Temozolomide Followed by Combination With Low-Dose Ipilimumab and Nivolumab in Patients With Microsatellite-Stable, O6-Methylguanine-DNA Methyltransferase-Silenced Metastatic Colorectal Cancer: The MAYA Trial

This is a multicenter, single-arm phase II trial evaluating the efficacy and safety of an immune-sensitizing strategy with temozolomide priming followed by a combination of low-dose ipilimumab and nivolumab in patients with microsatellite-stable (MSS) and O⁶-methylguanine–DNA methyltransferase (MGMT)–silenced metastatic colorectal cancer (mCRC).

MAYA shows that temozolomide priming followed by Ipi/Nivo combo induces durable benefit in MSS/MGMT-silenced mCRC.

Variant allele frequency in baseline circulating tumour DNA to measure tumour burden and to stratify outcomes in patients with RAS wild-type metastatic colorectal cancer: a translational objective of the Valentino study

INTRODUCTION

In patients with metastatic colorectal cancer (mCRC), baseline circulating tumour DNA (ctDNA) variant allele fraction (VAF) might serve as a surrogate of disease burden and should be evaluated in comparison with CEA and RECIST-defined sum of target lesions.

METHODS

In this pre-planned analysis of the VALENTINO trial, we included patients with RAS wild-type mCRC receiving upfront FOLFOX/panitumumab with available baseline liquid biopsy. CtDNA was analysed by means of a 14-gene NGS panel. For each patient, the gene with the highest VAF in ctDNA was selected.

RESULTS

The final cohort included 135 patients. The median VAF was 12.6% (IQR: 2.0-45.2%). Higher VAF was observed in patients with liver metastases and with synchronous metastases presentation. Patients with high VAF had poorer median OS compared to those with low VAF (21.8 vs 36.5 months; HR: 1.82, 95%CI: 1.20-2.76; p = 0.005). VAF outperformed baseline CEA and target lesion diameter in the prognostic stratification and remained significantly correlated with OS (p = 0.003) in a multivariate model. VAF was not significantly correlated with dimensional response and PFS.

CONCLUSION

CtDNA measured by VAF is prognostic in patients with RAS wild-type mCRC. Response and PFS after an anti-EGFR-based first-line strategy are independent from initial tumour burden.

Reinduction of an Anti-EGFR-based First-line Regimen in Patients with RAS Wild-type Metastatic Colorectal Cancer Enrolled in the Valentino Study

Background

In patients with RAS/BRAF wild-type metastatic colorectal cancer (mCRC), growing evidence supports anti-epidermal growth factor receptor (EGFR) retreatment, whereas little is known on the outcomes of anti-EGFR-based reinduction therapy during the upfront strategy.

Methods

We included patients enrolled in the Valentino study who had disease progression and received at least one dose of post-progression therapy. The Kaplan–Meier method and Cox proportional hazards regression were used for the survival analysis. When comparing the outcomes of anti-EGFR-based reinduction versus any second line, a propensity score–based matching was used.

Results

Liver-limited/single site of disease (P < .001 and P = .002), left-sidedness (P = .029), surgery of metastases (P = .003), early tumor shrinkage, and deeper responses (P = .018 and P = .036) were associated with the use of anti-EGFR-based reinduction versus any other second line. All patients treated with reinduction had an anti-EGFR-free interval of at least 3 months. In the propensity score–matched population, progression-free survival (PFS) was similar in the 2 treatment groups, the overall survival (OS) was significantly longer for patients treated with reinduction (P = .029), and the response rate was higher in patients treated with reinduction (P = .033). An oxaliplatin-free interval ≥12 months, left-sidedness, and molecular hyperselection beyond RAS/BRAF were associated with significantly better outcomes after anti-EGFR-based reinduction.

Conclusions

Reinduction strategies with anti-EGFR-based regimens are commonly used in clinical practice. Our data highlight the importance of clinical–molecular selection for re-treatments and the need for prospective strategy trials in selected populations.

Multi-institutional analysis of outcomes for thermosphere microwave ablation treatment of colorectal liver metastases: the SMAC study

OBJECTIVES

Oligometastatic colorectal cancer benefits of locoregional treatments but data concerning microwave ablation (MWA) are limited and interactions with systemic therapy are still debated. The aim of this study is to evaluate safety and effectiveness of Thermosphere™ MWA (T-MWA) of colorectal liver metastases (CLM) and factors affecting local tumor progression-free survival (LTPFS).

METHODS

In this multi-institutional retrospective study (January 2015-September 2019), patients who underwent T-MWA for CLM were enrolled. Complications according to SIR classification were collected, primary efficacy and LTP were calculated. Analyzed variables included CLM size at diagnosis and at ablation, CLM number, ablation margins, intra-segment progression, chemotherapy before ablation (CBA), variations in size (ΔS_DIA-ABL), and velocity of size variation (V_DIA-ABL) between CLM diagnosis and ablation. Uni/multivariate analyses were performed using mixed effects Cox model to account for the hierarchical structure of data, patient/lesions.

RESULTS

One hundred thirty-two patients with 213 CLM were evaluated. Complications were reported in 6/150 procedures (4%); no biliary complications occurred. Primary efficacy was achieved in 204/213 CLM (95.7%). LTP occurred in 58/204 CLM (28.4%). Six-, twelve-, and eighteen-month LTPFS were 88.2%, 75.8%, and 69.9%, respectively. At multivariate analysis, CLM size at ablation (p = 0.00045), CLM number (p = 0.046), ablation margin < 5 mm (p = 0.0035), and intra-segment progression (p < 0.0001) were statistically significant for LTPFS. ΔS_DIA-ABL (p = 0.63) and V_DIA-ABL (p = 0.38) did not affect LTPFS. Ablation margins in the chemo-naïve group were larger than those in the CBA group (p < 0.0001).

CONCLUSION

T-MWA is a safe and effective technology with adequate LTPFS rates. Intra-segment progression is significantly linked to LTPFS. CBA does not affect LTPFS. Anticipating ablation before chemotherapy may take the advantages of adequate tumor size with correct ablation margin planning.

KEY POINTS

• Thermosphere™-Microwave ablation is a safe and effective treatment for colorectal liver metastases with no registered biliary complications in more than 200 ablations. • Metastases size at time of ablation, intra-segment progression, and minimal ablation margin < 5 mm were found statistically significant for local tumor progression-free survival. • Chemotherapy before ablation modifies kinetics growth of the lesions but deteriorates ablation margins and does not significantly impact local tumor progression-free survival.

Italian results of the PRECONNECT study: safety and efficacy of trifluridine/tipiracil in metastatic colorectal cancer

The international PRECONNECT Phase IIIb study demonstrated safety and efficacy of trifluridine/tipiracil in the management of patients with metastatic colorectal cancer. Post-hoc analyses in a national context are important because of the differences in disease management across countries. Post-hoc safety and efficacy analyses in the PRECONNECT Italian patient subset were conducted. Patients' quality of life was assessed from baseline to end of treatment. In Italy, 161 patients were enrolled. The median age was 64 years, with a performance status of 0-1. The most common hematological drug-related adverse events ≥grade 3 were neutropenia (41.0%) and anemia (13.7%). The median progression-free survival was reached at 3.0 months, with a disease control rate of 28.6%. The Quality of Life Questionnaire Core 30 score improved in 25.4% of the patients. Safety, efficacy and quality of life results confirmed trifluridine/tipiracil as a feasible and favorable treatment option for metastatic colorectal cancer patients.

