KRAS Mutant Metastatic Colorectal Cancer Research Articles

Polo-like Kinase 1 Inhibition in KRAS-Mutated Metastatic Colorectal Cancer.

Inhibition of Polo-like kinase 1 (Plk1) is a promising new target and therapeutic strategy in metastatic colorectal cancer, especially those with KRAS mutations. New data support further development of onvansertib, and highlights the role of circulating tumor DNA in phase I clinical trials. See related article by Ahn et al., p. 2039.

Abstract 447: Anti-tumor efficacy of ompenaclid, a creatine transporter inhibitor, in KRAS mutant tumors, including NSCLC

Abstract Background: Pre-clinical studies identified creatine metabolism to be activated in KRAS mutant metastatic colorectal cancer (CRC) as a mechanism to fuel the increased energy demands of RAS mutant tumors. Metastatic colon cancer cells overexpress and subsequently release creatine kinase-B (CKB) into the extracellular space, where it phosphorylates creatine to generate the high energy metabolite phosphocreatine. Ompenaclid is a small molecule inhibitor of the creatine transporter SLC6A8. Inhibition of SLC6A8 by ompenaclid prevents import of phosphocreatine/creatine, resulting in depletion of intracellular creatine, phosphocreatine and ATP levels. This results in tumor apoptosis and robust anti-tumor efficacy in CRC models with a wide range of KRAS mutant alleles. Ompenaclid is currently in a Phase 2 trial, in combination with FOLFIRI and bevacizumab, in patients with RAS-mutated second-line advanced/metastatic colorectal cancer. Here, we assessed efficacy of ompenaclid in tumors beyond CRC, including KRAS WT and KRAS mutant NSCLC. Methods: Athymic mice were inoculated with CRC, pancreatic, gastric or NSCLC cancer cell lines and treated with ompenaclid once tumors reached ~150 mm3, until termination. Plasma metabolites were quantified by LC-MS/MS and tumoral expression of CKB and SLC6A8 in NSCLC and CRC tumors was measured by qPCR after treatment with a control or ompenaclid-supplemented diet for ~10 days. Combination treatment with MRTX849, a KRAS G12C inhibitor, was conducted in a pancreatic MiaPaca xenograft model. Results: Our studies demonstrate ompenaclid anti-tumor efficacy in NSCLC and pancreatic xenografts. Notably, and consistent with findings in CRC, efficacy in NSCLC was more robust in RAS mutant cancer models, relative to those bearing KRAS WT tumors. Metabolite analysis of the plasma of tumor-bearing mice at baseline revealed that mice harboring RAS mutant tumors had higher levels of p-creatine and lower levels of ATP, indicating that RAS mutant tumors utilize higher amounts of ATP, which may be converted to phosphocreatine by tumoral CKB, as confirmed by qPCR analysis. This finding is consistent with metastatic RAS mutant CRC tumors utilizing extracellular ATP to generate phosphocreatine and thus exhibiting greater dependency on creatine metabolism relative to RAS WT tumors. Treatment with ompenaclid also demonstrated additive efficacy in combination with KRAS G12C inhibitors. In summary, these data support development of ompenaclid in indications beyond CRC, including NSCLC, as well as in combination with KRAS G12C inhibitors. Citation Format: PuiChi Lo, Victor Sanz Chavez, Shugaku Takeda, Masoud Tavazoie, Isabel Kurth. Anti-tumor efficacy of ompenaclid, a creatine transporter inhibitor, in KRAS mutant tumors, including NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 447.

Onvansertib in Combination with FOLFIRI and Bevacizumab in Second-Line Treatment of KRAS-Mutant Metastatic Colorectal Cancer: A Phase Ib Clinical Study.

