Systematic literature review and network meta-analysis of pembrolizumab versus other interventions for previously untreated, unresectable or metastatic, microsatellite instability-high or mismatch repair-deficient colorectal cancer

Aim: To compare pembrolizumab with competing interventions for previously untreated, unresectable or metastatic microsatellite instability-high or mismatch repair-deficient colorectal cancer. Method: Trials were identified via a systematic literature review and synthesized using a Bayesian network meta-analysis with time-varying hazard ratios (HRs). Results: Using intention-to-treat data, HRs for overall survival were generally in favor of pembrolizumab but not statistically significant; however, statistical significance was reached versus all comparators by month 16 when accounting for crossover. Estimated HRs for progression-free survival significantly favored pembrolizumab versus all comparators by month 12. Pembrolizumab was also superior to all comparators in terms of grade ≥3 adverse events. Conclusion: These analyses suggest that pembrolizumab is a highly efficacious and safe treatment in this population.

Induction chemotherapy followed by chemoradiotherapy versus chemoradiotherapy alone as neoadjuvant treatment for locally recurrent rectal cancer: study protocol of a multicentre, open-label, parallel-arms, randomized controlled study (PelvEx II)

Background

A resection with clear margins (R0 resection) is the most important prognostic factor in patients with locally recurrent rectal cancer (LRRC). However, this is achieved in only 60 per cent of patients. The aim of this study is to investigate whether the addition of induction chemotherapy to neoadjuvant chemo(re)irradiation improves the R0 resection rate in LRRC.

Methods

This multicentre, international, open-label, phase III, parallel-arms study will enrol 364 patients with resectable LRRC after previous partial or total mesorectal resection without synchronous distant metastases or recent chemo- and/or radiotherapy treatment. Patients will be randomized to receive either induction chemotherapy (three 3-week cycles of CAPOX (capecitabine, oxaliplatin), four 2-week cycles of FOLFOX (5-fluorouracil, leucovorin, oxaliplatin) or FOLFORI (5-fluorouracil, leucovorin, irinotecan)) followed by neoadjuvant chemoradiotherapy and surgery (experimental arm) or neoadjuvant chemoradiotherapy and surgery alone (control arm). Tumours will be restaged using MRI and, in the experimental arm, a further cycle of CAPOX or two cycles of FOLFOX/FOLFIRI will be administered before chemoradiotherapy in case of stable or responsive disease. The radiotherapy dose will be 25 × 2.0 Gy or 28 × 1.8 Gy in radiotherapy-naive patients, and 15 × 2.0 Gy in previously irradiated patients. The concomitant chemotherapy agent will be capecitabine administered twice daily at a dose of 825 mg/m² on radiotherapy days. The primary endpoint of the study is the R0 resection rate. Secondary endpoints are long-term oncological outcomes, radiological and pathological response, toxicity, postoperative complications, costs, and quality of life.

Discussion

This trial protocol describes the PelvEx II study. PelvEx II, designed as a multicentre, open-label, phase III, parallel-arms study, is the first randomized study to compare induction chemotherapy followed by neoadjuvant chemo(re)irradiation and surgery with neoadjuvant chemo(re)irradiation and surgery alone in patients with locally recurrent rectal cancer, with the aim of improving the number of R0 resections.

Conversion strategies with chemotherapy plus targeted agents for colorectal cancer liver-only metastases: A systematic review

BACKGROUND

There is no consensus on the optimal systemic conversion therapy in patients with unresectable colorectal cancer liver-only metastases (CRLM) to achieve a complete resection. Interpretation of trials is complicated by heterogeneity of patients caused by emerging prognostic and predictive characteristics, such as RAS/BRAF mutation status, lack of consensus on unresectability criteria and lack of data on clinical outcome of secondary resections. A systematic review was performed of characteristics of study populations and methodology of trials regarding patients with initially unresectable colorectal cancer liver-only metastases.

METHODS

Phase II/III randomised trials, published after 2008, regarding first-line systemic conversion therapy in patients or subgroups of patients with CRLM were included. Data on secondary resection outcomes were collected.

RESULTS

Overall, 20 trials were included for analysis: seven prospective trials in patients with unresectable CRLM and 13 trials in the overall population of unresectable metastatic colorectal cancer (mCRC) with retrospective subgroup analysis of CRLM patients. Fourteen trials did not provide unresectability criteria at baseline, and criteria differed among the remaining studies. Trials and study populations were heterogeneous in prognostic/predictive factors, use of primary end-points, and reporting on long-term clinical outcomes. R0-resection rates in CRLM patients varied between CRLM studies and mCRC studies, with rates of 22-57% and 11-38%, respectively.

CONCLUSIONS

Cross-study comparison of (subgroups of) studies regarding first-line systemic treatment in patients with unresectable CRLM is hampered by heterogeneity in study populations, trial designs, use of (K)RAS/BRAF mutational tumour status, and differences/absence of unresectability criteria. No optimal conversion systemic regimen can be selected from available data. Prospective studies with well-defined criteria of these issues are warranted.

