Refractory Colorectal Cancer Research Articles

Abstract 3702: A novel nanoparticle-based theranostic agent targeting low-density lipoprotein receptor-related protein-1 enhances the efficacy of neoadjuvant radiotherapy in colorectal cancer

Abstract Neoadjuvant radiotherapy is becoming an important therapeutic option for colorectal cancer (CRC) patients, although complete tumor response is observed only in 20 to 30% patients. However, precise biologic mechanisms underlying resistance to radiotherapy remain to be elucidated. In this study, we established a radiotherapy-resistant CRC patient-derived xenograft (PDX) mouse model, and we discovered that low-density lipoprotein receptor-related protein-1 (LRP-1) is increased in radiotherapy-resistant tumors compared with radiotherapy-sensitive tumors. Immunohistochemistry, mRNA and protein expression analyses of radiotherapy-sensitive vs. -refractory CRC patient samples confirmed a statistically significant association between LRP-1 levels and radiotherapy resistance of CRC. We also found that LRP-1 expression is significantly associated with the prognosis of CRC patients by analyzing gene expression data of CRC patients in Gene Expression Omnibus public database. Subsequently, aiming to develop radio-sensitizing nanoparticles targeting LRP-1 for chemotherapeutic drug delivery and in vivo imaging, we screened and identified an LRP-1-binding peptide in a radiotherapy-resistant CRC PDX mouse model using M13 phage display. We next engineered human serum albumin nanoparticles (HSA NPs) containing the LRP-1-binding peptide (for tumor localization), 5-FU (for cytotoxic chemotherapy) and Cy7 fluorophore (for in vivo imaging). When administered in CRC PDX-bearing mice, the LRP-1-targeting HSA NPs accumulated specifically in the CRC tumor tissue and dramatically increased the efficacy of radiotherapy. In addition, whole-body fluorescence imaging of PDX CRC-bearing mice showed that the HSA-NP accumulated only in radiation-treated tumors with high ROI values. In summary, we identified that LRP-1 is a novel signature protein of radiotherapy-resistant CRC, and validated that LRP-1 is closely associated with the progression of CRC. We developed a novel HSA nanoparticle-based theranostic agent loaded with LRP-1-binding peptide, 5-FU and a fluorophore that is applicable to both diagnostic imaging and radio-sensitizing neoadjuvant therapy of CRC. This approach is clinically applicable to improve the effectiveness of neoadjuvant radiotherapy and increase the ratio of complete tumor response in radio-resistant CRC. Citation Format: Kyoung Jin Lee, Serk In Park, Seong-Yun Jeong, Eun Kyung Choi. A novel nanoparticle-based theranostic agent targeting low-density lipoprotein receptor-related protein-1 enhances the efficacy of neoadjuvant radiotherapy in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3702.

Prognostic Value of Thyroid Hormone Ratios in Patients With Advanced Metastatic Colorectal Cancer Treated With Regorafenib: The TOREADOR Study

BackgroundThe impact of free triiodothyronine (FT3)/free thyroxine (FT4) ratio on survival in hospitalized geriatric patients was recently described. Up today, there are no data regarding the prognostic role of FT3/FT4 ratio in patients with advanced cancer. We evaluated the impact of FT3/FT4 ratio on survival in patients with refractory colorectal cancer (CRC) treated with regorafenib. MethodsPatients with metastatic CRC treated with regorafenib with available clinical data and baseline measurement of FT3, FT4, and thyroid-stimulating hormone (TSH) were considered eligible. Exploratory analyses included subjects treated at Istituto Oncologico Veneto. A confirmatory analysis was planned based on FT3/FT4 ratio tertile results, and a validation cohort was built on data retrieved from University of Cagliari. ResultsIn an exploratory cohort, the median overall survival in patients with low, intermediate, and high FT3/FT4 ratios, according to tertiles' value, was 4.8, 5.0, and 7.6 months, respectively (P = .003). The differences were significant in the multivariate model (hazard ratio, 0.43; 95% confidence interval, 0.28-0.68; P = .0003). Confirmatory results were obtained in a validation cohort, both in univariate (P = .0002) and in multivariate (hazard ratio, 0.56; 95% confidence interval, 0.36-0.88; P = .0118) models. ConclusionsHigh baseline FT3/FT4 ratio is strongly associated to better outcome in patients with progressive metastatic CRC treated with regorafenib. Further investigations are ongoing to draw definitive conclusions regarding a potential predictive effect.