Onvansertib is a highly specific inhibitor of polo-like kinase 1 (PLK1), with demonstrated safety in solid tumors. We evaluated, preclinically and clinically, the potential of onvansertib in combination with chemotherapy as a therapeutic option for KRAS-mutant colorectal cancer. Preclinical activity of onvansertib was assessed (i) in vitro in KRAS wild-type and -mutant isogenic colorectal cancer cells and (ii) in vivo, in combination with irinotecan, in a KRAS-mutant xenograft model. Clinically, a phase Ib trial was conducted to investigate onvansertib at doses 12, 15, and 18 mg/m2 (days 1-5 and 14-19 of a 28-day cycle) in combination with FOLFIRI/bevacizumab (days 1 and 15) in patients with KRAS-mutant metastatic colorectal cancer who had prior oxaliplatin exposure. Safety, efficacy, and changes in circulating tumor DNA (ctDNA) were assessed. In preclinical models, onvansertib displayed superior activity in KRAS-mutant than wild-type isogenic colorectal cancer cells and demonstrated potent antitumor activity in combination with irinotecan in vivo. Eighteen patients enrolled in the phase Ib study. Onvansertib recommended phase II dose was established at 15 mg/m2. Grade 3 and 4 adverse events (AE) represented 15% of all treatment-related AEs, with neutropenia being the most common. Partial responses were observed in 44% of patients, with a median duration of response of 9.5 months. Early ctDNA dynamics were predictive of treatment efficacy. Onvansertib combined with FOLIFRI/bevacizumab exhibited manageable safety and promising efficacy in second-line treatment of patients with KRAS-mutant metastatic colorectal cancer. Further exploration of this combination therapy is ongoing. See related commentary by Stebbing and Bullock, p. 2005.

Real-World Study of Characteristics and Treatment Outcomes Among Patients with KRAS p.G12C-Mutated or Other KRAS Mutated Metastatic Colorectal Cancer.

BackgroundThe KRAS p.G12C mutation has recently become an actionable drug target. To further understand KRAS p.G12C disease, we describe clinicopathologic characteristics, treatment patterns, overall survival (OS), and real-world progression-free survival (rwPFS) in patients with metastatic colorectal cancer (mCRC), KRAS p.G12C mutations (KRAS G12C), and other KRAS mutations (KRAS non-G12C) using a de-identified database.Patients and MethodsClinical and tumor characteristics, including treatments received, genomic profile, and clinical outcomes were assessed for patients from a US clinical genomic database with mCRC diagnosed between January 1, 2011, and March 31, 2020, with genomic sequencing data available.ResultsOf 6477 patients with mCRC (mCRC cohort), 238 (3.7%) had KRAS G12C and 2947 (45.5%) had KRAS non-G12C mutations. Treatment patterns were generally comparable across lines of therapy (LOT) in KRAS G12C versus KRAS non-G12C cohorts. Median (95% CI) OS after the first LOT was 16.1 (13.0-19.0) months for the KRAS G12C cohort versus 18.3 (17.2-19.3) months for the KRAS non-G12C cohort, and 19.2 (18.5-19.8) months for the mCRC overall cohort; median (95% CI) rwPFS was 7.4 (6.3-9.5), 9.0 (8.2-9.7), and 9.2 (8.6-9.7) months, respectively. The different KRAS non-G12C mutations examined did not affect clinical outcomes. Median OS and rwPFS for all cohorts declined with each subsequent LOT.ConclusionsPatients with KRAS p.G12C-mutant mCRC have poor treatment outcomes, and outcomes appear numerically worse than for those without this mutation, indicating potential prognostic implications for KRAS p.G12C mutations and an unmet medical need in this population.

Liver Endothelium Promotes HER3-Mediated Cell Survival in Colorectal Cancer with Wild-Type and Mutant KRAS.

This body of work highlighted a potential strategy of using HER3 antibodies in combination with standard chemotherapy agents for treating patients with either KRAS wild-type or KRAS mutant metastatic colorectal cancer.

Abstract 425: Expanded access program of the PLK1 inhibitor onvansertib for treatment of patients with KRAS-mutant metastatic colorectal cancer

