Metastatic Colorectal Carcinoma Research Articles

PARP Inhibitors in Colorectal Malignancies: A 2023 Update.

Colorectal carcinoma (CRC) is one of the most common malignancies in the Western world, and metastatic disease is associated with a dismal prognosis. Poly-ADpribose polymerase (PARP) inhibitors gain increasing attention in the field of medical oncology, as they lead to synthetic lethality in malignancies with preexisting alterations in the DNA damage repair (DDR) pathway. As those alterations are frequently seen in CRC, a targeted approach through PARP inhibitors is expected to benefit these patients, both alone and in combination with other agents like chemotherapy, immunotherapy, antiangiogenics, and radiation. This review article aims to better clarify the role of PARP inhibitors as a treatment option in patients with metastatic CRC with alterations in the DDR pathway. We used the PubMed database to retrieve journal articles and the inclusion criteria were all human studies that illustrated the effective role of PARP inhibitors in patients with metastatic CRC with homologous repair deficiency (HRD) and the correct line of therapy. Current evidence supports the utilization of PARP inhibitors in CRC subgroups, as monotherapy and in combination with other agents. Up to now, data are insufficient to support a formal indication, and further research is needed. Efforts to precisely define the homologous repair deficiency (HRD) in CRC - and eventually the subgroup of patients that are expected to benefit the most - are also underway. DOI: dx.doi.org/10.17504/protocols.io.dm6gp3ey8vzp/v1.

Overcoming tight perihilar malignant biliary obstructions during percutaneous biliary intervention in Nigerian patients: case reports

BackgroundA major challenge of either endoscopic or percutaneous approach to placing palliative biliary stents is the difficulty in traversing tight perihilar malignant obstructions. This can be overcome with a rendezvous approach (combined endoscopic retrograde cholangiopancreatography (ERCP)/percutaneous approach) or may require initial placement of an external drain and reattempting later. Interventional radiology for biliary obstruction is still in infant days in our locality. Herein, we describe two cases of perihilar malignant biliary obstruction (MBO) managed at a private facility in Lagos, Nigeria, in which we had to come up with a creative approach to crossing these tight junctions in the absence of ERCP facilities. This was done by securing percutaneous retrograde access into the common bile duct and combining it with the initially unsuccessful anterograde approach. In both cases, this combined percutaneous anterograde/retrograde approach resulted in successful traversal of the malignant obstruction and placement of internal biliary stents.Case presentationWe present the case of two elderly patients with tight malignant biliary obstruction (MBO), one from a suspected cholangiocarcinoma and the other from hepatic metastatic colorectal carcinoma. Both patients had successful traversal of the obstruction via a combined percutaneous anterograde/retrograde approach and biliary stenting.ConclusionsOur case reports demonstrate an unusual approach that should assist interventional radiologists in resource-limited setting who seek for a viable option to those presently available for traversing perihilar MBOs in the percutaneous placement of internal stents.

EGFR-Targeted Antibody-Drug Conjugate to Different Aminobisphosphonates: Direct and Indirect Antitumor Effects on Colorectal Carcinoma Cells.

Antibody--drug conjugates (ADCs) are a promising delivery system that involves linking a monoclonal antibody (mAb) to a specific drug, such as a cytotoxic agent, to target tumor cells. This new class of antitumor therapy acts as a "biological missile" that can destroy tumor cells while increasing the therapeutic index and decreasing toxicity. One of the most critical factors in ADC design is selecting a target antigen that is highly expressed on the surface of cancer cells. In this study, we conjugated Cetuximab (Cet), a monoclonal antibody that targets the epidermal growth factor receptor (EGFR), to aminobisphosphonates (N-BPs) such as ibandronate (IBA) or risedronate (RIS) or zoledronate (ZA). Cetuximab is administered to patients with metastatic colorectal carcinoma (mCRC) with a wild-type (WT) EGFR transduction pathway. Also, it is well established that N-BPs can trigger the antitumor activity of Vδ2 T cells in both in vitro and in vivo experimental models. The resulting ADCs were added in co-culture to assess the effect on CRC cell line proliferation and sensitivity to Vδ2 T antitumor lymphocytes in comparison with the native antibody. These assays have been performed both in conventional and 3D spheroid cultures. We found that all three ADCs can increase the inhibitory effect on cell proliferation of the WT-EGFR cell line Caco-2 while only Cet-RIS and Cet-ZA can increase the cytotoxicity mediated by Vδ2 T cells against both WT and EGFR-mutated CRC cell lines (Caco-2, DLD-1, and HCT-116). Also, the ADCs can trigger the cell proliferation of Vδ2 T cells present in peripheral blood and tumor specimens. Our findings indicate that anti-EGFR antibodies bound to N-BPs can improve the antitumor effects of the native antibody possibly increasing the therapeutic effect.

