = 163). The PTR group showed a trend for longer OS (20.5 versus 16.0 months, p = 0.064) but was not related to OS in Cox regression multivariate analysis (p = 0.220). The male sex (p = 0.061), a good performance status (p = 0.078), the T3 stage (p = 0.060), the M1a stage (p = 0.042), <2 organ metastases (p = 0.035), an RAS wild tumor (p = 0.054), and the administration of targeted agents (p = 0.037), especially bevacizumab (p = 0.067), seemed to be related to PTR benefits. Upfront PTR could be considered beneficial in some subgroups, but these findings require larger studies to verify.

611P SHR-1701 in combination with BP102 and XELOX as first-line (1L) treatment for patients (pts) with unresectable metastatic colorectal cancer (mCRC): Data from a phase II/III study

611P SHR-1701 in combination with BP102 and XELOX as first-line (1L) treatment for patients (pts) with unresectable metastatic colorectal cancer (mCRC): Data from a phase II/III study

NEXUS trial: a multicenter phase II clinical study evaluating the efficacy and safety of the perioperative use of encorafenib, binimetinib, and cetuximab in patients with previously untreated surgically resectable BRAF V600E mutant colorectal oligometastases

BackgroundThe optimal treatment strategy for resectable BRAF V600E mutant colorectal oligometastases (CRM) has not been established due to the rarity and rapid progression of the disease. Since the unresectable recurrence rate is high, development of novel perioperative therapies are warranted. On December 2020, the BEACON CRC triplet regimen of encorafenib, binimetinib, and cetuximab was approved for unresectable metastatic colorectal cancer in Japan.MethodsThe NEXUS trial is a multicenter phase II clinical study evaluating the efficacy and safety of the perioperative use of encorafenib, binimetinib, and cetuximab in patients with previously untreated surgically resectable BRAF V600E mutant CRM. The key inclusion criteria are as follows: histologically diagnosed with colorectal adeno/adenosquamous carcinoma; RAS wild-type and BRAF V600E mutation by tissue or blood; and previously untreated resectable distant metastases. The triplet regimen (encorafenib: 300 mg daily; binimetinib: 45 mg twice daily; cetuximab: 400 mg/m2, then 250 mg/m2 weekly, 28 days/cycle) is administered for 3 cycles each before and after curative resection. The primary endpoint of the study is the 1-year progression-free survival (PFS) rate and the secondary end points are the PFS, disease-free survival, overall survival, and objective response rate. The sample size is 32 patients. Endpoints in the NEXUS trial as well as integrated analysis with the nationwide registry data will be considered for seeking regulatory approval for the perioperative use of the triplet regimen.DiscussionThe use of the triplet regimen in the perioperative period is expected to be safe and effective in patients with resectable BRAF V600E mutant CRM.Trial registrationjRCT2031220025, April. 16, 2022.

Drug-induced immune-mediated thrombocytopenia due to bevacizumab-FOLFOX therapy: a case report

Drug-induced immune thrombocytopenia (DITP) is a very rare disease, with an estimated annual incidence of 10 cases per million. Oxaliplatin and irinotecan are widely used as chemotherapy for high-risk stage II and III colorectal cancer, and DITP has been reported to occur in patients using those agents. To treat unresectable metastatic colorectal cancer, bevacizumab is used in combination with oxaliplatin or irinotecan, and there have been a few reports of DITP cases in patients receiving that regimen. In this report, we describe a 68-year-old male patient with metastatic colon cancer (KRAS mutant type) to the liver and lung who developed acute immune-mediated thrombocytopenia due to bevacizumab-FOLFOX (5-fluorouracil, leucovorin, and oxaliplatin) therapy. During treatment, he showed purpura in his lower extremities on 21st cycle day 2. Lab work revealed a platelet count of less than 2,000/mL, reflecting a decrease from 135,000/mL at the start of the cycle 1 day prior. He did not have any other types of cytopenia or significant changes in laboratory findings. We diagnosed DITP due to bevacizumab-FOLFOX, and the patient did not show isolated thrombocytopenia after switching to Ziv-aflibercept-FOLFIRI (5-fluorouracil, leucovorin, and irinotecan).

