Administration of cetuximab every 2 weeks in the treatment of metastatic colorectal cancer: an effective, more convenient alternative to weekly administration?

Model-informed Evidence for Clinical Non-inferiority of Every-2-Weeks Versus Standard Weekly Dosing Schedule of Cetuximab in Metastatic Colorectal Cancer

Cetuximab was initially developed and approved as a first-line treatment in patients with unresectable metastatic colorectal cancer (mCRC) for weekly administration (250 mg/m2 Q1W with 400 mg/m2 loading dose). An every-2-weeks schedule (500 mg/m2 Q2W) was approved recently by several health authorities. Being synchronized with chemotherapy, Q2W administration should improve patients' convenience and healthcare resource utilization. Herein, we present evidence of non-inferiority of Q2W cetuximab, compared with Q1W dosing using pharmacometrics modeling and clinical trial simulation (CTS). Pooled data from five phase I-III clinical trials in 852 patients with KRAS wild-type mCRC treated with Q1W or Q2W cetuximab were modeled using a population exposure-tumor size (TS) model linked to overall survival (OS); exposure was derived from a previously established population pharmacokinetic model. A semi-mechanistic TS model adapted from the Claret model incorporated killing rate proportional to cetuximab area under the concentration-time curve over 2 weeks (AUC) with Eastern Cooperative Oncology Group (ECOG) status as covariate on baseline TS. The OS was modeled with Weibull hazard using ECOG, baseline TS, primary tumor location, and predicted percent change in TS at 8 weeks as covariates. Model-based simulations revealed indistinguishable early tumor shrinkage and survival between Q2W vs. Q1W cetuximab. CTS evaluated OS non-inferiority (predefined margin of 1.25) in 1,000 trials, each with 2,000 virtual patients receiving Q2W or Q1W cetuximab (1:1), and demonstrated non-inferiority in 94% of cases. Taken together, these analyses provide model-based evidence for clinical non-inferiority of Q2W vs. Q1W cetuximab in mCRC with potential benefits to patients and healthcare providers.

Efficacy and safety of the combination of encorafenib/cetuximab with or without binimetinib in patients with BRAF V600E-mutated metastatic colorectal cancer: an AGEO real-world multicenter study

BACKGROUND

The combination of encorafenib with cetuximab has become the standard of care in patients with BRAF V600E-mutated metastatic colorectal cancer (mCRC) after a prior systemic therapy. This study aims to describe the efficacy and safety of encorafenib/cetuximab +/- binimetinib in patients with BRAF V600E-mutated mCRC in a real-world setting.

PATIENTS AND METHODS

This retrospective study included patients with BRAF V600E-mutated mCRC who received this combination from January 2020 to June 2022 in 30 centers.

RESULTS

A total of 201 patients were included, with 55% of women, a median age of 62 years, and an Eastern Cooperative Oncology Group performance status (ECOG-PS) >1 in 20% of cases. The main tumor characteristics were 60% of right-sided primary tumor, 11% of microsatellite instability/mismatch repair deficient phenotype, and liver and peritoneum being the two main metastatic sites (57% and 51%). Encorafenib/cetuximab +/- binimetinib was prescribed in the first, second, third, and beyond third line in 4%, 56%, 29%, and 11%, respectively, of cases, with the encorafenib/cetuximab/binimetinib combination for 21 patients (10%). With encorafenib/cetuximab treatment, 21% of patients experienced grade ≥3 adverse events (AEs), with each type of grade ≥3 AE observed in <5% of patients. The objective response rate was 32.2% and the disease control rate (DCR) was 71.2%. The median progression-free survival (PFS) was 4.5 months [95% confidence interval (CI) 3.9-5.4 months] and the median overall survival (OS) was 9.2 months (95% CI 7.8-10.8 months). In multivariable analysis, factors associated with a shorter PFS were synchronous metastases [hazard ratio (HR) 1.66, P = 0.04] and ECOG-PS >1 (HR 1.88, P = 0.007), and those associated with a shorter OS were the same factors (HR 1.71, P = 0.03 and HR 2.36, P < 0.001, respectively) in addition to treatment beyond the second line (HR 1.74, P = 0.003) and high carcinoembryonic antigen level (HR 1.72, P = 0.003).

CONCLUSION

This real-world study showed that in patients with BRAF V600E-mutated mCRC treated with encorafenib/cetuximab +/- binimetinib, efficacy and safety data confirm those reported in the BEACON registration trial. The main poor prognostic factors for this treatment are synchronous metastases and ECOG-PS >1.

Universal CAR 2.0 to overcome current limitations in CAR therapy

Chimeric antigen receptor (CAR) T cell therapy has effectively complemented the treatment of advanced relapsed and refractory hematological cancers. The remarkable achievements of CD19- and BCMA-CAR T therapies have raised high expectations within the fields of hematology and oncology. These groundbreaking successes are propelling a collective aspiration to extend the reach of CAR therapies beyond B-lineage malignancies. Advanced CAR technologies have created a momentum to surmount the limitations of conventional CAR concepts. Most importantly, innovations that enable combinatorial targeting to address target antigen heterogeneity, using versatile adapter CAR concepts in conjunction with recent transformative next-generation CAR design, offer the promise to overcome both the bottleneck associated with CAR manufacturing and patient-individualized treatment regimens. In this comprehensive review, we delineate the fundamental prerequisites, navigate through pivotal challenges, and elucidate strategic approaches, all aimed at paving the way for the future establishment of multitargeted immunotherapies using universal CAR technologies.

A phase II trial of paclitaxel plus biweekly cetuximab for patients with recurrent or metastatic head and neck cancer previously treated with both platinum-based chemotherapy and anti-PD-1 antibody

BACKGROUND

An important unmet need for new treatment options remains for patients with recurrent or metastatic head and neck squamous cell carcinoma (R/M-HNSCC) previously treated with both platinum-based chemotherapy and anti-programmed cell death protein 1 (PD-1) antibody. Retrospective studies suggest that previous treatment with immune checkpoint inhibitor might augment the efficacy of subsequent chemotherapy. Here, we conducted a phase II trial aimed to evaluate the efficacy and safety of paclitaxel plus biweekly cetuximab for patients in this setting.

PATIENTS AND METHODS

This was a single-arm, multicenter, phase II trial. Key eligibility criteria were R/M-HNSCC, and previous treatment with both platinum-based chemotherapy and PD-1 antibody. Paclitaxel plus biweekly cetuximab consisted of weekly paclitaxel 100 mg/m2 (days 1, 8, 15) and biweekly cetuximab 500 mg/m2 (days 1, 15) with a cycle of 28 days until progression or unacceptable toxicity. Primary endpoint was objective response rate (ORR). Secondary endpoints included progression-free survival (PFS), overall survival (OS), disease control rate (DCR), and adverse events (AEs) (Common Terminology Criteria for Adverse Events version 5.0).

RESULTS

Between August 2020 and August 2022, 35 patients were enrolled, of whom 33 were assessable for response. ORR was 69.6% (95% confidence interval 51.2% to 84.4%). With a median follow-up period for survivors of 16.6 months, median PFS and OS were 5.5 and 13.3 months, respectively. DCR was 93.7%. Twenty-three patients (65%) experienced grade 3 or 4 AEs, including neutropenia (34%), infection (14%), leukopenia (11%), mucositis (8%), and pneumonitis (8%). Eight patients discontinued study treatment due to treatment-related AEs, and no treatment-related death was observed.

CONCLUSIONS

Paclitaxel plus biweekly cetuximab showed highly encouraging efficacy and manageable toxicities in R/M-HNSCC patients previously treated with both platinum-based chemotherapy and PD-1 antibody. This combination therapy warrants further investigation in this setting.

Cetuximab every 2 weeks versus standard weekly dosing administration schedule

Cetuximab every 2 weeks (Q2W) dosing schedule is approved by the US FDA and by the Japanese Pharmaceuticals and Medical Devices Agency in patients with metastatic colorectal cancer and squamous cell carcinoma of the head and neck. Phase II trials have found comparable efficacy and safety for the weekly (Q1W) and Q2W schedules, and real-world studies have shown noninferiority of the Q2W compared with the Q1W schedule. Several guidelines recommend cetuximab Q2W administration as an alternative to the Q1W dosing schedule. Cetuximab Q2W can be administered with a Q2W dose of chemotherapy, making it a more convenient option to the Q1W schedule, potentially resulting in reduced costs for administration, increased flexibility for clinical staff and improved patient adherence.