MRNA expression profiling of leptin and adiponectin and its receptors in colorectal carcinoma – Biomarker development

BackgroundMetastatic colorectal carcinoma (CRC) is one of the leading causes of mortality of colorectal CRC. Very few prognostic markers and factors affecting progression are studied between metastatic CRC and early CRC. Adipokines are speculated to be associated with this area of interest. In the current study leptin, leptin receptor (Ob-R), adiponectin, adiponectin R1, and adiponectin R2 expression were measured at gene levels to determine a possible association between adipokines and early/metastatic cancer to ultimately identifying a definitive diagnostic marker. Materials and methodsTissue samples were obtained from 62 patients with radical specimens of CRC. Genes expression was determined by Quantitative Reverse-Transcription Polymerase Chain Reaction (qRT-PCR). The association between the clinicopathological parameters and gene expression levels were analyzed by statistical analysis. ResultsOverexpression of leptin mRNA is observed in small tumors (size< 5 cms) (P<0.05).b. Leptin receptor were overexpressed in advanced tumors (1.013 ± 0.152) than early tumors (0.453 ± 0.131). c.Adiponectin expression was higher in early tumors (1.535 ± 0.406) than in advanced tumors (0.48 ± 0.148). d. Distant organ metastasis shows under-expression of adipoR1. e.Overexpression of adipoR2 is seen in small (size<5 cms) (P<0.05) tumors. ConclusionLEPR is better indicator of advancement of tumor than Leptin. ADIPOR1 is a better indicator in advanced CRC than ADIPOR2 and ADIPOQ.

Final results of urelumab, an anti-CD137 agonist monoclonal antibody, in combination with cetuximab or nivolumab in patients with advanced solid tumors

BackgroundResistance to immune checkpoint inhibitors and targeted treatments for cancer is common; thus, novel immunotherapy agents are needed. Urelumab is a monoclonal antibody agonist that binds to CD137 receptors expressed...

Radiofrequency Combined with Intratumoral Immunotherapy: Preclinical Results and Safety in Metastatic Colorectal Carcinoma.

Radiofrequency ablation (RFA) of cancer induces an anti-tumor immunity, which is insufficient to prevent recurrences. In mice, RFA-intratumoral immunotherapy by granulocyte-macrophage colony-stimulating factor (GM-CSF) and Bacillus Calmette-Guerin resulted in complete metastases regression. Infectious risk in human needs replacement of live vaccines. Intratumoral purified protein derivatives (PPD) have never been tested in digestive cancers, and the safety of intratumoral immunotherapy after RFA has not yet been validated in human models. We investigated the therapeutic efficacy of combined radiofrequency ablation (RFA) and intratumoral immunotherapy (ITI) using an immune-muco-adherent thermogel (IMT) in a mouse model of metastatic colorectal cancer (CRC) and the safety of this approach in a pig model. Intratumoral stability of the immunogel was assessed using magnetic resonance imaging (MRI) and bioluminescent imaging. Seventy-four CT26 tumor-bearing female BALB/c mice were treated with RFA either alone or in combination with intratumoral IMT. Regression of distant metastasis and survival were monitored for 60 days. Six pigs that received liver radiofrequency and intralesional IMT injections were followed for 15 days. Experimental gel embolisms were treated using an intravascular approach. Pertinent rheology of IMT was confirmed in tumors, by the signal stability during 3 days in MRI and 7 days in bioluminescence imaging. In mice, the abscopal effect of RFA-intratumoral immunotherapy resulted in regression of distant lesions completed at day 16 vs. a volume of 350 ± 99.3 mm3 in the RFA group at day 25 and a 10-fold survival rate at 60 days. In pigs, injection of immunogel in the liver RFA area was safe after volume adjustment without clinical, hematological, and liver biology disorder. Flow cytometry showed an early increase in CD3 TCRγδ+T cells at D7 (p < 0.05) and a late decrease in CD29+-CD8 T cells at D15 (p < 0.05), reflecting the inflammation status changes. Systemic GM-CSF release was not detectable. Experimental caval and pulmonary thermogel embolisms were treated by percutaneous catheterism and cold serum infusion. RFA-intratumoral immunotherapy as efficient and safe mini-invasive interventional oncology is able to improve ablative treatment of colorectal liver metastases.