Tumor specific methylation of NPY compared to RAS mutation in plasma DNA in the monitoring of colorectal cancer patients treated with last-line regorafenib.

e15541Background: Regorafenib has a proven but small significant effect in refractory colorectal cancer. The objective of the present, post-marketing trial was to investigate the clinical outcome i...

Final results of a phase II of metformin plus irinotecan for refractory colorectal cancer.

e15527Background: Metformin (Met) may exert anticancer effects through activation of AMP-activated protein kinase (AMPK) and reduction of mTOR signaling. Our preclinical studies have shown synergis...

Immune effects of combinatorial repurposing drugs in refractory ovarian and colorectal cancer patients.

Abstract Background Some refractory cancer patients have a good Karnofsky despite refractory disease. We studied the potential immunomodulatory properties of approved drugs. We used fresh PBMC from refractory patients to study the immune effects of several drugs such as metformin, pidotimod, erdostein, esomeprazole, colchicine, bortezomib, gemcitabine, zoledronic acid and naproxen. Methods 25 high-grade serous ovarian cancer (HGSOC) and 25 colorectal cancer (CRC) subjects were included after approved protocol. The inclusion criteria include Karnofsky 80–100%, complete CT scan, acute phase proteins, granzyme B ELISPOT and antigen-specific ELISA. Results We found after 24 months of treatment in HGSOC 80% of complete response (CR), 15% of stable disease (SD) and 5 % of pseudo-progressive disease (PPD). In CRC we had 50% of CR, 30% of SD and 20% of PPD. In the patients with CR there was an immunological correlation of CD8 persistent immune response by granzyme B ELISPOT in HGSOC and CRC (p=0.0001) and PR (p=0.001), respectively. The combination was well tolerated and after 10 months of stopping the treatment some patients have persistent CD8 specific immune response by ELISPOT and ELISA. Discussion The combination of daily oral metformin, colchicine, pidotimod, erdostein, and naproxen plus weekly low dose of intravenous (IV) esomeprazole (80 mg), bortezomib (0.5 mg/m2), gemcitabine (0.5 mg/m2) and zoledronic acid (100 mg) is clinically feasible, with limited clinical toxicity. We now understand the importance of preserving the CD8 immune response and the use of immune biomarkers such as antigen specific ELISA to improve the rational and generate new combinations to improve clinical outcomes in patients with refractory HGSOC and CRC.

A miR-29b Byproduct Sequence Exhibits Potent Tumor-Suppressive Activities via Inhibition of NF-κB Signaling in KRAS-Mutant Colon Cancer Cells.

We previously demonstrated that miR-29b-3p is a hopeful miRNA-based therapy against colorectal cancer. In this study, we aimed to clarify a value of miR-29b-1-5p as a next-generation treatment, especially for KRAS-mutant colorectal cancer. RT-PCR assay showed that the expression of miR-29b-3p was high, and its partner strand, miR-29b-1-5p, level was only negligible in clinical colorectal cancer samples. Mimic-miR-29b-1-5p significantly inhibited proliferation of KRAS-mutant colorectal cancer cell lines DLD1 and SW480 and KRAS wild-type HT29 cells. Proliferative activity was further examined by either miR-29b-1-5p strand or its opposite complementary sequence because miR-29b-1-5p is a passenger miRNA and may have no physiologic function. We found that completely opposite complementary strand to miR-29b-1-5p, but not miR-29b-1-5p, possessed a potent antitumor effect and named this byproduct miRNA sequence "MIRTX." MIRTX directly targeted the 3'-UTR of CXCR2 and PIK3R1 mRNA and suppressed the NF-κB signaling pathway in KRAS-mutated colorectal cancer cells. MIRTX induced apoptosis in DLD1 with downregulation of antiapoptotic BCL2, BCL-xL, and MCL1 and upregulation of cleaved caspase-3 and cleaved PARP. In mouse xenograft models, systemic administration of MIRTX using a super carbonate apatite as a delivery vehicle significantly inhibited tumor growth of DLD1 and HT29 cells without any particular toxicities. In conclusion, these findings indicate that inhibition of NF-κB signaling by this novel miRNA-based therapeutic could be a promising treatment against refractory KRAS-mutant colorectal cancer and KRAS wild-type colorectal cancer. Mol Cancer Ther; 17(5); 977-87. ©2018 AACR.

