Early tumor shrinkage in metastatic colorectal cancer: retrospective analysis from an irinotecan-based randomized first-line trial

Exploratory analysis of serum HER2 extracellular domain for HER2 positive gastric cancer treated with SOX plus trastuzumab

BACKGROUND

The aim of this study was to explore the clinical utility of serum HER2 extracellular domain (sHER2 ECD) using data from a clinical trial evaluating trastuzumab combined S-1 plus oxaliplatin (SOX) in HER2 positive gastric cancer.

METHODS

sHER2 ECD were prospectively measured at baseline and subsequent treatment courses. Based on each quantile point of baseline sHER2 ECD levels and its early changes, patients were divided into two groups and compared clinical outcomes.

RESULTS

43 patients were enrolled, and 17 patients (39.5%) were positive for baseline sHER2 ECD. Higher baseline sHER2 ECD levels tended to have lower hazard ratios (HRs). When divided into two groups by baseline sHER2 ECD of 19.1 ng/ml, median progression-free survival (PFS) and overall survival (OS) was longer in the higher group (mPFS: 16.8 vs 8.7 months, p = 0.359. mOS: 35.5 vs 20.6 months, p = 0.270), respectively. After initiation of treatment, sHER2 ECD significantly decreased up until the third cycle. Higher reduction rates of sHER2 ECD within 3 cycles also tended to have lower HRs. When divided into two groups by reduction rate of 42.5%, mPFS and mOS was longer in the higher reduced group (mPFS: 17.2 vs 8.7 months, p = 0.095. mOS: 65.0 vs 17.8 months, p = 0.047), respectively. Furthermore, higher reduction rates could surrogate higher objective response rates (ORR) (ORR: 90% vs 63.2% for 29.5%, p = 0.065. 100% vs 70% for 42.5%, p = 0.085), respectively.

CONCLUSIONS

Baseline sHER2 ECD levels and its early decline may be useful biomarkers for SOX plus trastuzumab efficacy in HER2 positive gastric cancer.

First-line pembrolizumab plus chemotherapy for advanced/metastatic esophageal cancer: 1-year extended follow-up in the Japanese subgroup of the phase 3 KEYNOTE-590 study

BACKGROUND

First-line pembrolizumab plus chemotherapy (pembrolizumab-chemotherapy) demonstrated improved efficacy and a manageable safety profile versus placebo plus chemotherapy (placebo-chemotherapy) in the subgroup analysis of Japanese patients with advanced/metastatic esophageal cancer in KEYNOTE-590 at a median follow-up of 24.4 months. Longer-term data from the Japanese subgroup analysis of KEYNOTE-590 are reported.

METHODS

Patients were randomly assigned 1:1 to pembrolizumab 200 mg or placebo every 3 weeks for ≤ 35 cycles plus chemotherapy (cisplatin 80 mg/m2 and 5-fluorouracil 800 mg/m2/day). Endpoints included overall survival (OS) and progression-free survival (PFS; investigator-assessed per RECIST v1.1; dual primary) and safety (secondary). Early tumor shrinkage (ETS) and depth of response (DpR) were assessed post hoc.

RESULTS

Overall, 141 patients were enrolled in Japan. As of July 9, 2021, median follow-up was 36.6 months (range, 29.8-45.7). Pembrolizumab-chemotherapy showed a trend toward favorable OS (hazard ratio [HR], 0.70; 95% confidence interval [CI] 0.47-1.03) and PFS (0.57; 0.39-0.83) versus placebo-chemotherapy. In the pembrolizumab-chemotherapy group, patients with ETS ≥ 20% (55/74; 74.3%) versus < 20% (19/74; 25.7%) had favorable OS (HR, 0.23; 95% CI 0.12-0.42) and PFS (0.24; 0.13-0.43). Patients with DpR ≥ 60% (31/74; 41.9%) versus < 60% (43/74; 58.1%) had favorable OS (HR, 0.37; 95% CI 0.20-0.68) and PFS (0.24; 0.13-0.43). Grade 3-5 treatment-related adverse events occurred in 55/74 patients (74.3%) with pembrolizumab-chemotherapy and 41/67 patients (61.2%) with placebo-chemotherapy.

CONCLUSIONS

With longer-term follow-up of Japanese patients with advanced/metastatic esophageal cancer, efficacy continued to favor pembrolizumab-chemotherapy compared with placebo-chemotherapy, with no new safety signals observed.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT03189719.

Early Circulating Tumor DNA Dynamics Predict Neoadjuvant Therapy Response and Recurrence in Colorectal Liver Metastases: A Prospective Study

BACKGROUND

For patients with colorectal liver metastases (CRLM) who receive neoadjuvant therapy (NAT), reliable indicators that can early and accurately predict treatment response are lacking. This study was conducted to prospectively investigate the potential of early circulating tumor DNA (ctDNA) dynamics as a precise predictor of NAT response and recurrence in CRLM.

METHODS

This study prospectively enrolled 34 patients with CRLM who received NAT, with blood samples collected and subjected to deep targeted panel sequencing at two time points: 1 day before the first and the second cycles of NAT. Correlations of ctDNA mean variant allele frequency (mVAF) dynamics and treatment response were assessed. The performance of early ctDNA dynamics in predicting treatment response was assessed and compared with those of carcinoembryonic antigen (CEA) and cancer antigen 19-9 (CA19-9).

RESULTS

The baseline ctDNA mVAF was significantly associated with pre-NAT tumor diameter (r = 0.65; P < 0.0001). After one cycle of NAT, the ctDNA mVAF declined remarkably (P < 0.0001). The dynamic change in ctDNA mVAF of 50% or more was significantly correlated with better NAT responses. The discriminatory capacity of ctDNA mVAF changes was superior to that of CEA or CA19-9 in predicting radiologic response (area under the curve [AUC], 0.90 vs 0.71 vs 0.61) and pathologic tumor regression grade (AUC, 0.83 vs 0.64 vs 0.67). The early changes in ctDNA mVAF but not CEA or CA19-9 were an independent indicator of recurrence-free survival (RFS) (hazard ratio, 4.0; P = 0.023).

CONCLUSIONS

For CRLM patients receiving NAT, an early ctDNA change is a superior predictor of treatment response and recurrence compared with conventional tumor markers.

Early tumor shrinkage and depth of response in patients with metastatic esophageal cancer treated with 2-weekly docetaxel combined with cisplatin plus fluorouracil: an exploratory analysis of the JCOG0807

BACKGROUND

We herein investigated the association between early tumor shrinkage (ETS) and depth of response (DpR) and clinical outcomes in patients with metastatic esophageal cancer treated with 2-weekly docetaxel combined with cisplatin plus fluorouracil (bDCF) using data from the JCOG0807, a phase I/II trial of bDCF as first-line chemotherapy for metastatic esophageal cancer.

METHODS

ETS was defined as a percent decrease in the sum of the target lesions' longest diameter after 8 weeks, whereas DpR was defined as a percentage of the maximal tumor shrinkage during the treatment course. Multivariable analyses were conducted to identify significant prognostic variables in progression-free survival (PFS) and overall survival (OS): one for ETS and covariates, and another for DpR and covariates.

RESULTS

Among 53 patients, 35 patients with ETS ≥ 20% (66.0%) had longer PFS (7.5 vs. 3.4 months, hazard ratio [HR]: 0.26, 95% confidence interval [95% CI] 0.14-0.49), OS (13.8 vs. 6.1 months, HR 0.20, 95% CI 0.11-0.39), and PPS (6.4 vs. 2.8 months, HR 0.38, 95% CI 0.20-0.72) than those with ETS < 20%. In addition, 37 patients with DpR ≥ 30% (69.8%) had longer PFS (7.5 vs. 2.9 months, HR 0.17, 95% CI 0.08-0.34), OS (13.8 vs. 6.0 months, HR 0.14, 95% CI 0.07-0.27), and PPS (6.8 vs. 2.8 months, HR 0.30, 95% CI 0.15-0.58) than those with DpR < 30%. Multivariable analyses revealed that each ETS and DpR was an independent factor of longer PFS and OS.

CONCLUSIONS

ETS and DpR might be associated with clinical outcomes in patients with metastatic esophageal cancer treated with bDCF.

Standard diametric versus volumetric early tumor shrinkage as a predictor of survival in metastatic colorectal cancer: subgroup findings of the randomized, open-label phase III trial FIRE-3 / AIO KRK-0306

OBJECTIVES

Early tumor shrinkage (ETS) quantifies the objective response at the first assessment during systemic treatment. In metastatic colorectal cancer (mCRC), ETS gains relevance as an early available surrogate for patient survival. The aim of this study was to increase the predictive accuracy of ETS by using semi-automated volumetry instead of standard diametric measurements.

METHODS

Diametric and volumetric ETS were retrospectively calculated in 253 mCRC patients who received 5-fluorouracil, leucovorin, and irinotecan (FOLFIRI) combined with either cetuximab or bevacizumab. The association of diametric and volumetric ETS with overall survival (OS) and progression-free survival (PFS) was compared.

RESULTS

Continuous diametric and volumetric ETS predicted survival similarly regarding concordance indices (p > .05). In receiver operating characteristics, a volumetric threshold of 45% optimally identified short-term survivors. For patients with volumetric ETS ≥ 45% (vs < 45%), median OS was longer (32.5 vs 19.0 months, p < .001) and the risk of death reduced for the first and second year (hazard ratio [HR] = 0.25, p < .001, and HR = 0.39, p < .001). Patients with ETS ≥ 45% had a reduced risk of progressive disease only for the first 6 months (HR = 0.26, p < .001). These survival times and risks were comparable to those of diametric ETS ≥ 20% (vs < 20%).

CONCLUSIONS

The accuracy of ETS in predicting survival was not increased by volumetric instead of diametric measurements. Continuous diametric and volumetric ETS similarly predicted survival, regardless of whether patients received cetuximab or bevacizumab. A volumetric ETS threshold of 45% and a diametric ETS threshold of 20% equally identified short-term survivors.