Prospective, randomised, multicentre, open-label trial, designed to evaluate the best timing of closure of the temporary ileostomy (early versus late) in patients who underwent rectal cancer resection and with indication for adjuvant chemotherapy: the STOMAD (STOMa closure before or after ADjuvant therapy) randomised controlled trial

INTRODUCTION

Temporary ileostomy is a valuable aid in reducing the severity of complications related to rectal cancer surgery. However, it is still unclear what is the best timing of its closure in relation to the feasibility of an adjuvant treatment, especially considering patient-reported outcomes and health system costs. The aim of the study is to compare the results of an early versus late closure strategy in patients with indication to adjuvant chemotherapy after resection for rectal cancer.

METHODS AND ANALYSIS

This is a prospective multicentre randomised trial, sponsored by Rete Oncologica Piemonte e Valle d'Aosta (Oncology Network of Piedmont and Aosta Valley-Italy). Patients undergone to rectal cancer surgery with temporary ileostomy, aged >18 years, without evidence of anastomotic leak and with indication to adjuvant chemotherapy will be enrolled in 28 Network centres. An early closure strategy (between 30 and 40 days from rectal surgery) will be compared with a late one (after the end of adjuvant therapy). Primary endpoint will be the compliance to adjuvant chemotherapy with and without ileostomy. Complications associated with stoma closure as well as quality of life, costs and oncological outcomes will be assessed as secondary endpoints.

ETHICS AND DISSEMINATION

The trial will engage the Network professional teams in a common effort to improve the treatment of rectal cancer by ensuring the best results in relation to the most correct use of resources. It will take into consideration both the patients' point of view (patient-reported outcome) and the health system perspective (costs analysis). The study has been approved by the Ethical Review Board of Città della Salute e della Scienza Hospital in Turin (Italy). The results of the study will be disseminated by the Network website, medical conferences and peer-reviewed scientific journals.

TRIAL REGISTRATION NUMBER

NCT04372992.

The Added Value of Baseline Circulating Tumor DNA Profiling in Patients with Molecularly Hyperselected, Left-sided Metastatic Colorectal Cancer

PURPOSE

The routine use of liquid biopsy is not recommended for the choice of initial treatment for patients with metastatic colorectal cancer (mCRC).

EXPERIMENTAL DESIGN

We included patients with left-sided, RAS/BRAF wild-type, HER2-negative, and microsatellite stable mCRC, treated with upfront panitumumab/FOLFOX-4 in the Valentino study. We performed amplicon-based genomic profiling of 14 genes in baseline plasma samples and compared these data with tumor tissue ultra-deep sequencing results. Specific gene mutations in circulating tumor DNA (ctDNA) and their clonality were associated with progression-free survival (PFS), overall survival (OS), and radiological dynamics.

RESULTS

Ten and 15 of 120 patients had a mutation of RAS and PIK3CA in ctDNA, with a positive concordance with tissue deep sequencing of only 31.3% and 47.1%, respectively. Presence of RAS or PIK3CA mutations in baseline ctDNA was associated with worse median PFS [8 vs. 12.8 months; HR, 2.49; 95% confidence interval (CI), 1.28-4.81; P = 0.007 and 8.5 vs. 12.9 months; HR, 2.86; 95% CI, 1.63-5.04; P < 0.001] and median OS (17.1 vs. 36.5 months; HR, 2.26; 95% CI, 1.03-4.96; P = 0.042 and 21.1 vs. 38.9 months; HR, 2.18; 95% CI, 1.16-4.07; P = 0.015). RAS mutations in ctDNA were associated with worse RECIST response, early tumor shrinkage, and depth of response, while PIK3CA mutations were not. Patients with higher levels of RAS/PIK3CA variant allele fraction (VAF) in ctDNA had the worst outcomes (VAF ≥ 5% vs. all wild-type: median PFS, 7.7 vs. 13.1 months; HR, 4.02; 95% CI, 2.03-7.95; P < 0.001 and median OS, 18.8 vs. 38.9 months; HR, 4.07; 95% CI, 2.04-8.12; P < 0.001).

CONCLUSIONS

Baseline ctDNA profiling may add value to tumor tissue testing to refine the molecular hyperselection of patients with mCRC for upfront anti-EGFR-based strategies.

Response shift in health-related quality of life measures in the presence of formative indicators

Background

Response shift (RS) has been defined as a change in the meaning of an individual’s self-evaluation that needs to be accounted for when assessing longitudinal changes in health-related quality of life (HRQoL). RS detection through structural equation modeling is accomplished by adopting Oort’s procedure based on a measurement model in which the observed variables are defined as reflective indicators of the HRQoL latent variable; that is, the latent variable causes the variation in the reflective indicators. This study aims to propose a procedure that assesses RS when formative indicators are used in measuring HRQoL; in this last case, the latent variable is considered to be a function of some formative indicators. A secondary aim is to compare the new procedure with Oort’s procedure to highlight similarities and differences.

Methods

The data were retrieved from a consecutive series of 258 patients newly diagnosed with colorectal cancer and undergoing chemotherapy and/or surgery. The European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QOL-C30) was administered twice, once before and once six months after treatment. Structural equation modeling was used to evaluate RS and true change with the newly proposed method (in which fatigue and pain were defined as formative indicators) and with Oort’s procedure (in which fatigue and pain were defined as reflective indicators).

Results

According to the new procedure, there was no measurement bias, and on average, patients’ quality of life improved by 3.53 points (on a scale ranging from 0 to 100) at the 6-month follow-up. With Oort’s procedure, the loading of the pain indicator was not invariant across the two time points, suggesting the presence of reprioritization, whereas the estimation of true change was very similar to the previous one: 3.87.

Conclusions

RS and true change in HRQoL can be evaluated in the presence of formative indicators. Defining a measurement model by formative or reflective indicators can lead to different results.

Systemic doxycycline for pre-emptive treatment of anti-EGFR-related skin toxicity in patients with metastatic colorectal cancer receiving first-line panitumumab-based therapy: a post hoc analysis of the Valentino study

INTRODUCTION

The combination of anti-EGFRs and doublet chemotherapy is considered the optimal upfront option for patients with RAS/BRAF wild-type left-sided metastatic colorectal cancer (mCRC). The prophylactic or reactive treatment with tetracyclines for EGFR inhibitor-induced skin toxicity is currently clinical practice, though non-conclusive results are available.

METHODS

We performed a post hoc analysis of the Valentino study that randomized RAS wild-type mCRC patients to two panitumumab-based maintenance regimens after the first-line induction, aimed at assessing the safety and efficacy of the administration of a pre-emptive doxycycline prophylaxis for anti-EGFR-related skin toxicity. We assessed the rate of treatment-related and panitumumab-related adverse events (AEs), treatment intensity, progression-free survival (PFS), and overall survival (OS).

RESULTS

A total of 226 patients, out of the 229 enrolled in the Valentino study, were eligible for the analysis. Overall, 143 (63%) and 83 (37%) patients received or not the antibiotic prophylaxis for skin toxicity. Any grade and G3/4 panitumumab-related AEs were reported in 89% versus 92% (p = 0.650) and 27% versus 27% (p = 1.000) patients who received or not the pre-emptive prophylaxis, respectively. Any grade and G3/4 skin rash occurred in 81% versus 90% (p = 0.085) and 27% versus 25% (p = 0.876) patients receiving or not the prophylaxis, respectively. No significant differences in terms of treatment duration, treatment delays or dose reductions, PFS, and OS were observed in the two sub-populations.