Evaluating trifluridine + tipiracil hydrochloride in a fixed combination (TAS-102) for the treatment of colorectal cancer

ABSTRACTIntroduction: Despite major progress in treating advanced colorectal cancer (CRC), prognosis in this population after progression on standard treatment remains dismal and the development of new drugs represents an unmet need. Historically, fluoropyrimidines have played a major role in the treatment of metastatic CRC. TAS-102, a novel combination of trifluridine and tipiracil hydrochloride, has demonstrated improvement in overall survival in the refractory CRC setting, with a safe toxicity profile.Areas covered: A literature review of published clinical studies was performed. Herein, the authors review the pharmacological and clinical data of TAS-102 when used in metastatic CRC, both as a single agent as well as in novel combinations under investigation.Expert opinion: The addition of TAS-102 to the therapeutic armamentarium of metastatic CRC is an encouraging breakthrough considering the demonstrated survival benefit and favorable tolerability profile. Combinations with other agents are under clinical investigation in different settings in an attempt to widen its use. To optimize treatment in today’s era of molecular oncology, efforts should be focused on understanding primary and secondary resistance mechanisms, along with the identification of potential biomarkers of response.

Phase I clinical trials in refractory colorectal cancer (CRC): Do older adult patients benefit?

784 Background: Current clinical trial data are largely driven by younger participants, yet half the population diagnosed with CRC are 70+. Upon progression, many CRC patients (pts) with refractory cancer are referred to phase 1 clinical trials; however, tolerability and clinical benefit is unclear in the elderly. Given our robust phase 1 program, we assessed the efficacy and safety of early therapeutics in the elderly CRC pts. Methods: A historical cohort analysis included mCRC pts enrolled amongst 44 phase I trials from 3/2004 - 9/2012. Median Progression free survival (mPFS) and overall survival (mOS) were estimated from Kaplan-Meier curves and groups were statistically compared with the log rank test. The magnitude of association between dichotomous factors and survival was estimated with the hazard ratio (HR). Results: 139 pts, median age 59 (33-81), 70+ 16.5% (n = 23); KRAS mut 39.4 %. ≥3 prior lines of therapy 73.9 %; Prior EGFR-I 75.5% (100% of KRAS wt). Location: Right 20.9 %, Left 61.9 %, Transverse 4.3 %, Unknown 12.9 %. Phase I agents: VEGF I 19.4%, EGFR/Growth Factor I 9.3%. mOS for < 70 (n = 108) vs 70+ (n = 22): 6.5 vs 4.2 months (HR 1.88, p 0.007). mPFS for < 70 (n = 116) vs 70+ (n = 23): 2.0 months vs x 1.5 months (HR 1.73, P 0.03). There was not a statistical difference between < 70 versus 70+ in regards to dose cohort, number of cycles completed, or adverse events. Survival analysis in terms of risk factors in pts 70+ are in the Table below. Conclusions: Elderly CRC pts are underrepresented (16.5%) in phase 1 clinical trials and have worse survivals than non-elderly pts. Elderly CRC pts with liver and hematologic toxicities had a trend toward worse PFS but no OS. Phase I studies should incorporate prospective assessments to identify risk factors of morbidity and mortality in elderly CRC pts. [Table: see text]