Antibody dependent cell-mediated cytotoxicity selection pressure induces diverse mechanisms of resistance

Targeted monoclonal antibody therapy has emerged as a powerful therapeutic strategy for cancer. However, only a minority of patients have durable responses and the development of resistance remains a major clinical obstacle. Antibody-dependent cell-mediated cytotoxicity (ADCC) represents a crucial therapeutic mechanism of action; however, few studies have explored ADCC resistance. Using multiple in vitro models of ADCC selection pressure, we have uncovered both shared and distinct resistance mechanisms. Persistent ADCC selection pressure yielded ADCC-resistant cells that are characterized by a loss of NK cell conjugation and this shared resistance phenotype is associated with cell-line dependent modulation of cell surface proteins that contribute to immune synapse formation and NK cell function. We employed single-cell RNA sequencing and proteomic screens to interrogate molecular mechanisms of resistance. We demonstrate that ADCC resistance involves upregulation of interferon/STAT1 and DNA damage response signaling as well as activation of the immunoproteasome. Here, we identify pathways that modulate ADCC sensitivity and report strategies to enhance ADCC-mediated elimination of cancer cells. ADCC resistance could not be reversed with combinatorial treatment approaches. Hence, our findings indicate that tumor cells utilize multiple strategies to inhibit NK cell mediated-ADCC. Future research and development of NK cell-based immunotherapies must incorporate plans to address or potentially prevent the induction of resistance.

Evaluating the Time Toxicity of Cancer Treatment in the CCTG CO.17 Trial

PURPOSE

The time spent in pursuing treatments for advanced cancer can be substantial. We have previously proposed a pragmatic and patient-centered metric of these time costs-which we term time toxicity-as any day with physical health care system contact. This includes outpatient visits (eg, bloodwork, scans, etc), emergency department visits, and overnight stays in a health care facility. Herein, we sought to assess time toxicity in a completed randomized controlled trial (RCT).

METHODS

We conducted a secondary analysis of the Canadian Cancer Trials Group CO.17 RCT that evaluated weekly cetuximab infusions versus supportive care alone in 572 patients with advanced colorectal cancer. Initial results reported a 6-week improvement in median overall survival (OS) with cetuximab (6.1 v 4.6 months). Subsequent analyses reported that benefit was restricted to patients with K-ras wild-type tumors. We calculated patient-level time toxicity by analyzing trial forms. We considered days without health care contact as home days. We compared medians of time measures across arms and stratified results by K-ras status.

RESULTS

In the overall population, median time toxic days were higher in the cetuximab arm (28 v 10, P < .001) although median home days were not statistically different between arms (140 v 121, P = .09). In patients with K-ras-mutated tumors, cetuximab was associated with almost numerically equal home days (114 days v 112 days, P = .571) and higher time toxicity (23 days v 11 days, P < .001). In patients with K-ras wild-type tumors, cetuximab was associated with more home days (186 v 132, P < .001).

CONCLUSION

This proof-of-concept feasibility study demonstrates that measures of time toxicity can be extracted through secondary analyses of RCTs. In CO.17, despite an overall OS benefit with cetuximab, home days were statistically similar across arms. Such data can supplement traditional survival end points in RCTs. Further work should refine and validate the measure prospectively.

Real-world comparison between weekly versus biweekly dosing of cetuximab for metastatic colorectal cancer

Aim: This real-world study aims to compare overall survival (OS) associated with biweekly (Q2W) versus weekly (Q1W) cetuximab dosing regimens for metastatic colorectal cancer (mCRC) treatment in the US. Methods: Adult patients with KRAS wild-type mCRC who received cetuximab ± chemotherapy from 2013 to 2019 were selected using Flatiron Health's electronic health records database. Propensity score matching was used to balance Q2W and Q1W cohorts on baseline patient characteristics. The Kaplan-Meier method was used for survival analyses. Several sensitivity analyses were conducted to assess the robustness of findings from the main analysis. Results: Of 1075 patients in the study, 60.7% received cetuximab Q1W and 39.3% Q2W. Median OS (95% confidence interval) in months was 17.2 (15.3, 18.8) for Q2W versus 14.3 (12.8, 16.0) for Q1W; p = 0.246. Similar OS between the dosing cohorts was observed in sensitivity analyses. Conclusion: Weekly and biweekly cetuximab had comparable effectiveness in this real-world study.

A phase II study of daily encorafenib in combination with biweekly cetuximab in patients with BRAF V600E mutated metastatic colorectal cancer: the NEW BEACON study

BACKGROUND

Patients with BRAF V600E mutated metastatic colorectal cancer (mCRC) have a poor prognosis. The introduction of BRAF targeted therapy with encorafenib and weekly administered cetuximab have shown improved survival with a median progression free survival (PFS) of 4.3 months. However, a regimen with cetuximab given every second week may have comparable efficacy and is more convenient for patients. While BRAF targeted therapy is a new standard therapy in pre-treated patients with BRAF V600E mutated mCRC, resistance invariably occurs and is an emerging challenge. The aim of this study is to investigate the efficacy and tolerability of cetuximab given every second week in combination with daily encorafenib and to explore the correlation between markers of resistance and outcome.

METHODS

The study is an open label, single arm, phase II study, investigating the efficacy and tolerability of cetuximab given every second week in combination with encorafenib in patients with BRAF V600E mutated mCRC. Furthermore, we will be investigating mechanisms of response and resistance against BRAF targeted therapy though comprehensive genomic profiling on tumor tissue and blood for circulating tumor DNA analysis. A total of 53 patients (19 + 34 in two steps) will be included according to Simon's optimal two stage design. The primary end point of the study is 2 months PFS rate.

DISCUSSION

By combining BRAF inhibitor with cetuximab given every second week we can halve the number of visits in the hospital compared to the currently approved regimen with weekly cetuximab. This seems particularly relevant in a group of patients with a median overall survival of 9.3 months. Resistance after initial response to targeted therapy can be either adaptive (e.g., epigenetic, or transcriptomic alterations) or acquired (selective genetic alterations - e.g., activating de novo mutations) resistance. It is of great importance to untangle these complex mechanisms of resistance in patients with BRAF V600E mutated mCRC to improve treatment strategies in the future potentially even further.

TRIAL REGISTRATION

EU Clinical Trial Register, Eudract no. 2020-003283-10 . Registered on 11 November 2020.

Pharmacokinetics and pharmacodynamics of approved monoclonal antibody therapy for colorectal cancer

INTRODUCTION

The introduction of monoclonal antibodies to the chemotherapy backbone treatment has challenged the paradigm of metastatic colorectal cancer (mCRC) treatment. Their mechanism of action and pharmacokinetics are complex but important to understand in order to improve patient selection and treatment outcomes for mCRC population.

AREAS COVERED

This review examines the scientific data, pharmacodynamics, and pharmacokinetics of approved monoclonal antibodies used to treat mCRC patients, including agents targeting signaling via VEGFR (bevacizumab and ramucirumab), EGFR (cetuximab and panitumumab), HER2/3 target therapy, and immunotherapy agents such as pembrolizumab or nivolumab. Efficacy and mechanism of action of bispecific antibodies are also covered.

EXPERT OPINION

mCRC is a heterogeneous disease and the optimal selection and sequence of treatments is challenging. Monoclonal antibodies have complex pharmacokinetics and pharmacodynamics, with important interactions between them. The arrival of bioequivalent molecules to the market increases the need for the characterization of pharmacokinetics and pharmacodynamics of classic monoclonal antibodies to reach bioequivalent novel molecules.

Biweekly administration of cetuximab in Japanese patients with recurrent or metastatic head and neck cancer

BACKGROUND

Cetuximab (Cmab) plays an important role in the treatment for recurrent or metastatic head and neck cancer (R/M HNC). To date, however, no safety data on biweekly administration of cetuximab at a dose of 500 mg/m² (biweekly Cmab) for Japanese HNC patients have been available.

METHODS

We retrospectively reviewed the clinical records of five R/M HNC patients who received biweekly Cmab in our institute between January 2016 and September 2021 and compared the safety profile between two phases of weekly 250 mg/m² and biweekly 500 mg/m² Cmab in the identical patients.

RESULTS

All patients initially received Cmab in combination with chemotherapy. Chemotherapy consisted of paclitaxel plus carboplatin in two patients, cisplatin + 5-FU in one patient, and paclitaxel in two patients. Three patients switched treatment schedule from weekly Cmab to biweekly Cmab, while two patients received biweekly Cmab after completion of chemotherapy. The main reason for switching to biweekly Cmab was an unacceptably long commuting time to the hospital. The median duration of Cmab was 217 days (49-321) during weekly Cmab with or without chemotherapy and 42 days (28-175) during biweekly Cmab. Median dose of biweekly Cmab was 4 (3-12). During biweekly Cmab, worsened (Grade ≥ 2) toxicities were observed in two patients: one with grade 2 dry skin and the second with grade 2 skin infection. None developed grade ≥ 3 adverse events or discontinued treatment due to Cmab-related adverse events.