Effectiveness of immune checkpoint inhibitors in combination with tyrosine kinase inhibitors in patients with advanced or metastatic colorectal carcinoma with either mismatch repair proficient or metastatic microsatellite stable disease: A systematic review and meta‑analysis.

Immune checkpoint inhibitors (ICIs) have limited efficacy in mismatch repair proficient (pMMR) or metastatic microsatellite stable (MSS) advanced or metastatic colorectal cancer (mCRC). ICIs, in conjunction with tyrosine kinase inhibitors (TKIs) possessing anti-angiogenic properties, serve as a potential strategy for circumventing the resistance exhibited by MSS or pMMR mCRC to immunotherapeutic interventions. The present study aimed to evaluate efficacy and safety of ICIs + TKIs and provide a reference for the treatment of CRC. The present systematic review and meta-analysis was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed, Embase, Cochrane, Web of Science and ClinicalTrials.gov databases were screened from January 1, 2003 to July 28, 2023. A total of 14 studies were included in qualitative and quantitative analyses, with a total of 819 patients enrolled. The Newcastle-Ottawa scale scores of the 14 cohort studies included were ≥7, indicating they were of a high quality. The objective response rate (ORR) of ICIs + TKIs was 14% [95% confidence interval (CI), 0.08-0.24; P=0.132] in patients with advanced or metastatic MSS/pMMR CRC. The disease control rate (DCR) was 65% (95% CI, 0.58-0.74; P<0.0001). The overall incidence of adverse events of varying severity linked to combination of ICIs and TKIs in patients with advanced or metastatic MSS/pMMR CRC was 64% (95% CI, 0.52-0.78; P<0.0001). The incidence of grade ≥3 adverse reactions was 24% (95% CI, 0.14-0.4; P<0.0001). The sensitivity analysis indicated that the exclusion of individual studies did not yield statistically significant variations in combined analysis results. Based on the examination of publication bias, ORR and DCR, Begg's and Egger's tests had P-values of 0.114 and 0.395, respectively. Overall publication bias overall was absent in the Begg's funnel plot, as there was no apparent asymmetry. Nonetheless, the P-values of the Egger's and Begg's tests for adverse reactions and adverse reactions grade ≥3 were P=0.008 and P=0.048, respectively. The asymmetry of the Begg's funnel plots was evident, suggesting the presence of potential publication bias regarding adverse event results. In conclusion, the combination of ICIs and TKIs demonstrates a favorable effectiveness and notable safety profile in the management of patients with advanced or metastatic MSS/pMMR CRC.

Microscopic Growth Pattern of Metastatic Colorectal Carcinomas, Morphological Findings of the Non-Neoplastic Liver, and Their Relationship With Prognosis and Survival

Introduction. Various clinicopathological, radiological, and molecular parameters are predictive of prognosis in patients with colorectal carcinoma and distant organ metastases continue to have a significant place among them. Recent studies reveal that not only the presence of metastases but also the histopathological growth pattern of the metastatic tumor significantly affects prognosis. This study aimed to investigate the prognostic significance of the histopathological growth patterns of metastatic tumors, the morphological findings in the peritumoral non-neoplastic liver, and its relationship with survival in patients who have metastatic colorectal carcinoma. Materials and Method. Hematoxylin and eosin-stained slides of the tumors were re-examined in terms of histopathological diagnosis, growth pattern, presence and degree of peritumoral lymphocytic infiltration, steatosis, cholestasis, and peritumoral ductular reaction in the non-neoplastic liver. Results. In terms of histopathological growth patterns, 24 (47%) tumors showed replacement, 19 (37%) showed desmoplastic and 8 (16%) showed pushing growth pattern. In terms of total survival, there was a significant difference ( P = .011) between desmoplastic and replacement growth patterns, and the survival period was shorter in patients with replacement growth patterns. Conclusion. Recent studies show that histopathological growth patterns in metastatic liver tumors may be a promising prognostic and predictive parameter. It is important to include this parameter in the pathology reports as it does not require additional equipment for evaluation in routine pathology practice, does not bring additional costs, or takes a long time to evaluate. This feature can be evaluated standardly by every pathologist.