First-line therapies in metastatic colorectal cancer: integrating clinical benefit with the costs of drugs

PURPOSE

In light of the relevant expenses of pharmacological interventions, it might be interesting to make a balance between the cost of the new drugs administered and the added value represented by the improvement in progression free survival (PFS) in first-line for metastatic colorectal cancer CRC (mCRC).

METHODS

Phase III randomized controlled trials (RCTs) that compared at least two first-line chemotherapy regimens for mCRC patients were evaluated. Differences in PFS between the different arms were compared with the pharmacological costs (at the pharmacy of our hospital). The European Society for Medical Oncology Magnitude of Clinical Benefit Scale (ESMO-MCBS) was applied to the above RCTs.

RESULTS

Overall 28 phase III RCTs, including 19,958 patients, were analyzed. The FOLFOX resulted the least expensive (56 € per month of PFS gained) while the addition of irinotecan to FOLFOX (FOLFOXIRI) increased only marginally the costs (90 € per month of PFS gained). Treatments including the monoclonal antibodies showed a cost per month of PFS gained of 2823 € (FOLFIRI with cetuximab in KRAS wild-type patients and liver-only metastases), of € 15,822 (FOLFOX with panitumumab in KRAS wild type), and of 13,383 € (FOLFOX with bevacizumab). According to the ESMO-MCBS, the treatments including an EGFR-inhibitor (cetuximab or panitumumab) were associated with a score of 4, while the inclusion of bevacizumab reached a score of 3.

CONCLUSIONS

Our data demonstrate a huge difference in cost per month of PFS gained in modern first-line treatments in mCRC.

Optimising the use of cetuximab in the continuum of care for patients with metastatic colorectal cancer

The anti-epidermal growth factor receptor (EGFR) monoclonal antibody cetuximab in combination with chemotherapy is a standard of care in the first-line treatment of RAS wild-type (wt) metastatic colorectal cancer (mCRC) and has demonstrated efficacy in later lines. Progressive disease (PD) occurs when tumours develop resistance to a therapy, although controversy remains about whether PD on a combination of chemotherapy and targeted agents implies resistance to both components. Here, we propose that some patients may gain additional clinical benefit from the reuse of cetuximab after having PD on regimens including cetuximab in an earlier treatment line. We conducted a non-systematic literature search in PubMed and reviewed published and ongoing clinical trials, focusing on later-line cetuximab reuse in patients with mCRC. Evidence from multiple studies suggests that cetuximab can be an efficacious and tolerable treatment when continued or when fit patients with mCRC are retreated with it after a break from anti-EGFR therapy. Furthermore, on the basis of available preclinical and clinical evidence, we propose that longitudinal monitoring of RAS status may identify patients suitable for such a strategy. Patients who experience progression on cetuximab plus chemotherapy but have maintained RAS wt tumour status may benefit from continuation of cetuximab with a chemotherapy backbone switch because they have probably developed resistance to the chemotherapeutic agents rather than the biologic component of the regimen. Conversely, patients whose disease progresses on cetuximab-based therapy due to drug-selected clonal expansion of RAS-mutant tumour cells may regain sensitivity to cetuximab following a defined break from anti-EGFR therapy. Looking to the future, we propose that RAS status determination at disease progression by liquid, needle or excisional biopsy may identify patients eligible for cetuximab continuation and rechallenge. With this approach, treatment benefit can be extended, adding to established continuum-of-care strategies in patients with mCRC.

Analysis of Mutational Spectra in Metastatic Colorectal Carcinoma: KRAS as an Indicator of Oxaliplatin-Based Chemotherapy

Objective:

Mutation spectra in colorectal cancer with metastasis and its response to chemotherapy.

Summary of Background Data:

No molecular markers are available for selecting the optimal chemotherapeutic regimen (irinotecan or oxaliplatin) for metastatic colorectal cancer (mCRC).

Methods:

We enrolled 161 mCRC patients who underwent surgery for their primary tumors at Taipei Veterans General Hospital from 2004 to 2010. The prevalence of gene mutations was measured and correlated with responses to different cytotoxic agents.

Results:

We detected 1,836 mutations in 12 genes. KRAS mutants affected 44.3% of the tumors. The rate of good response was insignificantly higher for patients with KRAS mutant tumors who received oxaliplatin-based chemotherapy compared with patients with KRAS wild-type tumors (65.6% versus 47.0%; P = 0.15). For patients who received irinotecan-based chemotherapy, the rate of good response was similar in patients with wild-type (55.0%; n = 11) and those with KRAS mutant tumors (54.5%; n = 12; P = 1). In patients with KRAS mutant tumors treated with an oxaliplatin-based regimen, the overall survival was 38.5 months (95% CI: 26.6–50.5 months), which was insignificantly better than that for patients treated with an irinotecan-based regimen (30.4 months; 95% CI: 15.8–45.1 months; P = 0.206).

Conclusions:

Our data could not come to the conclusion that patient with KRAS mutation mCRC may have better response with oxaliplatin-based first-line chemotherapy. Further study is needed to confirm the relationship between gene mutation and chemotherapy response.