CONCLUSION

Biweekly Cmab was well tolerated and did not demonstrate severe toxicities related to Cmab for R/M HNC.

The roles of epidermal growth factor receptor in viral infections

Viruses are intracellular pathogen that exploit host cellular machinery for their propagation. Extensive research on virus-host interaction have shed light on an alternative antiviral strategy that targets host cell factors. Epidermal growth factor receptor (EGFR) is a versatile signal transducer that is involved in a range of cellular processes. Numerous studies have revealed how viruses exploit the function of EGFR in different stages of viral life cycle. In general, viruses attach onto the host cell surface and interacts with EGFR to facilitate viral entry, viral replication and spread as well as evasion from host immunosurveillance. Moreover, virus-induced activation of EGFR signalling is associated with mucin expression, tissue damage and carcinogenesis that contribute to serious complications. Herein, we review our current understanding of roles of EGFR in viral infection and its potential as therapeutic target in managing viral infection. We also discuss the available EGFR-targeted therapies and their limitations.

A Phase 1b Trial of Prexasertib in Combination with Standard-of-Care Agents in Advanced or Metastatic Cancer

BACKGROUND

The checkpoint kinase 1 (CHK1) inhibitor prexasertib exhibited modest monotherapy antitumor activity in prior trials, suggesting that combination with chemotherapy or other targeted agents may be needed to maximize efficacy.

OBJECTIVES

The aim of this study was to determine the recommended phase II dose and schedule of prexasertib in combination with either cisplatin, cetuximab, pemetrexed, or 5-fluorouracil in patients with advanced and/or metastatic cancer, and to summarize preliminary antitumor activity of these combinations.

PATIENTS AND METHODS

This phase Ib, nonrandomized, open-label study comprised dose-escalation phase(s) with multiple sub-arms evaluating different prexasertib-drug combinations: Part A, prexasertib + cisplatin (n = 63); Part B, prexasertib + cetuximab (n = 41); Part C, prexasertib + pemetrexed (n = 3); Part D, prexasertib + 5-fluorouracil (n =8). Alternate dose schedules/regimens intended to mitigate toxicity and maximize dose exposure and efficacy were also explored in sub-parts.

RESULTS

In Part A, the maximum tolerated dose (MTD) of prexasertib in combination with cisplatin (75 mg/m²) was declared at 80 mg/m², with cisplatin administered on Day 1 and prexasertib on Day 2 of a 21-day cycle. The overall objective response rate (ORR) in Part A was 12.7%, and 28 of 55 evaluable patients (50.9%) had a decrease in target lesions from baseline. The most frequent treatment-related adverse events (AEs) in Part A were hematologic, with the most common being white blood cell count decreased/neutrophil count decreased, experienced by 73.0% (any grade) and 66.7% (grade 3 or higher) of patients. In Part B, an MTD of 70 mg/m² was established for prexasertib administered in combination with cetuximab (500 mg /m²), both administered on Day 1 of a 14-day cycle. The overall ORR in Part B was 4.9%, and 7 of 31 evaluable patients (22.6%) had decreased target lesions compared with baseline. White blood cell count decreased/neutrophil count decreased was also the most common treatment-related AE (56.1% any grade; 53.7% grade 3 or higher). In Parts A and B, hematologic toxicities, even with the addition of prophylactic granulocyte colony-stimulating factor, resulted in frequent dose adjustments (> 60% of patients). In Part C, evaluation of prexasertib + pemetrexed was halted due to dose-limiting toxicities in two of the first three patients; MTD was not established. In Part D, the MTD of prexasertib in combination with 5-fluorouracil (label dose) was declared at 40 mg /m², both administered on Day 1 of a 14-day cycle. In Part D, overall ORR was 12.5%.

CONCLUSIONS

This study demonstrated the proof-of-concept that prexasertib can be combined with cisplatin, cetuximab, and 5-fluorouracil. Schedule was a key determinant of the tolerability and feasibility of combining prexasertib with these standard-of-care agents. Reversible hematologic toxicity was the most frequent AE and was dose-limiting. Insights gleaned from this study will inform future combination strategies for the development of prexasertib and next-generation CHK1 inhibitors. CLINICALTRIALS.

GOV IDENTIFIER

NCT02124148 (date of registration 28 April 2014).

Modified bi-weekly cetuximab-cisplatin and 5-FU/leucovorin based regimen for effective treatment of recurrent/metastatic head and neck squamous cell carcinoma to reduce chemotherapy exposure of patients

Background

The standard chemotherapy treatment protocol for patients with recurrent/metastatic head and neck squamous cell carcinoma (HNSCC) requires as long as 56 days of hospitalization over six months. Where the 5‐Fluorouracil (5‐FU) pump is available, most treatment will be on outpatient bases, however patients will still be under chemotherapy treatment for a comparable period of time (around 50 days).

Aim

A modified protocol was assessed to decrease hospitalization and/or chemotherapy treatment time without sacrificing outcomes, to potentially increase patient quality of life.

Methods and results

A retrospective analysis (2005–2018) of recurrent/metastatic HNSCC patients with a modified treatment protocol was performed. Treatment consisted of cisplatin, cetuximab, 5‐fluorouracil bolus and leucovorin administered on day 1 of a 2‐week cycle, and a continuous infusion of 5‐fluorouracil on days 1–2 of the cycle. Outcomes were measured by progression‐free survival, overall survival, and patient hospitalization time. Analysis was done using the Kaplan–Meier survival function curve.

The study cohort consisted of 27 patients. The modified treatment protocol resulted in a median progression‐free survival of nine months and median overall survival of 14 months, while hospitalization time was reduced by almost 80% in the first six months of treatment.

Conclusions

Modification of the cisplatin, cetuximab, 5‐FU and leucovorin protocol to a bi‐weekly regimen utilizing alternative drug delivery methods, significantly reduced patient hospitalization from 56 days to 12 days in the first 6 months of treatment. This was achieved without compromising treatment outcome, while significantly reducing the days patients were exposed to chemotherapy, and thus potentially improving quality of life.

Cetuximab plus irinotecan administered biweekly with reduced infusion time to heavily pretreated patients with metastatic colorectal cancer and related RAS and BRAF mutation status

Metastatic colorectal cancer (mCRC) is treated with cetuximab 250 mg/m2 administered weekly over 1 hour or biweekly (q2w) over 3.5 hours when combined with irinotecan. This prospective study investigated cetuximab 500 mg/m2 plus irinotecan 180 mg/m2 administered q2w over 1.5 hours independent of RAS or BRAF mutation status in mCRC patients in a third-line setting. The intention-to-treat population included 181 patients. No patients had complete response, 18% had partial responses (PR) and 48% stable disease (SD). For cetuximab, a relative dose intensity of ≥90% was reached in 78% and for irinotecan in 67% of the patients. Grade 3 to 4 toxicities were pain (17%), fatigue (9%), neutropenia (8%), diarrhea (8%), rash (8%), infection (7%) and hypersensitivity (3%). No deaths occurred. Next-generation sequencing in 96.7% of the patients revealed that 50.3% had RAS and BRAFV600E wild type (WT), with a mutation type (MT) in 45.1% of the RAS and 4.4% of the BRAFV600E genes. In patients with RAS-WT and RAS-MT tumors, a PR was obtained in 32% and 4% (P = .000003) and an SD in 43% and 53%, respectively, with a superior PFS (6.2 vs 3.7 months; hazard ratio [HR] 2.12, P = .00001) and OS (12.9 vs 8.8 months; HR 1.71, P = .0008). Treatment efficacy was poor in 7.4% of patients with an RAS mutation outside KRAS exon 2 and in 38% of patients with KRAS exon 2 mutations. Administration of cetuximab and irinotecan q2w, shortening treatment time from 3.5 to 1.5 hours, is recommended as standard therapy.

Real-world healthcare resource utilization and costs of weekly versus every-2-week cetuximab in metastatic colorectal cancer

Aim: To compare healthcare resource utilization (HRU) and healthcare costs (HC) for every-2-week (Q2W) versus weekly (Q1W) cetuximab in metastatic colorectal cancer (mCRC). Patients & methods: Patients with mCRC receiving cetuximab plus chemotherapy in a line-agnostic setting. Cohort study of patients with mCRC treated with cetuximab and chemotherapy in IBM MarketScan. Analyses were weighted by inverse probability of treatment based on propensity score. Results: HRU was numerically lower with the Q2W versus Q1W regimen (weighted mean, 8.1 vs 9.5 encounters per-patient-per-month). The weighted average of HC was $17,653 and $16,469 per-patient-per-month for the Q2W and Q1W regimens, respectively; the difference between regimens decreased when restricting to CRC-related claims. Conclusion: HRU was lower and HC were similar between the Q2W and Q1W regimens.