Abstract Introduction: Chemotherapy in combination with targeted agents are standard-of-care options for first and second-line treatment of metastatic colorectal cancer (mCRC) patients. Second-line treatment of KRAS-mutated mCRC confers a dismal patient outcome with response rates of 4% to FOLFIRI (5-fluorouracil (5FU), leucovorin, irinotecan) + bevacizumab and median progression-free survival of 5.5 months (Tournigand et al., JCO 2004). PLK1 is a serine/threonine kinase, master regulator of mitosis and its overexpression is associated with poorer outcomes in CRC (Weichert et al., World J. Gastroenterol. 2005). Onvansertib is an oral and highly selective PLK1 inhibitor with demonstrated efficacy as a single agent and synergistically with irinotecan and 5-FU in CRC preclinical models. Onvansertib was granted Fast Track Designation by the Food and Drug Administration for its clinical development program and is currently being investigated in combination with FOLFIRI + bevacizumab in a phase 1b/2 clinical study for second line treatment of patients with KRAS-mutated mCRC (NCT03829410). Preliminary results indicate that onvansertib in combination with chemotherapy is safe and efficacious and that early changes in plasma KRAS mutant are predictive of clinical response (ESMO 2020, Poster #2969). Method: An expanded access program (EAP) was initiated to provide access to onvansertib for treatment of patients who do not meet eligibility criteria for enrollment in the clinical trial, and provides an opportunity to collect safety and efficacy data outside of the clinical study. Patients must be at least 18 years old, have confirmed metastatic and unresectable CRC with a KRAS mutation and have failed or progressed on standard of care systemic therapy. Patients are treated with onvansertib (15 mg/m2, Days 1 to 5 of a 14-day cycle) in combination with FOLFIRI + bevacizumab (Day 1 of each cycle). Patients are being monitored for safety, efficacy by radiographic scans, and for changes in KRAS mutant allelic frequency (MAF) in circulating tumor DNA (ctDNA) by liquid biopsy. Result: The EAP was activated on June 9th 2020. As of November 12th 2020, 19 patients have been treated at 11 clinical sites across the United States. Changes in KRAS MAF after two cycles of therapy was evaluated in 17 patients. Thirteen patients had a KRAS mutation detected in ctDNA at baseline and 8 patients showed a decrease of >50% in KRAS MAF after the first two cycles. Clinical outcomes including efficacy and its correlation with changes in KRAS MAF will be presented at the AACR Annual meeting. Conclusions: The EAP provides a path for patients who may benefit clinically, but are not eligible for the ongoing clinical trial, to gain access to onvansertib treatment. Citation Format: Manish R. Sharma, Daniel Isaac, Ryan Ramaekers, Maya Ridinger, Mark Erlander, Lawrence Mendelsohn. Expanded access program of the PLK1 inhibitor onvansertib for treatment of patients with KRAS-mutant metastatic colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 425.

Random survival forests identify pathways with polymorphisms predictive of survival in KRAS mutant and KRAS wild-type metastatic colorectal cancer patients

KRAS status serves as a predictive biomarker of response to treatment in metastatic colorectal cancer (mCRC). We hypothesize that complex interactions between multiple pathways contribute to prognostic differences between KRAS wild-type and KRAS mutant patients with mCRC, and aim to identify polymorphisms predictive of clinical outcomes in this subpopulation. Most pathway association studies are limited in assessing gene–gene interactions and are restricted to an individual pathway. In this study, we use a random survival forests (RSF) method for identifying predictive markers of overall survival (OS) and progression-free survival (PFS) in mCRC patients treated with FOLFIRI/bevacizumab. A total of 486 mCRC patients treated with FOLFIRI/bevacizumab from two randomized phase III trials, TRIBE and FIRE-3, were included in the current study. Two RSF approaches were used, namely variable importance and minimal depth. We discovered that Wnt/β-catenin and tumor associated macrophage pathway SNPs are strong predictors of OS and PFS in mCRC patients treated with FOLFIRI/bevacizumab independent of KRAS status, whereas a SNP in the sex-differentiation pathway gene, DMRT1, is strongly predictive of OS and PFS in KRAS mutant mCRC patients. Our results highlight RSF as a useful method for identifying predictive SNPs in multiple pathways.

A phase Ib/II study of the polo-like kinase 1 (PLK1) inhibitor, onvansertib, in combination with FOLFIRI and bevacizumab for second-line treatment of patients with KRAS-mutated metastatic colorectal Cancer (mCRC).