The Clinicopathological Correlation of KRAS Mutation and PTEN Expression Status in Primary and Metastatic Colorectal Carcinoma.

Colorectal cancer (CRC) researchhas identified a consistent loss of PTEN expression in both primary tumors and metastasis, highlighting its potential role in this disease. However, the impact of PTEN on downstream proteins of KRAS mutation, namely p-AKT, p-ERK, and p65 (NFkB), remains unknown. This study aims to explore the inhibitory effect of PTEN on KRAS downstream proteins and its correlation with pathological features in CRC patients. From January 1, 2015, to December 31, 2021, 86 CRC cases were collected from governmental and private laboratories in the Duhok province. Formalin-fixed, paraffin-embedded tissue blocks were obtained, and the study involved histopathological analysis, immunohistochemistry of PTEN, AKT, ERK, and P65 markers, and molecular analysis of the KRAS gene. Among the 86 cases, there were 46 males (53.5%) and 40 females (46.5%), with an equal distribution between right colon and left colon/rectum. Tumors larger than 5cm were observed in 47 cases, predominantly displaying a polypoid or ulcerated growth pattern. Most cases were moderately differentiated adenocarcinomas, with stages II and III being the most prevalent 31 cases (36%) and 34 cases (39.5%) respectively. Significant associations were found between PTEN, ERK expressions, and tumor location in the right colon (P=0.031 and P=0.009 respectively). Tumor size correlated with P65 expression (P=0.042). KRAS mutation showed a positive relationship with the type of tumor growth (P=0.035). Tumor grade increased with KRAS mutations (P=0.043). PTEN expression correlated significantly with ERK and AKT markers (P=0.018 and 0.035 respectively). P65 exhibited an association with KRAS mutation (P=0.034). The study revealed PTEN expression in association with the inhibition of AKT and ERK, and the absence of KRAS gene mutation. Conversely, PTEN is not expressed with the positively reactive P65 and the presence of KRAS mutation. This study contributes valuable insights into the complex interplay between PTEN expression, KRAS mutation, and downstream signaling pathways in CRC. It suggests potential avenues for further research and therapeutic strategies in the context of CRC treatment.

BXQ-350: A phase 1b/2 placebo controlled, double blinded study on the efficacy and safety of BXQ-350 in combination with mFOLFOX7 and bevacizumab in newly diagnosed metastatic colorectal carcinoma (mCRC).

TPS224 Background: Ceramides and sphingosine-1-phosphate (S1P) are key bioactive signaling molecules. Ceramides are proapoptotic and mitigate chemoresistance. Conversely, S1P promotes cancer cell proliferation, activates multiple oncogenic pathways, and stimulates immuno-suppressor cell populations promoting a pro-tumoral microenvironment. Several studies in colorectal cancer patients have shown high levels of ceramides are associated with improved survival, while high S1P levels are associated with a poor prognosis. Hence, modulation of sphingolipid metabolism could be a promising therapeutic approach. BXQ-350 is a nanovesicle of Saposin C, an allosteric activator of sphingolipid metabolism, that lowers systemic S1P and increases C18 ceramide. BXQ-350 was investigated in a Phase 1 dose-escalation safety study in an cancer patients with advanced solid malignancies ( NCT02859857 ). BXQ-350 was safe and well-tolerated (no DLT, no MTD). Also, 13 patients (~17.8% of evaluable patients) had a clinical benefit up to cycle 6 and beyond (PR, SD). Among patients with PFS &gt; 6 months, there were 4 recurrent CRC patients: 1 patient had a PFS of ~12 months, 2 of ~18 months, and 1 is still on study after 6 years. Furthermore, there were signs that BXQ-350 may alleviate symptoms of CIPN as 4 out of 10 patients with chronic CIPN at time of enrollment experienced an improvement of their symptoms. Methods: BXQ-350 is being investigated in a Phase 1b/2 study in combination with mFOLFOX7 and Bevacizumab in newly diagnosed mCRC patients (NCT05322590) to assess the efficacy and safety of BXQ-350. Design of the Phase 1b (open label study): A safety dose escalation part to establish the RP2D: patients will initially receive 1.8 mg/kg BXQ-350 in combination with mFOLFOX7 and Bevacizumab. If safe (no MTD), dose of BXQ-350 will be increased to 2.4 mg/kg and 9 additional patients will be entered at this dose level. If safe, then this dose will be the RP2D and 21 additional patients will be enrolled, completing a 30 patient expansion cohort; Efficacy will then be evaluated for all patients entered at the RP2D. Primary objectives of the Phase 1b are to assess safety, identify RP2D, and assess preliminary efficacy of BXQ-350 in this combination. A secondary objective is to determine if BXQ-350 decreases CIPN. Design of the Phase 2, a double-blinded, placebo-controlled study: Eligible patients (up to 160 patients) will be randomized in a 1:1 fashion to receive either BXQ-350 or placebo with mFOLFOX7 + Bevacizumab. Primary and secondary objectives include efficacy, safety and CIPN incidence. Enrollment in the Phase 1b dose escalation portion is completed. After review of the safety results, the DSMB approved enrollment of the expansion cohort, with a planned 30 patients at the Phase 2 dose. Available Phase 1b data will be presented. Clinical trial information: NCT05322590 .