Noninferiority of cetuximab every-2-weeks versus standard once-weekly administration schedule for the first-line treatment of RAS wild-type metastatic colorectal cancer

AIM

This study assessed whether cetuximab 500 mg/m² administered every 2 weeks (Q2W), when combined with chemotherapy as a first-line (1L) treatment, was noninferior to the approved dose (400 mg/m² followed by 250 mg/m² once weekly [Q1W]) for overall survival (OS) in adults with RAS wild-type metastatic colorectal cancer (mCRC).

METHODS

This pooled analysis included patients receiving 1L treatment with cetuximab Q1W or Q2W in combination with chemotherapy from post-authorisation studies with patient-level data available to the sponsor. Baseline characteristics were adjusted with a propensity score using inverse probability of treatment weighting (IPTW). Noninferiority in terms of OS was tested with a noninferiority margin for the hazard ratio (HR) of 1.25 using a Cox proportional hazards regression model. Secondary outcomes were progression-free survival (PFS), overall response rate (ORR) and rates of lung/liver metastases resection and serious adverse events.

RESULTS

OS time was noninferior in the Q2W cohort (n = 554) compared to the Q1W cohort (n = 763), with a HR after IPTW (95% confidence interval) of 0.827 (0.715-0.956) and median OS times of 24.7 (Q1W) and 27.9 (Q2W) months. There were no major differences in PFS (HR: 0.915 [0.804-1.042]). The odds ratios (ORs) after IPTW for ORR (1.292 [1.031-1.617]) and the rates of lung/liver metastases resection (1.419 [1.043-1.932]) favoured the Q2W regimen. No differences were noted in the occurrence rate of any SAE between groups; the OR after IPTW was 1.089 (0.858-1.382).

CONCLUSIONS

The cetuximab Q2W regimen was noninferior to the Q1W regimen for OS in the 1L treatment of mCRC.

Comparative effectiveness of weekly versus every-2-weeks cetuximab in metastatic colorectal cancer in a US-insured population

Aim: To test the noninferiority of cetuximab administered every 2 weeks (Q2W) versus once weekly (Q1W) in treating metastatic colorectal cancer (mCRC) with regard to overall survival (OS). Patients: Patients receiving cetuximab plus chemotherapy for mCRC in a line-agnostic setting. Methods: This cohort study in IBM MarketScan followed patients from initiation of cetuximab for mCRC until the end of the data availability period, proxy-based death or loss of insurance coverage for >30 days. Results: The hazard ratio for OS was 0.94 (0.85-1.03), and the inferiority hypothesis was rejected at p < 0.001. No significant differences were noted in rates of safety events between Q2W and Q1W. Conclusion: Our real-world study confirmed the noninferiority of cetuximab administered Q2W versus Q1W for OS.

Phase I Study of Ficlatuzumab and Cetuximab in Cetuximab-Resistant, Recurrent/Metastatic Head and Neck Cancer

Cetuximab, an anti-EGFR monoclonal antibody (mAb), is approved for advanced head and neck squamous cell carcinoma (HNSCC) but benefits a minority. An established tumor-intrinsic resistance mechanism is cross-talk between the EGFR and hepatocyte growth factor (HGF)/cMet pathways. Dual pathway inhibition may overcome cetuximab resistance. This Phase I study evaluated the combination of cetuximab and ficlatuzumab, an anti-HGF mAb, in patients with recurrent/metastatic HNSCC. The primary objective was to establish the recommended Phase II dose (RP2D). Secondary objectives included overall response rate (ORR), progression-free survival (PFS), and overall survival (OS). Mechanistic tumor-intrinsic and immune biomarkers were explored. Thirteen patients enrolled with no dose-limiting toxicities observed at any dose tier. Three evaluable patients were treated at Tier 1 and nine at Tier 2, which was determined to be the RP2D (cetuximab 500 mg/m² and ficlatuzumab 20 mg/kg every 2 weeks). Median PFS and OS were 5.4 (90% CI = 1.9–11.4) and 8.9 (90% CI = 2.7–15.2) months, respectively, with a confirmed ORR of 2 of 12 (17%; 90% CI = 6–40%). High circulating soluble cMet levels correlated with poor survival. An increase in peripheral T cells, particularly the CD8⁺ subset, was associated with treatment response whereas progression was associated with expansion of a distinct myeloid population. This well-tolerated combination demonstrated promising activity in cetuximab-resistant, advanced HNSCC.

Pharmacotherapeutic considerations for elderly patients with colorectal cancer

Introduction: Oncology care in the elderly presents a dilemma. The majority of cancer cases are diagnosed in the elderly yet they are underrepresented in clinical trials. In addition to limited evidence-based medicine, the elderly is a heterogeneous population filled with pharmacotherapeutic challenges and barriers. Elderly metastatic colorectal cancer (mCRC) treatment decisions encompass these challenges.Areas covered: Treatment based solely on chronological age is an unacceptable practice. Physiologic factors such as function, cognition, comorbidities, polypharmacy, among others must be considered. Oncology guidelines emphasize using a geriatric assessment (GA) as opposed to traditional oncology performance status measures to best identify risks. Our review shines light on these issues as they pertain to elderly unresectable metastatic colorectal cancer (mCRC).Expert opinion: The practical use of GA tools in oncology remain to be determined. Current barriers are the lack of a consistent tool to unify decision-making, provider education, and evidence-based use/outcomes in specific cancers. mCRC antineoplastic data surrounding GAs are scarce, and current mCRC national treatment algorithms are not stratified to encompass GA-driven therapy. Therefore, providers lack clear guidance or practicality of use. We hope mCRC trial designs will abandon age cutoffs and instead place more focus on GAs for inclusion and outcomes.

Budget impact of bimonthly use of cetuximab in patients diagnosed with metastatic colorectal cancer

Aim: Cetuximab is used for the treatment of RAS wild-type metastatic colorectal cancer patients. Standard administration schedule is once a week; however, the bioequivalence of an every-other-week (EOW) schedule was demonstrated. Methods: We compared a base case scenario of 100% weekly administration to an EOW at 50 or 100%. Medical examinations, patient management and loss of productivity were considered. Results: Base case was estimated at €100.6 million versus €92.8 million and €84.9 million of EOW 50 and 100%, which showed a cost reduction of 8 and 16%, respectively. Indirect costs accounted for 65% in both scenarios. Conclusion: The adoption of an EOW administration schedule of cetuximab reduced direct and indirect costs substantially.

Rationale and budget impact of bimonthly use of Cetuximab in patients with recurrent and/or metastatic head and neck cancer

BACKGROUND

In recurrent and/or metastatic head and neck squamous cell cancer, Cetuximab is administered once a week, followed by weekly doses. We present the clinical rationale of a different schedule of maintenance Cetuximab and we estimate the potential economic benefits on the health care budget from a societal perspective in Italy.

METHODS

A budget impact (BI) excel-based model was developed comparing a base case scenario of 100% weekly administration with a dose of 250 mg/m² to an every-other-week (EOW) administration at 50% or 100% with a dose of 500 mg/m² .

RESULTS

In the EOW, 50% scenario it was calculated a cost reduction of €347 000 of which 70% attributable to indirect costs, increasing to €694 000 after 4 months.

CONCLUSIONS

In our analysis, we showed that this simplified schedule could also reduce the costs of treatments both for the health system (direct costs) and for the society (indirect costs).

Targeted Therapies for Targeted Populations: Anti-EGFR Treatment for EGFR-Amplified Gastroesophageal Adenocarcinoma

Previous anti-EGFR trials in unselected patients with gastroesophageal adenocarcinoma (GEA) were resoundingly negative. We identified EGFR amplification in 5% (19/363) of patients at the University of Chicago, including 6% (8/140) who were prospectively screened with intention-to-treat using anti-EGFR therapy. Seven patients received ≥1 dose of treatment: three first-line FOLFOX plus ABT-806, one second-line FOLFIRI plus cetuximab, and three third/fourth-line cetuximab alone. Treatment achieved objective response in 58% (4/7) and disease control in 100% (7/7) with a median progression-free survival of 10 months. Pretreatment and posttreatment tumor next-generation sequencing (NGS), serial plasma circulating tumor DNA (ctDNA) NGS, and tumor IHC/FISH for EGFR revealed preexisting and/or acquired genomic events, including EGFR-negative clones, PTEN deletion, KRAS amplification/mutation, NRAS, MYC, and HER2 amplification, and GNAS mutations serving as mechanisms of resistance. Two evaluable patients demonstrated interval increase of CD3+ infiltrate, including one who demonstrated increased NKp46+, and PD-L1 IHC expression from baseline, suggesting an immune therapeutic mechanism of action. EGFR amplification predicted benefit from anti-EGFR therapy, albeit until various resistance mechanisms emerged.Significance: This paper highlights the role of EGFR inhibitors in EGFR-amplified GEA-despite negative results in prior unselected phase III trials. Using serial ctDNA and tissue NGS, we identified mechanisms of primary and acquired resistance in all patients, as well as potential contribution of antibody-dependent cell-mediated cytotoxicity to their clinical benefit. Cancer Discov; 8(6); 696-713. ©2018 AACR.See related commentary by Strickler, p. 679This article is highlighted in the In This Issue feature, p. 663.