Sintilimab plus bevacizumab, oxaliplatin and capecitabine as first-line therapy in RAS-mutant, microsatellite stable, unresectable metastatic colorectal cancer: an open-label, single-arm, phase II trial

Microsatellite stable (MSS) and RAS-mutant metastatic colorectal cancer (mCRC) patients are characterized by an immunosuppressive microenvironment and a low response rate to immunotherapy. Chemotherapy and anti-angiogenesis therapy have been reported to potentially promote immunotherapy response. This study aims to assess the preliminary anti-tumor activity and safety of sintilimab plus bevacizumab, oxaliplatin and capecitabine as a treatment option for patients with RAS-mutant MSS mCRC. This study was an open-label, single-arm, phase II trial in China. Patients with unresectable, RAS-mutant and MSS metastatic colorectal adenocarcinoma received treatment by intravenous sintilimab (200mg, day 1) plus bevacizumab (7.5mg/kg, day 1), oxaliplatin (135mg/m2, day 1) and oral capecitabine (1g/m2, day 1-14) in each 21-day cycle. The primary endpoints included objective response rate (ORR) and adverse events. Biomarker analysis was performed to identify potential predictors of good response to treatment. This study is registered with ClinicalTrials.gov, number NCT04194359. Between April 2021 and December 2021, 25 patients were enrolled. Two (8%) patients showed complete response (CR), 19 (76%) had partial response (PR) and 4 (16%) presented with stable disease. ORR reached 84% (95% CI, 63.9-95.5) and the disease control rate was 100% (95% CI, 86.3-100). The median progression-free survival (PFS) was 18.2 months for the full analysis set. The most common treatment-related adverse events (TRAEs) in all grades were anemia (21/25, 84%), neutropenia (20/25, 80%), and hand-foot syndrome (14/25, 56%). The most frequent grade 3 or 4 TRAEs were neutropenia (3/25, 12%) and increased alanine transaminase (2/25, 8%). No grade 5 adverse events occurred. In the exploration of biomarkers, 5 patients could be characterized as TTN/OBSCN "double-hit" after treatment, and the copy number variants burden was significantly decreased in tumor tissues after treatment compared with the baseline. Nanostring panel RNA sequencing analysis indicated a better tumor immune microenvironment cell infiltration in CR/PR patients compared with non-CR/PR patients as well as the PFS-long (≥12.5 months) group compared with the PFS-short group. Combination treatment with sintilimab plus bevacizumab, oxaliplatin and capecitabine as first-line treatment demonstrated a promising antitumor activity and a manageable safety profile in RAS-mutant, MSS and unresectable mCRC. Exploratory biomarker assessment analysis showed that some RAS-mutant and MSS patients changed into "immune-hot" subtype after the treatment. This study was supported by the Key R&D Program of Zhejiang Province (2021C03125 to Ying Yuan), the National Natural Science Foundation of China (81872481 to Ying Yuan, 82072624 to Kefeng Ding), the Fundamental Research Funds for the Central Universities (No. 226-2022-00009 to Kefeng Ding), and the Zhejiang Provincial Natural Science Foundation of China (No. LY22H160024 to Hanguang Hu).

CDX2 Is a Prognostic Biomarker for Unresectable Metastatic Colorectal Cancer.

Colorectal cancer (CRC) with reduced expression of the homeobox transcription factor CDX2, a master gene essential for the development and maintenance of the intestinal tract, is known as a poor prognosis subtype of CRC. The recurrence rate is high in patients with CDX2low CRC. However, the prognostic significance of CDX2 in advanced CRC is unclear. This study aimed to elucidate the prognostic significance of CDX2 in unresectable metastatic CRC (mCRC). Twenty-nine patients with unresectable mCRC who underwent primary site resection at the Kobe University Hospital during a 6-year period from January 2008 to January 2015 were included. The tissues from those patients were immunohistochemically stained with anti-CDX2 antibody (clone: CDX2-88). The patients were divided into CDX2high CRC group and CDX2low CRC group and their prognoses were analyzed. There were no clear differences in background between the two groups. A low CDX2 expression was associated with reduced overall survival (37.67 months vs. 25.32 months, p=0.03) and tended to associate with reduced progression-free survival (17.4 months vs. 12.9 months, p=0.37). Two patients received chemotherapy after resection of the primary lesion and obtained pathological complete response. CDX2 expression might be a possible prognostic biomarker for unresectable mCRC.

