Irinotecan For Metastatic Colorectal Cancer Research Articles

113P p16 immunohistochemical (IHC) expression (exp) predicts benefit from irinotecan in metastatic colorectal cancer (mCRC): A translational analysis of the TRIBE and TRIBE2 studies

113P p16 immunohistochemical (IHC) expression (exp) predicts benefit from irinotecan in metastatic colorectal cancer (mCRC): A translational analysis of the TRIBE and TRIBE2 studies

Effect of p16 immunohistochemical expression (exp) on irinotecan in metastatic colorectal cancer (mCRC): A translational analysis of the TRIBE and TRIBE2 studies.

3562 Background: CDKN2A encodes the inhibitor of the cyclin-dependent kinases p16 and is frequently methylated in colorectal cancer, thus reducing the exp levels of p16 protein. In pre-clinical models of colorectal cancer cells, the demethylation of CDKN2A gene induces topoisomerase I upregulation increasing the sensitivity to irinotecan. In metastatic colorectal cancer (mCRC) pts, the role of p16 expression has been poorly investigated. Methods: Tumour samples of pts randomized in the phase III TRIBE2 study comparing upfront FOLFOXIRI/bevacizumab (bev) versus (vs) FOLFOX/bev were assessed for p16 immunohistochemical exp. A validation analysis in patients treated with FOLFIRI/bev in the TRIBE study was conducted. Results: Out of 679 patients enrolled in the TRIBE2 study, 231 tumours were assessed for p16 exp. Overall, 152 (66%), and 79 (34%) were classified as positive (pos) (IHC 2+ and 3+) and negative (neg) (IHC 0 and 1+), respectively. In the p16 pos group, 69 (45%) and 83 (55%) pts received FOLFOXIRI/bev and FOLFOX/bev, respectively, while in the p16 neg cohort, FOLFOXIRI/bev was administered in 37 (47%) and FOLFOX/bev in 42 (53%) cases. Pts with p16 neg tumours had more frequently an ECOG-PS of 1-2 (16% vs 6%, p=0.0098) and a BRAF mut tumour (26% vs 7%, p=0.0002). No PFS difference was observed between p16 neg and pos patients, while a trend for a longer OS was shown in favour of p16 pos pts (25.5 vs 21.3 months; HR: 0.74, 95%CI: 0.53-1.02, p=0.068) that was not confirmed at the multivariate analysis (p=0.61). Among patients with p16 pos tumours, those treated with FOLFOXIRI/bev reported longer PFS (12.8 vs 9.4 months, HR: 0.55, 95%CI: 0.39-0.78, p=0.0008) and OS (30.0 vs 21.4 months, HR: 0.66, 95%CI: 0.46-0.95, p=0.026) than those receiving FOLFOX/bev. On the other hand, no significant difference was observed among p16 neg patients in terms of both PFS (9.0 vs 9.4 months, HR: 0.91, 95%CI: 0.57-1.46, p=0.69) and OS (21.3 vs 19.5 months, HR: 0.95, 95%CI: 0.58-1.57, p=0.85), thus suggesting a differential treatment effect according to p16 exp (pinteraction for PFS =0.12; pinteraction for OS =0.19). Among patients treated with FOLFIRI/bev in the TRIBE study (N=58) patients with p16 pos tumours reported longer PFS and OS than those with p16 neg. (HR for PFS: 0.45, 95%CI: 0.22-0.92, p=0.026; HR for OS: 0.41, 95%CI: 0.20-0.85, p=0.013). Conclusions: In mCRC, p16 pos exp seems associated with higher benefit from irinotecan. Prospective confirmation in independent randomized series is warranted.

The adjuvant oxaliplatin-irinotecan paradox.

e15655 Background: A pervasive pattern in oncology is that chemotherapeutic agents which achieve acceptance for adjuvant use are the ones that have shown superior efficacy in the treatment of metastatic disease. The greater the efficacy in metastatic disease, the greater the likelihood that adjuvant use will be statistically viable. Oxaliplatin is the exception to this, having paradoxically shown similar outcomes to irinotecan in metastatic colorectal cancer (CRC) but superiority in the adjuvant setting. In this study, the TriNetX research database was used to better evaluate the adjuvant efficacy of oxaliplatin use in real-world patients. Methods: The TriNetX research database was used for this study. The TriNetX platform provides access to anonymized medical record information on more than 91 million patients in 75 large healthcare organizations. Three cohorts of stage III colorectal patients were created for comparison, utilizing International Classification of Disease-10 (ICD-10) codes and medication codes provided in the TriNetX platform. All patients were required to have a diagnosis of colon cancer (C18) and lymph node involvement (C77), with the absence of any liver or lung metastases (C78.7 and C78.0, respectively). Adjuvant oxaliplatin use was identified by the presence of the oxaliplatin medication code within 9 months of CRC diagnosis. The adjuvant oxaliplatin cohort was compared to a cohort with no oxaliplatin exposure, identified by the exclusion of the oxaliplatin medication code for 12 months following CRC diagnosis. The cohorts were balanced for age, race, gender, and ethnicity. The endpoint of the comparisons was all-cause mortality at 5 years. Results: Adjuvant use of oxaliplatin was associated with a 2.3% absolute decrease in the risk of death at 5 years (risk ratio 0.88, 95% CI (0.79,0.97), p-value 0.01). See figure 1. Conclusions: This study shows that adjuvant use of oxaliplatin is associated with a 2.3% absolute survival advantage in stage III colorectal cancer patients. This small absolute benefit is likely why occasional retrospective analyses have been unable to replicate it. A controlled interrupted time series analysis from Huang, et. al. showed no benefit to adjuvant oxaliplatin in the stage III setting for Taiwanese patients. Such a small benefit may also explain why the ACHIEVE trial found three months of adjuvant oxaliplatin to be equivalent to six. When a benefit is very small, a shorter duration of treatment would be more likely to result in statistical equivalency than if the benefit was more substantial. [Table: see text]