Modified biweekly cisplatin, docetaxel plus cetuximab (TPEx) as first-line treatment for patients with recurrent/metastatic head and neck cancer

Three weekly high-dose chemotherapy regimens in combination with weekly cetuximab are the treatment of choice for patients with recurrent/metastatic (R/M) head and neck squamous cell carcinoma (SCCHN), although the majority of patients suffer from severe side effects. Thus, we investigated the efficacy and safety of an alternative, more convenient and less toxic biweekly modified cisplatin, docetaxel plus cetuximab (TPEx) regimen in this retrospective analysis. Thirty-eight patients receiving off-protocol cisplatin (50 mg/m2) in combination with docetaxel (50 mg/m2) plus cetuximab (500 mg/m2) every other week were included. Data collection included baseline demographic, response rate (ORR) and toxicity data as well as disease control rate, overall survival (OS) and progression-free survival (PFS). The median age was 60 years, and the majority of patients suffered from oral cavity carcinomas (44.7%) followed by oropharyngeal (28.9%) and laryngeal (17.9%) carcinomas. The ORR was 50%, and four (10.5%) patients achieved a complete response, while 15 (39.5%) patients had a partial response. The OS and PFS were 10.8 months (95% CI 6.7-14.2) and 6.3 months (95% CI 5.7-6.8), respectively. The one-year survival rate was 44.7%. The therapy was well tolerated, and the most common grade 3/4 adverse events were myelosuppression (13.2%), hypomagnesaemia (23.7%) and acne-like rash (13.1%). In conclusion, modified biweekly TPEx is of comparable efficacy with conventional TPEx and represents a well-tolerated regimen in R/M SCCHN patients. Further evaluation of this protocol in prospective clinical trials is warranted.

Development of a radiolabeled caninized anti-EGFR antibody for comparative oncology trials

Due to large homology of human and canine EGFR, dogs suffering from spontaneous EGFR+ cancer can be considered as ideal translational models. Thereby, novel immunotherapeutic compounds can be developed for both human and veterinary patients. This study describes the radiolabeling of a canine anti-EGFR IgG antibody (can225IgG) with potential diagnostic and therapeutic value in comparative clinical settings. Can225IgG was functionalized with DTPA for subsequent chelation with the radionuclide ^99mTc. Successful coupling of 10 DTPA molecules per antibody on average was proven by significant mass increase in MALDI-TOF spectroscopy, gel electrophoresis and immunoblots. Following functionalization and radiolabeling, ^99mTc-DTPA-can225IgG fully retained its binding capacity towards human and canine EGFR in flow cytometry, immuno- and radioblots, and autoradiography. The affinity of radiolabeled can225IgG was determined to K_D 0.8 ±0.0031 nM in a real-time kinetics assay on canine carcinoma cells by a competition binding technique. Stability tests of the radiolabeled compound identified TRIS buffered saline as the ideal formulation for short-term storage with 87.11 ±6.04% intact compound being still detected 60 minutes post radiolabeling. High stability, specificity and EGFR binding affinity pinpoint towards ^99mTc-radiolabeled can225IgG antibody as an ideal lead compound for the first proof-of-concept diagnostic and therapeutic applications in canine cancer patients.

Multicenter phase II study of infusional 5-fluorouracil (5-FU), leucovorin, and oxaliplatin, plus biweekly cetuximab as first-line treatment in patients with metastatic colorectal cancer (CELINE trial)

The current phase II study investigated the efficacy and safety of biweekly cetuximab combined with standard oxaliplatin-based chemotherapy [infusional 5-fluorouracil (5-FU), leucovorin, and oxaliplatin (FOLFOX-6)] in the first-line treatment of KRAS wild-type metastatic colorectal cancer (mCRC). Sixty patients with a median age of 64 years (range, 38-82 syears) received a biweekly intravenous infusion of cetuximab (500 mg/m² on day 1) followed by FOLFOX-6 (2-hour oxaliplatin 85 mg/m² infusion on day 1 in tandem with a 2-h leucovorin 200 mg/m² infusion on days 1 and 2, and 5-FU as a 400 mg/m² bolus followed by a 46-hour 2,400 mg/m² infusion on days 1-3). Patient response rate was 70%, with 95% disease control rates. The median progression-free survival was 13.8 months. Thirteen patients (21.7%) were able to undergo resection of previously unresectable metastases, with the aim of curing them. The median follow-up was 22.7 months, and median overall survival was 31.0 months. Cetuximab did not increase FOLFOX-6 toxicity and was generally well tolerated. The results of the current study demonstrate that the combination of biweekly cetuximab with FOLFOX-6 was well tolerated and had a manageable safety profile for the first-line treatment of KRAS wild-type metastatic colorectal cancer. Efficacy was comparable to other treatment regimens. The results support the administration of biweekly cetuximab in combination with FOLFOX-6, which may be more convenient and provide treatment flexibility in this setting for patients with metastatic colorectal cancers.

Docetaxel plus cetuximab biweekly is an active regimen for the first-line treatment of patients with recurrent/metastatic head and neck cancer

For patients with recurrent/metastatic (R/M) head and neck squamous cell carcinoma (SCCHN) limited therapeutic options exist. Only a subset of patients is suitable for combination chemotherapy regimens. Biweekly docetaxel plus cetuximab might be an alternative option. Thus, we performed this retrospective analysis in unselected patients in order to investigate the efficacy and safety of this regimen. Thirty-one patients receiving off protocol docetaxel (50 mg/m(2)) plus cetuximab (500 mg/m(2)) biweekly were included. Data collection included baseline demographic, response rate (ORR), disease control rate (DCR), overall survival (OS), progression free survival (PFS) as well as toxicity. OS and PFS were 8.3 months (95% CI 4.8-11.8) and 4.0 months (95% CI 1.0-7.0), respectively. Three (9.7%) patients achieved a complete response and one patient (3.2%) a partial response. The DCR was 41.9% and we observed an ORR of 12.9%. The one-year survival rate was 25.8%. The therapy was well tolerated and the most common grade 3/4 adverse events were neutropenia (19.4%), hypomagnesaemia (12.9%) and acne-like rash (9.7%). Biweekly cetuximab/docetaxel is an effective regimen and well tolerated in R/M SCCHN patients not suitable for platinum doublet treatment. Further evaluation of this regimen in prospective clinical trials is warranted.

Effectiveness of bevacizumab and cetuximab in metastatic colorectal cancer across selected public hospitals in Queensland

AIM

Metastatic colorectal cancer has a large burden of disease in Australia. Medical therapy is fundamental to extending survival and improving quality of life. The benefits of two costly medicines, bevacizumab and cetuximab, used in Australia remain unclear. The aim of this study was to retrospectively examine the use of these two medicines in metastatic colorectal cancer across five public hospitals in south east Queensland and to compare clinical outcomes to those of published clinical trials.

METHODS

We extracted data from the chemotherapy prescribing database for patients planned for bevacizumab or cetuximab therapy between 2009 and 2013. Median overall survival was estimated using Kaplan-Meier methods.

RESULTS

There were 490 bevacizumab-containing protocols planned and 292 patients received at least one dose of bevacizumab. Median overall survival was 17.2 months (95% confidence interval [CI], 15.4-19.3). Of 208 planned cetuximab-containing protocols, 134 patients received at least one dose of cetuximab. Median overall survival was 9.1 months (95% CI, 7.6-12.0). Thirty-day mortality rates from date of first dose were 0.7% for bevacizumab and 7.5% for cetuximab.

CONCLUSION

Overall survival of patients receiving bevacizumab and cetuximab was consistent with clinical trials, providing some assurance that benefits seen in trials are observed in usual practice. This study provides a methodology of using routinely collected health data for clinical monitoring and research. Because of the high cost of these medicines and the lack of toxicity data in this study, further analysis in the postmarketing setting should be explored.