Napabucasin versus placebo in refractory advanced colorectal cancer: a randomised phase 3 trial

Napabucasin is a first-in-class cancer stemness inhibitor that targets STAT3, which is a poor prognostic factor in colorectal cancer. This study aimed to test napabucasin in advanced colorectal cancer. This study was a double-blind randomised phase 3 trial done at 68 centres in Canada, Australia, New Zealand, and Japan. Patients with advanced colorectal cancer with a good Eastern Cooperative Oncology Group (ECOG) performance status (0-1) for whom all available standard therapies had failed were eligible for the study. Patients were randomly assigned (1:1) to receive placebo or napabucasin through a web-based system with a permuted block method, after stratification by ECOG performance status, KRAS status, previous VEGF inhibitor treatment, and time from diagnosis of metastatic disease. Napabucasin 480 mg or matching placebo was taken orally every 12 h. All patients received best supportive care. The primary endpoint was overall survival assessed in an intention-to-treat analysis. This is the final analysis of this trial, which is registered at ClinicalTrials.gov, number NCT01830621. Accrual began on April 15, 2013, and was stopped for futility on May 23, 2014, at which point 282 patients had undergone randomisation (138 assigned to the napabucasin group and 144 to the placebo group). Overall survival did not differ significantly between groups: median overall survival was 4·4 months (95% CI 3·7-4·9) in the napabucasin group and 4·8 months (4·0-5·3) in the placebo group (adjusted hazard ratio [HR] 1·13, 95% CI 0·88-1·46, p=0·34). The safety population included 136 patients in the napabucasin group and 144 patients in the placebo group. More patients who received napabucasin had any grade of treatment-related diarrhoea (108 [79%] of 136 patients), nausea (69 [51%]), and anorexia (52 [38%]) than did patients who received placebo (28 [19%] of 144 patients, 35 [24%], and 23 [16%], respectively). The most common severe (grade 3 or worse) treatment-related adverse events were abdominal pain (five [4%] patients receiving napabucasin vs five [3%] receiving placebo), diarrhoea (21 [15%] vs one [1%]), fatigue (14 [10%] vs eight [6%]), and dehydration (six [4%] vs one [1%]). 251 (89%) patients had data on pSTAT3 expression, of whom 55 (22%) had pSTAT3-positive tumours (29 in the napabucasin group, 26 in the placebo group). In a prespecified biomarker analysis of pSTAT3-positive patients, overall survival was longer in the napabucasin group than in the placebo group (median 5·1 months [95% CI 4·0-7·5] vs 3·0 months [1·7-4·1]; HR 0·41, 0·23-0·73, p=0·0025). Although there was no difference in overall survival between groups in the overall unselected population, STAT3 might be an important target for the treatment of colorectal cancer with elevated pSTAT3 expression. Nevertheless, these results require validation. Canadian Cancer Society Research Institute and Boston Biomedical.

Pemetrexed Monotherapy as Salvage Treatment in Patients with Metastatic Colorectal Cancer Refractory to Standard Chemotherapy: A Phase II Single-arm Prospective Trial.

Background: We designed a single-arm, open-label phase II study to determine the efficacy and toxicity of pemetrexed monotherapy with vitamin supplementation in patients with refractory colorectal cancer (CRC) that failed to respond to standard treatments including 5-fluorouracil, oxaliplatin, and irinotecan with or without biologic agents.Methods: Patients were treated with pemetrexed 500 mg/m2 on day 1 every 3 weeks, with folic acid and vitamin B12 supplementation. Treatment was continued until disease progression or intolerable toxicity. Between June 2016 and October 2016, 24 patients were enrolled in this study.Results: One patient withdrew consent, leaving a total of 23 patients for evaluation. The median age of the patients was 54.0 years (range, 23.0 to 67.0), and the median ECOG performance status was 1 (1-2). The median number of previous systemic chemotherapies was 3 (range, 2 to 5). There was no patient with complete response (CR) or partial response (PR). However, stable disease was observed in 10 patients (43.4%) and maintained more than 6 months in 7 of 10 patients. The median progression-free survival was 1.6 months (95% CI, 1.1-2.0) and the median overall survival was 9.8 months (95% CI, 5.9-13.6). Grade 3 treatment-related adverse events occurred in one patient with elevated liver enzymes and hematologic adverse event of grade 2 anemia was observed in one patient. There were no cases of dose reduction or treatment-related deaths and all toxicities were manageable.Conclusions: Pemetrexed monotherapy showed moderate disease control and acceptable toxicity profile as salvage therapy for refractory CRC.