KEY POINTS

• ETS based on volumetric measurements did not predict survival more accurately than ETS based on standard diametric measurements. • Continuous diametric and volumetric ETS predicted survival similarly in patients receiving FOLFIRI with cetuximab or bevacizumab. • A volumetric ETS threshold of 45% and a diametric ETS threshold of 20% equally identified short-term survivors.

Response and Disease Dynamics in Untreated Metastatic Colorectal Cancer With Bevacizumab-Based Sequential vs. Combination Chemotherapy—Analysis of the Phase 3 XELAVIRI Trial

Introduction

Early tumor shrinkage (ETS), depth of response (DpR), and time to DpR represent exploratory endpoints that may serve as early efficacy parameters and predictors of long-term outcome in metastatic colorectal cancer (mCRC). We analyzed these endpoints in mCRC patients treated with first-line bevacizumab-based sequential (initial fluoropyrimidines) versus combination (initial fluoropyrimidines plus irinotecan) chemotherapy within the phase 3 XELAVIRI trial.

Methods

DpR (change from baseline to smallest tumor diameter), ETS (≥20% reduction in tumor diameter at first reassessment), and time to DpR (study randomization to DpR image) were analyzed. We evaluated progression-free survival and overall survival with ETS as stratification parameter according to treatment arm, molecular subgroup, and sex.

Results

In 370 patients analyzed, a higher rate of ETS (60.9% vs. 43.5%; p = 0.001) and significantly greater DpR (-40.0% vs. -24.7%; p < 0.001) were observed in the initial combination therapy arm. The improvement was pronounced in RAS/BRAF wild-type tumors. ETS correlated with improved survival irrespective of treatment arm (PFS: p < 0.001; OS: p = 0.012) and molecular subgroup (PFS: p < 0.001; OS: p < 0.001). Male patients in contrast to female patients with ETS had survival benefit (PFS: p < 0.001, HR 0.532; OS: p < 0.001, HR 0.574 vs. PFS: p = 0.107; OS: p = 0.965).

Conclusions

Initial irinotecan-based combination therapy with bevacizumab improved ETS and DpR in mCRC patients with a particularly high irinotecan sensitivity of RAS/BRAF wild-type tumors. ETS seems to be a suitable prognostic marker for fluoropyrimidine- and bevacizumab-based combinations in mCRC. This finding was rather driven by male patients, potentially indicating that ETS might be less predictive of long-term outcome in an elderly, female population.

Assessing prognostic value of early tumor shrinkage and depth of response in first-line therapy for patients with advanced unresectable pancreatic cancer

Background

The prognostic potential of early tumor shrinkage (ETS) and depth of response (DpR) in pancreatic cancer (PC) is unclear. Here, we recruited 90 patients with recurrent and metastatic PC (RMPC) who had received chemotherapy as first-line therapy to assess the prognostic potential of these markers.

Methods

ETS is characterized as a ≥ 20% depletion in the sum-of-the-longest-diameters (SLD) of measurable tumor lesions at 6–12 weeks than the baseline. DpR is the maximum shrinkage (%) from the baseline to nadir. We evaluated corrections in ETS and DpR with survival.

Results

Of the 63 patients in which ETS assessment was possible, 21 (33.3%) achieved ETS. We found a significant association between the incidence of ETS and an improved rate of progression-free survival (PFS; 6.5 vs. 2.2 months; p < 0.001) and overall survival (OS; 12.1 vs. 6.0 months; p = 0.014). The median value of DpR was − 23.66%. DpR was also related to improved PFS (9.3 vs. 3.1 months; p < 0.001) and OS (18.2 vs. 7.3 months; p < 0.001). Patients who had distant metastasis, not local recurrence, with ETS showed markedly better outcomes. In a multivariate model, both ETS and DpR were independent predictors of OS in the whole population.

Conclusions

ETS and DpR may predict favorable outcomes for RMPC patients who had received chemotherapy as first-line therapy, independent of the agents used. Further studies on the exploratory analyses of the optimum ETS cut-off value in recurrent PC patients to predict favorable clinical outcomes are required.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01870-x.

Effect of early tumor response on the health-related quality of life among patients on second-line chemotherapy for advanced gastric cancer in the ABSOLUTE trial

BACKGROUND

This study evaluated the association between early tumor response at 8 weeks, previously reported as a positive outcome prognosticator, and health-related quality of life (HRQOL) in advanced gastric cancer (AGC) patients enrolled in the ABSOLUTE trial.

METHODS

HRQOL was assessed using the EuroQol-5 Dimension (EQ-5D) utility index score in patients with complete response (CR) + partial response (PR) and progressive disease (PD) at 8 weeks, and time-to-deterioration (TtD) of the EQ-5D score, with the preset minimally important difference (MID) of 0.05, was compared between these populations. Among the enrolled patients, 143 and 160 patients were assessable in weekly solvent-based paclitaxel (Sb-PTX) arm and weekly nanoparticle albumin-bound paclitaxel (nab-PTX) arm, respectively.

RESULTS

Changes of the EQ-5D score from baseline to 8 weeks in the nab-PTX arm were 0.0009 and - 0.1229 in CR + PR and PD patients, respectively; the corresponding values for the Sb-PTX arm were - 0.0019 and - 0.1549. For both treatments, changes of the EQ-5D score from baseline at 8 weeks were significantly larger in patients with PD than in those with CR + PR. The median TtD was 3.9 and 2.2 months in patients with CR + PR and PD, respectively, for nab-PTX [hazard ratio (HR) = 0.595, 95% confidence interval (CI) 0.358-0.989]. For Sb-PTX, the corresponding values were 4.7 and 2.0 months (HR = 0.494, 95% CI 0.291-0.841).

CONCLUSIONS

Early tumor shrinkage was associated with maintained HRQOL in AGC patients on the second-line chemotherapy with taxanes.

Dynamics in treatment response and disease progression of metastatic colorectal cancer (mCRC) patients with focus on BRAF status and primary tumor location: analysis of untreated RAS-wild-type mCRC patients receiving FOLFOXIRI either with or without panitumumab in the VOLFI trial (AIO KRK0109)

PURPOSE

In mCRC, disease dynamics may play a critical role in the understanding of long-term outcome. We evaluated depth of response (DpR), time to DpR, and post-DpR survival as relevant endpoints.

METHODS

We analyzed DpR by central review of computer tomography images (change from baseline to smallest tumor diameter), early tumor shrinkage (≥ 20% reduction in tumor diameter at first reassessment), time to DpR (study randomization to DpR-image), post-DpR progression-free survival (pPFS = DpR-image to tumor progression or death), and post-DpR overall survival (pOS = DpR-image to death) with special focus on BRAF status in 66 patients and primary tumor site in 86 patients treated within the VOLFI-trial, respectively.

RESULTS

BRAF wild-type (BRAF-WT) compared to BRAF mutant (BRAF-MT) patients had greater DpR (- 57.6% vs. - 40.8%, p = 0.013) with a comparable time to DpR [4.0 (95% CI 3.1-4.4) vs. 3.9 (95% CI 2.5-5.5) months; p = 0.8852]. pPFS was 6.5 (95% CI 4.9-8.0) versus 2.6 (95% CI 1.2-4.0) months in favor of BRAF-WT patients (HR 0.24 (95% CI 0.11-0.53); p < 0.001). This transferred into a significant difference in pOS [33.6 (95% CI 26.0-41.3) vs. 5.4 (95% CI 5.0-5.9) months; HR 0.27 (95% CI 0.13-0.55); p < 0.001]. Similar observations were made for patients stratified for primary tumor site.

CONCLUSIONS

BRAF-MT patients derive a less profound treatment response compared to BRAF-WT patients. The difference in outcome according to BRAF status is evident after achievement of DpR with BRAF-MT patients hardly deriving any further disease control beyond DpR. Our observations hint towards an aggressive tumor evolution in BRAF-MT tumors, which may already be molecularly detectable at the time of DpR.

Early response evaluation during preoperative chemotherapy for colorectal liver metastases: Combined size and morphology-based criteria predict pathological response and survival after resection

BACKGROUND

Short treatment-duration with early restaging is crucial to avoid liver injury after preoperative chemotherapy (preopCTX) for colorectal liver metastases (CRLM). Response evaluation according to response evaluation criteria in solid tumors (RECIST) criteria implies several limitations. Early tumor shrinkage (ETS; ≥20% size reduction <6-12 weeks) or morphological criteria (MC) may better predict oncological outcome.

METHODS

In patients undergoing resection after preopCTX between 2003-2017 pathological and radiological response was reassessed according to Blazer classification, ETS, MC, and RECIST within 90 days and correlated with survival.

RESULTS

Seventy-two patients were included, with a median of two (1-10) liver lesions, 53% bilobar involvement, and 7% extrahepatic disease. PreopCTX was applied for 3 months in median (1-6). During restaging after a median of 62 days, presence of ETS was associated with improved median overall survival (OS; 57.1 vs 33.7 months; P = .010) and disease-free survival (16 vs 7.2 months; P = .025). MC significantly correlated with major pathological response (P = .021). When combining ETS with optimal MC, presence of one or both factors was associated with pathological response (61.5% and 92.3%; P = .044) and OS in log-rank (P = .011), and multivariable analysis (hazard ratio [HR] 0.41; 95% confidence interval [CI], 0.19-0.90 and HR 0.32; 95%CI, 0.11-0.97).

CONCLUSION

Response-grading by combined ETS/MC criteria less than 90 days after preopCTX initiation predicts pathological response and postoperative survival in CRLM.

Early change in circulating tumor DNA as a potential predictor of response to chemotherapy in patients with metastatic colorectal cancer

The impact of ctDNA changes after chemotherapy on the clinical outcomes of patients with metastatic colorectal cancer (mCRC) remains unclear. The present study evaluated the clinical implications of the early change in ctDNA levels as a predictor of objective response and clinical outcome in mCRC patients who received chemotherapy. We investigated the effects of after/before ratio of ctDNA levels 2 and 8 weeks after initiation of second-line chemotherapy, on objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). ctDNA was detected using amplicon-based deep sequencing with a molecular barcode encompassing >240 hotspot mutations in 14 colon cancer-related genes. In multivariate analysis, as compared to baseline, patients with lower ctDNA level (≤50%) 8 weeks after initiation of chemotherapy showed significantly longer PFS and OS than the patients with higher (>50%) ctDNA level. In patients achieving a partial response or stable disease, the after/before ratio of ctDNA level 8 weeks after initiation of chemotherapy was significantly lower than those in patients with progressive disease. The present study suggests that an early change in the ctDNA level might serve as a biomarker to predict the chemotherapeutic efficacy and clinical outcomes in patients with mCRC.