A phase I/II study of arfolitixorin and 5-fluorouracil in combination with oxaliplatin (plus or minus bevacizumab) or irinotecan in metastatic colorectal cancer

Background5-fluorouracil (5-FU) combined with a folate remains an essential treatment component for metastatic colorectal cancer (mCRC). Leucovorin is the folate most often used, but requires intracellular conversion to a reduced folate, and has high pharmacokinetic variability and limited bioavailability in patients with low folate pathway gene expression. Arfolitixorin is an immediately active form of folate, [6R]-5,10-methylenetetrahydrofolate ([6R]-MTHF), and may improve outcomes.Patients and methodsThis open-label, multicenter, phase I/II study in patients with mCRC (NCT02244632) assessed the tolerability and efficacy of first- or second-line arfolitixorin (30, 60, 120, or 240 mg/m2 intravenous) with 5-FU alone, or in combination with oxaliplatin (plus or minus bevacizumab) or irinotecan, every 14 days. Safety, efficacy, and pharmacokinetics were assessed before and after four cycles (8 weeks) of treatment.ResultsIn 105 treated patients, investigators reported 583 adverse events (AEs) in 86 patients (81.9%), and 256 AEs (43.9%) were potentially related to arfolitixorin and 5-FU. Dose adjustments were required in 16 patients (15.2%). At 8 weeks, 9 out of 57 patients assessed for efficacy achieved an objective response (15.8%), and all 9 achieved a partial response. Six of these nine patients had received arfolitixorin as a first-line treatment. A further 33 patients (57.9%) achieved stable disease. Pharmacokinetics were assessed in 35 patients. The average tmax was 10 min, and area under the plasma concentration–time curve from time 0 to 1 h increased linearly between 30 and 240 mg/m2. No accumulation was observed for [6R]-MTHF following repeated administration, and there were no major pharmacokinetic differences between cycle 1 and cycle 4 at any dose.ConclusionsArfolitixorin is a well-tolerated moderator of 5-FU activity. It is suitable for further investigation in mCRC and has the potential to improve treatment outcomes in patients with low folate pathway gene expression. Arfolitixorin can easily be incorporated into current standard of care, requiring minimal changes to chemotherapy regimens.

Germline polymorphisms in genes maintaining replication fork to predict the efficacy of oxaliplatin and irinotecan in metastatic colorectal cancer (mCRC) patients enrolled in MAVERICC trial.

3139 Background: Protection of replication forks is critical for the survival of cancer cells. Chemotherapeutic drugs such as oxaliplatin and irinotecan can impede the progression of replication forks by inducing DNA lesions, which cause fork collapse and generate double-strand breaks. We hypothesized that functional genetic variants in genes involved in the maintenance of replication forks may predict the efficacy of cytotoxic drugs in mCRC patients. Methods: We analyzed genomic and clinical data from MAVERICC, a phase II trial which compared mFOLFOX6 and FOLFIRI in combination with bevacizumab in untreated mCRC patients. Genomic DNA extracted from blood samples was genotyped using an OncoArray (Illumina, Inc., San Diego, CA, USA). Candidate six missense single nucleotide polymorphisms (SNPs) ( SLFN11 rs9898983, SLFN11 rs12453150, RPA1 rs5030749, MCM3 rs2230240, TIMELESS rs2291739, and TIMELESS rs774047) were tested for association with progression-free survival (PFS) and overall survival (OS), using Cox proportional hazards model. To confirm the predictive value, the treatment-by-SNP interaction was tested. Results: A total of 324 patients were available for the SNP analyses (mFOLFOX6 plus bevacizumab arm [OHP arm]: n = 161; FOLFIRI plus bevacizumab arm [IRI arm]: n = 163). In the OHP arm, univariable analysis showed a significantly better PFS in patients with G/G genotype of TIMELESS rs2291739 compared to those with any A allele, and in patients with T/T genotype of TIMELESS rs774047 compared to those with any C allele. However, neither of these SNP’s associations were confirmed by multivariable analysis: TIMELESS rs2291739 (any A allele vs G/G, hazard ratio [HR] = 0.60, 95% confidence interval [CI] = 0.31–1.17, p = 0.12) and TIMELESS rs774047 (any C allele vs T/T, HR = 0.74, 95% CI = 0.41–1.36, p = 0.33). In the IRI arm, univariable analysis showed a significantly worse OS in patients with G/G genotype of TIMELESS rs2291739 compared to those with any A allele, and in patients with T/T genotype of TIMELESS rs774047 compared to those with any C allele. Multivariable analysis confirmed the significant associations in these SNPs: TIMELESS rs2291739 (any A allele vs G/G, HR = 3.06, 95% CI = 1.49–6.25, p < 0.01) and TIMELESS rs774047 (any C allele vs T/T, HR = 2.95, 95% CI = 1.43–6.08, p < 0.01). Treatment-by-SNP interaction test confirmed the significant predictive value of both SNPs, both on PFS and OS. Conclusions: Germline polymorphisms in the TIMELESS gene involved in the protection of replication forks may predict efficacy of oxaliplatin and irinotecan in mCRC patients. Our novel findings warrant further validation studies.