Intraarterial chemotherapy of liver metastases of colorectal cancer. Experience of National Cancer Institute of Ukraine.

e15619 Background: Liver - is the most often site of colorectal cancer metastases. Although surgical resection of primary tumor and liver metastases is the most radical type of treatment, only 10-25% of patients are eligible for this approach. Our aim was to evaluate efficacy of intraarterial chemotherapy for patients with primary unresectable metastatic colorectal cancer (mCRC) to improve prognosis and overall response for treatment. Methods: records of 73 patients with primary unresectable mCRC, who undergone catheterization of liver artery and received intraartetial chemotherapy (with 5-FU) in period 2008-2018 years at the Clinic of National Cancer Institute (Ukraine). Results: the figure of overall response: 57.5% (n = 42) - partial response, 8.2% (n = 6) - complete radiological response, 12.3% (n = 9) - stable disease, 21.9% (n = 16) - chemoresistant tumor. 46.6% (n = 34) of patient undergone resection of previously unresectable liver metastases. In 4.1% (n = 3) complete histological response was estimated. Surgical mortality and morbidity rate were 1.3% and 6.8% respectively. Cause of postoperative mortality was lung embolism, complications included bacterial infections and hemorrhage in postoperative period. Main reason for inability to perform operations were post chemotherapeutic toxicity, which did not resolved on optimal terms for operation. The overall 5-year survival rate was 29.4% in group who undergone resection and 17.9% in group, were patients were not radically operated (p &lt; 0.05). Conclusions: catheterization of liver artery with further intraarterial chemotherapy can potentially convert unresectable metastases into resectable, therefore improving treatment results and overall survival.

FOLFOXIRI plus bevacizumab and atezolizumab as upfront treatment of unresectable metastatic colorectal cancer (mCRC): Updated and overall survival results of the phase II randomized AtezoTRIBE study.

3500 Background: AtezoTRIBE (NCT03721653) is a phase II randomized trial in which unresectable mCRC pts were randomized 1:2 to 1st-line FOLFOXIRI/bev [arm A] or FOLFOXIRI/bev/atezo [arm B]. Adding atezo to FOLFOXIRI/bev was safe and improved PFS (primary endpoint), with a modest benefit also among pts with pMMR tumors. Subgroup analyses suggest that TMB and Immunoscore IC (IS IC) -an IHC biomarker measuring CD8 and PD-L1 cell densities and their proximity- may identify pts with pMMR tumors deriving benefit from adding atezo to FOLFOXIRI/bev. Methods: The study had 85% power to detect a HR for PFS (time from randomization to 1st PD or death [PD1]) of .66 in favor of arm B with 1-sided α error of .10. Secondary endpoints included PFS2 (time from randomization to PD on any treatment given after PD1 or death [PD2]), 2nd PFS (time from PD1 to PD2), and OS. MMR, TMB, IS IC were correlated to clinical outcome. Results: 218 pts (arm A/B:73/145) were enrolled. Main pts’ characteristics were right-sided 44%/45%, RAS mut 71%/74%, BRAF mut 14%/8%, dMMR 7%/6%, high TMB 10%/12%, high IS IC 32%/32%. At a median follow-up of 37.0 mos, 175 (80%, arm A/B: 64/111) PD1, 150 (69%, arm A/B: 53/97) PD2, and 118 (54%, arm A/B: 43/75) OS events were collected. Out of 175 pts with a PD1 event, 135 (77%, arm A/B:50/85) received a subsequent treatment; among them, 121 pts (arm A/B: 43/78) had a PD2 event. PFS, PFS2, 2nd PFS and OS results in the intention-to-treat (ITT) population and the pMMR group are listed in the Table. In the ITT population, significant interactions between treatment and MMR status (Pint .011), TMB (Pint .008), and IS IC (Pint .037) were reported in terms of PFS. Only IS IC was associated with a differential OS benefit (Pint .065), with pts bearing IS IC-high tumors deriving benefit from adding atezo (HR 0.43, 95%CI 0.19-1.00), differently than those with IS IC-low tumors (HR 1.09, 95%CI 0.65-1.83). In the pMMR group, significant interactions between treatment and TMB and IS IC were reported in terms of PFS (Pint .016 and .051, respectively) and OS (Pint .043 and .063, respectively). Pts bearing IS IC-high tumors derived higher OS benefit from adding atezo (HR 0.44, 95%CI 0.19-1.03), than those with IS IC-low tumors (HR 1.15, 95% CI 0.67-1.97). Conclusions: Pts with IS IC-high and/or TMB high pMMR mCRC seem to derive a survival benefit from adding atezo to FOLFOXIRI/bev as upfront treatment. These findings deserve confirmation in a properly designed phase III trial. Clinical trial information: NCT03721653 . [Table: see text]

Modified FOLFOXIRI plus cetuximab and avelumab as initial therapy in RAS wild-type unresectable metastatic colorectal cancer: Results of the phase II AVETRIC trial by GONO.