Quantitative evaluation of liver metastases density on computed tomography: A new tool to evaluate early response to bevacizumab-containing chemotherapy

BACKGROUND

Response Evaluation Criteria in Solid Tumors (RECIST) are used to assess tumour shrinkage after cytotoxic chemotherapy, but may be inadequate for efficacy evaluation of anti-angiogenic therapies.

AIMS

This study aimed to identify novel radiologic tumour response criteria based on early changes in tumour size and density, observed on computed tomography (CT), in patients with colorectal liver metastases (CRLM) treated with bevacizumab-containing chemotherapy.

METHODS

CT of 71 and 68 CRLM patients treated with bevacizumab and non-bevacizumab-based regimens, respectively, were retrospectively reviewed. Tumour size, tumour density, and tumour-to-liver density (TTLD) ratio were determined at baseline and at first restaging. We tested their correlation with progression-free (PFS) and overall survival (OS) using the log-rank test.

RESULTS

In the bevacizumab group, neither RECIST response nor tumour density variation was correlated with PFS or OS. In contrast, PFS and OS were significantly longer in patients with tumour size reduction ≥15% (RECIST_-15%) and/or decrease in TTLD ratio not exceeding -10% (TTLD_-10%) than in patients who did not reach any of those criteria, in univariate and multivariate analysis. Only size-response criteria predicted clinical outcome in the non-bevacizumab group.

CONCLUSIONS

This study highlights new quantitative CT criteria that may early predict the efficacy of bevacizumab in CRLM patients.

Analysis of response-related endpoints in trials of first-line medical treatment of metastatic colorectal cancer

BACKGROUND

Tumor radiologic response after systemic chemotherapy has been used as endpoint of trials of patients with metastatic colorectal cancer (mCRC), which can report the best overall response rate (ORR) and the disease control rate (DCR) by RECIST criteria as well as the early tumor shrinkage (ETS). The present study perform a trial-level analysis to verify whether such response-related endpoints are predictive of overall survival (OS).

METHODS

After a systematic search, randomized clinical trials (RCTs) were selected each time they evaluated the three response endpoints and progression-free survival (PFS). Two arms per trial were selected, and the correlation between the difference in each endpoint and the difference in OS was calculated. The analysis then evaluated the effects of treatment on ∆ORR, or ∆DCR, ∆ETS, ∆PFS, and on ∆OS, using separate linear regressions for each of them, and the proportion of variability explained (R²_trial) on OS for each of the four endpoints was calculated.

RESULTS

The systematic review of the literature led to the selection of 12 RCTs, 7 phase-3 and 5 phase-2. ETS reported a different performance in the entire sample compared to phase-3 trials (R²_trial = 0.172 vs. 0.842), differently from DCR (R²_trial = 0.541 vs. 0.816) and ORR (R²_trial = 0.349 vs. 0.740). Surprisingly, PFS predicted OS with a weak correlation, which was not significant in the subgroup of phase-3 studies (R²_trial = 0.455 vs. 0.466).

CONCLUSION

The results of the present trial-level analysis report a good performance of two response-related endpoints, DCR and ETS, and suggest that they could be differently used depending on the setting of disease and the type of medical treatment.

Colorectal liver metastases: An update on multidisciplinary approach

Liver metastasis is the commonest form of distant metastasis in colorectal cancer. Selection criteria for surgery and liver-directed therapies have recently been extended. However, resectability remains poorly defined. Tumour biology is increasingly recognized as an important prognostic factor; hence molecular profiling has a growing role in risk stratification and management planning. Surgical resection is the only treatment modality for curative intent. The most appropriate surgical approach is yet to be established. The primary cancer and the hepatic metastasis can be removed simultaneously or in a two-step approach; these two strategies have comparable long-term outcomes. For patients with a limited future liver remnant, portal vein embolization, combined ablation and resection, and associating liver partition and portal vein ligation for staged hepatectomy have been advocated, and each has their pros and cons. The role of neoadjuvant and adjuvant chemotherapy is still debated. Targeted biological agents and loco-regional therapies (thermal ablation, intra-arterial chemo- or radio-embolization, and stereotactic radiotherapy) further improve the already favourable results. The recent debate about offering liver transplantation to highly selected patients needs validation from large clinical trials. Evidence-based protocols are missing, and therefore optimal management of hepatic metastasis should be personalized and determined by a multi-disciplinary team.

Optimizing sequential treatment with anti-EGFR and VEGF mAb in metastatic colorectal cancer: current results and controversies

Anti-EGFR mAb (cetuximab or panitumumab) and anti-VEGF mAb (bevacizumab) are the two main targeted agents available for RAS wild-type (WT) metastatic colorectal cancer (mCRC) treatment. Nonetheless, three head-to-head clinical trials evaluating anti-EGFR mAb vs -VEGF mAb in first-line treatment failed to conclude a uniform result. Recently, a few small clinical studies revealed that prior use of bevacizumab may impair the effect of cetuximab or panitumumab. Preclinical studies have also suggested that pretreatment with bevacizumab may lead to simultaneous resistance to anti-EGFR mAb. Therefore, we performed this review to summarize the available data regarding the optimal sequential treatment of anti-EGFR and -VEGF mAb for RAS or KRAS WT mCRC and discuss the potential mechanisms that may explain this phenomenon. Primary tumor location and early tumor shrinkage have emerged as new potential prognostic and predictive factors in mCRC. We also collected information to explore whether these factors affect the optimal sequencing of targeted therapy in mCRC. However, definite conclusions cannot be made, and we can only speculate on optimal treatment recommendations based on the contradictory results.

Early tumor shrinkage after first-line medical treatment of metastatic colorectal cancer: a meta-analysis

BACKGROUND

Early tumor shrinkage (ETS) is a response-related endpoint of clinical trials of chemotherapy (CHT) of patients with metastatic colorectal cancer (mCRC). It identifies a dimensional reduction of tumor size by at least 20-30% after 6-8 weeks of CHT.

METHODS

A literature search of randomized trials of systemic treatment including CHT with or without antiangiogenics or anti-EGFR inhibitors in patients with mCRC has been conducted, and studies reporting the results of the relationship of ETS with overall survival (OS) and progression-free survival (PFS) were selected.

RESULTS

Twelve trials, including 3117 patients, have been included; all data were retrospective and only 72% of the enrolled patients have been evaluated for ETS. Two meta-analyses, each including 20 study cohorts from the selected 12 trials, reported a strong relationship of ETS with OS (HR 0.62; CIs 0.55-0.69) and of ETS with PFS (HR 0.66; CIs 0.60-0.73). However, both meta-analyses displayed a high level of heterogeneity. Among nine possible moderators, three variables (median age, surgery of metastases, and publication year) were able to explain at least a part of this heterogeneity.

CONCLUSION

ETS is a simple and interesting intermediate endpoint for clinical practice and future trials of medical treatments of patients with mCRC, but a large prospective analysis and validation are mandatory.

Tumor-size responses to first-line is a predictor of overall survival in metastatic colorectal cancer

OBJECTIVES

Early tumor shrinkage (ETS) has been reported to be associated with survival of metastatic colorectal cancer (mCRC) patients. Our aim was to analyze long-term tumor-size evolution, according to early mCRC best responses during the first-line therapy, to evaluate first best response-survival links.

METHODS

Sixty-five patients with unresectable mCRCs, treated between 2010 and 2015, were included retrospectively in this descriptive monocenter study and grouped according to their RECIST 1.1 first-line best responses: progressive disease (PD_fl), stable disease with tumor-size evolution between 0 and + 19% (SD_fl+) or 0 and - 29% (SD_fl-), and partial responders (PRs), who were classed PR with ETS (ETS_fl) or without (PR_fl). Tumor-size evolution and best tumor responses to each chemotherapy line were analyzed.

RESULTS

Tumor loads of ETS_fl or PR_fl mCRCs tended to remain inferior to their initial values: 60% of patients died with target lesion sums below baseline. For first-line SD_fl+ or PD_fl mCRCs, rapid tumor load increases continued during successive lines: > 80% died with target lesion sums above baseline. ETS_fl mCRCs responded better to subsequent lines (37.5% second-line PR), whereas PD_fl mCRCs remained refractory to other therapies (0% second- and third-line PR). Overall survival rates were significantly (p = 0.03) longer for the ETS_fl group (29.9 [95% CI: 12.6-47.1] months) and shorter for the PD_fl group (17.1 [95% CI: 1.5-37.5] months).

CONCLUSION

Tumors responding to first-line chemotherapy also responded better to subsequent lines, whereas PD_fl mCRCs remained refractory, which may explain the better survival associated with ETS_fl.

KEY POINTS

• Early shrinking tumors under first-line chemotherapy responded better to subsequent lines, maintaining low tumor loads, potentially explaining the link between early tumor shrinkage and overall survival of metastatic colorectal cancer (mCRC) patients. • mCRCs progressing under first-line chemotherapy remained refractory to other therapies and their tumor loads increased rapidly. • Even outside a clinical trial, an early first CT scan reevaluation with RECIST criteria 8 weeks after starting first-line therapy is crucial to determine long-term mCRC evolution.

Early tumor shrinkage and depth of response in patients with advanced gastric cancer: a retrospective analysis of a randomized phase III study of first-line S-1 plus oxaliplatin vs. S-1 plus cisplatin

BACKGROUND

We investigated early tumor shrinkage (ETS) and depth of response (DpR) using data from the G-SOX study comparing S-1 plus oxaliplatin with S-1 plus cisplatin as the first-line treatment for advanced gastric cancer (AGC).