CONCLUSION

The adequate management of anti-EGFR-related skin toxicity is fundamental to optimize the outcome of mCRC patients, balancing the survival benefit with patients' quality of life, especially in the first-line setting.

Metastatic colorectal cancer prior to expanded RAS assessment: evidence from long-term outcome analysis of a real-life cohort within a dedicated colorectal cancer unit

BACKGROUND

Molecular assessment and treatment of metastatic colorectal cancer (mCRC) quickly evolved during the last decades, hampering longitudinal evaluation of prognostic markers. The aim of this study was to evaluate prognostic predictors of long-term survival in a retrospective series of mCRC, treated prior to the expanded RAS assessment era.

METHODS

mCRC cases treated at the Città della Salute e della Scienza University Hospital (Turin, Italy) between January 2004 and December 2012 were evaluated, including cases with ≥ 5-year follow-up only. Long-term survival was defined as an overall survival (OS) ≥ 4 years based on the observed OS interquartile range values. Univariate/multivariate Cox proportional hazards regression models were performed to assess the prognostic significance of the clinical/biological features, while binary logistic regression models were used to verify their associations with long-term survival.

RESULTS

Two hundred and forty-eight mCRC cases were included and analyzed. Sixty out of two hundred and forty-eight (24%) patients were long-term survivors. Univariate binary logistic regression analysis demonstrated a significant association between long-term survival and age at diagnosis < 65 (OR = 2.28, p = 0.007), single metastatic site (OR = 1.89, p = 0.039), surgical resection of metastases (OR = 5.30, p < 0.001), local non-surgical treatment of metastases (OR = 4.74, p < 0.001), and a bevacizumab-including first-line treatment schedule (OR = 2.19, p = 0.024). Multivariate binary logistic regression analysis confirmed the prognostic significance of surgical resection of metastases (OR = 3.96, p < 0.001), local non-surgical treatment of metastases (OR = 3.32, p = 0.001), and of bevacizumab-including first-line treatment schedule (OR = 2.49, p = 0.024).

CONCLUSION

Long-term survival could be achieved in a significant rate of patients with mCRC even in an era of limited molecular characterization. Local treatment of metastases proved to be a significant predictor of long-term survival.

Tailoring chemotherapy supply according to patients' preferences: a quantitative method in colorectal cancer care

Objectives: The aim of this study was to conduct a discrete choice experiment with patients affected by colorectal cancer to understand their preferences for different attributes of the chemotherapy supply. Our overall goal is to provide evidence on the relative importance of each attribute in order to tailor chemotherapy supply according to patients' priorities in the design or reorganization processes of cancer services.Methods: Focus groups were used to identify the attributes and levels for the discrete choice experiment. The attributes were: continuity of care, understanding, information, treatment choice, and time for therapy. Respondents were asked to choose between two mutually exclusive hypothetical alternatives of chemotherapy supply. Patients completed the discrete choice experiment along with the health-related quality of life and patients' satisfaction questions. Conditional and mixed logistic models were used to analyses the data.Results: Patients with colorectal cancer treated with chemotherapy (n = 76) completed the survey. The most important aspects of chemotherapy supply were: "Providing detailed and complete information" and "High ability in understanding" patients. Preferences were also influenced by the availability of a trusted doctor. Except for one attribute (waiting time for therapy), all other characteristics significantly influenced respondents' preferences.Conclusions: Results should support a policy of strengthening medical doctors' capabilities to communicate with patients, providing them complete information and involving them in the clinical decisions. Specifically, the findings should be used to improve the current provision of cancer care by identifying areas of preferred intervention from the perspectives of patients in order to tailor the service supply accordingly.

Prognostic and predictive role of neutrophil/lymphocytes ratio in metastatic colorectal cancer: a retrospective analysis of the TRIBE study by GONO

Background

Neutrophil/lymphocyte ratio (NLR), defined as absolute neutrophils count divided by absolute lymphocytes count, has been reported as poor prognostic factor in several neoplastic diseases but only a few data are available about unresectable metastatic colorectal cancer (mCRC) patients (pts). The aim of our study was to evaluate the prognostic and predictive role of NLR in the TRIBE trial.

Patients and methods

Pts enrolled in TRIBE trial were included. TRIBE is a multicentre phase III trial randomizing unresectable and previously untreated mCRC pts to receive FOLFOXIRI or FOLFIRI plus bevacizumab. A cut-off value of 3 was adopted to discriminate pts with low (NLR < 3) versus high (NLR ≥ 3) NLR, as primary analysis. As secondary analysis, NLR was treated as an ordinal variable with three levels based on terciles distribution.

Results

NLR at baseline was available for 413 patients. After multiple imputation at univariate analysis, patients with high NLR had significantly shorter progression-free survival (PFS) [hazard ratio (HR) 1.27 (95% CI 1.05-1.55), P = 0.017] and overall survival (OS) [HR 1.56 (95% CI 1.25-1.95), P < 0.001] than patients with low NLR. In the multivariable model, NLR retained a significant association with OS [HR 1.44 (95% CI 1.14-1.82), P = 0.014] but not with PFS [HR 1.18 (95% CI 0.95-1.46), P = 0.375]. No interaction effect between treatment arm and NLR was evident in terms of PFS (P for interaction = 0.536) or OS (P for interaction = 0.831). Patients with low [HR 0.84 (95% CI 0.64-1.08)] and high [HR 0.73 (95% CI 0.54-0.97)] NLR achieved similar PFS benefit from the triplet and consistent results were obtained in terms of OS [HR 0.83 (95% CI 0.62-1.12) for low NLR; HR 0.82 (95% CI 0.59-1.12) for high NLR].

Conclusion

This study confirmed the prognostic role of NLR in mCRC pts treated with bevacizumab plus chemotherapy in the first line, showing the worse prognosis of pts with high NLR. The advantage of the triplet is independent of NLR at baseline.

Negative Hyperselection of Patients With RAS and BRAF Wild-Type Metastatic Colorectal Cancer Who Received Panitumumab-Based Maintenance Therapy

PURPOSE

We assessed the prognostic/predictive role of primary tumor sidedness and uncommon alterations of anti-epidermal growth factor receptor (EGFR) primary resistance (primary resistance in RAS and BRAF wild-type metastatic colorectal cancer patients treated with anti-EGFR monoclonal antibodies [PRESSING] panel) in patients with RAS/BRAF wild-type (wt) metastatic colorectal cancer (mCRC) who were randomly assigned to panitumumab plus fluorouracil, leucovorin, and oxaliplatin (FOLFOX-4) induction followed by maintenance with panitumumab with or without fluorouracil (FU) plus leucovorin (LV); Valentino trial (ClinicalTrials.gov identifier: NCT02476045).

PATIENTS AND METHODS

This prespecified retrospective analysis included 199 evaluable patients with RAS/BRAF wt. The PRESSING panel included the following: immunohistochemistry (IHC) and in situ hybridization for HER2/MET amplification, IHC with or without RNA sequencing for ALK/ROS1/NTRKs/RET fusions, next-generation sequencing for HER2/PIK3CAex.20/PTEN/AKT1 and RAS mutations with low mutant allele fraction, and multiplex polymerase chain reaction for microsatellite instability. PRESSING status (any positive biomarker v all negative) and sidedness were correlated with overall response rate (ORR), progression-free survival (PFS), and overall survival (OS) in the study population and by treatment arm.