3575 Background: The modified schedule of FOLFOXIRI (mFOLFOXIRI) in combination with an anti-EGFR agent showed a manageable safety profile and remarkable activity in RAS wild-type (wt) metastatic colorectal cancer (mCRC). The association of an active cytotoxic regimen with cetuximab (cet) may increase the exposure of tumour-associated neoantigens and induce immunogenic cell death and antibody-dependent cell-mediated cytotoxicity thus enabling the effect of immune checkpoint inhibitors. The AVETRIC study aimed at exploring the efficacy and safety of first-line mFOLFOXIRI plus cet and avelumab (ave) in RAS wt mCRC patients (pts). Methods: AVETRIC is a prospective, open label, multicenter, phase II, single arm trial in which initially unresectable and previously untreated RAS wt mCRC pts received mFOLFOXIRI (irinotecan 150 mg/sqm, oxaliplatin 85 mg/sqm, folinate 200 mg/sqm leucovorin [LV], and 5-fluorouracil [5FU] 2400 mg/sqm) plus cet (500 mg/sqm) and ave (800 mg) every 2 weeks up to 12 cycles followed by maintenance with 5FU/LV plus cet and ave until disease progression. A safety run-in phase including the first 6 enrolled pts was planned. Due to the occurrence of grade 3-4 diarrhoea in 2 (33%) pts, the protocol study was amended to reduce the irinotecan dose to 130 mg/sqm. Primary endpoint was Progression Free Survival (PFS). Fifty-eight pts were needed to detect an increase in median PFS (mPFS) from 10.0 to 19.4 months (mos), setting one-sided α and β errors at 0.05 and 0.10, respectively. The trial is registered at Clinicaltrial.gov, NCT04513951. Results: Between Jun 2020 and Dec 2021, 62 pts were enrolled in 16 Italian centres. Main pts' characteristics were: median age 56 yrs, ECOG PS 0 87%, synchronous metastases 94%, liver-only disease 42%, left-sided primary tumour 89%; all pts had BRAF wt and proficient MMR (pMMR) tumours. The primary endpoint was met. At a median follow-up of 16.0 months, 39 (63%) events were recorded and mPFS was 14.1 months (90% CI 12.0-16.7, Brookmeyer-Crowley test p &lt; 0.001). Response rate and disease control rate were 82% and 98%, respectively, and R0 resection rate was 21% (27% in liver-only subgroup). Early tumour shrinkage was achieved in 74% pts and median deepness of response was 56%. In pts treated after study amendment (n = 56), main grade 3-4 adverse events were neutropenia (27%), diarrhoea (27%), skin rash (14%), asthenia (14%), nausea (11%), stomatitis (7%), febrile neutropenia (2%). Grade 3-4 immune-related adverse events occurred in 6% of pts. Overall survival results are still immature. Conclusions: AVETRIC study met its primary endpoint, showing that combining mFOLFOXIRI plus cet and ave achieves promising results in terms of PFS as well as response rate, in pts with pMMR RAS and BRAF wt mCRC. Translational analyses to evaluate the impact of immune-related biomarkers are ongoing. Clinical trial information: NCT04513951 .

Serial ctDNA monitoring to predict response in mCRC patients treated with anlotinib in combination with oxaliplatin and capecitabine (CAPEOX) as the first-line therapy.