METHODS

ETS was determined as % decrease in the sum of the longest diameters of the target lesions at the first evaluation of week 6 compared to baseline. DpR was the maximum % shrinkage during the study treatment. The impact of ETS (cutoff value 20%) and DpR (continuous value) on progression-free survival (PFS) and overall survival (OS) were assessed by the log-rank test and Cox regression analysis including prognostic factors obtained in the G-SOX study; ECOG performance status, baseline sum of tumor diameters, disease status (recurrent/unresectable), and histology (diffuse/intestinal).

RESULTS

Among 685 patients enrolled in the G-SOX study, 632 patients who had the first tumor evaluation were analyzed. Patients with ETS ≥ 20% had longer PFS (median 4.5 vs. 2.8 months, p < 0.0001) and OS (median 14.8 vs. 10.5 months, p < 0.0001) than those with ETS < 20%. Adjusted hazard ratios of ETS < 20 vs. ≥ 20% were 0.606 (95% confidence interval (CI) 0.506-0.725) for PFS and 0.589 (95% CI 0.492-0.704) for OS. DpR was also significantly associated with PFS and OS (both p < 0.0001). These results were similar between the SOX and CS groups.

CONCLUSIONS

In AGC patients receiving the first-line therapy, ETS and DpR might be predictors for PFS and OS.

Change in non-small-cell lung cancer tumor size in patients treated with nintedanib plus docetaxel: analyses from the Phase III LUME-Lung 1 study

Background

Nintedanib in combination with docetaxel is approved in the European Union and other countries for the treatment of patients with advanced non-small-cell lung cancer (NSCLC) of adenocarcinoma histology after first-line chemotherapy, based on the overall survival findings of Phase III LUME-Lung 1 study. Change in target lesion size over time as a treatment effect was assessed in patients from this study.

Methods

Tumor size was evaluated using predefined tumor measurements. Mixed-effects models were used to quantify individual relationships between time from randomization and tumor burden, measured as the sum of longest diameter (SLD) of target lesions and assessed by an independent review (Response Evaluation Criteria In Solid Tumors [RECIST] v1.0). Exploratory analyses were conducted on the overall adenocarcinoma population, adenocarcinoma patients with time from start of first-line therapy <9 months (TSFLT <9), adenocarcinoma patients who had progressive disease as best response to first-line therapy (PD-FLT), and in squamous cell carcinoma patients.

Results

Estimated mean baseline SLD was 82.5 mm in the adenocarcinoma (n=658), 88.3 mm in the TSFLT <9 (n=405), 98.1 mm in the PD-FLT (n=117), and 94.3 mm in the squamous cell carcinoma (n=555) populations. Treatment with nintedanib/docetaxel showed a significant reduction in tumor size over time (P<0.0001) in patients with adenocarcinoma compared with placebo/docetaxel, and in patients with squamous cell carcinoma (P=0.0049). Treatment difference at 6 months was 9.7 mm in the overall adenocarcinoma population, 16.8 mm in the TSFLT <9 population, 19.7 mm in the PD-FLT population, and 6.8 mm in the squamous cell carcinoma population. SLD at 2 months post-randomization was identified as a surrogate endpoint for overall survival, in addition to progression-free survival, for all except the PD-FLT population.

Conclusion

Treatment with nintedanib/docetaxel significantly decreased tumor burden and decelerated tumor size over time compared with placebo/docetaxel in the overall adenocar-cinoma population, including in patients with the poorest prognosis due to aggressive tumor dynamics.

Comparison of early radiological predictors of outcome in patients with colorectal cancer with unresectable hepatic metastases treated with bevacizumab

OBJECTIVE

The purpose was to validate the prognostic value of an early optimal morphological response on CT in patients treated with bevacizumab-containing chemotherapy for unresectable colorectal cancer liver metastases (CLM). It also evaluated the prognostic value of size-based criteria and the association of optimal morphological response with the receipt of bevacizumab.

DESIGN

141 patients treated first using bevacizumab and 142 patients from a randomised study evaluating the addition of bevacizumab to oxaliplatin-based chemotherapy were retrospectively analysed. Radiologists evaluated pretreatment and restaging CT scans using morphological response criteria. Responses were also assessed with size-based criteria: Response Evaluation Criteria in Solid Tumors (RECIST), early tumour shrinkage (ETS) and deepness of response (DpR). The ability of each criterion to predict progression-free survival (PFS), overall survival (OS) and postprogression survival (PPS) was determined using a univariate Cox proportional hazards model.

RESULTS

In both populations, median PFS was significantly longer for patients achieving an optimal morphological response (10.4 vs 6.8 months, p=0.03; and 8.3 vs 4.9 months, p<00001, respectively). Neither RECIST nor ETS responses were associated with a prolonged PFS. Median OS was longer for those with an optimal morphological response but only at second restaging in the first population (n=141, 20.8 vs 12.3 months, p=0.002). DpR but not optimal morphological response was associated with PPS. In the randomised study, an optimal morphological response was 6.2 times more likely among patients receiving bevacizumab (p<0.0001).

CONCLUSION

In patients with unresectable CLM, early morphological response may be a better predictor of PFS than size-based response. The addition of bevacizumab improves morphological response rate.

Depth of response is a significant predictor for long-term outcome in advanced gastric cancer patients treated with trastuzumab

Purpose

We aimed to determine and compare the predictive values of depth of response (DpR) and early tumor shrinkage (ETS) on long-term outcomes in gastric cancer patients treated with trastuzumab.

Results

From a total of 368 computed tomography examinations, DpR and ETS were evaluated. DpR was a significant tumor-size metric in predicting PFS and OS, and showed better discriminatory ability (higher Cτ indices, 0.6957 for PFS; 0.7191 for OS) than ETS. DpR ≥ 45% (vs. < 45%) was the optimal cutoff value, as it was best able to identify patients with longer PFS (median 9.0 vs. 6.3 months, hazard ratio [HR] = 0.608; 95% confidence interval [CI]: 0.335 to 1.104; P = 0.102) and OS (median 23.5 vs. 13.1 months, HR = 0.441; 95% CI: 0.203 to 0.955; P = 0.038).

Materials and Methods

Sixty-one gastric cancer patients who received first-line trastuzumab-based chemotherapy were assessed for DpR and ETS. We employed Kaplan-Meier estimates, log-rank tests, Cox proportional hazards regression models, time-dependent receiver operating characteristics, and Youden's J index to evaluate and determine cutoff values of DpR and ETS as predictors of progression-free survival (PFS) and overall survival (OS).

Conclusions

DpR and ETS were significant predictors of long-term outcomes in gastric cancer patients treated with first-line trastuzumab. Validation in prospective trials with larger patient populations is needed.

Associations between early tumor shrinkage and depth of response and clinical outcomes in patients treated with 1st-line chemotherapy for advanced gastric cancer

BACKGROUND

Although early tumor shrinkage (ETS) predictions of the efficacy and depth of response (DpR) reflects clinical outcomes in chemotherapy with epidermal growth factor receptor inhibitor regimens to treat metastatic colorectal cancer, their value in assessing treatments for advanced gastric cancer (AGC) is unclear. Here we evaluated relationships between ETS and DpR and clinical outcomes in AGC patients treated with first-line chemotherapy.

METHODS

We retrospectively enrolled 612 consecutive patients treated with first-line chemotherapy for AGC between January 2010 and June 2016. ETS and DpR were defined as changes from baseline in summed longest diameters in target lesions at 8 (±4) weeks for ETS and at the smallest observed volume for DpR.

RESULTS

Eligible patients were sorted into HER2⁺ (n = 100) and HER2^- (n = 186) groups. Median follow-up was 14.8 months. The overall response rate and disease control rates were 64 and 87% in the HER2⁺ group and 53.2 and 86.0% in the HER2^- group. Respective median PFS and OS were HER2⁺: 7.9 and 20.8 months and HER2^-: 6.6 and 13.8 months. The respective ETS rate and median DpR were HER2⁺: 70 and 44% and HER2^-: 57.5 and 24%. Clinical outcomes and ETS/DpR were correlated, especially in the HER2⁺ group (OS: P < 0.0001; PFS: P < 0.0001). In multivariate analysis, ETS was an independent predictor for OS in the HER2⁺ group and for PFS in both groups.

CONCLUSION

These results indicate that ETS may be an early-on treatment predictor of the efficacy of HER2⁺ advanced gastric cancer treated with first-line chemotherapy that includes trastuzumab.

Exploration of time points and cut-off values for early tumour shrinkage to predict survival outcomes of patients with metastatic colorectal cancer treated with first-line chemotherapy using a biexponential model for change in tumour size

Background

Several studies reported that early tumour shrinkage (ETS) was associated with overall survival in patients with metastatic colorectal cancer (mCRC) treated with first-line chemotherapy. However, appropriate time point and cut-off value for ETS remain unclear because these varied in previous studies.

Patients and methods

We investigated patients with mCRC who received FOLFOX or FOLFIRI with/without molecular-targeted agents as first-line treatment between 2005 and 2014. Using a biexponential model for change in tumour size, a relative change in the sum of the longest diameters of target lesions from baseline was estimated at a certain time point in each individual patient. Associations of survival outcomes with ETS at various time points based on various cut-off values were evaluated by Cox regression analysis with a landmark approach.

Results

Among the 67 patients reviewed, the objective response rate was 73.1% (95% CI 62.5% to 83.7%), the median progression-free survival was 10.9 months (95% CI 8.7 to 13.0 months) and the median overall survival was 25.6 months (95% CI 20.1 to 27.3 months). The model for change in tumour size agreed with the actual measured sizes well. Multivariate Cox regression analysis, including performance status, number of metastatic sites and use of targeted agents, showed that ETS at 8 weeks based on a cut-off value of 20% was most significantly associated with overall survival (HR: 0.404, 95% CI 0.231 to 0.707, P=0.0015).

Conclusion

It is suggested that a time point of 8 weeks and a cut-off value of 20% may be optimal criteria for defining ETS.