Consensus molecular subtypes and RAS status as biomarker of treatment intensity with fluoropyrimidine, bevacizumab, and irinotecan in metastatic colorectal cancer (XELAVIRI, AIO KRK 0110).

3552 Background: Prognostic biomarkers beside RAS/BRAF status are necessary to identify metastatic colorectal cancer (mCRC) patients who benefit from combined (COMB) versus sequential (SEQ) treatment with fluoropyrimidine, bevacizumab and irinotecan (randomized phase III XELAVIRI trial). Methods: mRNA was extracted from formalin-fixed paraffin embedded (FFPE) tumor tissue of 337 patients, gene expression was measured by the Nanostring PanCancer Progression Panel. Consensus molecular subtypes (CMS) classification was re-derived using a multinomial regression model. Data of Guinney et al. (Nat. Med. 2015. 21:1350-6) and FIRE-3 served as training and validation set. RAS/BRAF MUT were assessed by pyrosequencing. Median overall (OS) and progression free survival (PFS), hazard ratios (HR) and 95% confidence interval (CI) were estimated by Kaplan-Meier method and univariate Cox regression. Results: The multinomial regression model employed in the present analysis correctly predicted CMS labels in 98.3 % of the original Guinney- and 100.0 % of FIRE-3 population. In XELAVIRI, CMS subgroups were predicted as follows: CMS1: n = 62 (18.4 %); CMS2: n = 174 (51.6 %); CMS3: n = 9 (2.7 %); CMS4: n = 92 (27.3 %). A general prognostic impact of CMS was not observed when all patients were analysed. In RAS/BRAF WT mCRC patients, substantial benefit of COMB versus SEQ treatment was shown for OS and PFS in CMS2 and CMS4, but not in CMS1. Conversely, OS was significantly longer for COMB treatment in patients with RAS MUT and CMS1 mCRC, while SEQ treatment was not inferior in RAS MUT and CMS2 or CMS4 subgroups (see TABLE). Additional data for overall response rates, early tumor shrinkage and sidedness might be presented at the meeting. Conclusions: This retrospective analysis of XELAVIRI suggests that CMS may serve as biomarker that predicts response to initially combined versus less intensive sequential chemotherapy in patients with RAS/BRAF WT mCRC.[Table: see text]

Gender-dependent survival benefit from first-line irinotecan in metastatic colorectal cancer. Subgroup analysis of a phase III trial (XELAVIRI-study, AIO-KRK-0110)

BackgroundXELAVIRI compared sequential (Arm A) versus initial (Arm B) irinotecan in combination with fluoropyrimidine plus bevacizumab in patients with metastatic colorectal cancer, trial identification: NCT01249638. In the full analysis set of the study, non-inferiority of time to failure of strategy (TFS) was not shown. The present analysis was performed to evaluate the effect of gender on treatment outcome and tolerability. MethodsThe study end-points overall response rate (ORR), progression-free survival (PFS), TFS and overall survival (OS) were evaluated in female versus male patients and in molecular subgroups (i.e. RAS mutational status). Interaction of treatment and gender was tested by likelihood ratio tests. ResultsIn total, 281 male and 140 female patients (n = 421) were evaluated. Among the male patients, the ORR was 33.6% without and 58.3% with initial irinotecan (P < 0.001). PFS (hazard ratio [HR] 0.54; 95% confidence interval [CI] 0.42–0.69; P < 0.001) and OS (HR 0.63; 95% CI 0.47–0.85; P = 0.002) were also significantly better with initial irinotecan. Among the female patients, the ORR was 42.7% in Arm A and 43.1% in Arm B, PFS was similar (HR 1.09; 95% CI 0.76–1.55; P = 0.649) without and with initial irinotecan. A strong trend for inferior outcome with regard to OS with initial irinotecan was observed (HR 1.46; 95% CI 0.95–2.24; P = 0.081) and the trend reached significance in the multivariate analysis (HR 1.78; 95% CI 1.08–2.95; P = 0.02). Formal interaction of treatment and gender was observed for ORR (P = 0.018), PFS (P = 0.002) and OS (P = 0.001). Treatment-related adverse events were not significantly different between male and female patients. ConclusionsThe present analysis suggests that gender interacts with efficacy of initial irinotecan when used in combination with fluoropyrimidines and bevacizumab. Although male patients derived a significant and clinically meaningful benefit from initial combination chemotherapy, this was not observed in female patients.