TPS155 Background: Chemotherapy in combination with targeted agents are standard-of-care options for patients for mCRC with response rates > 50% in first line. In the second line setting, efficacy of chemotherapy and targeted agents are much lower with response rates of 5% for FOLFIRI (5-fluorouracil, leucovorin, irinotecan) + bevacizumab (anti-VEGF). New treatment options are urgently needed in particular for the 50 % of patients harboring a KRAS mutation. PLK1 is a serine/threonine kinase, master regulator of the mitotic checkpoint and cell division. PLK1 is overexpressed in CRC and its overexpression is associated with poor prognostic. A genome wide RNAi screen identified PLK1 as a synthetic lethal target in KRAS mutant CRC cells, inducing cell cycle arrest and apoptosis upon inhibition. Onvansertib is an oral, highly selective PLK1 inhibitor that demonstrates single agent and synergistic activity with irinotecan and 5-FU in preclinical CRC models. Additionally, KRAS mutated versus wild-type cells showed higher sensitivity to onvansertib. PLK1 inhibition is a potential target in KRAS-mutated mCRC, and the combination of onvansertib + FOLFIRI + bevacizumab may provide a new second-line treatment option. Methods: The primary objective of this single-arm Phase 1b/2 study is to assess the safety and preliminary efficacy of onvansertib in combination with FOLFIRI and bevacizumab in the second line setting for KRAS-mutated mCRC patients. For the Phase 1b segment, a standard 3 + 3 dose-escalation design is used to determine the maximum tolerated dose or recommended phase 2 dose (RP2D) of onvansertib. As of September 15th 2020, the first two dose levels have been cleared for safety and the third is enrolling. Efficacy will be determined by objective response rate (ORR) according to RECIST v1.1 (primary endpoint), progression-free survival and reduction in KRAS allelic burden in liquid biopsies (secondary endpoints). Biomarker analyses include genomic profiling of circulating tumor DNA genomic to evaluate altered pathways that correlate with patient clinical response. Based on a one-sided one sample log-rank test with 10% Type I error, there will be at least 90% power to detect an improvement in ORR from 5% to 20% with 32 patients. Clinical trial information: NCT03829410.

Prognostic and predictive value of KRAS mutation number in metastatic colorectal cancer.

Colorectal cancer (CRC) is the third most common cancer in the world and is the second leading cause of cancer-related deaths. Several mutations are involved in the development of CRC. The prognostic significance of the KRAS mutation has been discussed in many studies. We aimed to investigate the prognostic significance of the number of KRAS mutations in metastatic CRC (mCRC).Patients with mutations in the KRAS gene were included in the study. They were divided into 2 groups as single mutation and multiple mutations in the KRAS gene.For the study, 425 CRC patients were screened. KRAS mutation was positive in 191 patients (45%). One hundred ninety-one patients were included in the study, 171 patients (90%) had single mutations and 20 patients (10%) had multiple mutations. Median progression-free survival was 12.8 months in patients with multiple mutations, while it was 8.8 months in patients with single mutations (P: .05). The median overall survival of patients with multiple mutations was 40.7 months, while it was 22.7 months for patients with single mutations (P = .01)We found that the presence of multiple mutations in KRAS mutant patients was associated with better overall survival and progression-free survival than a single mutation.

436P Phase Ib/II study of the polo-like kinase 1 (PLK1) inhibitor, onvansertib, in combination with FOLFIRI and bevacizumab for second line treatment of KRAS-mutated metastatic colorectal cancer

436P Phase Ib/II study of the polo-like kinase 1 (PLK1) inhibitor, onvansertib, in combination with FOLFIRI and bevacizumab for second line treatment of KRAS-mutated metastatic colorectal cancer

Abstract CT235: A phase 1b/2 study of onvansertib (PCM-075) in combination with FOLFIRI and bevacizumab for second line treatment of patients with KRAS-mutated metastatic colorectal cancer (mCRC)