Early Tumor Shrinkage and Depth of Response as Predictors of Favorable Treatment Outcomes in Patients with Metastatic Colorectal Cancer Treated with FOLFOX Plus Cetuximab (JACCRO CC-05)

BACKGROUND

Retrospective studies have found that early tumor shrinkage (ETS) and depth of response (DpR) are associated with favorable outcomes in patients with metastatic colorectal cancer (mCRC); however, few prospective studies have evaluated ETS and DpR.

PATIENTS AND METHODS

We performed a phase II study of FOLFOX plus cetuximab as first-line treatment in Japanese patients with KRAS wild-type mCRC. The primary endpoint was response rate (RR), and secondary endpoints included progression-free survival (PFS), overall survival (OS), chronological tumor shrinkage (evaluated every 8 weeks), and safety. The association of ETS and DpR with survival time was analyzed using Spearman's rank correlation coefficient.

RESULTS

In 54 participants, the RR, median PFS, and OS were 66.7 % (95 % CI, 53.4-77.8 %), 11.1 months, and 33.9 months, respectively. There was no unexpected toxicity. Forty (80 %) of 50 assessable patients had ETS, which was associated with prolonged PFS and OS (11.3 vs. 3.7 months, HR 0.26, p = 0.0003; 42.8 vs. 9.0 months, HR 0.40, p = 0.0279, respectively). Median DpR was 56.3 %. The DpR correlated with OS (r _s = 0.314, p = 0.027) as well as post-progression survival (PPS) (r _s = 0.366, p = 0.017). Interestingly, DpR was moderately associated with OS and PPS (r _s = 0.587, r _s = 0.570, respectively) in patients harboring tumors with larger target lesions, but was not associated with OS or PPS in patients with smaller target lesions. FOLFOX plus cetuximab was active as a first-line treatment for Japanese mCRC patients, with no unexpected toxicities.

CONCLUSIONS

Our prospective evaluation of chronological tumor shrinkage showed that ETS and DpR correlate with outcomes in patients with KRAS wild-type mCRC who receive cetuximab-based chemotherapy (UMIN000004197).

Exploratory analyses assessing the impact of early tumour shrinkage and depth of response on survival outcomes in patients with RAS wild-type metastatic colorectal cancer receiving treatment in three randomised panitumumab trials

Purpose

To report exploratory analyses of early tumour shrinkage (ETS) and depth of response (DpR) in patients with RAS wild-type (WT) metastatic colorectal cancer (mCRC), receiving the first-line treatment in three randomised panitumumab trials.

Methods

Data from the PRIME (NCT00364013), PEAK (NCT00819780) and PLANET (NCT00885885) studies were included. Median DpR, the proportion of patients achieving ETS ≥ 20% or ≥ 30% at week 8, and the impact of ETS and DpR (including by category) on outcome were analysed. Factors associated with ETS and DpR and the optimal ETS/DpR cut-off values for predicting improved overall survival (OS) were assessed.

Results

Overall, 505, 170 and 53 patients had RAS WT mCRC in PRIME, PEAK and PLANET, respectively. Patients receiving panitumumab had higher ETS rates (≥ 30%: PRIME 59% vs. 38%; PEAK 64% vs. 45%) and greater DpR (PRIME: 54% vs. 46%; PEAK: 65% vs. 46%) than those receiving treatment without panitumumab. In multiple regression analyses, panitumumab treatment, liver-only metastases and WT BRAF status were consistently associated with improved ETS and DpR outcomes. Irrespective of treatment, ETS and DpR were associated with improved progression-free survival, overall survival and resection rates; most resections occurred in patients in the two highest DpR categories. In PRIME and PEAK, respectively, the optimal cut-offs for predicting improved OS were 32 and 34% for ETS, and 59 and 70% for DpR.

Conclusions

These exploratory analyses suggest that panitumumab is associated ETS and DpR benefits in patients with RAS WT mCRC and that achieving these endpoints during first-line treatment is linked with favourable outcomes.

Electronic supplementary material

The online version of this article (doi:10.1007/s00432-017-2534-z) contains supplementary material, which is available to authorized users.

Role of depth of response and MTHFR genotype as predictors of fluorouracil rechallenge therapy for refractory metastatic colorectal cancer

There is limited data on the clinical and biological parameters that enable the prediction of the benefits derived from additional chemotherapy after disease progression compared with standard chemotherapy in patients with metastatic colorectal cancer (mCRC). The present study evaluated the role of tumor response as a clinical parameter and single nucleotide polymorphisms (SNPs) as a biomarker to predict the benefit of additional 5-fluorouracil (5-FU) rechallenge chemotherapy in patients with refractory mCRC. Tumor responses were retrospectively reviewed based on the Response Evaluation Criteria in Solid Tumors, early tumor shrinkage (ETS) and depth of response (DoR) following first-line chemotherapy in patients with stage IV CRC. Together with these parameters, SNPs known to be associated with the response to chemotherapy were analyzed with survival outcomes. In total, the tumor responses of 242 patients with mCRC were evaluated. Overall response and ETS were identified in 110 (45.4%) and 103 patients (42.6%), respectively, and the median DoR was 38.5±30.08%. ETS and DoR were significantly associated with survival outcomes, including progression-free survival, post-progression survival and overall survival. Among these patients, SNPs were analyzed in 171 patients. X-ray repair cross complementing 1 (XRCC1) (AG/AA) with a DoR >60%, good performance status and the absence of bone lesions were associated with improved overall survival. In patients receiving third-line chemotherapy with 5-FU rechallenge therapy, the methylenetretrahydrofolate reductase (MTHFR) (C677T) CC genotype and a DoR >60% were significantly associated with a good prognosis in multivariate analysis. XRCC1 (AG/AA) was also associated with a good prognosis in patients with mCRC. Patients with a DoR >60% following first-line chemotherapy and a MTHFR (C677T) CC genotype exhibited a survival benefit from 5-FU retreatment. Therefore, the DoR and MTHFR genotype are potential markers for selecting patients with refractory mCRC that would benefit from 5-FU rechallenge therapy.

Relation of early tumor shrinkage (ETS) observed in first-line treatment to efficacy parameters of subsequent treatment in FIRE-3 (AIOKRK0306)

We explored the association of early tumor shrinkage (ETS) and non-ETS with efficacy of first-line and consecutive second-line treatment in patients with KRAS wild-type metastatic colorectal cancer treated in FIRE-3. Assessment of tumor shrinkage was based on the sum of longest diameters of target lesions, evaluated after 6 weeks of treatment. Shrinkage was classified as ETS (shrinkage by ≥ 20%), mETS (shrinkage by 0 to <20%), mPD (minor progression >0 to <20%) and PD (progression ≥20%). Overall survival (OS) was 33.2 (95% CI 28.0-38.4) months in ETS patients, while non-ETS was associated with less favorable outcome (mETS 24.0 (95% CI 21.2-26.9) months, mPD 19.0 (95% CI 13.0-25.0) months, PD 12.8 (95% CI 11.1-14.5) months). Differences in PFS of first-line therapy were less pronounced. ETS subgroups defined in first-line therapy also correlated with efficacy of second-line therapy. Progression-free survival in second-line (PFS2nd) was 6.5 months (5.8-7.2) for ETS, and was 5.6 (95% CI 4.7-6.5) months for mETS, 4.9 (95% CI 3.7-6.1) months for mPD and 3.3 (95% CI 2.3-4.3) months for PD. PFS of first-line and PFS2nd showed a linear correlation (Bravais-Pearson coefficient: 0.16, p = 0.006). While ETS is associated with the most favorable outcome, non-ETS represents a heterogeneous subgroup with distinct characteristics of less favorable initial tumor response to treatment. This is the first analysis to demonstrate that early tumor response observed during first-line FOLFIRI-based therapy may also relate to efficacy of second-line treatment. Early response parameters may serve as stratification factors in trials recruiting pretreated patients.

Modified two-dimensional response as surrogate marker of overall survival in patients with metastatic colorectal cancer

The identification of surrogate markers for long‐term outcomes in patients with metastatic colorectal cancer (mCRC) may help in designing treatment regimens. The aim of this study was to assess whether two‐dimensional response (2‐DR) can serve as a new surrogate marker for overall survival (OS) in patients with mCRC. The study group consisted of 99 patients with mCRC from two independent cohorts who were treated with oxaliplatin‐based chemotherapy plus bevacizumab. Two‐dimensional response was defined as an area enclosed by coordinate points, including early tumor shrinkage at 8 weeks, depth of response at nadir, and 20% increase over nadir at progression. Each variable was weighted by its contribution rate to OS. The model was developed and internally validated in the learning cohort, and the performance of this model was externally verified in the validation cohort. Spearman correlation coefficients for 2‐DR and OS in the learning and validation cohorts were 0.593 and 0.661, respectively. The C‐indexes in predicting OS were 0.724 (95% confidence interval, 0.623–0.815) in the learning cohort and 0.762 (95% confidence interval, 0.651–0.873) in the validation cohort. Overall survival was significantly longer in patients with high 2‐DR values than in patients with low 2‐DR values in both the learning (37.0 vs. 24.1 months, P < 0.001) and validation (41.2 vs. 20.4 months, P < 0.001) cohorts. In contrast, differences in early tumor shrinkage and depth of response were not statistically significant. Multivariate analyses showed that 2‐DR was an independent prognostic factor for OS.

Early tumour response as a survival predictor in previously- treated patients receiving triplet hepatic artery infusion and intravenous cetuximab for unresectable liver metastases from wild-type KRAS colorectal cancer

BACKGROUND

Early tumour shrinkage has been associated with improved survival in patients receiving cetuximab-based systemic chemotherapy for liver metastases from colorectal cancer (LM-CRC). We tested this hypothesis for previously treated LM-CRC patients receiving cetuximab (500 mg/m²) and triplet hepatic artery infusion (HAI) within European trial OPTILIV.

METHODS

Irinotecan (180 mg/m²), 5-fluorouracil (2800 mg/m²) and oxaliplatin (85 mg/m²) were given as chronomodulated or conventional delivery. Patients were retrospectively categorised as early responders (complete or partial RECIST response after three courses) or non-early responders (late or no response). Prognostic factors were determined using multivariate logistic or Cox regression models.