Gender and survival benefit from initial irinotecan in metastatic colorectal cancer: Analysis of the XELAVIRI (AIOKRK0110) study.

3559 Background: XELAVIRI compared initial vs sequential irinotecan (iri) in combination with fluoropyrimidine (FP) plus bevacizumab (bev) in patients (pts) with mCRC, trial identification: NCT01249638. In the full analysis set of the study, non-inferiority of time to failure of strategy (TFS) was not shown (primary endpoint). Pts with RAS/BRAF wildtype (wt) tumors benefitted from initial iri. Methods: The study endpoints objective response rate (ORR), progression-free survival (PFS), time to failure of strategy (TFS) as well as overall survival (OS) were evaluated in female vs. male pts as well as molecular subgroups (i.e. RAS mutational status). Interaction of treatment and gender was tested by likelihood ratio tests. Results: Of 421 patients, 281/140 were male/female. In male patients, ORR was 33.6% without and 58.3% with initial iri (P &lt; 0.001). PFS (HR: 0.54 (95%CI 0.42-0.69) P &lt; 0.001) and OS (HR: 0.63 (95%CI 0.47-0.85), P = 0.002), were also significantly better with initial iri. In the subgroup analysis, this effect was especially pronounced in pts with RAS/BRAF wt tumors. In female pts, ORR was 43% in both arms, PFS was similar (HR: 1.09 (95%CI 0.76-1.55), P = 0.65) without and with initial iri. In OS, a strong trend for inferior outcome with initial iri was seen (HR: 1.46 (95%CI 0.95-2.24), P = 0.08) that reached significance in the multivariate analysis (HR: 1.73 (95%CI 1.04-2.86, P = 0.034). Female patients with RAS/BRAF wt tumors did not benefit from initial iri (HR 1.05 (95% CI 0.46-2.41), P = 0.903 for OS). Formal interaction of treatment and gender was seen for ORR (P = 0.018), PFS (P = 0.002) and OS (P = 0.001). There were some trends for more pronounced toxicities in female pts treated with Irinotecan. Conclusions: This unplanned exploratory analysis suggests that gender might interact with efficacy of initial iri when used in the context of FP and bev. While especially male RAS wild-type patients derived a significant and clinically meaningful benefit from initial use of iri, this was not observed in female patients with RAS wt tumors. Clinical trial information: NCT01249638.

Gender and survival benefit from initial irinotecan in metastatic colorectal cancer: Analysis of the XELAVIRI (AIOKRK0110) study.

549 Background: XELAVIRI compared initial versus sequential irinotecan (iri) in combination with fluoropyrimidine (FP) plus bevacizumab (bev) in patients (pts) with mCRC, trial identification: NCT01249638. In the full analysis set of the study, non inferiority of time to failure of strategy (TFS) of the sequential use could not be demonstrated (primary endpoint). Methods: The secondary endpoints overall response rate (ORR), progression-free survival (PFS) as well as overall survival (OS) were evaluated in female versus male pts as well as molecular subgroups (RAS mutational status). Interaction of treatment and gender was tested by likelihood ratio tests. Results: Of 421 patients, 281/140 were male/female. In female pts, ORR was 43% in both arms, PFS was 8.9 (95% CI 6.8-11.1) versus 10.1 (95% CI 8.5-11.8) months (HR: 1.09 (95% CI 0.76-1.55), P = 0.65) in pts with initial iri versus pts without initial iri, respectively. In females, a trend for inferior OS with initial iri was seen: 21.8 (95% CI 14.8-28.8) months with initial iri versus 28.4 (95% CI 21.9-34.9) months without initial iri (HR: 1.46 (95% CI 0.95-2.24), P = 0.08). This difference was significant in the multivariate analysis (HR: 1.73 (95% CI 1.04-2.86, P = 0.034). Male pts benefitted across all analysed endpoints from initial iri: ORR was 58.3% with initial iri and 33.6% without iri (P &lt; 0.001), PFS was 10.1 (95% CI 9.2-11.0) versus 7.4 (95% CI 6.3-8.5) months (HR: 0.54 (95% CI 0.42-0.69) P &lt; 0.001) and OS 23.9 (95% CI 19.1- 28.6) versus 20.5 (95% CI 18.1-22.9) months (HR: 0.63 (95% CI 0.47-0.85), P = 0.002), with initial iri versus without initial iri, respectively. Interaction of treatment and gender was seen for ORR (P = 0.018), PFS (P = 0.002) and OS (P = 0.001). Additional data including treatment and toxicities will be presented at the meeting. Conclusions: This unplanned exploratory analysis suggests that gender might interact with efficacy of initial iri when used in the context of FP and bev. While male patients derived a significant and clinically meaningful benefit from initial use of iri, this was not observed in female patients. Clinical trial information: NCT01249638.