A Phase 1 Study of Cabozantinib and Trifluridine/Tipiracil in Metastatic Colorectal Adenocarcinoma

IntroductionThis study determined the safety and recommended phase 2 dose (RP2D) of the multikinase inhibitor cabozantinib in combination with trifluridine/tipiracil (FTD/TPI) in refractory metastatic colorectal carcinoma (mCRC). Patients and MethodsSingle institution investigator-initiated phase 1 study using 3+3 design. Eligible mCRC patients had received prior standard regimens. Cabozantinib was given orally (p.o.) at 20 mg (dose level [DL] 0) or 40 mg (DL 1) daily on days 1-28, and FTD/TPI p.o. at 35 mg/m2 on days 1-5 and 8-12 every 28 days. Prophylactic growth-factor support was allowed. ResultsFifteen patients were enrolled. Median age 56 years (31-80), male (12/15), ECOG 0/1 = 9/6. Three patients were treated at DL 0 and another nine were treated at DL 1, none exhibiting a DLT. Most common any grade (G) treatment related adverse events (TRAE) were diarrhea (50%), nausea (42%), neutropenia (42%), fatigue (33%), and rash (25%). G3-4 TRAE were neutropenia (25%) and thrombocytopenia, hypokalemia, and weight loss (each 8%). No serious TRAE or G5 were reported. The RP2D was determined to be DL 1. Median PFS was 3.8 months (95% CI 1.9-6.8) and disease control rate was 86.7%. ConclusionThe combination of cabozantinib and FTD/TPI is feasible and tolerable at standard doses with the use of growth factors and showed encouraging clinical activity in refractory mCRC. ClinicalTrials.GovNCT04868773.

Bcl-xL mediates interferon-beta secretion by protease-activated receptor 2 deficiency through the mitochondrial permeability transition pore in colorectal cancer metastasis

Cellular plasticity and immune escape are synergistic drivers of tumor colonization in metastatic organs. Activation of protease-activated receptor 2 (PAR2) signaling promotes metastasis of colorectal carcinoma (CRC). The role of PAR2 in regulating the immune microenvironment and cancer progression remains unclear. We demonstrated that the regulation of liver metastasis by PAR2 requires a competent immune system. PAR2 knockdown enhanced liver infiltration of activated CD8+ T cells prior to metastatic foci formation in an interferon receptor-dependent manner. PAR2 depletion increased interferon (IFN)-β production via the cGAS-STING and RIG-1 pathways. PAR2 inhibition increased mitochondrial permeability and cytosolic accumulation of mitochondrial DNA, which was reversed by Bcl-xL expression. Strikingly, shRNA against PAR2 with an immune checkpoint blocker (ICB) acted synergistically to suppress liver metastasis. Analysis of single-cell sequence data and 24 paired samples confirmed the regulatory effect of PAR2 on the metastatic immune environment in human CRC. Therefore, PAR2 signaling is involved in stabilizing the mitochondrial membrane and regulating the immune microenvironment through IFN-β during liver metastasis in CRC. The synergistic effect of the PAR2 inhibitor and ICB provides a potential therapeutic strategy for metastatic CRC treatment.

Cetuximab every 2 weeks versus standard weekly dosing administration schedule.