Anti-EGFR monoclonal antibodies for treatment of colorectal cancers: development of cetuximab and panitumumab

Over the last decade, anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (mAbs) have been firmly established as essential drugs for the treatment of metastatic colorectal cancer (CRC). Cetuximab and panitumumab have been approved by American and European drug agencies. This review aims at exploring the main outcomes of clinical studies performed during their clinical development, from phase I to III trials, and hence at giving a comprehensive review of the scientific rational and up-to-date evidence sustaining the use of these drugs. Many areas are still under active investigation such as administration schedules, their efficacy in comparison with bevacizumab, their role in adjuvant therapy, molecular predictors, and management of side effects.

Maintenance Therapy With Cetuximab Every Second Week in the First-Line Treatment of Metastatic Colorectal Cancer: The NORDIC-7.5 Study by the Nordic Colorectal Cancer Biomodulation Group

BACKGROUND

In the NORDIC-7.5 trial, how cetuximab might safely and conveniently be added to an intermittent treatment strategy in patients with prospectively selected Kirsten rat sarcoma viral oncogene homolog wild type (KRASwt) metastatic colorectal cancer (mCRC) was investigated. Patients were treated in a multicenter phase II trial with cetuximab in combination with the Nordic bolus FLOX (oxaliplatin, 5-fluorouracil, and folinic acid) for 4 months followed by maintenance cetuximab.

PATIENTS AND METHODS

Patients had KRASwt, nonresectable mCRC, no previous chemotherapy, and Eastern Cooperative Group performance status of 0 to 2. Patients received 8 courses of Nordic FLOX (oxaliplatin 85 mg/m(2) over 1 hour on day 1, and 5-fluorouracil 500 mg/m(2) as a bolus injection, followed 30 minutes later with bolus folinic acid 60 mg/m(2) on days 1 and 2). Cetuximab was administered every 2 weeks at a dose of 500 mg/m(2) for 16 weeks followed by cetuximab as maintenance therapy until disease progression.

RESULTS

Between July 2008 and September 2010, 152 KRASwt patients were included. The response rate was 62% (95% confidence interval [CI], 54%-69%), median progression-free survival was 8.0 months (95% CI, 7.5-8.9) and median overall survival was 23.2 (95% CI, 18.1-27.4) months. Twenty-one patients (14%) had later R0-resection of metastasis. FLOX with cetuximab was reintroduced in 47 of 85 patients (55%). The most common Grade 3/4 nonhematologic adverse events were diarrhea in 14 patients (9%), skin rash in 13 patients (9%), infection without neutropenia in 11 patients (7%), and fatigue in 11 patients (7%).

CONCLUSION

In a prospectively selected KRASwt population, biweekly cetuximab was safely integrated in an intermittent chemotherapy strategy and might have added to a longer chemotherapy-free interval. However, the combination of biweekly cetuximab with chemotherapy needs to be validated in trials using FOLFOX (oxaliplatin, fluorouracil, and leucovorin) or FOLFIRI (irinotecan, fluorouracil, and leucovorin).

Biweekly cetuximab in combination with FOLFOX-4 in the first-line treatment of wild-type KRAS metastatic colorectal cancer: final results of a phase II, open-label, clinical trial (OPTIMIX-ACROSS Study)

BACKGROUND

This phase II study aims to evaluate the efficacy and safety of biweekly cetuximab in combination with oxaliplatin, leucovorin, and fluorouracil (FOLFOX-4) as first-line treatment of metastatic wild-type KRAS colorectal cancer.

METHODS

Previously untreated patients with wild-type KRAS tumours received biweekly cetuximab (500 mg/m2 on day 1) plus FOLFOX-4 (oxaliplatin 85 mg/m2 on day 1, leucovorin 200 mg/m2 on days 1 and 2, and fluorouracil as a 400 mg/m2 bolus followed by a 22-hour 600 mg/m2 infusion on day 1 and 2). Treatment was continued until disease progression, onset of unacceptable toxicities, metastases surgery, or discontinuation request. The primary endpoint was ORR.

RESULTS

The intention-to-treat population included 99 patients with a median age of 64.1 years (range, 34-82). The ORR was 60.6% (95% CI, 50.3% to 70.3%). The median follow-up was 17.8 months; the median OS and PFS were 20.8 and 10.1 months, respectively. Metastases from colorectal cancer were surgically resected in 26 (26.3%) patients, with complete resection achieved in 18 (69.2%) patients. Median PFS and OS in patients undergoing metastatic resection were 12.6 and 29.5 months, respectively. The most common grade 3-4 toxicities were neutropenia (32.3%), acne-like rash (15.2%) and diarrhoea (11.1%).

CONCLUSIONS

The efficacy of the biweekly combination of cetuximab with FOLFOX-4 in patients with wild-type KRAS tumours supports the administration of cetuximab in a dosing regimen more convenient for patients and healthcare providers. The activity of the biweekly administration is similar to what has been reported for the weekly regimen. Reported toxicity was also consistent with the known toxicity profile of weekly cetuximab.

TRIAL REGISTRATION

EudraCT Number 200800690916.

Dual inhibition of EGFR with afatinib and cetuximab in kinase inhibitor-resistant EGFR-mutant lung cancer with and without T790M mutations

EGFR-mutant lung cancers responsive to reversible EGFR inhibitors (gefitinib/erlotinib) develop acquired resistance, mediated by second-site EGFR T790M mutation in >50% of cases. Preclinically, afatinib (irreversible ErbB family blocker) plus cetuximab (anti-EGFR monoclonal antibody) overcomes T790M-mediated resistance. This phase Ib study combining afatinib and cetuximab enrolled heavily pretreated patients with advanced EGFR-mutant lung cancer and acquired resistance to erlotinib/gefitinib. Patients provided post-acquired-resistance tumor samples for profiling EGFR mutations. Among 126 patients, objective response rate (overall 29%) was comparable in T790M-positive and T790M-negative tumors (32% vs. 25%; P = 0.341). Median progression-free survival was 4.7 months (95% confidence interval, 4.3-6.4), and the median duration of confirmed objective response was 5.7 months (range, 1.8-24.4). Therapy-related grade 3/4 adverse events occurred in 44%/2% of patients. Afatinib-cetuximab demonstrated robust clinical activity and a manageable safety profile in EGFR-mutant lung cancers with acquired resistance to gefitinib or erlotinib, both with and without T790M mutations, warranting further investigation.

SIGNIFICANCE

This article reports the results of a trial combining afatinib and cetuximab in patients with acquired resistance and details the first clinical proof-of-concept for the preclinical hypothesis that a significant proportion of tumors in patients with acquired resistance to gefitinib/erlotinib remain dependent on EGFR signaling for survival.

Epidermal growth factor receptor: pathway, therapies, and pipeline

BACKGROUND

The epidermal growth factor receptor (EGFR) pathway is important in tumor growth, survival, and metastasis and is now the target of several therapeutic agents.

OBJECTIVES

This paper seeks to review the EGFR pathway, the study and use of EGFR-directed agents in non-small-cell lung cancer (NSCLC) and colorectal cancer (CRC), and related new drug development.

METHODS

PubMed was searched for English-language articles by MeSH and title terms of EGFR published from 2006 to 2013, using the limits of clinical trials as well as reviews. Reference lists were assessed for relevant articles, and guidelines were searched. Clinicaltrials.gov and meeting abstracts were queried for investigational agents. Eligible papers included those concerning EGFR biology, NSCLC or CRC studies involving EGFR-directed agents, and/or investigational drugs targeting EGFR and/or associated pathways.

RESULTS

The activity of oral tyrosine kinase inhibitors (TKIs) against EGFR has improved survival in NSCLC, and these agents particularly effective in cancers with an EGFR mutation. Resistance to TKIs is most commonly related to a second, T790M, mutation, or to MET amplification, with newer agents directed against these mechanisms. Conversely, in CRC, TKIs have been ineffective, whereas monoclonal antibodies have improved survival. Both primary and secondary KRAS mutations in CRC abrogate mAb effectiveness. Several targets, including MET, BRAF, and PI3K, may serve useful in combination with anti-EGFR drugs.

CONCLUSIONS

Exploitation of EGFR-directed therapies has offered improvement in survival and quality of life in NSCLC and CRC. New therapies directed at EGFR may offer further improvements. However, resistance mechanisms suggest that combination therapies or multitargeted agents will be crucial in making significant future advances.