RESULTS

Overall, left- and right-sided tumors were 85.4% and 14.6%, respectively, and PRESSING-negative and -positive tumors were 75.4% and 24.6%, respectively. At a median follow-up of 26 months, inferior outcomes were consistently observed in right- versus left-sided tumors for ORR (55.2% v 74.1%; P = .037), PFS (8.4 v 11.5 months; P = .026), and OS (2-year rate: 50.2% v 65.1%; P = .062). Similar results were observed in the PRESSING-positive versus PRESSING-negative subgroup for ORR (59.2% v 75.3%; P = .030), PFS (7.7 v 12.1 months; P < .001), and OS (2-year rate: 48.1% v 68.1%; P = .021). The PFS benefit of FU plus LV added to panitumumab maintenance, reported in the study, was independent from sidedness and PRESSING status (interaction for PFS P = .293 and .127, respectively). However, outcomes were extremely poor in patients who received single-agent panitumumab and had right-sided tumors (median PFS, 7.7 months; 2-year OS, 38.5%) or PRESSING-positive tumors (median PFS, 7.4 months; 2-year OS, 47.0%).

CONCLUSION

The combined assessment of sidedness and molecular alterations of anti-EGFR primary resistance identified a consistent proportion of patients with RAS/BRAF-wt mCRC who had inferior benefit from initial anti-EGFR-based regimens, particularly after maintenance with single-agent anti-EGFRs.

HER2 Positivity Predicts Unresponsiveness to EGFR-Targeted Treatment in Metastatic Colorectal Cancer

BACKGROUND

HER2 amplification is detected in 3% of patients with colorectal cancer (CRC), making tumors in the metastatic setting vulnerable to double pharmacological HER2 blockade. Preclinical findings show that it also might impair response to anti-epidermal growth factor receptor (EGFR) treatment.

SUBJECTS AND METHODS

Patients with KRAS exon 2 wild-type metastatic CRC underwent molecular screening of HER2 positivity by HERACLES criteria (immunohistochemistry 3+ or 2+ in ≥50% of cells, confirmed by fluorescence in situ hybridization). A sample of consecutive HER2-negative patients was selected as control. A regression modeling strategy was applied to identify predictors explaining the bulk of HER2 positivity and the association with response to previous anti-EGFR treatment.

RESULTS

From August 2012 to April 2018, a total of 100 HER2-positive metastatic CRC tumors were detected out of 1,485 KRAS exon 2 wild-type screened patients (6.7%). HER2-positive patients show more frequently lung metastases (odds ratio [OR], 2.04; 95% confidence interval [CI], 1.15-3.61; p = .014) and higher tumor burden (OR, 1.48; 95% CI, 1.10-2.01; p = .011), and tumors were more likely to be left sided (OR, 0.50; 95% CI, 0.22-1.11; p = .088). HER2-positive patients who received treatment with anti-EGFR agents (n = 79) showed poorer outcome (objective response rate, 31.2% vs. 46.9%, p = .031; progression-free survival, 5.7 months vs. 7 months, p = .087).

CONCLUSION

Testing for HER2 should be offered to all patients with metastatic CRC because the occurrence of this biomarker is unlikely to be predicted based on main clinicopathological features. Patients with HER2-amplified metastatic CRC are less likely to respond to anti-EGFR therapy.

IMPLICATIONS FOR PRACTICE

Patients with HER2-amplified/overexpressed metastatic colorectal cancer (mCRC) harbor a driver actionable molecular alteration that has been shown in preclinical models to hamper efficacy of the anti-epidermal growth factor receptor (EGFR) targeted therapies. The present study confirmed that this molecular feature was associated with worse objective tumor response and shorter progression-free survival in response to previous anti-EGFR therapies. Moreover, it was found that the occurrence of this biomarker is unlikely to be predicted based on main clinicopathological features. Therefore, HER2 status assessment should be included in the molecular diagnostic workup of all mCRC for speedy referral to clinical trials encompassing HER2-targeted double blockade independently of previous anti-EGFR treatment.

Maintenance Therapy With Panitumumab Alone vs Panitumumab Plus Fluorouracil-Leucovorin in Patients With RAS Wild-Type Metastatic Colorectal Cancer: A Phase 2 Randomized Clinical Trial

Importance

Few studies are available on the role of maintenance strategies after induction treatment regimens based on anti-epidermal growth factor receptors, and the optimal regimen for an anti-epidermal growth factor receptors-based maintenance treatment in patients with RAS wild-type metastatic colorectal cancer is still to be defined.

Objective

To determine whether maintenance therapy with single-agent panitumumab was noninferior to panitumumab plus fluorouracil and leucovorin after a 4-month induction treatment regimen.

Design, Setting, and Participants

This open-label, randomized phase 2 noninferiority trial was conducted from July 7, 2015, through October 27, 2017, at multiple Italian centers. Patients with RAS wild-type, unresectable metastatic colorectal adenocarcinoma who had not received previous treatment for metastatic disease were eligible. Induction therapy consisted of panitumumab plus FOLFOX-4 (panitumumab, 6 mg/kg, oxaliplatin, 85 mg/m2 at day 1, leucovorin calcium, 200 mg/m2, and fluorouracil, 400-mg/m2 bolus, followed by 600-mg/m2 continuous 24-hour infusion at days 1 and 2, every 2 weeks). Cutoff date for analyses was July 30, 2018.

Interventions

Patients were randomized (1:1) to first-line panitumumab plus FOLFOX-4 for 8 cycles followed by maintenance therapy with panitumumab plus fluorouracil-leucovorin (arm A) or panitumumab (arm B) until progressive disease, unacceptable toxic effects, or consent withdrawal. The minimization method was used to stratify randomization by previous adjuvant treatment and number of metastatic sites.

Main Outcomes and Measures

The prespecified primary end point was 10-month progression-free survival (PFS) analyzed on an intention-to-treat basis with a noninferiority margin of 1.515 for the upper limit of the 1-sided 90% CI of the hazard ratio (HR) of arm B vs A.

Results

Overall, 229 patients (153 male [66.8%]; median age, 64 years [interquartile range (IQR), 56-70 years]) were randomly assigned to arm A (n = 117) or arm B (n = 112). At a median follow-up of 18.0 months (IQR, 13.1-23.3 months]), a total of 169 disease progression or death events occurred. Arm B was inferior (upper limit of 1-sided 90% CI of the HR, 1.857). Ten-month PFS was 59.9% (95% CI, 51.5%-69.8%) in arm A vs 49.0% (95% CI, 40.5%-59.4%) in arm B (HR, 1.51; 95% CI, 1.11-2.07; P = .01). During maintenance, arm A had a higher incidence of grade 3 or greater treatment-related adverse events (36 [42.4%] vs 16 [20.3%]) and panitumumab-related adverse events (27 [31.8%] vs 13 [16.4%]), compared with arm B.

Conclusions and Relevance

In patients with RAS wild-type metastatic colorectal cancer, maintenance therapy with single-agent panitumumab was inferior in terms of PFS compared with panitumumab plus fluorouracil-leucovorin, which slightly increased the treatment toxic effects.

Trial Registration

ClinicalTrials.gov identifier: NCT02476045.