Cetuximab every 2 weeks (Q2W) dosing schedule is approved by the US FDA and by the Japanese Pharmaceuticals and Medical Devices Agency in patients with metastatic colorectal cancerand squamous cell carcinoma of the head and neck. Phase II trials have found comparable efficacy and safety for the weekly (Q1W) and Q2W schedules, and real-world studies have shown noninferiority of the Q2W compared with the Q1W schedule. Several guidelines recommend cetuximab Q2W administration as an alternative to the Q1W dosing schedule. Cetuximab Q2W can be administered with a Q2W dose of chemotherapy, making it a more convenient option to the Q1W schedule, potentially resulting in reduced costs for administration, increased flexibility for clinical staff and improved patient adherence.

The Oncology Biomarker Discovery framework reveals cetuximab and bevacizumab response patterns in metastatic colorectal cancer

Precision medicine has revolutionised cancer treatments; however, actionable biomarkers remain scarce. To address this, we develop the Oncology Biomarker Discovery (OncoBird) framework for analysing the molecular and biomarker landscape of randomised controlled clinical trials. OncoBird identifies biomarkers based on single genes or mutually exclusive genetic alterations in isolation or in the context of tumour subtypes, and finally, assesses predictive components by their treatment interactions. Here, we utilise the open-label, randomised phase III trial (FIRE-3, AIO KRK-0306) in metastatic colorectal carcinoma patients, who received either cetuximab or bevacizumab in combination with 5-fluorouracil, folinic acid and irinotecan (FOLFIRI). We systematically identify five biomarkers with predictive components, e.g., patients with tumours that carry chr20q amplifications or lack mutually exclusive ERK signalling mutations benefited from cetuximab compared to bevacizumab. In summary, OncoBird characterises the molecular landscape and outlines actionable biomarkers, which generalises to any molecularly characterised randomised controlled trial.

Trivalvular nonbacterial thrombotic endocarditis in a patient with colon adenocarcinoma: a case report

BackgroundNonbacterial thrombotic endocarditis is a rare complication of prothrombotic states such as neoplasms that can cause valvular dysfunction and life-threatening complications. Nonbacterial thrombotic endocarditis usually affects the left-sided valves; however, only a minority of cases involving the tricuspid valve have been reported in medical literature.Case presentationThe current report describes trivalvular involvement by nonbacterial thrombotic endocarditis in a 54-year-old Azeri female patient with metastatic colorectal carcinoma. This case underlines the necessity of evaluating nonbacterial thrombotic endocarditis as a possible consequence in cancer patients. When thromboembolic events are found in the presence of a hypercoagulable state (such as malignancy) and no growth on blood cultures, nonbacterial thrombotic endocarditis could be suspected as the cause.ConclusionIt is critical to achieve early diagnosis in such a setting to initiate treatment plans and prevent further complications rapidly.

Transient receptor potential ankyrin 1 (TRPA1) mediates reactive oxygen species-induced Ca2+ entry, mitochondrial dysfunction, and caspase-3/7 activation in primary cultures of metastatic colorectal carcinoma cells

Colorectal carcinoma (CRC) represents the fourth most common cancer worldwide and is the third most common cause of malignancy-associated mortality. Distant metastases to the liver and lungs are the main drivers of CRC-dependent death. Pro-oxidant therapies, which halt disease progression by exacerbating oxidative stress, represent an antitumour strategy that is currently exploited by chemotherapy and ionizing radiation. A more selective strategy to therapeutically exploit reactive oxygen species (ROS) signaling would consist in targeting a redox sensor that is up-regulated in metastatic cells and is tightly coupled to the stimulation of cancer cell death programs. The non-selective cation channel, Transient Receptor Potential Ankyrin 1 (TRPA1), serves as a sensor of the cellular redox state, being activated to promote extracellular Ca2+ entry by an increase in oxidative stress. Recent work demonstrated that TRPA1 channel protein is up-regulated in several cancer types and that TRPA1-mediated Ca2+ signals can either engage an antiapoptotic pro-survival signaling pathway or to promote mitochondrial Ca2+ dysfunction and apoptosis. Herein, we sought to assess for the first time the outcome of TRPA1 activation by ROS on primary cultures of metastatic colorectal carcinoma (mCRC cells). We found that TRPA1 channel protein is up-regulated and mediates enhanced hydrogen peroxide (H2O2)-induced Ca2+ entry in mCRC cells as compared to non-neoplastic control cells. The lipid peroxidation product 4-hydroxynonenal (4-HNE) is the main ROS responsible for TRPA1 activation upon mCRC cell exposure to oxidative stress. TRPA1-mediated Ca2+ entry in response to H2O2 and 4-HNE results in mitochondrial Ca2+ overload, followed by mitochondrial depolarization and caspase-3/7 activation. Therefore, targeting TRPA1 could represent an alternative strategy to eradicate metastatic CRC by enhancing its sensitivity to oxidative stress.