Pacritinib to inhibit JAK/STAT signaling in refractory metastatic colon and rectal cancer.

Treatment options for patients with refractory colorectal cancer are limited and typically provide a chance of only modest benefit. The goal of this study was to evaluate the benefit of inhibiting the JAK/STAT inflammatory pathway with single agent pacritinib in patients with metastatic refractory colorectal adenocarcinoma. A single arm institutional trial was initiated and enrolled patients with metastatic colorectal cancer refractory to at least two standard lines of treatment. Pacritinib 400 mg daily was administered orally continuously in 28 day cycles. The trial was discontinued prior to reaching the planned accrual due to an FDA hold on pacritinib and a lack of treatment benefit. Eleven patients were enrolled and seven were evaluated for response. Median baseline C-reactive protein level was 12.1 (2.1-147) mg/L. One patient had stable disease at eight weeks by RECIST criteria and six progressed. There were no grade 4 or 5 adverse events while patients were on study. The grade 2 and lower AE events experienced were consistent with prior pacritinib trials. In seven evaluable patients there were no objective responses. The trial was discontinued prior to completing planned accrual based on a low likelihood that the progression free survival goal of 4 months would be met.

Abstract 3021: CCR5 inhibition: macrophage repolarization therapy for colorectal cancer

Abstract In patients with metastatic colorectal cancer (CRC), the local immune response influences the clinical course. An in-depth analysis of the invasive margin of human CRC liver metastases revealed a distinct immunological microenvironment. Within this microenvironment, two distinct subsets of myeloid cells induce an influx of T cells into the invasive margin via CXCL9/CXCL10. CCL5 is produced by these T cells and stimulates pro-tumoral effects via CCR5, creating an exploitive loop. CCR5 was found on macrophages, lymphocytes and on the vast majority of tumor cells. Inhibition of CCR5 in patient-derived functional in vitro organotypic culture models showed a promising macrophage repolarization with anti-tumoral effects. These effects are mediated by activation of an antiviral program in macrophages, leading to interferon and reactive oxygen species production and subsequent selective tumor cell death. These anti-tumoral effects were confirmed in a phase I trial with a CCR5 antagonist in 14 patients with liver metastases of advanced refractory CRC. Treatment with the oral CCR5 Inhibitor was very well tolerated and objective responses were seen, especially in combination with previously ineffective chemotherapy. Biopsies revealed mitigation of tumor-promoting inflammation within the tumor tissue, confirming the validity of the explant model and highlighting the feasbility of this approach. It furthermore shows the proof-of-concept for macrophage repolarization in cancer patients. Citation Format: Niels Halama, Inka Zoernig, Anna Berthel, Christoph Kahlert, Fee Klupp, Meggy Suarez-Carmona, Karsten Brand, Juergen Krauss, Felix Lasitschka, Alexis Ulrich, Juergen Weitz, Martin Schneider, Markus Buechler, Laurence Zitvogel, Thomas Herrmann, Axel Benner, Christina Kunz, Stephan Luecke, Christoph Springfeld, Christine S. Falk, Dirk Jaeger. CCR5 inhibition: macrophage repolarization therapy for colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3021. doi:10.1158/1538-7445.AM2017-3021

Treatment of metastatic refractory colorectal cancer following regorafenib failure.