A systematic review of salvage therapy to patients with metastatic colorectal cancer previously treated with fluorouracil, oxaliplatin and irinotecan +/- targeted therapy

Oxaliplatin, irinotecan and 5-fluorouracil in combination with or without targeted therapies are well-documented treatment options for first- and second-line treatments of metastatic colorectal cancer. However, there are much less data on the beneficial effect on systemic therapy in the third-line setting. We therefore performed a systematic review of the current literature on third or later lines of treatment to patients with metastatic colorectal cancer after the use of approved drugs or combinations.

METHODS

A computer-based literature search was carried out using Pubmed and data reported at international meetings. Original studies reporting ≥15 patients who had previously received 5-fluorouracil, oxaliplatin and irinotecan were included. Furthermore, patients with KRAS wild type tumours should had received EGFR-directed therapy.

RESULTS

Conventional chemotherapeutic agents as capecitabine, mitomycin C, and gemcitabine have limited or no activity. Retreatment with oxaliplatin might be an option in selected patients. In addition, rechallenge with EGFR-directed therapy might be a valuable strategy. Data also suggest that angiogenetic drugs may postpone further progression and prolong survival. Lately, regorafinib has been approved. In conclusion, our current knowledge is based on many retrospective studies, some phase II studies and very few randomized clinical trials. Further prospective phase III trials comparing an investigational drug or combination with best supportive care in third- or later lines of treatment in metastatic colorectal cancer are highly warranted. Identification of predictive biomarkers and improvement of our understanding of molecular mechanisms is crucial.

Management of advanced colorectal cancer, Part 2

PURPOSE

Important developments in chemotherapy for advanced colorectal cancer over the past 15 years are reviewed, with an emphasis on the most recently published data from clinical trials of newer multidrug regimens, administration techniques, and dosing schedules.

SUMMARY

Eight agents are approved by the Food and Drug Administration (FDA) for use in treating patients with advanced colorectal cancer. Fluorouracil and leucovorin still constitute the foundation of most chemotherapy regimens for this population; combination fluorouracil-leucovorin therapy plus either irinotecan (the FOLFIRI regimen) or oxaliplatin (the FOLFOX regimen) are two firmly established first-line treatments shown to produce similar outcomes. In Phase III trials conducted over the past six to seven years, regimens of capecitabine plus oxaliplatin (CapeOx) were demonstrated to have clinical effectiveness comparable to that of FOLFOX therapy. Response rates of 35-55% and median overall survival of ≥20 months have been documented with some of the newer regimens. Research to define the optimal role of the three monoclonal antibody agents approved by FDA for use in managing advanced colorectal cancer is ongoing; bevacizumab has been shown to confer significant survival benefits when added to certain chemotherapy regimens, and other monoclonal antibodies (cetuximab and panitumumab) also appear to offer significant benefits in select patients as first- or second-line therapies.

CONCLUSION

Over the past 15 years, a shift toward multiagent treatment strategies including a variety of chemotherapy agents and monoclonal antibodies has yielded improved rates of response and prolonged survival among patients with advanced colorectal cancer. The CapeOx, FOLFOX, and FOLFIRI regimens are currently among the most widely used first-line treatments.

Safety and feasibility of every-other-week maintenance cetuximab after first-line chemotherapy in patients with recurrent or metastatic head and neck squamous cell cancer

BACKGROUND

In patients with recurrent and/or metastatic head and neck squamous cell cancer (HNSCC), there are no data about an every-other-week cetuximab maintenance schedule after chemotherapy plus cetuximab as first-line treatment.

METHODS

We reviewed the safety and feasibility of every-other-week maintenance cetuximab administered at 3 different European centers.

RESULTS

Thirty-one patients with recurrent or metastatic HNSCC were treated from 2006 to 2010. Mean cetuximab dose intensity in the maintenance phase was 93%. The major toxicities reported during every-other-week maintenance cetuximab were skin rash (grade 3, 16%; grade 2, 23%), fatigue (grade 3, 3%; grade 2, 16%), diarrhea (grade 3, 7%; grade 2, 13%), hypomagnesemia (grade 4, 3%; grade 3, 3%; grade 2, 19%), and mucositis (grade 3, 3%; grade 2, 23%).

CONCLUSIONS

Every-other-week maintenance cetuximab schedule was well tolerated and did not worsen toxicity that occurred during chemotherapy. In daily practice, this simplified schedule could improve compliance and possibly improve quality of life in patients with recurrent or metastatic HNSCC that showed no progression during first-line chemotherapy.

Cetuximab in metastatic colorectal cancer

Management of metastatic colorectal cancer has evolved in the last 10 years, with the availability of targeted therapies resulting in improvement in quality of life and overall survival. Cetuximab is a chimeric monoclonal antibody that binds to the EGF receptor, and the net effects are inhibition of tumor growth, invasion, angiogenesis and metastasis. Cetuximab binding to the EGF receptor is also known to augment the effects of chemotherapy and radiotherapy. Only tumors expressing wild-type KRAS respond to cetuximab and improvements in progression-free survival and overall survival are seen, whereas patients with mutant KRAS are considered to be resistant. Cetuximab is currently available worldwide for use as monotherapy or in combination with chemotherapy in first-, second- or third-line settings in metastatic colorectal cancer patients with wild-type KRAS.

Phase II study of biweekly cetuximab in combination with irinotecan as second-line treatment in patients with platinum-resistant gastro-oesophageal cancer

BACKGROUND

The purpose of this phase II trial was to evaluate the efficacy and safety of cetuximab and irinotecan as second-line treatment in patients with gastro-oesophageal adenocarcinoma.

PATIENTS AND METHODS

Patients with failure to first-line platinum-based chemotherapy received cetuximab 500 mg/m(2) and irinotecan 180 mg/m(2) every second week until disease progression. Toxicity was evaluated according to The Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) v. 3.0. Antitumour activity was assessed according to Response Evaluation Criteria in Solid Tumours (RECIST) v. 1.0.

RESULTS

Sixty-three patients were enrolled, median age was 60 years, median performance status was 1 (0-1), 35 patients had two or more organs involved. The median number of courses was 5 (range 1-25). Response rate was 11% (6 partial response (PR)) and 37% had stable disease. Median progression free survival was 2.8 months and overall survival (OS) was 6.1 months. Grade 3-4 toxicity included: diarrhoea (6%), fatigue (5%), vomiting (5%) and neutropenia (16%). Two patients developed febrile neutropenia. Forty-six patients (73%) had developed grade 1-2 skin rash. Patients developing skin rash had a prolonged survival with an OS at 7.1 months.

CONCLUSIONS

The combination of cetuximab and irinotecan is active as second-line therapy in patients with gastro-oesophageal cancer. Cetuximab induced skin rash was associated with prolonged survival.

Pneumatosis intestinalis after cetuximab-containing chemotherapy for colorectal cancer

Cetuximab, a chimeric monoclonal antibody to epidermal growth factor receptor, is an effective chemotherapeutic agent for patients with metastatic colorectal cancer. Whereas several specific adverse reactions to cetuximab such as skin rash and nail toxicity have been reported, there have been few reports of pneumatosis intestinalis related to cetuximab-containing chemotherapy. We describe here three patients with colorectal cancer who developed pneumatosis intestinalis during treatment with cetuximab-containing chemotherapy, which developed after 7, 19 and 47 weeks of cetuximab treatment, and discovered on routine follow-up computed tomographic scans for response evaluations. None of these patients complained of abdominal pain, showed signs of peritoneal irritation on physical examination or had elevated serum concentrations of acute inflammatory markers. Following cessation of cetuximab and conservative medical treatment, all three patients showed complete resolution of pneumatosis intestinalis on abdominal pelvic computed tomographic scans.

Biweekly cetuximab and irinotecan as second-line therapy in patients with gastro-esophageal cancer previously treated with platinum

BACKGROUND

Until recently there has been no proven second-line therapy for patients with advanced gastro-esophageal cancer (GEC). Since 2004, Denmark has had a national health program where non-proven therapy can be offered to patients with advanced cancer, after approval by an expert panel appointed by the National Board of Health. This program has accelerated the introduction and implementation of new therapies in Denmark. Inspired by therapy in metastatic colorectal cancer, a combination of cetuximab and irinotecan (Cetiri) was chosen for second-line therapy in GEC patients. We report our experience with Cetiri as second-line therapy in patients with GEC.

METHODS

All patients had histologically confirmed GEC and all patients had progressive disease during or after first-line platinum-containing chemotherapy. The patients received cetuximab 500 mg/m(2) on day 1 and irinotecan 180 mg/m(2) on day 1 every 2nd week until progression or unacceptable toxicity. Toxicity was prospectively evaluated according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) version 3.0.