Discovery of methylated circulating DNA biomarkers for comprehensive non-invasive monitoring of treatment response in metastatic colorectal cancer

OBJECTIVE

Mutations in cell-free circulating DNA (cfDNA) have been studied for tracking disease relapse in colorectal cancer (CRC). This approach requires personalised assay design due to the lack of universally mutated genes. In contrast, early methylation alterations are restricted to defined genomic loci allowing comprehensive assay design for population studies. Our objective was to identify cancer-specific methylated biomarkers which could be measured longitudinally in cfDNA (liquid biopsy) to monitor therapeutic outcome in patients with metastatic CRC (mCRC).

DESIGN

Genome-wide methylation microarrays of CRC cell lines (n=149) identified five cancer-specific methylated loci (EYA4, GRIA4, ITGA4, MAP3K14-AS1, MSC). Digital PCR assays were employed to measure methylation of these genes in tumour tissue DNA (n=82) and cfDNA from patients with mCRC (n=182). Plasma longitudinal assessment was performed in a patient subset treated with chemotherapy or targeted therapy.

RESULTS

Methylation in at least one marker was detected in all tumour tissue samples and in 156 mCRC patient cfDNA samples (85.7%). Plasma marker prevalence was 71.4% for EYA4, 68.5% for GRIA4, 69.7% for ITGA4, 69.1% for MAP3K14-AS1% and 65.1% for MSC. Dynamics of methylation markers was not affected by treatment type and correlated with objective tumour response and progression-free survival.

CONCLUSION

This five-gene methylation panel can be used to circumvent the absence of patient-specific mutations for monitoring tumour burden dynamics in liquid biopsy under different therapeutic regimens. This method might be proposed for assessing pharmacodynamics in clinical trials or when conventional imaging has limitations.

Dose to Pelvic Bone Marrow Defined with FDG-PET Predicts for Hematologic Nadirs in Anal Cancer Patients Treated with Concurrent Chemo-radiation

PURPOSE

To investigate whether irradiated volume of pelvic active bone marrow (^ACTBM) may predict decreased blood cells nadirs in anal cancer patients undergoing concurrent chemo-radiation.

METHODS

Forty-four patients were analyzed and pelvic active bone marrow (^ACTBM) was characterized employing ¹⁸FDG-PET. Dosimetric parameters on dose-volume histograms were correlated to nadirs with generalized linear modeling.

RESULTS

^ACTBM mean dose was significantly correlated to white blood cell (β = -1.338; 95%CI: -2.455/-0.221; p = 0.020), absolute neutrophil count (β = -1.651; 95%CI: -3.284/-0.183; p = 0.048), and platelets (β = -0.031; 95%CI: -0.057/-0.004; p = 0.024) nadirs. Other dosimetric parameters were found to be correlated (^ACTBM-V_10,-V_20,-V₃₀and-V₄₀).

CONCLUSIONS

¹⁸FDG-PET is able to define active bone marrow and may predict for decreased blood cells count nadirs.

Hemolytic uremic syndrome induced by infusion of oxaliplatin: A case report

Introduction

Oxaliplatin is a third-generation platinum compound with proven antitumor activity in the treatment of colorectal cancer. The occurrence of life-threating hemolitic uremic syndrome has been observed after oxaliplatin therapy. The kind of tumor and treatment modalities seem to influence the onset of hemolitic uremic syndrome.

Methods

The clinical course of the case is reviewed and compared with reports of other similar cases in the literature.

Results

We describe the development of hemolitic uremic syndrome as a result of prolonged oxaliplatin treatment of a colon cancer patient.

Conclusions

Although this rare event requires the concurrence of other unknown factors, it should be considered in a decision-making setting.

Abstract A089: Exploiting clonal evolution and liquid biopsy to overcome resistance to anti-EGFR treatment in metastatic colorectal cancer: the CHRONOS trial

Background: The EGFR-targeted antibodies cetuximab and panitumumab (MAB-EGFRs) are used for the treatment of RAS-axis wild-type metastatic colorectal cancer (mCRC). Unfortunately, acquired resistance to MAB-EGFRs inevitably develops, dramatically curtailing their clinical use (Misale et al., Cancer Discov 2014). We found that mutations in KRAS, NRAS, and BRAF are the main culprit of this acquired resistance, and that high ctDNA levels of these mutated genes can be found in plasma of progressing patients. However, in preclinical models made resistant to cetuximab, acquired RAS-axis mutated clones decay upon cetuximab withdrawal, allowing tumor cells to regain sensitivity to further anti-EGFR treatment. Paralleling this behavior, RAS-axis WT patients who occasionally benefited from a rechallenge treatment with MAB-EGFRs exhibited corresponding pulsatile levels of mutant RAS ctDNA (Siravegna et al., Nat Med 2015). Collectively, these results suggest that the CRC genome adapts dynamically to intermittent MAB-EGFRs schedules, and provide a molecular rational for rechallenge therapies based on EGFR blockade. Methodology: CHRONOS is a liquid biopsy-driven trial to assess the efficacy of rechallenging with panitumumab (PAN) mCRC patients with ct-DNA-proven RAS-mediated acquired resistance. CHRONOS patients’ selection is based on a progressive enrichment strategy. In the SCREENING phase, multiple wild-type patients [MWTP, i.e., patients not harboring any drivers of resistance to MAB-EGFRs at tumor level (Bertotti et al., Nature 2015)] are identified upfront with a multiplex mCRC-specific tissue-genotyping panel (FUNNEL). In the MOLECULAR phase, MWTP responding to a 1st-line treatment inclusive of MAB-EGFR and developing RAS-mutated ctDNA clones at progression (PD), start 2nd-line chemotherapy and are blood monitored for RAS-related clones' decay. MWTP experiencing a &gt;50% drop in ctDNA RAS levels at 2nd-line PD enter the TRIAL phase and are rechallenged with PAN. The main endpoint is objective response (OR), aiming to achieve a 30% OR rate. 129 MWTP responding and progressing to 1st-line MAB-EGFR-based therapy will be blood-monitored from first to second PD. We expect to find detectable (&gt;3 MAF) ctDNA RAS mutated clones in 80% of cases (N 36), decaying &gt;50% during 2nd-line "EGFR-therapy holiday" (60% of cases). These “ctDNA eligible” patients will receive PAN at 6 mg/kg Q2 weeks until PD or unacceptable toxicity. 27 MWTP will be recruited in TRIAL phase with 6 responses necessary to declare the study positive (β 0.15; α 0.05). Liquid biopsy will be used to correlate the decay kinetics of RAS-extended clone(s) during MAB-EGFR treatment holiday with response to PAN rechallenge, and to link the blood presence of RAS-extended clone(s) during PAN treatment with response and its duration. The tumor ctDNA plasma will be analysed by NGS before and after PAN rechallenge and potential associations identified between different mutated ctDNA clones (RAS or others) and response to PAN rechallenge. Conclusion: This is the 1st trial in mCRC exploiting liquid biopsy and the clonal evolution of tumor cell under treatment pressure, to extend the use of anti-EGFR therapy beyond the point of clinically established resistance in mCRC. (NCT03227926.) Funded by AIRC grant #9970.

Citation Format: Salvatore Siena, Alberto Bardelli, Andrea Sartore-Bianchi, Sara Lonardi, Francesco Leone, Francesca Bergamo, Giuseppe Tonini, Filippo De Braud, Filippo Pietrantonio, Lorenza Rimassa, Armando Santoro, Giulia Siravegna, Benedetta Mussolin, Francesco Rua, Erica Francesca Bonazzina, Alessio Amatu, Patrizia Racca, Andrea Ardizzoni, Vittorina Zagonel, Silvia Marsoni. Exploiting clonal evolution and liquid biopsy to overcome resistance to anti-EGFR treatment in metastatic colorectal cancer: the CHRONOS trial [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A089.