At present, there is no set strategy for the treatment of patients with colorectal cancer subsequent to the failure of standard treatment, other than the use of regorafenib (RGR) and TAS-102. The best order in which to use these drugs, and their safety and efficacy in combination with other drugs, are currently under investigation. It has been reported that RGR has a resensitizing effect on tumors that have previously failed to respond to anticancer drugs; this makes it a promising salvage therapy for colorectal cancer. The present report describes the results of a retrospective study on 17 patients with metastatic colorectal cancer who received RGR treatment following the failure of standard therapy. Following RGR failure, 71% of the patients were fit for further anticancer treatment, and these patients survived longer than those who did not receive further treatment. Furthermore, this intervention did not shorten the period of best supportive care. As a considerable number patients were fit for further anticancer therapy after RGR treatment, which resulted in prolonged survival without shortening the period of best supportive care, it may be beneficial for future research to focus on finding the optimal time at which to switch from RGR to further anticancer therapy.

PEGylated human IL-10 (AM0010) monotherapy in refractory metastatic colorectal cancer.

3571 Background: Colorectal Cancer (CRC) has been refractory to immune therapies. The clinical benefit of immunotherapy is thought to depend on the expansion of activated, intratumoral, tumor specific cytotoxic CD8+ T cells which are low in most CRCs. AM0010 stimulates the survival, expansion and cytotoxicity of intratumoral CD8+ T cells. Patients with CRC who have progressed on SOC first and second line of therapy have a reported 7.1 months OS with TAS-102 (Meyer et al. NEJM372;20, 2015). In this Phase 1 study the efficacy of AM0010 was studied in refractory metastatic CRC patients. Methods: CRC pts progressing on a median of 4 prior therapies (range 2-7) were treated daily with AM0010 in doses of 1 ug/kg SQ daily to 40 ug/kg in a dose escalation design. Tumor responses were assessed using irRC. Serum cytokines, activation of blood derived T cells and peripheral T cell clonality were analyzed. Pretreatment archival tissue samples were evaluated by IHC for tumor infiltration by CD8+T cells. Results: AM0010 was tolerated with reversible TrAEs. 10 pts (of 27) had a G3/4 TrAE. There were no objective responses. 11 patients were treated in dose escalation cohorts (1-10 ug/kg) and 16 pts were treated at or above RP2D (20 ug/kg or 40 ug/kg). Seven of 25 pts with at least one radiographic response evaluation had stable disease at 8 weeks. One patient had SD for 19.4 months. The mPFS (ITT n = 27 pts) was 1.6 months, mOS was 11.7 (range 2.4 – 32+) months. The median follow-up is 25.2 months (range 13-35). AM0010 increased Th1 cytokines IL-18 and IFNg in the serum of patients, while decreasing mediators of chronic, tumor promoting inflammation (Th17 cytokines) and TGFb. Tumor infiltrating granzyme B+ CD8+ T cells increased during the treatment. AM0010 induced de-novo oligoclonal expansion of T cell clones in patients. Conclusions: AM0010 is well tolerated in patients with refractory CRC. Although objective tumor responses were not seen in this very advanced CRC population, the observed immune activation including clonal T cell expansion, prolonged stable disease, and the mOS of 11.7 months is encouraging in this advanced CRC population. Future study of AM0010 in combination with FOLFOX in a second – line of therapy colorectal cancer patients is being planned. Clinical trial information: NCT02009449.