Abstract Background: Chemotherapy in combination with targeted agents are standard-of-care options for patients for mCRC with response rates >50% in first line. In the second line setting, efficacy of chemotherapy and targeted agents are much lower with response rates of 5% for FOLFIRI (5-fluorouracil, leucovorin, irinotecan) + bevacizumab (anti-VEGF). New treatment options are urgently needed in particular for the 50 % of patients harboring a KRAS mutation. Polo-like kinase 1 (PLK1) is a serine/threonine kinase, master regulator of the mitotic checkpoint and cell division. PLK1 is overexpressed in CRC and its overexpression is associated with poor prognostic. A genome wide RNAi screen identified PLK1 as a synthetic lethal target in KRAS mutant CRC cells, inducing cell cycle arrest and apoptosis upon inhibition. Onvansertib is an oral, highly selective PLK1 inhibitor that demonstrates single agent and synergistic activity with irinotecan in preclinical CRC models. Additionally, KRAS mutated vs wild-type cells showed higher sensitivity to onvansertib. PLK1 inhibition is a potential target in KRAS-mutated mCRC and onvansertib + FOLFIRI + bevacizumab may provide a new second-line treatment option. Trial design: The primary objective of this single-arm Phase 1b/2 study is to assess the safety and preliminary efficacy of onvansertib in combination with FOLFIRI and bevacizumab in the second line setting for KRAS-mutated mCRC patients. For the Phase 1b segment, a standard 3 + 3 dose-escalation design is used to determine the maximum tolerated dose or recommended phase 2 dose (RP2D) of onvansertib. As of January 24th 2020, enrollment in the second dose level is ongoing. Efficacy will be determined by objective response rate (ORR) according to RECIST v1.1 (primary endpoint), progression-free survival and reduction in KRAS allelic burden in liquid biopsies (secondary endpoints). In the phase 2, based on a one-sided one sample log-rank test with 10% Type I error, there will be at least 90% power to detect an improvement in ORR from 5% to 20% with 26 patients. Exploratory endpoints include genomic studies of circulating tumor cells and ctDNA to evaluate altered pathways that correlate with patient response. Clinical trial identification NCT03829410. Citation Format: Afsaneh Barzi, Heinz-Josef Lenz, Errin Samuëlsz, Maya Ridinger, Mark Erlander, Tanios S. Bekaii-Saab, Daniel H. Ahn. A phase 1b/2 study of onvansertib (PCM-075) in combination with FOLFIRI and bevacizumab for second line treatment of patients with KRAS-mutated metastatic colorectal cancer (mCRC) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT235.

Abstract B11: Whole-exome sequencing analysis of urine transrenal tumor DNA in metastatic colorectal cancer patients

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

A phase Ib/II study of the polo-like kinase 1 (PLK1) inhibitor, onvansertib, in combination with FOLFIRI and bevacizumab for second-line treatment of patients with KRAS-mutated metastatic colorectal cancer (mCRC).

TPS4116 Background: Chemotherapy in combination with targeted agents are standard-of-care options for patients for mCRC with response rates >50% in first line. In the second line setting, efficacy of chemotherapy and targeted agents are much lower with response rates of 5% for FOLFIRI (5-fluorouracil, leucovorin, irinotecan) + bevacizumab (anti-VEGF). New treatment options are urgently needed in particular for the 50 % of patients harboring a KRAS mutation. PLK1 is a serine/threonine kinase, master regulator of the mitotic checkpoint and cell division. PLK1 is overexpressed in CRC and its overexpression is associated with poor prognostic. A genome wide RNAi screen identified PLK1 as a synthetic lethal target in KRAS mutant CRC cells, inducing cell cycle arrest and apoptosis upon inhibition. Onvansertib is an oral, highly selective PLK1 inhibitor that demonstrates single agent and synergistic activity with irinotecan in preclinical CRC models. Additionally, KRAS mutated vs wild-type cells showed higher sensitivity to onvansertib. PLK1 inhibition is a potential target in KRAS-mutated mCRC, and the combination of onvansertib + FOLFIRI + bevacizumab may provide a new second-line treatment option. Methods: The primary objective of this single-arm Phase 1b/2 study is to assess the safety and preliminary efficacy of onvansertib in combination with FOLFIRI and bevacizumab in the second line setting for KRAS-mutated mCRC patients. For the Phase 1b segment, a standard 3 + 3 dose-escalation design is used to determine the maximum tolerated dose or recommended phase 2 dose (RP2D) of onvansertib. As of January 24, 2020, enrollment in the second dose level is ongoing. Efficacy will be determined by objective response rate (ORR) according to RECIST v1.1 (primary endpoint), progression-free survival and reduction in KRAS allelic burden in liquid biopsies (secondary endpoints). In the phase 2, based on a one-sided one sample log-rank test with 10% Type I error, there will be at least 90% power to detect an improvement in ORR from 5% to 20% with 26 patients. Exploratory endpoints include genomic studies of circulating tumor cells and ctDNA to evaluate altered pathways that correlate with patient clinical response. Clinical trial information: NCT03829410 .

Afatinib as a novel potential treatment option for NRG1 fusion-positive tumors.