Abstract A087: Empowering precision medicine in metastatic colorectal cancer: preliminary results from the FUNNEL platform

Background: Metastatic colorectal cancer still has a dismal 5-yr survival of less than 10%. Chemotherapy, targeted therapies, and immune-checkpoint inhibitors are effective in only a fraction of patients, and even in responders, long-term remission are rare. To harness insight into the evolving heterogeneity of mCRC, and to combat it therapeutically, we have established the logistic research matrix FUNNEL that integrates the topographic acquisition of patient samples with the clinical validation of hypothesis-driven trials in primary or secondary resistance disease. Methods: FUNNEL will follow 1000 sequential cases from diagnosis to death, acquiring biologic specimens, imaging, and clinical data at critical steps along the disease continuum. At diagnosis of metastatic disease, patients are genotyped with a CRC-specific panel designed to map the landscape of primary resistance to anti-EGFR therapies (Bertotti A. et al,, Nature 2015). Paraffin samples are centrally processed and tested using Sequenom® (with a 5% detection sensitivity for 168 mutations in KRAS, BRAF, NRAS, PIK3CA, EGFR, HER2, IDH1, MEK1) and NanoString® technologies [measuring gene copy number variation (CNV) for RAF1, EGFR, FGRF1/2/3, HER2, IGF1/2, IGF1R, KRAS, MET, and NF1]. Genes are considered amplified with a CNV ≥ 10 cut-off validated by FISH. Dynamic data of centralized disease assessments imaging coupled with longitudinal liquid biopsies are also collected at significant clinical events (baseline, response to therapy, and progression of sequential treatment’s lines). Proteomics and neoantigenic profile of cancer cells in parallel with function and tumor specificity of infiltrating T cells will also be determined in retrospectively selected patients. Results: From 7/2015 to 6/2017, 428 patients have been successfully genotyped. Overall we found 52% mutated and 6% amplified tumors (2% both amplified and mutated). Of these, 81% (N 180) had a single gene mutation in KRAS (67%), BRAF (13%), PIK3CA (11%), or NRAS (9%). Remaining cases had a double gene alteration in PIK3CA (N 38) and KRAS (81%) or BRAF (7%) or NRAS (5%), or BRAF (N3: KRAS, NRAS, IDH1 ). 29% of the 24 amplified tumors showed concomitant mutations, while 16% had multiple amplifications. Interestingly, 2 out of 13 HER2-amplified tumors also harbored KRAS (G12D) and PIK3CA mutations (E542K and E545A). Conclusion: Upfront genotyping detected 44% multiple wild type and 9% patients with potentially actionable drivers including HER2, FGFR1 and 3, EGFR, MET, IGF1 and 2, and IGF1R. Two embedded trials for HER2-amplified (HERACLES - EudraCT 2012-002128-33, NCT03225937) and multiple wild type patients (CHRONOS EudraCT 2016-002597-12, NCT03227926) are ongoing. Beyond "molecular triage" purposes, FUNNEL is also building an integrated repository of lifetime clinical and molecular information, that all together will allow a comprehensive insight of mCRC clonal evolution, laying the groundwork to design further innovative trials, and, eventually, inform patient care. Funded by AIRC Grant 9970; Italian Ministry of Health grant NET-2011-02352137.

Citation Format: Cosimo Martino, Enrico Berrino, Carmine Dell'Aglio, Laura Casorzo, Mara Panero, Salvatore Siena, Andrea Sartore-Bianchi, Andrea Cassingena, Vittorina Zagonel, Sara Lonardi, Fotios Loupakis, Giuseppe Tonini, Patrizia Racca, Livio Trusolino, Andrea Bertotti, Ilaria Depetris, Antonella Balsamo, Anna Sapino, Silvia Marsoni. Empowering precision medicine in metastatic colorectal cancer: preliminary results from the FUNNEL platform [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A087.

Image-guided IMRT with simultaneous integrated boost as per RTOG 0529 for the treatment of anal cancer

AIM

To report on clinical outcomes of simultaneous integrated boost intensity-modulated radiation therapy (IMRT) and concurrent chemotherapy as per Radiation Therapy Oncology Group (RTOG) 0529 protocol in anal cancer patients.

METHODS

Clinical stage T1-T4 N0-N3 anal cancer patients were submitted to concomitant chemoradiation. Patients with cT2N0 disease were prescribed 50.4 Gy/28 fractions to the gross tumor planning target volume (PTV) and 42 Gy/28 fractions to the elective nodal PTV. Patients staged as cT3-T4/N0-N3 were given 54 Gy/30 fractions to the macroscopic anal PTV, while clinical nodes were prescribed 50.4 Gy/30 fractions if <3 cm or 54 Gy/30 fractions if ≥3 cm; elective nodal PTV was prescribed 45 Gy/30 fractions. Two cycles of concomitant 5-fluorouracil and mitomycin C were planned for all patients. Oncological outcomes, acute and late toxicity profiles and pattern of failure were reported.

RESULTS

The 3-year colostomy-free survival rate was 64% (95% CI 0.52-0.75). The 3-year local control, disease-free and overall survival rates were 69% (95% CI 0.57-0.79), 71% (95% CI 0.59-0.80) and 79% (95% CI 0.66-0.87), respectively. The cumulative incidence of colostomies was 15.1% (95% CI 8.15-23.88) at 24 months. The cumulative incidence of cancer-specific deaths was 16.4% (95% CI 8.60-26.47) at 36 months. Major acute toxicity consisted of hematological (G3-G4: 26%) and cutaneous (G3-G4: 16%) events. Only one case of ≥G3 late toxicity was documented.

CONCLUSIONS

Simultaneous integrated boost IMRT and concurrent chemotherapy as per RTOG 0529 protocol seems to be safe and feasible with consistent oncological outcomes and a mild acute and late toxicity profile in anal cancer patients.

Hematologic toxicity in anal cancer patients during combined chemo-radiation: a radiation oncologist perspective

INTRODUCTION

Hematologic toxicity is an important side effect occurring in patients affected with anal cancer, undergoing combined radio-chemotherapy, with consistent clinical meaningfulness. Areas covered: Since more than a half of bone marrow is comprised within the pelvic region, the radiation dose received by this functional compartment is crucial. Modern imaging modalities may provide a useful tool to identify bone marrow and new delivery technology may enhance the radiation oncologist's possibility to selectively spare these structures, potentially decreasing acute hematologic toxicity profile in this setting. Expert commentary: Correlation between dose to pelvic structures and acute hematologic toxicity has been studied in several oncological settings, mainly on a retrospective frame. Different dose metrics were found to be correlated including mean doses and different points within the dose-volume histogram ranging from low to medium-high doses. Several imaging modalities were used to identify bone marrow both morphological and functional. Several clinical endpoints were used. In general, accounting for bone marrow during the treatment planning process may be important to decrease the acute hematologic toxicity profile during concurrent chemo-radiation in anal cancer patients. The most appropriate strategy to address this issue need further investigation and deserve validation in a prospective clinical framework.