Potential role of PIN1 genotypes in predicting benefit from oxaliplatin-based and irinotecan-based treatment in patients with metastatic colorectal cancer.

PIN1-mediated substrate isomerization plays a role in the repair of DNA double-strand breaks. We hypothesized that genetic polymorphisms in PIN1-related pathways may affect tumor sensitivity to oxaliplatin or irinotecan in metastatic colorectal cancer (mCRC) patients. We analyzed genomic DNA from five cohorts of mCRC patients (total 950) treated with different first-line treatments: oxaliplatin cohorts 1 (n=146) and 2 (n=70); irinotecan cohorts 1 (n=228) and 2 (n=276); and combination cohort (n=230). Single nucleotide polymorphisms of candidate genes were analyzed by PCR-based direct sequencing. In the oxaliplatin cohort 1, patients carrying any PIN1 rs2233678 C allele had shorter progression-free survival (PFS) and overall survival (OS) than the G/G variant (PFS, 7.4 vs. 15.0 months, hazard ratio [HR] 3.24, P<0.001; OS, 16.9 vs. 31.5 months, HR: 2.38, P=0.003). In contrast, patients with C allele had longer median PFS than patients with G/G (11.9 vs. 9.4 months, HR: 0.64, 95%CI: 0.45–0.91, P=0.009) in the irinotecan cohort 1. No significant differences were observed in the combination cohort. In comparison between the irinotecan cohort 1 and combination cohort, the patients carrying the G/G variant benefit greatly from the combination compared with irinotecan-based regimen (PFS, 11.6 vs. 9.4 months, HR 0.61, 95%CI: 0.47–0.78, P<0.001; OS, 30.6 vs. 24.0 months, HR 0.79, 95%CI: 0.62–1.02, P=0.060), while no significant difference was shown in any C allele. Germline PIN1 polymorphisms may predict clinical outcomes in mCRC patients receiving oxaliplatin- or irinotecan-based therapy, and identify specific populations favorable to oxaliplatin plus irinotecan combination therapy.

Decoy receptor 1 (DCR1) promoter hypermethylation and response to irinotecan in metastatic colorectal cancer.

Diversity in colorectal cancer biology is associated with variable responses to standard chemotherapy. We aimed to identify and validate DNA hypermethylated genes as predictive biomarkers for irinotecan treatment of metastatic CRC patients.Candidate genes were selected from 389 genes involved in DNA Damage Repair by correlation analyses between gene methylation status and drug response in 32 cell lines. A large series of samples (n=818) from two phase III clinical trials was used to evaluate these candidate genes by correlating methylation status to progression-free survival after treatment with first-line single-agent fluorouracil (Capecitabine or 5-fluorouracil) or combination chemotherapy (Capecitabine or 5-fluorouracil plus irinotecan (CAPIRI/FOLFIRI)).In the discovery (n=185) and initial validation set (n=166), patients with methylated Decoy Receptor 1 (DCR1) did not benefit from CAPIRI over Capecitabine treatment (discovery set: HR=1.2 (95%CI 0.7-1.9, p=0.6), validation set: HR=0.9 (95%CI 0.6-1.4, p=0.5)), whereas patients with unmethylated DCR1 did (discovery set: HR=0.4 (95%CI 0.3-0.6, p=0.00001), validation set: HR=0.5 (95%CI 0.3-0.7, p=0.0008)). These results could not be replicated in the external data set (n=467), where a similar effect size was found in patients with methylated and unmethylated DCR1 for FOLFIRI over 5FU treatment (methylated DCR1: HR=0.7 (95%CI 0.5-0.9, p=0.01), unmethylated DCR1: HR=0.8 (95%CI 0.6-1.2, p=0.4)).In conclusion, DCR1 promoter hypermethylation status is a potential predictive biomarker for response to treatment with irinotecan, when combined with capecitabine. This finding could not be replicated in an external validation set, in which irinotecan was combined with 5FU. These results underline the challenge and importance of extensive clinical evaluation of candidate biomarkers in multiple trials.

Abstract NG02: A network of deeply conserved synthetic-lethal interactions for exploration of precision cancer therapy

Abstract NG02: A network of deeply conserved synthetic-lethal interactions for exploration of precision cancer therapy

Phase II trial of panitumumab with irinotecan as salvage therapy for patients with advanced or recurrent colorectal cancer (TOPIC study).