e15581 Background: Circulating tumour DNA (ctDNA) sequencing offers a non-invasive approach to monitor therapeutic efficacy in colorectal cancer. However, the mutational landscape of ctDNA during treatment and its impact on clinical outcomes remain unknown. This study aimed to investigate the value of ctDNA in predicting treatment response and PFS in mCRC patients treated with anlotinib plus CAPEOX as first-line therapy. Methods: We conducted a multicenter, single-arm, phase II, exploratory study of patients with RAS/BRAF wild-type unresectable metastatic colorectal cancer (mCRC) who underwent Anlotinib in combination with CAPEOX as the first-line therapy (NCT04080843). Plasma samples from 26 patients were collected at three timepoints: 1 week before treatment (baseline), close to the time of optimal remission (C1) and the time of the last blood collection or the time of disease progression (C2). The maximum somatic allele frequency (MSAF) was calculated for each case and used to provide an estimate of the ctDNA fraction in the blood. Results: 77 plasma samples from the 26 enrolled mCRC patients were sequenced by NGS based on a panel comprising 202 genes. 90 variations were detected in baseline plasma, with a positive rate of 96.2% (25/26). Adenomatous polyposis coli ( APC), was the most mutated gene (84.6%, 22/26). Other mutated genes were TP53 (80.8%, 21/26), FBXW7 (19.2%, 5/26), KRAS (11.5%, 3/26), PIK3CA (11.5%, 3/26) and ROS1 (11.5%, 3/26). The median MSAF of baseline ctDNA was significantly higher in patients who had only liver metastases. Compared with baseline, the ctDNA MSAF level at C1 timepoint was decreased among the whole 26 patients (p &lt; 0.001). By comparing ctDNA positive group (ctDNA MSAF &gt; 0) and ctDNA negative group (ctDNA MSAF = 0) at C1 timepoint, CR cases were mainly in ctDNA negative group, while PD cases accounted for a high proportion in the ctDNA positive group. The median progression-free survival (mPFS) of the whole patients was 11.27 months (95%CI 7.33m to 14.52m). The mPFS was 14.52 months (95% CI 14.4 to NR) of patients with ctDNA negative at C1, which was longer than 9.17 months (95% CI 7.16 to 14.06) of patients with ctDNA positive at C1 (p = 0.012). For 25 patients who had plasma samples of three timepoints, we divided the patients into Non-PD group and PD group according to the clinical outcome at C2 timepoint. Compared with C1 timepoint, the ctDNA MSAF level at C2 timepoint was increased in both Non-PD group and PD group. However, the increment of ctDNA MSAF level in PD group was higher than that in non-PD group (p = 0.000069 vs p = 0.024). Conclusions: This ctDNA profiling study revealed the utility of ctDNA in predicting clinical outcomes in mCRC patients under first-line treatment. Serial ctDNA monitoring might become useful in an active surveillance strategy for the management of mCRC. Clinical trial information: NCT04080843 .

SO-27 Modified FOLFOXIRI plus cetuximab and avelumab as initial therapy in RAS wild-type unresectable metastatic colorectal cancer: Results of the phase II AVETRIC trial by GONO

SO-27 Modified FOLFOXIRI plus cetuximab and avelumab as initial therapy in RAS wild-type unresectable metastatic colorectal cancer: Results of the phase II AVETRIC trial by GONO

Cost-Effectiveness Analysis of Monoclonal Antibodies Associated With Chemotherapy in First-Line Treatment of Metastatic Colorectal Cancer

ObjectivesThis study aimed to evaluate the cost-effectiveness of anti–epidermal growth factor receptor (cetuximab and panitumumab) or anti–vascular endothelial growth factor (bevacizumab) monoclonal antibodies associated with conventional chemotherapy (CT) (fluorouracil and leucovorin with irinotecan) as a first-line treatment for unresectable metastatic colorectal cancer. MethodsA partitioned survival analysis model was adopted to simulate direct health costs and benefits comparing therapeutic options in a 10 years’ time horizon. Model data were extracted from the literature and costs were obtained from Brazilian official government databases. The analysis considered the perspective of the Brazilian Public Health System; costs were measured in local currency (BRL) and benefits in quality-adjusted life-years (QALY). A 5% discount rate was applied to costs and benefits. Alternative willingness-to-pay scenarios, varying from 3 to 5 times the cost-effectiveness threshold established in Brazil, were estimated. The results were presented incremental cost-effectiveness ratio (ICER), and both deterministic and probabilistic sensitivity analyses were performed. ResultsThe most cost-effective choice would be the association of CT with panitumumab, with an ICER of $58 330.15/QALY compared with isolated CT. The second-best option was CT with bevacizumab and panitumumab, with an ICER of $71 195.40/QALY compared with panitumumab alone. Although having higher costs, the second-best option was the most effective. Both strategies were cost-effective in part of the Monte Carlo iterations, considering the 3× threshold. ConclusionsThe therapeutic option CT + panitumumab + bevacizumab represents the most significant effectiveness gain in our study. It is the second-lowest cost-effectiveness, and this option includes monoclonal antibodies association for patients with and without KRAS mutation.

Unresectable metastatic colorectal cancer in fit patients - a practical algorithm of treatment sequencing from the Brazilian Group of Gastrointestinal Tumours (GTG).

Recent advances in biomarker-driven therapies have changed the landscape of unresectable metastatic colorectal cancer (mCRC) and brought not only access issues but also difficulties for the treating physician (especially generalist oncologists) in choosing the most suitable treatment for each individual patient. This manuscript proposes an algorithm developed by The Brazilian Group of Gastrointestinal Tumours with the aim of bringing easy-to-follow steps in the management of unresectable mCRC. The algorithm is based on evidence for fit patients to facilitate therapeutic decisions in the clinical practice and assumes that there are no access and resource limitations.