Recommendations for the Prophylactic Management of Skin Reactions Induced by Epidermal Growth Factor Receptor Inhibitors in Patients With Solid Tumors

: Inhibition of the epidermal growth factor receptor (EGFR) is an established treatment that extends patient survival across a variety of tumor types. EGFR inhibitors fall into two main categories: anti-EGFR monoclonal antibodies, such as cetuximab and panitumumab, and first-generation tyrosine kinase inhibitors, such as afatinib, gefitinib, and erlotinib. Skin reactions are the most common EGFR inhibitor-attributable adverse event, resulting in papulopustular (acneiform) eruptions that can be painful and debilitating, and which may potentially have a negative impact on patients' quality of life and social functioning, as well as a negative impact on treatment duration. Shortened treatment duration can, in turn, compromise antineoplastic efficacy. Similarly, appropriate management of skin reactions is dependent on their accurate grading; however, conventional means for grading skin reactions are inadequate, particularly within the context of clinical trials. Treating a skin reaction only once it occurs (reactive treatment strategies) may not be the most effective management approach; instead, prophylactic approaches may be preferable. Indeed, we support the viewpoint that prophylactic management of skin reactions should be recommended for all patients treated with EGFR inhibitors. Appropriate prophylactic management could effectively reduce the severity of skin reactions in patients treated with EGFR inhibitors and therefore has the potential to directly benefit patients and improve drug adherence. Accordingly, here we review published and still-emerging data, and provide practical and evidence-based recommendations and algorithms regarding the optimal prophylactic management of EGFR inhibitor-attributable skin reactions.

IMPLICATIONS FOR PRACTICE

Epidermal growth factor receptor (EGFR) inhibitors extend patient survival across a variety of tumor types. The most common EGFR inhibitor-attributable adverse events are skin reactions. Prophylactic-rather than reactive-management of skin reactions for all patients receiving EGFR inhibitors should be recommended because appropriate prophylaxis could effectively reduce the severity of skin reactions; thus, the derivation of highly effective prophylactic strategies has the potential to directly benefit patients. Accordingly, a review of the available data leads to practical and evidence-based recommendations and algorithms regarding the optimal prophylactic management of EGFR inhibitor-attributable skin reactions.

Lumbar-sacral bone marrow dose modeling for acute hematological toxicity in anal cancer patients treated with concurrent chemo-radiation

The aim of the study was to model acute hematologic toxicity (HT) and dose to pelvic osseous structures in anal cancer patients treated with definitive chemo-radiation (CT-RT). A total of 53 patients receiving CT-RT were analyzed. Pelvic bone marrow and corresponding subsites were contoured: ilium, lower pelvis and lumbosacral spine (LSBM). Dose-volume histograms points and mean doses were collected. Logistic regression was performed to correlate dosimetric parameters and ≥G3 HT as endpoint. Normal tissue complication probability (NTCP) was evaluated with the Lyman-Kutcher-Burman (LKB) model. Logistic regression showed a significant correlation between LSBM-mean dose and ≥G3 leukopenia (β coefficient 0.122; p = 0.030; 95% CI 0.012-0.233). According to NTCP modeling, the predicted HT probability had the following parameters: TD₅₀: 37.5 Gy, γ ₅₀: 1.15, m: 0.347. For node positive patients, TD₅₀: 35.2 Gy, γ ₅₀: 2.27, m: 0.176 were found. Node positive patients had significantly higher PBM-V₁₅ (Mean 81.1 vs. 86.7%; p = 0.04), -V₂₀ (Mean 72.7 vs. 79.9%; p = 0.01) and V₃₀ (Mean 50.2 vs. 57.3%; p = 0.03). Patients with a mean LSBM dose >32 Gy had a 1.81 (95% CI 0.81-4.0) relative risk to develop ≥G3 leukopenia. For node positive patients, those risks were 2.67 (95% CI 0.71-10). LKB modeling seems to suggest that LSBM-mean dose should be kept below 32 Gy to minimize ≥G3 HT in anal cancer patients treated with IMRT and concurrent chemotherapy. The contribution of LSBM dose in the development of HT above 25 Gy seems steeper in node positive patients.

Observational study on quality of life, safety, and effectiveness of first-line cetuximab plus chemotherapy in KRAS wild-type metastatic colorectal cancer patients: the ObservEr Study

Cetuximab improves efficacy when added to chemotherapy for metastatic colorectal cancer (mCRC). Effective management of skin reactions from cetuximab improves quality of life (QoL), and treatment compliance in clinical trials. No data are available from real‐world settings. The ObservEr observational, multicenter, prospective study evaluated QoL, the incidence of skin reactions, and management of chemotherapy plus cetuximab in first‐line for mCRC. The primary endpoint was QoL measured with the Dermatology Life Quality Index (DLQI) and EORTC QLQ‐C30. Secondary endpoints were the incidence of skin and serious adverse events, median overall and progression‐free survival, tumor response, and resection rates. Between May 2011 and November 2012, 228 patients with KRASwt mCRC were enrolled at 28 Italian centers, 225 evaluable, median age 65 years. QoL did not change during treatment and was not affected by the choice of prophylactic or reactive skin management. The incidence of cetuximab‐specific grade ≥3 skin reactions was 14%, with no grade 4/5 events. Skin reactions correlated with survival (P = 0.016), and their incidence was influenced by chemotherapy regimen (oxaliplatin vs. irinotecan—Incidence rate ratio [IRR] 1.72, P < 0.0001) and gender (male vs. female—IRR 1.38, P = 0.0008). Compliance at first postbaseline evaluation was 97.75%. Median overall survival was 23.6 months, median progression‐free survival 8.3 months. Cetuximab plus chemotherapy did not compromise QoL in the routine clinical setting when patients receive close monitoring plus prophylactic or reactive management of skin reactions. We observed the same correlation between overall survival (OS) and skin reactions reported in controlled clinical trials, also in this setting.

Dual-targeted therapy with trastuzumab and lapatinib in treatment-refractory, KRAS codon 12/13 wild-type, HER2-positive metastatic colorectal cancer (HERACLES): a proof-of-concept, multicentre, open-label, phase 2 trial

BACKGROUND

We previously found that dual HER2 blockade with trastuzumab and lapatinib led to inhibition of tumour growth in patient-derived xenografts of HER2-amplified metastatic colorectal cancer. In this study, we aimed to assess the antitumour activity of trastuzumab and lapatinib in patients with HER2-positive colorectal cancer.

METHODS

HERACLES was a proof-of-concept, multicentre, open-label, phase 2 trial done at four Italian academic cancer centres. We enrolled adult patients with KRAS exon 2 (codons 12 and 13) wild-type and HER2-positive metastatic colorectal cancer refractory to standard of care (including cetuximab or panitumumab), an Eastern Cooperative Oncology Group performance status of 0 or 1, and at least one measurable lesion. We defined HER2 positivity in tumour samples by use of immunohistochemistry and fluorescence in-situ hybridisation in accordance with our previously validated colorectal cancer-specific diagnostic criteria. Eligible patients received intravenous trastuzumab at 4 mg/kg loading dose followed by 2 mg/kg once per week, and oral lapatinib at 1000 mg per day until evidence of disease progression. The primary endpoint was the proportion of patients achieving an objective response (defined as complete response or partial response), which was assessed by independent central review in the intention-to-treat population. This trial is registered with EudraCT, number 2012-002128-33.