Immuno-PET of colorectal cancer with a CEA-targeted [68Ga]Ga-nanobody: from bench to bedside.

An accurate diagnosis of colorectal carcinoma (CRC) can assist physicians in developing reasonable therapeutic regimens, thereby significantly improving the patient's prognosis. Carcinoembryonic antigen (CEA)-targeted PET imaging shows great potential for this purpose. Despite showing remarkable abilities to detect primary and metastatic CRC, previously reported CEA-specific antibody radiotracers or pretargeted imaging are not suitable for clinical use due to poor pharmacokinetics and complicated imaging procedures. In contrast, radiolabeled nanobodies exhibit ideal characteristics for PET imaging, for instance, rapid clearance rates and excellent distribution profiles, allowing same-day imaging with sufficient contrast. In this study, we developed a novel CEA-targeted nanobody radiotracer, [68Ga]Ga-HNI01, and assessed its tumor imaging ability and biodistribution profile in preclinical xenografts and patients with primary and metastatic CRC. The novel nanobody HNI01 was acquired by immunizing the llama with CEA proteins. [68Ga]Ga-HNI01 was synthesized by site-specifically conjugating [68Ga]Ga with tris(hydroxypyridinone) (THP). Small-animal PET imaging and biodistribution studies were performed in CEA-overexpressed LS174T and CEA-low-expressed HT-29 tumor models. Following successful preclinical assessment, a phase I study was conducted on 9 patients with primary and metastatic CRC. Study participants received 151.21 ± 25.25MBq of intravenous [68Ga]Ga-HNI01 and underwent PET/CT scans at 1h and 2h post injection. Patients 01-03 also underwent whole-body dynamic PET imaging within 0-40min p.i. All patients underwent [18F]F-FDG PET/CT imaging within 1week after [68Ga]Ga-HNI01 imaging. Tracer distribution, pharmacokinetics, and radiation dosimetry were calculated. [68Ga]Ga-HNI01 was successfully synthesized within 10min under mild conditions, and the radiochemical purity was more than 98% without purification. Micro-PET imaging with [68Ga]Ga-HNI01 revealed clear visualization of LS174T tumors, while signals from HT-29 tumors were significantly lower. Biodistribution studies indicated that uptake of [68Ga]Ga-HNI01 in LS174T and HT-29 was 8.83 ± 3.02%ID/g and 1.81 ± 0.87%ID/g, respectively, at 2h p.i. No adverse events occurred in all clinical participants after the injection of [68Ga]Ga-HNI01. A fast blood clearance and low background uptake were observed, and CRC lesions could be visualized with high contrast as early as 30min after injection. [68Ga]Ga-HNI01 PET could clearly detect metastatic lesions in the liver, lung, and pancreas and showed superior ability in detecting small metastases. A significant accumulation of radioactivity was observed in the kidney, and normal tissues physiologically expressing CEA receptors showed slight uptakes of [68Ga]Ga-HNI01. An interesting finding was that strong uptake of [68Ga]Ga-HNI01 was found in non-malignant colorectal tissues adjacent to the primary tumor in some patients, suggesting abnormal CEA expression in these healthy tissues. [68Ga]Ga-HNI01 is a novel CEA-targeted PET imaging radiotracer with excellent pharmacokinetics and favorable dosimetry profiles. [68Ga]Ga-HNI01 PET is an effective and convenient imaging tool for detecting CRC lesions, particularly for identifying small metastases. Furthermore, its high specificity for CEA in vivo makes it an ideal tool for selecting patients for anti-CEA therapy.