Outcome of use of regorafenib in metastatic colorectal cancer in routine clinic practice in Saudi Arabia.

e15021 Background: Regorafenib is a multi-kinase inhibitor that was FDA approved for the treatment of refractory advanced colorectal cancer. It has been found in the clinical trials to have modest benefit and relatively high toxicity, but the outcome of its routine use in the clinic practice is lacking. Our aim is to assess the outcome in our local clinic practice. Methods: Records of all colorectal cases who were treated with regorafenib were reviewed. Structured CRF was developed. Clinical, pathological and molecular data were collected. Efficacy and toxicity details were analyzed. Results: Thirty-two cases of metastatic colorectal cancer were treated with regorafenib from February 2014 to February 2016. All patients received prior oxaliplatin, irinotecan and bevacizumab based regimens, and cetuximab if wild type. Median age: 53.5 years. Male: 15 (46.9%). Primary tumor was right sided in 10 patients (31.3%), and left sided (including rectum) in 22 (68.7%). Pan RAS mutant: 21 (65.6%). Fifteen patients (46.9 %) had ECOG Performance Status of one, whereas 16 patients (50%) have ECOG 2. Starting dose was reduced to 120mg in 11 (34.4%). Only 5 (15.6%) continued beyond 3 cycles. 18 patients (56.3%) required dose reduction. Overall response: PR/CR: zero; Stable disease: 4 (12.5%); Progressive disease: 25 (78.1%); Clinical progression in 1 (3.1%), and 2 cases were not evaluated. After median follow up of 7 months, 22 patients (68.8%) have died, 5 (15.6%) are still alive and 5 (15.6%) are lost to follow up. Median survival: 9.3 months, and median PFS: 2.5 months. Conclusions: Regorafenib has poor tumor response in the routine clinic practice when given to patients with ECOG PS > 1. The median survival in this series is probably overestimated because of the relatively high rate of loss to follow up. Selection of patients is required in the routine clinic practice. Predictive markers are more important for such treatment with modest benefit, and significant toxicity and cost.

Dose escalation results from a first-in-human, phase 1 study of the glucocorticoid-induced TNF receptor-related protein (GITR) agonist AMG 228 in patients (Pts) with advanced solid tumors.

2521 Background: AMG 228 is an agonistic human IgG1 monoclonal antibody that binds to GITR (CD357), a TNFSFR costimulatory molecule expressed by effector/regulatory T cells. Dose escalation of this open label, first in human, phase 1 study evaluated the safety, pharmacokinetics (PK), pharmacodynamics, and maximum tolerated dose (MTD) and recommended phase 2 dose of AMG 228 in pts with advanced solid tumors. Methods: Pts with refractory advanced colorectal cancer (n = 13), squamous cell carcinoma of head and neck (n = 10), non–small cell lung cancer (n = 2), urothelial transitional cell carcinoma (n = 4), and melanoma (n = 1) received AMG 228 IV Q3W. Dose escalation was in two stages: single-pt cohorts until AMG 228-related grade > 2 adverse events (AEs), efficacy, or 90 mg dose reached (4 cohorts: 3, 9, 30, and 90 mg), followed by rolling six design (n = 2 to 6) until MTD or highest planned dose of 1200 mg reached (5 cohorts: 180, 360, 600, 900, and 1200 mg). Primary endpoints included incidence of dose-limiting toxicities (DLTs) and AEs and PK. Additional endpoints were objective response (RECIST 1.1) and evidence of biological activity. Results: In total, 30 pts (median age 63 y) were treated (3, 9, 30, and 90 mg, n = 1; 180 mg, n = 6; 360 mg, n = 4; 600 mg, n = 6; 900 mg, n = 4; 1200 mg, n = 6). Twenty-seven (90%) pts had treatment-emergent AEs; the most common were hypophosphatemia (23%), fatigue (23%), anemia (23%), nausea (20%), and pyrexia (20%). No DLTs occurred; the MTD was not reached. AMG 228 exposure was dose-related, with PK profiles at low doses (3 to 90 mg) consistent with target mediated drug disposition; doses > 360 mg achieved serum levels needed for 95% receptor occupancy on activated PBMCs. No evidence of T cell activation was observed despite complete target coverage in both tumor and peripheral blood. Among 29 evaluable pts, none had an objective response. Conclusions: In this population of pts with advanced solid tumors, AMG 228 Q3W was tolerable up to the highest tested dose (1200 mg), showing favorable PK. However, no clinical or immunological activity was observed in this limited number of pts. Clinical trial information: NCT02437916.