FINDINGS

Between Aug 27, 2012, and May 15, 2015, we screened 914 patients with KRAS exon 2 (codons 12 and 13) wild-type metastatic colorectal cancer and identified 48 (5%) patients with HER2-positive tumours, although two died before enrolment. Of these patients, 27 were eligible for the trial. All were evaluable for response. At the time of data cutoff on Oct 15, 2015, with a median follow-up of 94 weeks (IQR 51-127), eight (30%, 95% CI 14-50) of 27 patients had achieved an objective response, with one patient (4%, 95% CI -3 to 11) achieving a complete response, and seven (26%, 95% CI 9-43) achieving partial responses; 12 (44%, 95% CI 25-63) patients had stable disease. Six (22%) of 27 patients had grade 3 adverse events, which consisted of fatigue in four patients, skin rash in one patient, and increased bilirubin concentration in one patient. No grade 4 or 5 adverse events were reported. We detected no drug-related serious adverse events.

INTERPRETATION

The combination of trastuzumab and lapatinib is active and well tolerated in treatment-refractory patients with HER2-positive metastatic colorectal cancer.

FUNDING

Associazione Italiana Ricerca Cancro (AIRC), Fondazione Oncologia Niguarda Onlus, and Roche.

Locally Advanced (T3-T4 or N+) Anal Cancer Treated with Simultaneous Integrated Boost Radiotherapy and Concurrent Chemotherapy

AIM

To report on clinical outcomes of a consecutive series of locally advanced (T3-T4N0-N3) anal cancer patients treated with intensity-modulated radiotherapy (IMRT) and a simultaneous integrated boost (SIB) approach similarly to the RTOG 05-29 trial.

PATIENTS AND METHODS

A cohort of 45 patients underwent SIB-IMRT employing a schedule consisting of 54 Gy/30 fractions to the macroscopic anal planning target volume (PTV), while clinical nodes were prescribed 50.4 Gy/30 fractions if sized ≤3 cm or 54 Gy/30 fractions if >3 cm. Elective nodal PTV was prescribed 45 Gy/30 fractions. Chemotherapy was administered concurrently following the Nigro regimen. Primary end-point was colostomy-free survival (CFS). Secondary end-points were locoregional control (LRC), disease-free survival (DFS), cancer-specific survival (CSS) and overall survival (OS).

RESULTS

Median follow-up was 39.7 months. The actuarial 3-year CFS was 63.4 % (95% confidence interval (CI=44.8-77.1%). Actuarial 3-year OS and CSS were 67.7% (95%CI=48.7-80.9%) and 72.9% (95%CI=53.8-85.1%), while DFS was 55.8% (95%CI=37.5.4-70.7%). Actuarial 3-year LRC was 74.1% (95%CI=56.7-85.4%). On multivariate analysis, male sex (hazard ratio (HR)=10.9; p=0.004; 95%CI=2.2-55.5%) had a significant impact on CFS, while higher clinical stage (Stage IIIB vs. others) had borderline significance (HR=2.7; p=0.062; 95%CI=1.8-5.9%). A shorter package time (HR=0.94; p=0.007; 95%CI=0.91-0.98%) predicted for higher CFS. Maximum detected events included: skin (G3): 13%; gastrointestinal (GI) (G3): 13%; genitourinary (GU) (G2): 38%; genitalia (G2): 45%; anemia (G2): 4%; leukopenia (G3): 24%, (G4):7%; neutropenia (G3): 16%; (G4): 11%; thrombocytopenia (G3): 9%, (G4): 2%.

CONCLUSION

Our clinical results support the use of SIB-IMRT in the combined modality treatment of locally advanced anal cancer patients.

Dosimetric predictors of acute hematologic toxicity during concurrent intensity-modulated radiotherapy and chemotherapy for anal cancer

PURPOSE

This study aimed at investigating whether the irradiated volume of pelvic bone marrow (PBM) and specific subsites may predict the occurrence of acute hematologic toxicity (HT) in anal cancer patients undergoing concurrent chemo-radiation.

METHODS

50 patients, submitted to IMRT and concurrent chemotherapy, were analyzed. Several bony structures were defined on planning-CT: PBM and lumbar-sacral (LSBM), lower pelvis (LPBM) and iliac (IBM) bone marrow. On dose-volume histograms, dosimetric parameters were taken. Endpoints included white blood-cell-count (WBC), absolute-neutrophil-count (ANC), hemoglobin (Hb) and platelet nadirs and acute hematologic toxicity (HT) according to RTOG scoring scale. Generalized linear modeling was used to find correlations between dosimetric variables and blood cell nadirs, while logistic regression analysis was used to test correlation with ≥G3 HT. Receiver Operating Characteristic (ROC) curve analysis was used to evaluate the optimal cut-off points for predictive dosimetric variables with the Youden method.

RESULTS

Maximum detected acute HT comprised 38 % of ≥G3 leukopenia and 32 % of ≥G3 neutropenia. Grade 2 anemia was observed in 4 % of patients and ≥G3 thrombocytopenia in 10 %. On multivariate analysis a higher PBM-V ₂₀ was associated with lower WBC nadir. Increased LSBM-V ₄₀ was correlated with a higher likelihood to develop ≥G3 HT. A cut-off point at 41 % for LSBM-V ₄₀ was found. Patients with LSBM-V ₄₀ ≥41 % were more likely to develop ≥G3 HT (55.3 vs. 32.4 %; p < 0.01).

CONCLUSIONS

Increased low-dose to pelvic bony structures significantly predicted for WBC decrease. Medium-high dose to specific osseous subsites was associated with a higher probability of HT. LSBM-V ₄₀ was a strong predictor of ≥G3 HT. A threshold at 41 % for LSBM-V ₄₀ could be used to limit HT.

Early-stage Node-negative (T1-T2N0) Anal Cancer Treated with Simultaneous Integrated Boost Radiotherapy and Concurrent Chemotherapy

AIM

To report clinical outcomes of a consecutive series of patients with early-stage (T1-T1N0) anal cancer treated with intensity-modulated radiotherapy (IMRT) and a simultaneous integrated boost (SIB) approach similarly to the RTOG 05-29 trial.

PATIENTS AND METHODS

A cohort of 43 patients underwent SIB-IMRT employing a schedule consisting of 50.4 Gy/28 fractions to the gross tumor volume and 42 Gy/28 fractions to the elective nodal volumes for cT1N0 cases, and 54 Gy/30 fractions and 45 Gy/30 fractions to the same volumes for cT2N0 cases. Chemotherapy was administered concurrently following Nigro's regimen. The primary endpoint was colostomy-free survival (CFS). Secondary endpoints were locoregional control (LRC), disease-free (DFS), cancer-specific (CSS) and overall (OS) survival.

RESULTS

Median follow-up was 39.7 months. The actuarial 3-year CFS was 79.4% [95% confidence interval (CI)=61.4-89.7%]. Actuarial 3-year OS and CSS were 90.8% (95% CI=74.1-96.9%) and 93.8% (95% CI=77.3-98.4%), while DFS was 75.5% (95% CI=56.4-87.1%). Actuarial 3-year LRC was 86.1% (95% CI=69.6-94%). On multivariate analysis, tumor size >3 cm showed a trend towards significance in predicting CFS [hazard ratio (HR)=8.6, 95% CI=84.7-88.1%; p=0.069]. Maximum detected adverse events included: skin (G3): 18%; gastrointestinal tract (G2): 67%; genitourinary tract (G3): 3%; genitalia (G2): 30%; anemia (G2): 7%; leukopenia (G3): 26%, leukopenia (G4):7%; neutropenia (G3): 15%; neutropenia (G4): 12%; thrombocytopenia (G3): 9%.

CONCLUSION

Our clinical results support the use of SIB-IMRT in the combined modality treatment of patients with anal cancer.