110 Background: Neuregulin 1 (NRG1) is a growth factor that binds HER3/4 and activates ErbB signalling pathways. NRG1 gene fusions function as oncogenic drivers and represent a potential therapeutic target across tumour types. Afatinib, an ErbB-family blocker, is a potential treatment option for some patients with NRG1 fusion-positive ( NRG1+) tumours, as supported by preclinical evidence and clinical case reports. Of 13 patients with NRG1+ lung adenocarcinoma (ADC; n = 9), pancreatic ADC (n = 2), cholangiocarcinoma (n = 1), and ovarian cancer (n = 1) treated with afatinib, eight patients achieved a best response of partial response (PR; median duration 7.3 months, range 3–12), three patients had stable disease (SD) and two patients had progressive disease. Methods: Here, we report the clinico-pathological and molecular characteristics and current status of four additional cases of afatinib-treated NRG1+ tumours. Results: Patient 1, 66 year-old female, never-smoker with metastatic non-mucinous lung ADC. CD74-NRG1 fusion was identified, and 5th-line afatinib initiated. PR is ongoing after 16 months. Patient 2, 43 year-old female, non-smoker with advanced invasive mucinous lung ADC. CD74-NRG1 fusion was identified and 3rd-line afatinib initiated (PR, 18 months); treatment is ongoing following local progression. Patient 3, 69 year-old male, with KRAS-mutated metastatic colorectal cancer. Following a right hemicolectomy and liver/lung metastasectomies, a novel POMK-NRG1 fusion was detected and afatinib initiated (SD, 4 months). Eight months after initiation, afatinib treatment is ongoing, in combination with radiotherapy, with SD. Patient 4, 54 year-old male, with KRAS-wild-type metastatic pancreatic cancer. Following progression on chemotherapy, APP-NRG1 fusion was detected as part of the Personalized Oncogenomics study (NCT02155621), and afatinib initiated; PR is ongoing after 7 months. Conclusions: These findings add to a growing body of evidence that afatinib is a potential treatment option for patients with NRG1+ tumours. Prospective study is ongoing/planned in the Drug Rediscovery Protocol trial (DRUP; NCT02925234) and Targeted Agent and Profiling Utilization Registry study (TAPUR; NCT02693535).

A personalized platform identifies trametinib plus zoledronate for a patient with KRAS-mutant metastatic colorectal cancer.

Colorectal cancer remains a leading source of cancer mortality worldwide. Initial response is often followed by emergent resistance that is poorly responsive to targeted therapies, reflecting currently undruggable cancer drivers such as KRAS and overall genomic complexity. Here, we report a novel approach to developing a personalized therapy for a patient with treatment-resistant metastatic KRAS-mutant colorectal cancer. An extensive genomic analysis of the tumor's genomic landscape identified nine key drivers. A transgenic model that altered orthologs of these nine genes in the Drosophila hindgut was developed; a robotics-based screen using this platform identified trametinib plus zoledronate as a candidate treatment combination. Treating the patient led to a significant response: Target and nontarget lesions displayed a strong partial response and remained stable for 11 months. By addressing a disease's genomic complexity, this personalized approach may provide an alternative treatment option for recalcitrant disease such as KRAS-mutant colorectal cancer.

Whole exome sequencing analysis of urine trans-renal tumour DNA in metastatic colorectal cancer patients

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

565P - Dose finding and safety study of reovirus (Reo) with irinotecan/ fluorouracil/ leucovorin/ bevacizumab (FOLFIRI/B) in patients with KRAS mutant metastatic colorectal cancer (mCRC): Final results

565P - Dose finding and safety study of reovirus (Reo) with irinotecan/ fluorouracil/ leucovorin/ bevacizumab (FOLFIRI/B) in patients with KRAS mutant metastatic colorectal cancer (mCRC): Final results