RESULTS

Response was assessed in 57 of 64 registered patients (89%), who had previously received one to three prior systemic chemotherapy protocols. An early response occurred at 6 weeks in 16 patients (28%; 9 men, 7 women), aged 33-76 years, with a median of 12 liver metastases (LMs) (2-50), involving five segments (1-8). Ten patients had a late response, and 31 patients had no response. Grade 3-4 fatigue selectively occurred in the non-early responders (0% versus 26%; p = 0.024). Early tumour response was jointly predicted by chronomodulation-odds ratio (OR): 6.0 (1.2-29.8; p = 0.029)-and LM diameter ≤57 mm-OR: 5.3 (1.1-25.0; p = 0.033). Early tumour response predicted for both R0-R1 liver resection-OR: 11.8 (1.4-100.2; p = 0.024) and overall survival-hazard ratio: 0.39 (0.17-0.88; p = 0.023) in multivariate analyses.

CONCLUSIONS

Early tumour response on triplet HAI and systemic cetuximab predicted for complete macroscopic liver resection and prolonged survival for LM-CRC patients within a multicenter conversion-to-resection medicosurgical strategy. Confirmation is warranted for early response on HAI to guide decision making. Protocol numbers: EUDRACT 2007-004632-24 NCT00852228.

A study-level meta-analysis of efficacy data from head-to-head first-line trials of epidermal growth factor receptor inhibitors versus bevacizumab in patients with RAS wild-type metastatic colorectal cancer

BACKGROUND

Head-to-head trials comparing first-line epidermal growth factor receptor inhibitor (EGFRI) versus vascular endothelial growth factor inhibitor (bevacizumab) therapy yielded differing results, and debate remains over optimal first-line therapy for patients with RAS wild-type (WT) metastatic colorectal cancer (mCRC).

METHODS

A PubMed search identified first-line mCRC trials comparing EGFRI plus chemotherapy versus bevacizumab plus chemotherapy; data were subsequently updated using recent congress presentations. This study-level meta-analysis estimated the overall survival (OS) treatment effect of first-line chemotherapy plus EGFRIs or bevacizumab in patients with RAS WT mCRC. Secondary end-points were progression-free survival (PFS), objective response rate (ORR), resection rate and safety. Early tumour shrinkage (ETS) of ≥20% at week 8 was an exploratory end-point.

RESULTS

Three trials comprising data from 1096 patients with RAS WT mCRC were included. OS (hazard ratio [HR]: 0.80 [95% confidence interval: 0.68-0.93]), ORR (odds ratio [OR]: 0.57) and ETS (OR: 0.48) favoured EGFRIs plus chemotherapy versus bevacizumab plus chemotherapy. PFS (HR: 0.98) and resections (OR: 0.93) were similar between treatments. For patients with KRAS exon 2 WT/'other' RAS mutant mCRC the OS HR was 0.70. A safety meta-analysis was not possible due to a lack of data; in the individual studies, skin toxicities and hypomagnesaemia were more common with EGFRIs, nausea and hypertension were more common with bevacizumab.

CONCLUSIONS

This meta-analysis supports a potential benefit for first-line EGFRI plus chemotherapy versus bevacizumab plus chemotherapy with respect to OS, ORR and ETS in patients with RAS WT mCRC. A patient-level meta-analysis is awaited.

FOLFIRI plus cetuximab versus FOLFIRI plus bevacizumab for metastatic colorectal cancer (FIRE-3): a post-hoc analysis of tumour dynamics in the final RAS wild-type subgroup of this randomised open-label phase 3 trial

BACKGROUND

FIRE-3 compared first-line 5-fluorouracil, leucovorin, and irinotecan (FOLFIRI) plus cetuximab with FOLFIRI plus bevacizumab in patients with KRAS exon 2 wild-type metastatic colorectal cancer. The same study also reported an exploratory analysis of a subgroup of patients with tumours that were wild-type at other RAS genes (KRAS and NRAS exons 2-4). We report here efficacy results for the FIRE-3 final RAS (KRAS/NRAS, exons 2-4) wild-type subgroup. Moreover, new metrics of tumour dynamics were explored during a centralised radiological review to investigate how FOLFIRI plus cetuximab conferred overall survival benefit in the absence of differences in investigator-assessed objective responses and progression-free survival.

METHODS

FIRE-3 was a randomised phase 3 trial comparing FOLFIRI plus cetuximab with FOLFIRI plus bevacizumab in the first-line treatment of patients with KRAS exon 2 wild-type metastatic colorectal cancer. The primary endpoint of the FIRE-3 study was the proportion of patients achieving an objective response according to Response Evaluation Criteria In Solid Tumors (RECIST) 1.0 in the intention-to-treat population. A centralised radiological review of CT scans was done in a post-hoc analysis to assess objective response according to RECIST 1.1, early tumour shrinkage, depth of response, duration of response, and time to response in the final RAS wild-type subgroup. Comparisons between treatment groups with respect to objective response rate and early tumour shrinkage were made using Fisher's exact test (two-sided), while differences in depth of response were investigated with a two-sided Wilcoxon test. This trial is registered at ClinicalTrials.gov, number NCT00433927.

FINDINGS

In the final RAS wild-type population (n=400), median overall survival was better in the FOLFIRI plus cetuximab group than the FOLFIRI plus bevacizumab group (33·1 months [95% CI 24·5-39·4] vs 25·0 months [23·0-28·1]; hazard ratio 0·70 [0·54-0·90]; p=0·0059), although investigator-assessed objective response and progression-free survival were comparable between treatment groups. Centralised radiological review of CT-assessable patients (n=330) showed that the proportion of patients achieving an objective response (113 of 157, 72·0% [95% CI 64·3-78·8] vs 97 of 173, 56·1% [48·3-63·6]; p=0·0029), frequency of early tumour shrinkage (107 of 157, 68·2% [60·3-75·4] vs 85 of 173, 49·1% [41·5-56·8]; p=0·0005), and median depth of response (-48·9% [-54·3 to -42·0] vs -32·3% [-38·2 to -29·2]; p<0·0001) were significantly better in extended RAS wild-type patients receiving FOLFIRI plus cetuximab versus those receiving FOLFIRI plus bevacizumab. No differences in duration of response and time to response were observed between treatment groups.

INTERPRETATION

This analysis provides a new framework that connects alternative metrics of response to overall survival. Superior response-related outcome parameters, such as early tumour shrinkage and depth of response, obtained by centralised radiological review correlated with the overall survival benefit conferred by FOLFIRI plus cetuximab compared with FOLFIRI plus bevacizumab in the extended RAS wild-type subgroup.

FUNDING

Merck KGaA and Pfizer.

Timing and extent of response in colorectal cancer: critical review of current data and implication for future trials

The identification of new surrogate endpoints for advanced colorectal cancer is becoming crucial and, along with drug development, it represents a research field increasingly studied. Although overall survival (OS) remains the strongest trial endpoint available, it requires larger sample size and longer periods of time for an event to happen. Surrogate endpoints such as progression free survival (PFS) or response rate (RR) may overcome these issues but, as such, they need to be prospectively validated before replacing the real endpoints; moreover, they often bear many other limitations. In this narrative review we initially discuss the role of time-to-event endpoints, objective response and response rate as surrogates of OS in the advanced colorectal cancer setting, discussing also how such measures are influenced by the tumor assessment criteria currently employed. We then report recent data published about early tumor shrinkage and deepness of response, which have recently emerged as novel potential endpoint surrogates, discussing their strengths and weaknesses and providing a critical comment. Despite being very compelling, the role of such novel response measures is yet to be confirmed and their surrogacy with OS still needs to be further investigated within larger and well-designed trials.

Computational Identification of Key Regulators in Two Different Colorectal Cancer Cell Lines

Transcription factors (TFs) are gene regulatory proteins that are essential for an effective regulation of the transcriptional machinery. Today, it is known that their expression plays an important role in several types of cancer. Computational identification of key players in specific cancer cell lines is still an open challenge in cancer research. In this study, we present a systematic approach which combines colorectal cancer (CRC) cell lines, namely 1638N-T1 and CMT-93, and well-established computational methods in order to compare these cell lines on the level of transcriptional regulation as well as on a pathway level, i.e., the cancer cell-intrinsic pathway repertoire. For this purpose, we firstly applied the Trinity platform to detect signature genes, and then applied analyses of the geneXplain platform to these for detection of upstream transcriptional regulators and their regulatory networks. We created a CRC-specific position weight matrix (PWM) library based on the TRANSFAC database (release 2014.1) to minimize the rate of false predictions in the promoter analyses. Using our proposed workflow, we specifically focused on revealing the similarities and differences in transcriptional regulation between the two CRC cell lines, and report a number of well-known, cancer-associated TFs with significantly enriched binding sites in the promoter regions of the signature genes. We show that, although the signature genes of both cell lines show no overlap, they may still be regulated by common TFs in CRC. Based on our findings, we suggest that canonical Wnt signaling is activated in 1638N-T1, but inhibited in CMT-93 through cross-talks of Wnt signaling with the VDR signaling pathway and/or LXR-related pathways. Furthermore, our findings provide indication of several master regulators being present such as MLK3 and Mapk1 (ERK2) which might be important in cell proliferation, migration, and invasion of 1638N-T1 and CMT-93, respectively. Taken together, we provide new insights into the invasive potential of these cell lines, which can be used for development of effective cancer therapy.

'Deepness of Response' Is Associated with Overall Survival in Standard Systemic Chemotherapy for Metastatic Colorectal Cancer

BACKGROUND

The identification of responders is an important issue in chemotherapy for metastatic colorectal cancer (mCRC). 'Deepness of response' (DpR), defined as the maximum rate of reduction from the initial tumor burden, was recently proposed as a novel hypothetical parameter associated with overall survival (OS) in first-line chemotherapy plus cetuximab for mCRC. We determined whether this concept was universally applicable to diverse standard chemotherapeutic regimens for mCRC.