Little is known about the clinical impact of salvage panitumumab with irinotecan for metastatic colorectal cancer (mCRC) patients. The present study conducted a single-arm, multicenter phase II trial for mCRC with skin toxicity prevention program. The subjects were mCRC patients with wild-type KRAS, who showed resistance to fluoropyrimidine, oxaliplatin and irinotecan. Panitumumab was administered at a dose of 6 mg/kg every 2 weeks by intravenous infusion over 60 min, and irinotecan was administered at a dose of 100-180 mg/m2 every 2 weeks by intravenous infusion over 90 min, depending on the preceding treatment dose. To prevent skin toxicities, a moisturizer was applied and oral antibiotics (100 mg minocycline twice daily) were initiated for 6 weeks. The primary endpoint was the response rate (RR) determined by independent reviewers. Secondary endpoints were the disease control rate (DCR), progression-free survival (PFS) time, overall survival (OS) time and adverse events. A total of 35 patients were enrolled between October 2010 and March 2012. The median age was 61 years (range, 41-76 years), with 25 male and 10 female patients. The initial irinotecan dose was 150 mg/m2 in 19 patients and 180 mg/m2 in 1 patient. The remaining patients were treated with ≤120 mg/m2. A central review indicated a partial response in 8 patients (22.9%) and stable disease in 6 patients (17.1%), with an RR of 22.9% (95% confidence interval, 12.1-39.0) and a DCR of 40%. The RR of the patients with standard-dose irinotecan (150 or 180 mg/m2) was 30%, although that of low-dose irinotecan (100-120 mg/m2) was 13%. The median PFS time was 2.7 months, and the median OS time was 6.3 months. A grade 3 or above acne-like rash developed in 25.7% of patients. In conclusion, panitumumab and irinotecan as salvage therapy for mCRC KRAS wild-type patients with skin toxicity prevention exhibits limited efficacy. In particular, the effect of low-dose irinotecan with panitumumab appears to be clinically insignificant. Routine use of skin toxicity prevention is currently under evaluation.

Efficacy of Triplet Combination Chemotherapy with Oxaliplatin, Irinotecan and Capecitabine (OCX) in Metastatic Colorectal Cancer in Relation to RAS/RAF Mutation Status: Results of a Retrospective Analysis

SummaryBackground: The triplet combination of fluorouracil, oxaliplatin and irinotecan for metastatic colorectal cancer improves efficacy at the cost of increased toxicity. Preliminary reports indicate that triplet combination regimens might improve outcome in the RAS/RAF-mutated subgroup. Patients and Methods: This retrospective analysis included 25 patients with metastatic colorectal cancer, who received treatment with OCX (oxaliplatin, irinotecan, capecitabine). The regimen consisted of oxaliplatin 70 mg/m² on days 1 and 15, irinotecan 100 mg/m² on days 8 and 22, and capecitabine 1,400 mg/m² on days 1-29 every 5 weeks. KRAS, NRAS, and BRAF mutations were determined by Sanger sequencing. Results: 23 patients received at least 1 cycle and were evaluable for efficacy. In 10 patients, a KRAS or BRAF mutation was detected. Partial remission rate was 61%, median progression-free survival 9.8 months, and median overall survival 32.9 months for all evaluable patients. No difference in efficacy was detected between the RAS/RAF wild-type and the mutant group. OCX was well tolerated with no grade 3/4 haematological events. Diarrhoea was the major non-haematological toxicity (24% grade 3). Conclusion: In this retrospective analysis, triplet chemotherapy with OCX was well tolerated and achieved encouraging efficacy in metastatic colorectal cancer irrespective of RAS/RAF mutation status.

A phase II study of panitumumab plus irinotecan for metastatic colorectal cancer with wild KRAS, resistant to fluoropyrimidine, oxaliplatin, and irinotecan in Japanese (OGSG1001).

607 Background: Anti-epidermal growth factor receptor (EGFR) antibody therapy showed to be effective in treatment for metastatic colorectal cancer (mCRC) with wild KRAS. Especially, combination chemotherapy with anti-EGFR antibody plus irinotecan is expected more effective than anti-EGFR antibody alone, resistant to irinotecan. We conducted a phase II trial of panitumumab plus irinotecan for mCRC with wild KRAS resistant to fluoropyrimidine, oxaliplatin, and irinotecan in Japanese. Methods: Subjects were mCRC patients with wild KRAS, who showed resistance to fluoropyrimidine, oxaliplatin, and irinotecan and had measurable disease, ECOG PS 0-2. Panitumumab (6 mg/kg) plus irinotecan (same dose as prior irinotecan) was administered every two weeks. This treatment was provided until progression. The primary endpoint was response rate (RR). Secondary endpoints were disease control rate (DCR), progression-free survival (PFS), overall survival (OS), response duration, and adverse event (AE). Results: A total of 31 subjects were enrolled between July 2010 and July 2012. Median age was 64 years old (range 42-74). Nineteen patients had liver metastasis, 11 had lung metastasis, and 3 had lymph node metastasis. An independent review committee evaluated for efficacy in eligible 31 subjects in accordance with the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. The RR of primary endpoint was 29.0% (95% confidence interval (CI), 14.2-48.0 %). DCR was 74.2% (95%CI, 55.4-88.1%) and median PFS was 5.6 months.(95%CI: 3.4-8.7) In 31 subjects for safety evaluation, the incidence of any Grade 3 or greater adverse events was 58.1%. Major adverse events of grade 3 were diarrhea (19.4%), rash acneiform (12.9%), fatigue (9.7%), anorexia (9.7%). A sudden death and an infusion related reaction were occurred. Conclusions: Combination chemotherapy with panitumumab plus irinotecan was demonstarated to be safe and more effective than Japanese single arm phase II of panitumumab alone for mCRC, resistant to fluoropyrimidine, oxaliplatin and irinotecan. This result in Japanese is equal to other reports of panitumumab plus irinotecan. Clinical trial information: UMIN000003819.