Exploring proteoforms of the IgG2 monoclonal antibody panitumumab using microchip capillary electrophoresis-mass spectrometry

The IgG2 type monoclonal antibody panitumumab is an anti-epidermal growth factor receptor (EGFR) drug used for the treatment of EGFR-expressing, chemotherapy resistant, metastatic colorectal carcinoma. In this study, panitumumab drug product was first analysed using size exclusion chromatography coupled to mass spectrometry for rapid identity testing. The experimental data led to the identification of two panitumumab isoforms with several prominent forms remaining unidentified, despite apparently low sample complexity. Microchip capillary electrophoresis-mass spectrometry (CE-MS) was subsequently utilised for a more detailed characterization. It was observed that panitumumab is subject to partial N-terminal pyroglutamate formation. Incomplete conversion is uncharacteristic for N-terminally exposed glutamines and in case of panitumumab gives rise to forms which show successive mass offsets of 17 Da, respectively. If not separated before mass spectrometric analysis, e.g. by capillary electrophoresis, such near isobaric species coalesce into single MS peaks, which subsequently hampers or prevents their assignment. With a total of 42 panitumumab isoforms assigned by CE-MS, these observations highlight a potential pitfall of commonly applied rapid identity testing workflows and demonstrate that even low complexity biopharmaceuticals can require separation strategies which offer high separation selectivity for species close in mass.

P-132 Underrepresentation of racial and ethnic minorities in metastatic colorectal carcinoma clinical trials within the United States

P-132 Underrepresentation of racial and ethnic minorities in metastatic colorectal carcinoma clinical trials within the United States

Nipavect: Phase II study of niraparib and panitumumab in advanced RAS WT colorectal cancer.

3579 Background: Panitumumab (Pmab) is a recombinant monoclonal antibody that binds specifically to the human epidermal growth factor receptor (EGFR) and it is indicated for the treatment of metastatic colorectal carcinoma (mCRC). However, the objective response rates (ORR) for the single agent are historically about 8-11%. EGFR inhibition induces synthetic lethality with poly ADP ribose polymerase inhibitors (PARPi) such as Niraparib, by attenuating DNA repair pathways. Combining PARP and EGFR inhibition has the potential to confer synergistic benefit, while also ameliorating resistance mechanism to EGFRi. We conducted this study to define the safety and efficacy of the combination of Niraparib and Pmab in RAS wildtype (WT) mCRC. Methods: Patients (pts) with RAS WT mCRC who have progressed on at least one line of systemic chemotherapy were eligible for the trial. Other selected inclusion criteria were ≥18 years of age, ECOG PS 0-1 and measurable disease per RECIST 1.1. Pmab was administered at 6 mg/kg IV on days 1 &amp; 15 of each 28-day cycle, while Niraparib was taken orally at 200mg or 300mg (based on body weight and platelet count) daily throughout the cycle. The primary endpoint was clinical benefit rate (CBR) defined as complete (CR) + partial (PR) response + stable disease (SD) per RECIST v1.1. Multiple secondary endpoints included safety/tolerability, ORR, progression-free survival (PFS), overall survival (OS), and duration of response (DoR). Results: A safety run-in cohort of 6 pts was initially enrolled. Following a preplanned safety analysis showing an acceptable toxicity profile, an additional 19 pts were enrolled. Of the total 25 enrolled pts, 24 were evaluable for response. Male - 50%; Whites/African Americans/Asians – 65.2%/21.7%/13%; median age – 58.5yrs. The majority had left sided tumor (92%) and the median line of prior therapy was 2 (range 1-4). CBR was 83.3% (0 CR, 6 PR, 14 SD) and ORR was 25%. mPFS – 5.6mos (95% CI: 3.7, 6.9); mOS – 20.9mos (95% CI: 9.2, NR). Six-month PFS and OS rates were 48.4% and 100% respectively. At a median follow up time of 7.5mos (95% CI: 4.2, 10.4), 3 patients remained on treatment and DoR was yet to be determined. Muco-cutaneous adverse events (AEs) of any grade included rash (58.4%), oral mucositis (20.8%), dry skin (16.7%) and paronychia (4.2%). Most common (grade &gt; 2) treatment related AEs (TRAEs) were anemia (G3; 12.5%), dermatitis, oral mucositis, hypertension and neutropenia (G3; 4.2% each). There were no grade 4-5 TRAEs. Conclusions: The combination of Pmab and Niraparib had an acceptable safety profile, and showed considerable antitumor activity in pts with advanced RAS WT mCRC compared to historical rates. Additional biomarker analyses such as survival correlation with immune cell infiltration in paired skin biopsies and HER2/BRAF mutational status are ongoing. Funding and product (Niraparib) for the study were provided by GSK (NCT03983993). Clinical trial information: NCT03983993 .