METHODS

We reviewed mCRC patients who received the first-line systemic chemotherapy regimens FOLFOX, CapeOX or FOLFIRI (with biologics) at our department between June 2005 and March 2015. Data such as clinicopathological parameters, metastasized organs, chemotherapeutic regimens, the best response by RECIST v1.1, progression-free survival (PFS) and OS were retrospectively retrieved for patients who exhibited tumor shrinkage. DpR was calculated as the uni-dimensional maximum reduction rate of measurable tumors. We addressed the association between DpR and survival.

RESULTS

Of the 156 patients receiving first-line chemotherapy regimens, tumor shrinkage was observed in 63 (41 of whom were men; median age 62 years). Complete remission was achieved in 6 patients, partial remission in 42 and stable disease in 15. The median DpR was 44.2% and was employed as the cutoff, in line with previous reports. DpR ≥45% (31 patients) was correlated with longer PFS (median 16.4 vs. 8.1 months for DpR <45%, p = 0.006) and OS (median 58.6 vs. 30.9 months for DpR <45%, p = 0.041). There was basically no difference in the subsequent chemotherapy between the DpR ≥45% and DpR <45% groups.

CONCLUSION

DpR correlated with OS in various first-line systemic upfront chemotherapy regimens for mCRC.

Early tumour shrinkage (ETS) and depth of response (DpR) in the treatment of patients with metastatic colorectal cancer (mCRC)

BACKGROUND

Response evaluation criteria in solid tumours (RECIST) are used to define degrees of response to anti-tumour agents. In retrospective analyses, early tumour shrinkage (ETS) has been investigated as an alternative early-on-treatment predictor of treatment efficacy with regard to progression-free and overall survival. While cut-off based analysis of ETS facilitates the categorisation of patients into responders and non-responders after a defined period of treatment, depth of response (DpR) serves as a continuous measure, which defines the nadir of tumour response.

METHODS

A systematic literature search for 'early tumour shrinkage' or 'tumour size decrease' in 'metastatic colorectal cancer' reported from January 2000 to July 2014 was performed. The present review summarises available data concerning ETS and DpR and evaluates their potential as predictive markers for the clinical management of patients with metastatic colorectal cancer (mCRC).

RESULTS

A total of 10 clinical trials investigated the role of ETS as a marker of clinical outcome in patients with mCRC. In addition, DpR was investigated using the efficacy data from three of these trials. Available data show that ETS differentiates patients with high sensitivity to treatment and more favourable prognosis from a heterogeneous group of patients classified as non-ETS patients. ETS is an early indicator of the potentially achievable response. In contrast, DpR estimates the nadir of tumour response as a continuous measure, which may affect the subsequent disease history, thus translating into superior survival.

CONCLUSIONS

The concepts of ETS and DpR offer potential as clinical end-points to aid the clinical decision making process and thus further optimise mCRC patient management in the era of tailored therapy approaches.

Managing synchronous liver metastases from colorectal cancer: a multidisciplinary international consensus

An international panel of multidisciplinary experts convened to develop recommendations for managing patients with colorectal cancer (CRC) and synchronous liver metastases (CRCLM). A modified Delphi method was used. CRCLM is defined as liver metastases detected at or before diagnosis of the primary CRC. Early and late metachronous metastases are defined as those detected ⩽12months and >12months after surgery, respectively. To provide information on potential curability, use of high-quality contrast-enhanced computed tomography (CT) before chemotherapy is recommended. Magnetic resonance imaging is increasingly being used preoperatively to aid detection of subcentimetric metastases, and alongside CT in difficult situations. To evaluate operability, radiology should provide information on: nodule size and number, segmental localization and relationship with major vessels, response after neoadjuvant chemotherapy, non-tumoral liver condition and anticipated remnant liver volume. Pathological evaluation should assess response to preoperative chemotherapy for both the primary tumour and metastases, and provide information on the tumour, margin size and micrometastases. Although the treatment strategy depends on the clinical scenario, the consensus was for chemotherapy before surgery in most cases. When the primary CRC is asymptomatic, liver surgery may be performed first (reverse approach). When CRCLM are unresectable, the goal of preoperative chemotherapy is to downsize tumours to allow resection. Hepatic resection should not be denied to patients with stable disease after optimal chemotherapy, provided an adequate liver remnant with inflow and outflow preservation remains. All patients with synchronous CRCLM should be evaluated by a hepatobiliary multidisciplinary team.

Impact of early tumour shrinkage and resection on outcomes in patients with wild-type RAS metastatic colorectal cancer

BACKGROUND

Tumour shrinkage (TS) increases the possibility of resection in metastatic colorectal cancer (mCRC) and may improve tumour-related symptoms. Here we report prespecified secondary response-related end-points and exploratory TS/resection outcomes for patients with RAS wild-type (WT) tumours (no mutations in KRAS/NRAS exons 2/3/4) from the PRIME study (NCT00364013).

METHODS

PRIME was a randomised phase 3 study comparing first-line panitumumab+FOLFOX4 versus FOLFOX4 in mCRC patients. Tumour response analyses were conducted to compare response rates and their impact on survival outcomes.

RESULTS

Overall, 505 patients had RAS WT mCRC. More patients receiving panitumumab+FOLFOX4 versus FOLFOX4 had ⩾30% (59% versus 38%; P<0.001) or ⩾20% (72% versus 57%; P<0.001) TS at week 8 (early TS); consistent TS benefits were observed over the first ∼40weeks of treatment. Objective response rate (P=0.003), duration of response (P=0.0027), depth of response (P=0.0149), progression-free survival (PFS; P=0.0015) and overall survival (OS; P=0.0057) were improved in the panitumumab+FOLFOX4 group. Both early TS and resection were associated with improved PFS and OS. 2-year OS rates for patients who did (n=64) versus did not (n=441) undergo resection were 88% versus 40%; 2-year OS rates for patients who did (n=45) versus did not (n=460) undergo complete resection were 96% versus 41%.

CONCLUSIONS

More patients receiving panitumumab+FOLFOX4 versus FOLFOX4 had ⩾30% or ⩾20% TS at week 8; PFS and OS were also improved with panitumumab+FOLFOX4. The clinical value of achieving early TS in mCRC warrants further investigation.

Impact of early tumor shrinkage on clinical outcome in wild-type-KRAS colorectal liver metastases treated with cetuximab

BACKGROUND AND AIM

To evaluate the impact of early tumor shrinkage (ETS) on long-term outcome in patients with wild-type Kirsten rat sarcoma viral oncogene homolog (KRAS) unresectable colorectal liver metastases (CLM) receiving cetuximab plus chemotherapy.

METHODS

A total of 138 patients in a randomized controlled trial (70 in armA received cetuximab plus chemotherapy, 68 in armB received chemotherapy alone), as previously reported (Ye et al., 2013) were included into this analysis. The cut-off date updated for overall survival (OS) was June 2014. ETS was defined as a ≥ 20% reduction of the longest diameters of the target lesions compared with baseline at the first evaluation (8 weeks). Outcome measures were progression-free survival (PFS) and OS.

RESULTS

There were 132 patients available for evaluation, and ETS occurred more frequently in armA than that in armB (P = 0.003). ETS was associated with longer OS (armA: 35.7 vs. 19.5 months, P < 0.001; armB 28.7 vs. 18.7 months, P = 0.01) and PFS (armA: 13.4 vs. 4.2 months, P < 0.001; armB 7.0 vs. 4.2 months, P = 0.001) compared with patients with no-ETS. Among patients with ETS, there was a significant difference between armA and armB in PFS (P = 0.03), but not in OS (P = 0.19). All 23 patients who underwent liver surgery achieved ETS. In armA, for patients without liver surgery, patients observed ETS also gained an increased survival benefit over those no-ETS in OS (P = 0.02) and PFS (P < 0.001). ETS was an independent predictor of improved OS (hazard ratio 0.56, P = 0.007).

CONCLUSION

ETS may serve as a predictor of favorable outcome in patients with wild-type KRAS CLM receiving cetuximab plus chemotherapy.

Early tumour shrinkage as a prognostic factor and surrogate end-point in colorectal cancer: a systematic review and pooled-analysis

PURPOSE

Early tumour shrinkage (ETS), defined as a reduction of at least 20% in tumour size at first reassessment, has been recently investigated retrospectively in first-line trials of metastatic colorectal cancer (CRC), and appears to be associated with better outcomes. We have performed a systematic review and meta-analysis of published trials to evaluate the prognostic value of ETS in CRC in terms of overall survival (OS) and progression-free survival (PFS).

MATERIAL AND METHODS

An electronic search of the PubMed, SCOPUS, EMBASE, the Web of Science, and the Cochrane Central Register of Controlled Trial databases identified trials that compared outcomes of patients with or without ETS during first-line chemotherapy for metastatic CRC. The OS, reported as a hazard ratio (HR) with a 95% confidence interval (CI), was the primary outcome measure; the correlation coefficient (R) between ETS with median OS was also estimated.

RESULTS

Twenty-one trials from 10 publications were analysed. Overall, patients with ETS were associated with a better OS (HR, 0.58; 95% CI, 0.53 to 0.64; P<0.00001) and PFS (HR, 0.57; 95% CI, 0.47-0.69; P<0.00001) compared with patients who were early non-responders. However, ETS was poorly correlated with OS in terms of surrogacy (R=0.37; 95% CI - 0.31-0.78; P=0.28).

CONCLUSIONS

ETS is a good prognostic factor but an inappropriate surrogate for predicting outcome in CRC patients. These findings support ETS as prognostic tool in ascertaining earlier non-responders; however, its role as a surrogate end-point deserves further evaluation.

Comparison between three oxaliplatin-based regimens with bevacizumab in patients with metastatic colorectal cancer

BACKGROUND

A previous pivotal Phase III study (NO16966) demonstrated the benefit of the addition of bevacizumab (BV) to oxaliplatin-based regimens in metastatic colorectal cancer (MCRC). Our study evaluated the safety and efficacy of three oxaliplatin-based chemotherapy regimens (FOLFOX4 [intravenous twice-bolus and twice-infusional 5-fluorouracil/folinic acid plus oxaliplatin], mFOLFOX6 [intravenous once-bolus and once-infusional 5-fluorouracil/folinic acid plus oxaliplatin], and XELOX [capecitabine plus oxaliplatin]) plus BV in the first-line treatment of MCRC patients.