Association of DNA promoter hypermethylation of decoy receptor 1 (DCR1) with poor response to irinotecan in metastatic colorectal cancer.

3552 Background: Heterogeneity in the biology of colorectal cancer (CRC) is associated with variable responses to standard chemotherapy. We aimed to identify DNA hypermethylated genes as predictive biomarkers for irinotecan treatment of patients with metastatic CRC. Methods: The presence of DNA methylation for a selected panel of 22 genes was assessed by methylation specific PCR (MSP) on primary tumors of 185 patients with metastatic CRC treated with first-line capecitabine (CAP, n=90) or a combination of capecitabine and irinotecan (CAPIRI, n=95) in the phase 3 CAIRO trial. Methylation status of each gene was correlated to progression free survival (PFS) by treatment regimen. Genes for which methylation status associated with response to irinotecan, were validated in 166 patients treated with first-line CAP (n=78) or CAPIRI (n=88). Results: Decoy Receptor 1 (DCR1) was identified as a novel hypermethylated gene in CRC. In CAPIRI treated patients, DCR1 methylation was correlated to a shorter PFS compared to patients with unmethylated DCR1 (hazard ratio [HR]=0.4 (95%CI =0.3-0.7), p = 0.0009). In patients with methylated DCR1 PFS did not improve with CAPIRI treatment, compared to treatment with CAP (discovery set: HR=0.8 (95%CI=0.5-1.3, p=0.4); validation set: HR=1.1 (95%CI 0.7-1.7, p=0.6)), in contrast to patients with unmethylated DCR1 (discovery set: HR=2.5 (95%CI 1.7-3.3, p=0.00004); validation set: HR=1.7 (95%CI 1.1-2.0, p=0.004)). Conclusions: CRC patients with methylated DCR1 did not benefit from adding irinotecan to capecitabine therapy, indicating that DCR1 methylation status may guide selecting metastatic CRC patients for irinotecan-based therapy.

Assessment of the topoisomerase I gene copy number as a predictive biomarker of objective response to irinotecan in metastatic colorectal cancer

Objective. DNA topoisomerase I is a putative biomarker of irinotecan efficacy with clinical associations previously demonstrated at the protein level. The purpose of the present study was to perform the first clinical investigation of the association between the DNA topoisomerase I gene (TOP1) copy number and objective response following irinotecan treatment in patients with metastatic colorectal cancer. Materials and methods. Formalin-fixed, paraffin-embedded tumor samples from 78 patients, who received irinotecan monotherapy in second line, were included. TOP1 was assessed by fluorescence in situ hybridization using a technically validated dual-probe combination that hybridizes to TOP1, located at 20q12-q13.1, and to the centromere region of chromosome 20 (CEN-20). In univariate logistic regression models, the TOP1 signal count per cell and the TOP1/CEN-20 ratio were associated with objective response, which was evaluated according to RECIST v.1.1. Results. Gain of TOP1 was identified in 52.6% and 37.2% using the following cutoff values: TOP1 signal count per cell ≥3.6 and TOP1/CEN-20 ≥1.5, respectively. A borderline significant association (Odds ratio (OR): 1.62; p = 0.07) between a stepwise increase in the TOP1 signal count and objective response was demonstrated. In relation to the applied cutoff values, nonsignificant associations with objective response were identified for the TOP1 signal count (OR: 2.41; p = 0.23) and for the TOP1/CEN-20 ratio (OR: 2.05; p = 0.30). Conclusions. Despite limitations of the study the positive associations between TOP1 and objective response suggest that further analysis in larger tumor material, preferably in a randomized setting, is highly warranted.