A phase 2 study of temozolomide in pretreated metastatic colorectal cancer with MGMT promoter methylation

Background:Presently, few options are available for refractory colorectal cancer (CRC). O6-methyl-guanine-DNA-methyltransferase (MGMT) promoter methylation is a frequent and early event in CRC tumourigenesis. This epigenetic silencing is a predictor of response to the alkylating drug temozolomide in glioblastoma. Preclinical evidences and some case reports showed temozolomide activity in CRC with MGMT silencing, but the available data from clinical trials are inconsistent.Methods:This was a multicentre, phase 2 trial, planned according to a two-stage Simon’s optimal design to investigate activity and safety of temozolomide in refractory CRC harbouring MGMT promoter methylation. The primary end point was overall response rate (ORR). Patients who failed two or more prior treatments received temozolomide at a dose of 150–200 mg m−2 per day on days 1–5 every 28 days.Results:From July 2012 to June 2016, 225 patients were screened, 80 showed MGMT promoter methylation and 41 were enrolled. Overall response rate was 10% and disease control rate was 32%. Median progression-free survival and overall survival were 1.9 and 5.1 months, respectively.Conclusions:Temozolomide showed a modest activity in this heavily pretreated population and the study did not meet its primary end point. The role of temozolomide in CRC remains still controversial and further research is warranted.

The role of pharmacogenetics in the new ESMO colorectal cancer guidelines.

The role of pharmacogenetics in the new ESMO colorectal cancer guidelines.

EGFR Gene Amplification and KRAS Mutation Predict Response to Combination Targeted Therapy in Metastatic Colorectal Cancer.

Genetic variability in KRAS and EGFR predicts response to cetuximab in irinotecan refractory colorectal cancer. Whether these markers or others remain predictive in combination biologic therapies including bevacizumab is unknown. We identified predictive biomarkers from patients with irinotecan refractory metastatic colorectal cancer treated with cetuximab plus bevacizumab. Patients who received cetuximab plus bevacizumab for irinotecan refractory colorectal cancer in either of two Phase II trials conducted were identified. Tumor tissue was available for 33 patients. Genomic DNA was extracted and used for mutational analysis of KRAS, BRAF, and p53 genes. Fluorescence in situ hybridization was performed to assess EGFR copy number. The status of single genes and various combinations were tested for association with response. Seven of 33 patients responded to treatment. KRAS mutations were found in 14/33 cases, and 0 responded to treatment (p=0.01). EGFR gene amplification was seen in 3/33 of tumors and in every case was associated with response to treatment (p<0.001). TP53 and BRAF mutations were found in 18/33 and 0/33 tumors, respectively, and there were no associations with response to either gene. EGFR gene amplification and KRAS mutations are predictive markers for patients receiving combination biologic therapy of cetuximab plus bevacizumab for metastatic colorectal cancer. One marker or the other is present in the tumor of half of all patients allowing treatment response to be predicted with a high degree of certainty. The role for molecular markers in combination biologic therapy seems promising.

Metabolic Adaptation to Nutritional Stress in Human Colorectal Cancer.

Tumor cells respond to their microenvironment, which can include hypoxia and malnutrition, and adapt their metabolism to survive and grow. Some oncogenes are associated with cancer metabolism via regulation of the related enzymes or transporters. However, the importance of metabolism and precise metabolic effects of oncogenes in colorectal cancer remain unclear. We found that colorectal cancer cells survived under the condition of glucose depletion, and their resistance to such conditions depended on genomic alterations rather than on KRAS mutation alone. Metabolomic analysis demonstrated that those cells maintained tricarboxylic acid cycle activity and ATP production under such conditions. Furthermore, we identified pivotal roles of GLUD1 and SLC25A13 in nutritional stress. GLUD1 and SLC25A13 were associated with tumor aggressiveness and poorer prognosis of colorectal cancer. In conclusion, GLUD1 and SLC25A13 may serve as new targets in treating refractory colorectal cancer which survive in malnutritional microenvironments.