METHODS

Patients with MCRC who started treatment between June 2007 and September 2010 were evaluated in this retrospective cohort study. We also evaluated early objective tumor response (EOTR) within 12 weeks, which was defined as a relative change of ≥30% in the sum of the longest diameters of target lesions when compared with baseline. The primary study endpoints were progression-free survival (PFS) and response rate.

RESULTS

A total of 185 patients received the following chemotherapy: FOLFOX4 + BV (FF4 arm, n=85), mFOLFOX6 + BV (FF6 arm, n=40), and XELOX + BV (XELOX arm, n=60). The overall response rates were 61.2%, 72.5%, and 75.0% (95% confidence interval: 50.6%-71.8%, 58.0%-87.0%, and 63.7%-86.3%). Median PFS was 18.0, 15.5, and 13.7 months, respectively (log-rank: P=0.254; data cut-off: May 2013). Patients with EOTR (n=117) had significantly better PFS than those without-EOTR (n=68) (17.5 versus 12.7 months, P=0.004).

CONCLUSION

This study suggests that these three BV plus oxaliplatin-based treatments might have comparable benefit in terms of tumor response and PFS. Moreover, EOTR may be a predictive factor for PFS in patients with MCRC.

Prognostic value of treatment-related factors in metastatic colorectal cancer using a stop-and-go strategy

PURPOSE

The purpose of this study is to identify treatment-related factors prognostic of survival in a cohort of patients with metastatic colorectal cancer (mCRC) receiving a palliative, stop-and-go chemotherapy regimen.

METHODS

Consecutive patients receiving first-line treatment with biweekly FLIRI plus bevacizumab were included. The outcome was overall survival. Cox regression analysis was used to identify predictors of outcome. We analysed reduction in chemotherapy dosage (no vs. ≤25 or >25 % reduction), bevacizumab administrated to <50, or ≥50 % to chemotherapy treatments, best response during the first 24 weeks of treatment, and local treatment of metastases.

RESULTS

We included 257 patients. Median survival was 23.6 months. Chemotherapy reduction did not influence outcome. Bevacizumab administrations (≥50 %) were associated with improved outcome: hazard ratios (HR) 0.56 (95 % confidence interval (CI) 0.34-0.90, p = 0.018). Partial response (PR) vs. no change (NC) was borderline significant: HR 0.66 (95 % CI 0.43-0.99, p = 0.048), whereas progressive disease (PD) vs. NC increased mortality HR 2.48 (95 % CI 1.19-5.19, p = 0.016). Local treatment of metastases improved outcome: HR 0.30 (95 % CI 0.15-0.61, p = 0.001).

CONCLUSIONS

In a cohort of mCRC patients, receiving a palliative, stop-and-go regimen, administration of bevacizumab to ≥50 % of chemotherapy treatments and local treatment of metastases were associated with better survival. PR improved outcome compared to NC, whereas PD was prognostic of increased mortality.

Epirubicin combined with oxaliplatin and 5-day continuous infusion of 5-fluorouracil as a first-line treatment for metastatic gastric cancer: treatment outcomes and analysis of prognostic factors

PURPOSE

In order to confirm the efficacy, tolerability, and baseline prognostic factors of an epirubicin (EPR)-containing triplet regimen, the EOF5 regimen, in patients with metastatic gastric cancer (MGC), we conducted the phase II trial and retrospective analysis.

METHODS

MGC patients received the EOF5 regimen (EPR 50 mg/m(2) and oxaliplatin (OX) 130 mg/m(2) on day 1 followed by continuous infusion of 5-fluorouracil (5-FU) 375-425 mg/m(2)/days for 5 days every 3 weeks). Log-rank tests were used for univariate analysis of time to progression (TTP) and overall survival rate (OS), and stepwise Cox proportional hazards regression modeling was performed to generate a prognostic index.

RESULTS

A total of 158 patients received the EOF5 regimen. Of the 150 evaluable patients, complete remission, partial remission, and stable disease were observed in 5 (3.3%), 70 (46.7%), and 58 patients (38.7%), respectively. The median TTP and OS were 6.0 (95% CI 5.4-6.6) and 12.6 months (95% CI 8.2-16.9), respectively. Grade 3-4 neutropenia (44.0%), thrombocytopenia (25.3%), and anemia (6.7%) were recorded. A prognostic index that included liver and lung metastasis, ascites/pleural effusion, and baseline serum CA19-9 was used to categorize the patients into three groups: good risk (0 risk factors), moderate risk (1 or 2 risk factors), and poor risk (3 or 4 risk factors). The median OS for these groups was 30.4, 12.4, and 5.6 months, respectively (P < 0.001).

CONCLUSIONS

EOF5 is an effective regimen and a suitable alternative for the first-line treatment of MGC. According to the prognostic index used in our study, patients with no risk factors have a better OS when treated with EOF5 than those with one or more risk factors.

Anti-EGFR and anti-VEGF agents: Important targeted therapies of colorectal liver metastases

Colorectal liver metastasis (CLM) is common worldwide. Targeted therapies with monoclonal antibodies have been proven effective in numerous clinical trials, and are now becoming standards for patients with CLM. The development and application of anti-epidermal growth factor receptor (anti-EGFR) and anti-vascular endothelial growth factor (anti-VEGF) antibodies represents significant advances in the treatment of this disease. However, new findings continue to emerge casting doubt on the efficacy of this approach. The Kirsten rat sarcoma viral oncogene (KRAS) has been proven to be a crucial predictor of the success of anti-EGFR treatment in CLM. Whereas a recent study summarized several randomized controlled trials, and showed that patients with the KRAS G13D mutation significantly benefited from the addition of cetuximab in terms of progress-free survival (PFS, 4.0 mo vs 1.9 mo, HR = 0.51, P = 0.004) and overall survival (OS, 7.6 mo vs 5.7 mo, HR = 0.50, P = 0.005). Some other studies also reported that the KRAS G13D mutation might not be absolutely predictive of non-responsiveness to anti-EGFR therapy. At the same time, “new” RAS mutations, including mutations in neuroblastoma RAS viral (v-ras) oncogene homolog (NRAS) and exons 3 and 4 of KRAS, have been suggested to be predictors of a poor treatment response. This finding was first reported by the update of the PRIME trial. The update showed that for patients with non-mutated KRAS exon 2 but other RAS mutations, panitumumab-fluorouracil, leucovorin, and oxaliplatin (FOLFOX)4 treatment led to inferior PFS (HR = 1.28, 95%CI: 0.79-2.07) and OS (HR = 1.29, 95%CI: 0.79-2.10), which was consistent with the findings in patients with KRAS mutations in exon 2. Then, the update of the PEAK trial and the FIRE-III trial also supported this finding, which would reduce candidates for anti-EGFR therapy but enhance the efficacy. In first-line targeted combination therapy, the regimens of cetuximab plus FOLFOX was called into question because of the inferior prognosis in the COIN trial and the NORDIC-VII trial. Also, bevacizumab plus oxaliplatin-based chemotherapy was questioned because of the NO16966 trial. By the update and further analysis of the COIN trial and the NORDIC-VII trial, cetuximab plus FOLFOX was reported to be reliable again. But bevacizumab plus oxaliplatin-based chemotherapy was still controversial. In addition, some trials have reported that bevacizumab is not suitable for conversion therapy. The results of the FIRE-III trial showed that cetuximab led to a significant advantage over bevacizumab in response rate (72% vs 63%, P = 0.017) for evaluable population. With the balanced allocation of second-line treatment, the FIRE-III trial was expected to provide evidence for selecting following regimens after first-line progression. There is still no strong evidence for the efficacy of targeted therapy as a preoperative treatment for resectable CLM or postoperative treatment for resected CLM, although the combined regimen is often administered based on experience. Combination therapy with more than one targeted agent has been proven to provide no benefit, and even was reported to be harmful as first-line treatment by four large clinical trials. However, recent studies reported positive results of erlotinib plus bevacizumab for maintenance treatment. The mechanism of antagonism between different targeted agents deserves further study, and may also provide greater understanding of the development of resistance to targeted agents.

Changes in mutational status during third-line treatment for metastatic colorectal cancer--results of consecutive measurement of cell free DNA, KRAS and BRAF in the plasma

KRAS and BRAF mutations are responsible for primary resistance to epidermal growth factor receptor (EGFR) MoAbs in metastatic colorectal cancer (mCRC), but it is unknown what causes wildtype (wt) patients to develop resistance during treatment. We measured circulating free DNA (cfDNA), KRAS and BRAF in plasma and report the changes during third line treatment with cetuximab and irinotecan. One-hundred-and-eight patients received irinotecan 350 mg/m2 q3w and weekly cetuximab (250 mg/m2) until progression (RECIST) or unacceptable toxicity. cfDNA and number of mutated KRAS/BRAF alleles in plasma at baseline and before each cycle was analyzed by an in-house qPCR. cfDNA and pKRAS levels decreased from baseline to cycle three and increased at time of progression (p = 0.008). The decrease was larger in responding patients than in non-responding (p < 0.05). Two patients with primary mutant disease had different types of mutations detected in the plasma, including synchronous KRAS and BRAF. Twelve patients had a primary KRAS mutant tumor, but wild-type disease according to baseline plasma analysis, eight of these obtained stabilization of disease. In five patients with primary wt disease a mutation appeared in plasma before radiological evidence of progression. Loss of mutations may explain observed benefit of treatment in primary mutant disease, whereas appearance of mutations during therapy may be responsible for acquired resistance in primary wt disease. Benefit from EGFR MoAbs may be influenced by the quantitative level of mutational alleles rather than by mutational status alone, and plasma levels of cfDNA, KRAS and BRAF could be used to monitor patients during treatment.