Abstract 385: HIF1A can regulate Wnt signaling in human colon cancer cells

Abstract Standard-of-care treatment for KRAS mutant metastatic colorectal cancer (mCRC) combines a cytotoxic chemotherapy backbone (FOLFOX) with an antiangiogenesis biologic agent (i.e., bevacizumab). Despite significant efforts to improve treatment, the prognosis for this type of cancer remains poor with an average 5-year overall survival of ~11%. Oncogenic KRAS mutations lead to the overactivation of RAS/ERK/MAPK pathwa,y driving many hallmarks of cancer such as cell proliferation, growth, and altered metabolism. In particular, several studies have shown that oncogenic activation of KRAS leads to normoxic stabilization of HIF1A protein, which can then reprogram cellular metabolism towards aerobic glycolysis. Our studies have discovered that overactive Wnt signaling can also reprogram cancer cell metabolism towards aerobic glycolysis. Of note, KRAS (~40%) and Wnt signaling (~90%) are very frequently coactivated in colorectal cancer. Interestingly, an important, key metabolic gene targeted by Wnt signaling, Pyruvate Dehydrogenase Kinase I (PDK1), is also directly regulated by HIF1A, suggesting there may be crosstalk between the HIF1A and Wnt pathways. Indeed, several published studies support the idea that HIF1A can influence Wnt signaling, and our data show this may occur through regulation of the Wnt mediating transcription factors LEF1 and TCF1 (TCF7 gene). Using luciferase reporters driven by LEF/TCF promoters, we observed significantly increased LEF1/TCF7 promoter activity in hypoxic colon cancer cells but not for other TCF family members (TCF7L1/TCF7L2). We identified putative hypoxia responsive elements (HREs) in the human LEF1 promoter, and deletion of these HREs reduced responsiveness to hypoxia. Furthermore, we have found that targeting glycolysis and Wnt can be synergistic in inhibiting colon cancer cell colony growth. We find that HIF1A and LEF/TCF/beta-catenin complexes coregulate gene expression of metabolic targets as well as Wnt signaling components (e.g., LEF1 and TCF7). These data suggest that cross-regulation between the HIF1A and Wnt signaling pathway is important and may be a potential Achilles heel for novel therapeutics in targeting KRAS mutant colon cancer. Current studies are under way to further investigate the mechanisms of crosstalk and joint regulation of metabolic reprogramming in KRAS mutant colon cancer cells. Citation Format: Yung Lyou, George Chen, Marian Waterman. HIF1A can regulate Wnt signaling in human colon cancer cells [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 385.

Serial analysis of mutant KRAS in circulation cell-free DNA (cfDNA) of patients with KRAS mutant metastatic colorectal cancer: A translational study of the KRK0207 trial.

e15599Background: Circulating tumor DNA (ctDNA) is a promising marker for monitoring tumor burden and therapy response in metastatic colorectal cancer (mCRC). The AIO KRK 0207 trial investigated di...

Immune response to reovirus (REO) in phase I study with chemotherapy in patients with KRAS mutant metastatic colorectal cancer (mCRC).

217 Background: Viruses are well known immune sensitizing agents. The therapeutic efficacy of oncolytic reovirus in combination with chemotherapy is underway in a phase 1 study of mCRC. This study evaluates the nature of immune response by determining the distribution of antigen presenting cells (APCs) and activated T lymphocytes along with the cytokine expression pattern in peripheral circulation. Methods: REO was administered as a 60-minute intravenous infusion for 5 consecutive days every 28 days, at a tissue culture infective dose (TCID50) of 3x106. Serum was collected pre- and post- REO on days 1, pre REO on days 2-5, and days 8, 15, 22, and 29. Peripheral blood mononuclear cells (PBMC) were isolated and stained with fluorophore labelled antibodies against CD4, CD8, CD56, CD70, and CD123. Stained cells were fixed and evaluated by flow cytometry. The expression profile of 25 cytokines in plasma was assessed (post PBMC isolation) on an EMD Millipore multiplex Luminex platform. Results: Patients mount a robust immune response with dendritic cell maturation at 48 hrs (p < 0.01) followed by activation of cytotoxic T (CD8+) cells at Day 8 (p < 0.01). Cytokine assay indicated upregulation of Interleukin 1 beta (IL-1β; p = 0.004), Granulocyte-macrophage colony-stimulating factor (GM-CSF; p = 0.05), the chemokine Macrophage Inflammatory Proteins (MIP-1β; p = 0.05) at day 15. Furthermore, consistent upregulation of inflammatory cytokine IL-6 was seen from days 3 through 8 (p < 0.05), and decrease in IL-8 at 72 hrs (p = 0.03) was observed. Conclusions: REO induces strong immune response in patients with mCRC. APCs are stimulated within 48 hrs and activated (CD8+ CD70+) T cells within 168 hrs. Cytokine profiling indicates stimulation for maturation of APCs, chemotactic induction for macrophages and activation of T cells as highlighted by release of IL-1β, GM-CSF and MIP-1β respectively. Sustained increased expression of IL-6 (triggering lymphocyte maturation) and downregulation of IL-8 (pro-angiogenic cytokine) is also observed. REO thus functions bimodally as an oncolytic agent causing lysis of tumor cells, and facilitator of immune-mediated recognition and destruction of tumor cells. Clinical trial information: NCT01274624.