FOLFIRINOX for the treatment of colorectal cancer: latest evidence from clinical trials

FOLFIRINOX for the treatment of colorectal cancer: latest evidence from clinical trials

Phase I Study of Cetuximab, Irinotecan, and Vandetanib (ZD6474) as Therapy for Patients with Previously Treated Metastastic Colorectal Cancer

BackgroundTo determine the maximum tolerated dose (MTD) and safety, and explore efficacy and biomarkers of vandetanib with cetuximab and irinotecan in second-line metastatic colorectal cancer.MethodsVandetanib (an orally bioavailable VEGFR-2 and EGFR tyrosine kinases inhibitor) was combined at 100 mg, 200 mg, or 300 mg daily with standard dosed cetuximab and irinotecan (3+3 dose-escalation design). Ten patients were treated at the MTD and plasma angiogenesis biomarkers (VEGF, PlGF, bFGF, sVEGFR1, sVEGFR2, IL-1β, IL-6, IL-8, TNF-α, SDF1α) were measured before and after treatment.ResultsTwenty-seven patients were enrolled at 4 dose levels and the MTD. Two dose-limiting toxicities (grade 3 QTc prolongation and diarrhea) were detected at 300 mg of vandetanib with cetuximab and irinotecan resulting in 200 mg being the MTD. Seven percent of patients had a partial response, 59% stable disease and 34% progressed. Median progression-free survival was 3.6 months (95% CI, 3.2–5.6) and median overall survival was 10.5 months (95% CI, 5.1–20.7). Toxicities were fairly manageable with grade 3 or 4 diarrhea being most prominent (30%). Vandetanib and cetuximab treatment induced a sustained increase in plasma PlGF and a transient decrease in plasma sVEGFR1, but no changes in plasma VEGF and sVEGFR2.ConclusionsVandetanib can be safely combined with cetuximab and irinotecan for metastatic colorectal cancer. Exploratory biomarker analyses suggest differential effects on certain plasma biomarkers for VEGFR inhibition when combined with EGFR blockade and a potential correlation between baseline sVEGFR1 and response. However, while the primary endpoint was safety, the observed efficacy raises concern for moving forward with this combination.Trial RegistrationClinicaltrials.gov NCT00436072.

UGT1A1predicts outcome in colorectal cancer treated with irinotecan and fluorouracil

To evaluate effects of UDP-glucuronosyltransferase1A1 (UGT1A1) and thymidylate synthetase (TS) gene polymorphisms on irinotecan in metastatic colorectal cancer (mCRC). Two irinotecan- and fluorouracil-based regimens, FOLFIRI and IFL, were selected as second-line therapy for 138 Chinese mCRC patients. Genomic DNA was extracted from peripheral blood samples before treatment. UGT1A1 and TS gene polymorphisms were determined by direct sequencing and restriction fragment length polymorphism, respectively. Gene polymorphisms of UGT1A1*28, UGT1A1*6 and promoter enhancer region of TS were analyzed. The relationship between genetic polymorphisms and clinical outcome, that is, response, toxicity and survival were assessed. Pharmacokinetic analyses were performed in a subgroup patients based on different UGT1A1 genotypes. Plasma concentration of irinotecan and its active metabolite SN-38 and inactive metabolite SN-38G were determined by high performance liquid chromatography. Differences in irinotecan and its metabolites between UGT1A1 gene variants were compared. One hundred and eight patients received the FOLFIRI regimen, 29 the IFL regimen, and one irinotecan monotherapy. One hundred and thirty patients were eligible for toxicity and 111 for efficacy evaluation. One hundred and thirty-six patients were tested for UGT1A1*28 and *6 genotypes and 125 for promoter enhancer region of TS. Patients showed a higher frequency of wild-type UGT1A1*28 (TA6/6) compared with a Caucasian population (69.9% vs 45.2%). No significant difference was found between response rates and UGT1A1 genotype, although wild-type showed lower response rates compared with other variants (17.9% vs 24.2% for UGT1A1*28, 15.7% vs 26.8% for UGT1A1*6). When TS was considered, the subgroup with homozygous UGT1A1*28 (TA7/7) and non-3RG genotypes showed the highest response rate (33.3%), while wild-type UGT1A1*28 (TA6/6) with non-3RG only had a 13.6% response rate, but no significant difference was found. Logistic regression showed treatment duration was closely linked to clinical response. In toxicity comparison, UGT1A1*28 TA6/6 was associated with lower incidence of grade 2-4 diarrhea (27.8% vs 100%), and significantly reduced the risk of grade 4 neutropenia compared with TA7/7 (7.8% vs 37.5%). Wild-type UGT1A1*6 (G/G) tended to have a lower incidence of grade 3/4 diarrhea vs homozygous mutant (A/A) genotype (13.0% vs 40.0%). Taking UGT1A1 and TS genotypes together, lower incidence of grade 2-4 diarrhea was found in patients with non-3RG TS genotypes, when TA6/6 was compared with TA7/7 (35.3% vs 100.0%). No significant association with time to progression (TTP) and overall survival (OS) was observed with either UGT1A1 or TS gene polymorphisms, although slightly longer TTP and OS were found with UGT1A1*28 (TA6/6). Irinotecan PK was investigated in 34 patients, which showed high area under concentration curve (AUC) of irinotecan and SN-38, but low AUC ratio (SN-38G / SN-38) in those patients with UGT1A1*28 TA7/7. A distinct distribution pattern of UGT1A1 genotypes in Chinese patients might contribute to relatively low toxicity associated with irinotecan and 5-fluorouracil in mCRC patients.