RESULTS

From December 2007 to February 2009, 50 consecutive patients received Cetiri as second-line therapy. Median performance status (PS) was 1. The median number of courses was seven. Seven patients (14%) had a partial response. Median progression-free survival (PFS) was 3.3 months and overall survival (OS) was 5.5 months; two patients are still alive without progressive disease. Major toxicities were: diarrhea (8%), fatigue (10%), neutropenia (16%), and febrile neutropenia (2%).

CONCLUSION

Cetiri every two weeks is a convenient and well-tolerated second-line regimen in GEC patients. A promising effect was seen in patients with PS 0-1 and in patients who developed a rash.

Consensus recommendations for the use of anti-egfr therapies in metastatic colorectal cancer

In January 2010, a panel of Canadian oncologists with particular expertise in colorectal cancer (crc) gathered to develop a consensus guideline on the use of therapies against the epidermal growth factor receptor (egfr) in the management of metastatic crc (mcrc). This paper uses a case-based approach to summarize the consensus recommendations developed during that meeting.These are the consensus recommendations:Testing for the KRAS status of the tumour should be performed as soon as an egfr inhibitor is being considered as an option for treatment.Anti-egfr therapies are not recommended for the treatment of patients with tumours showing mutated KRAS status.For a patient with wild-type KRAS and an Eastern Cooperative Oncology Group status of 0-2, whose mcrc has previously been treated with a fluoropyrimidine, irinotecan, and oxaliplatin, switching to an egfr inhibitor is a recommended strategy.Cetuximab, cetuximab plus irinotecan, and panitumumab are all options for third-line therapy in patients with wild-type KRAS, provided that tolerability is acceptable.

Bevacizumab in combination with cetuximab and irinotecan after failure of cetuximab and irinotecan in patients with metastatic colorectal cancer

BACKGROUND

The efficacy and safety of concurrent administration of irinotecan with the two monoclonal antibodies cetuximab and bevacizumab as fourth line therapy in heavily pretreated patients with metastatic colorectal cancer were evaluated.

PATIENTS AND METHODS

Patients with metastatic colorectal cancer who had progressed on therapy with 5-FU, oxaliplatin and irinotecan in the first and second line setting and on the combination of irinotecan and cetuximab in third line setting independent of their KRAS mutation status, were treated with irinotecan and cetuximab combined with bevacizumab in a dosage of 5 mg/kg. All drugs were administered every second week.

RESULTS

From January 2007 to November 2008 27 patients were treated with cetuximab, irinotecan and bevacizumab. The triple-combination was well tolerated. Progression free survival (PFS) was 8.3 months and median overall survival (mOS) was 12.0 months. Two patients without KRAS mutation (7%) obtained a partial response and 17 (63%) had stable disease for at least two months. A retrospective KRAS mutation analysis revealed that there was a trend toward longer PFS and mOS in patients without KRAS mutations compared to patients with KRAS mutations with a PFS of 8.9 vs. 5.1 months and a mOS of 12.7 vs. 9.0 months.

CONCLUSION

Bevacizumab is safe to add to irinotecan and cetuximab with a toxicity profile that seems to be similar to what would be expected from the agents alone. The results indicate that adding bevacizumab to irinotecan and cetuximab in a fourth line setting may induce a high rate of disease control in heavily pretreated patients with metastatic colorectal cancer.

Progress in metastatic colorectal cancer: growing role of cetuximab to optimize clinical outcome

The prognosis of metastatic colorectal cancer remains poor despite advances made in recent years, particularly with new treatments directed towards molecular targets. Cetuximab, a chimeric immunoglobulin (Ig)G1 monoclonal antibody that targets the ligand-binding domain of the epidermal growth factor receptor (EGFR), is active in metastatic colorectal cancer. As an IgG1 antibody, cetuximab may exert its antitumour efficacy through both EGFR antagonism and antibody-dependent cell-mediated cytotoxicity. The benefits of cetuximab in metastatic colorectal cancer are well documented in clinical trials and are acknowledged in the approval and licensing of this agent. There is evidence of the role of cetuximab not only in irinotecan-refractory or heavily pretreated patients, but also of the efficacy and safety of the addition of this agent to FOLFIRI (irinotecan/5-fluorouracil/leucovorin) in first-line metastatic colorectal cancer, with an enhanced effect in 5-fluorouracil patients with Kirsten rat sarcoma (KRAS) wild-type tumours. In these patients, a recent meta-analysis of the pooled Cetuximab Combined with Irinotecan in First-Line Therapy for Metastatic Colorectal Cancer (CRYSTAL) and Oxaliplatin and Cetuximab in First-Line Treatment of mCRC (OPUS) patient populations confirms that the addition of cetuximab to first-line chemotherapy achieves a statistically significant improvement in the best overall response, overall survival time, and progression-free survival (PSF) compared with chemotherapy alone. In nonresectable colorectal liver metastases, cetuximab plus FOLFOX-6 (oxaliplatin/5-fluorouracil/leucovorin) or cetuximab plus FOLFIRI increased significantly resectability of liver metastases, including R0 resections. Also, preliminary data indicate that cetuximab can be administered in a more convenient 2-week schedule in combination with standard chemotherapy. Cetuximab is generally well tolerated. Acne-form rash is the most frequent toxicity. Up to the present time, the results obtained with targeted therapy combinations are not as encouraging as initially expected. The identification of biomarkers associated with disease control, including KRAS and BRAF mutation status in patients treated with cetuximab, is changing the current management of metastatic colorectal cancer. Clinical and molecular predictive markers of response are under active evaluation in order to better select patients who could benefit from cetuximab treatment, with the aim of both optimising patient outcomes and avoiding unnecessary toxicities.

Addition of sunitinib to cetuximab and irinotecan in patients with heavily pre-treated advanced colorectal cancer

Results of continuous sunitinib, in combination with cetuximab and irinotecan every other week (SIC) for compassionate use in heavily pre-treated patients with mCRC are presented.

PATIENTS AND METHODS

Patients with mCRC resistant to oxaliplatin, irinotecan, 5-FU and cetuximab received SIC at two Danish oncologic departments. The regimen consisted of sunitinib given as a continuous-dosing in combination with cetuximab and irinotecan every other week (CetIri). The first six patients started with a daily oral dose of sunitinib of 12.5 mg. Subsequent patients started at a daily dose of 25 mg with the possibility to escalate to 37.5 mg.

RESULTS

Twenty-nine patients received SIC. No patient had an objective response, but 13 patients had subjective relief and 42% had stable disease. The median time to progression was 3.2 months and median overall survival was 7.4 months. Fatigue and leukopenia were the most frequently reported severe adverse event (18% grade 3 and 18% grade 3/4, respectively).

DISCUSSION

Sunitinib continuous-dosing with 25 mg/day can safely be combined with CetIri administered every other week.

Efficacy of the monoclonal antibody EGFR inhibitors for the treatment of metastatic colorectal cancer

Two anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (MoAbs) have been approved in Canada for the treatment of metastatic colorectal cancer (mCRC) - cetuximab, a mouse-human chimeric MoAb, and panitumumab, a fully human MoAb. This paper reviews the efficacy of the anti-EGFR monoclonal antibodies cetuximab and panitumumab - both as monotherapy and in combination with cytotoxic chemotherapy - in the treatment of mCRC. Both cetuximab and panitumumab have demonstrated clinical efficacy in monotherapy in patients with mCRC, an advantage that has recently been found to be limited largely to those with wild-type KRAS tumors. Advantages of using these agents in monotherapy include reduced cost and toxicity. While the addition of cetuximab to irinotecan has shown superior progression-free survival and response compared with cetuximab monotherapy, there is currently no evidence for a benefit of panitumumab in combination with irinotecan.

Cetuximab in combination therapy: from bench to clinic

Cetuximab, a chimeric IgG(1) monoclonal antibody directed against the ligand-binding domain of the epidermal growth factor receptor, offers a paradigm for the combination of molecularly targeted therapies with cytotoxic agents. In preclinical models, the addition of cetuximab to chemotherapy or radiation therapy enhances antitumor activity. Proposed mechanisms include reducing tumor cell proliferation, angiogenesis, and DNA repair capacity; increasing apoptosis; and inducing cell cycle arrest at treatment-sensitive points. These effects may enhance and restore tumor sensitivity to cytotoxic therapies. In clinical trials, the addition of cetuximab to chemotherapy improves outcomes of patients who had previously failed such agents, as illustrated in irinotecan-resistant and oxaliplatin-refractory metastatic colorectal cancer. As initial therapy, the addition of cetuximab to chemotherapy extends survival in colorectal cancer, lung cancer, and head and neck cancer. Combining cetuximab with radiation therapy extends survival in locally advanced head and neck cancer. As predictive biomarkers are identified, it may become possible to select patients most likely to benefit from such combinations.