A Review of Clinical Studies and Practical Guide for the Administration of Triplet Chemotherapy Regimens with Bevacizumab in First-line Metastatic Colorectal Cancer

Colorectal cancer is the third most common cancer worldwide. A significant proportion of patients presents with unresectable metastatic disease or develops metachronous metastases following surgical resection of the primary tumor. The prognosis of the disease has improved over the past two decades, with extended multimodality treatment options and the development of increasingly intensified chemotherapy regimens that now typically include targeted biologics. A recent advance in therapy is a treatment regimen composed of three chemotherapeutic agents (i.e., triplet chemotherapy: 5-fluorouracil [5-FU]/leucovorin [LV], oxaliplatin, and irinotecan; FOLFOXIRI) in combination with the vascular endothelial growth factor inhibitor bevacizumab. This regimen has been shown to elicit significantly improved objective response rates and median progression-free survival compared with 5-FU/LV and irinotecan in combination with bevacizumab. However, triplet chemotherapy has been associated with increased rates of chemotherapy-related adverse events, and treatment-emergent adverse events should be properly managed to minimize treatment interruption or discontinuation. We present herein a review of clinical studies evaluating the safety and efficacy of FOLFOXIRI with bevacizumab in metastatic colorectal cancer, and propose a practical guide for the management of adverse events associated with the regimen.

The Pharmacological Costs of Complete Liver Resections in Unselected Advanced Colorectal Cancer Patients: Focus on Targeted Agents. A Review of Randomized Clinical Trials

BACKGROUND

The aim of this study was to evaluate the pharmacological costs of conversion chemotherapy with targeted biological agents in an unselected population of advanced colorectal cancer (CRC) patients in order to achieve an R0 liver resection.

METHODS

Full reports and updates of randomized clinical trials (RCTs) that compared at least two front-line therapy regimens with targeted biological agents for advanced CRC patients were selected. The present evaluation was restricted to randomized phase II and III trials. The costs of drugs are at the Pharmacy Hospital and are expressed in euros (€).

RESULTS

Our study began with the evaluation of 683 abstracts. Forty-eight trials were considered appropriate for further analysis. A more in-depth evaluation looking for the trials reporting the liver resection rates following conversion chemotherapy brought to the exclusion of other 37 trials, leaving 11 randomized trials (three phase II trials, including 522 patients and eight phase III trials, including 7191 patients). The pharmacological costs of conversion therapy increased with the substitution of prolonged infusion 5-Fluorouracil by capecitabine and, to a much higher extent, with the introduction of biologicals.

CONCLUSIONS

Two key issues are presented in this review. First, the pharmacological costs of commonly used front line regimens based on the targeted biological agents for the treatment of advanced CRC are highly variable. Second, the performance of the published schemes, in terms of resection rates, depends on patient's selection, tumor characteristics, and on the type of the scheme.

BRAZILIAN CONSENSUS FOR MULTIMODAL TREATMENT OF COLORECTAL LIVER METASTASES. MODULE 3: CONTROVERSIES AND UNRESECTABLE METASTASES

In the last module of this consensus, controversial topics were discussed. Management of the disease after progression during first line chemotherapy was the first discussion. Next, the benefits of liver resection in the presence of extra-hepatic disease were debated, as soon as, the best sequence of treatment. Conversion chemotherapy in the presence of unresectable liver disease was also discussed in this module. Lastly, the approach to the unresectable disease was also discussed, focusing in the best chemotherapy regimens and hole of chemo-embolization.

Is more not better?: combination therapies in colorectal cancer treatment

The treatment of colorectal cancer has evolved dramatically in recent years with the availability of new chemotherapeutic agents and inhibitors of the vascular endothelial growth factor- and epidermal growth factor-signaling pathways. The incremental benefit of each individual line of therapy for advanced disease is relatively small. Advances in our ability to select patients should improve the cost-effectiveness of our treatment strategies (avoiding unnecessary toxicity in the patients who are unlikely to benefit and accepting the potential for adverse events in the patients who stand to benefit the most from a given regimen).

Bevacizumab beyond first disease progression in metastatic colorectal cancer: a review of recent clinical trial data

SUMMARY 

The continuum of care for patients with metastatic colorectal cancer continues to evolve as data from clinical trials evaluating novel agents, treatment combinations or treatment sequencing become available. The concept of continued angiogenesis suppression through multiple lines of therapy has been hypothesized to be beneficial in terms of increased overall survival. This has been evaluated in clinical trials, suggesting that exposure to bevacizumab in the first-line setting and continued beyond first disease progression was associated with statistically significant improvements in survival outcomes. Here, we will discuss the concept of bevacizumab beyond first disease progression in the context of recent clinical trials of bevacizumab, other antiangiogenic agents and other targeted therapies for metastatic colorectal cancer in first- and later-line disease settings.

The pharmacological costs of complete liver resections in unselected advanced colorectal cancer patients: a review of published Phase II and III trials

The pharmacological costs of regimens used as front-line therapy in advanced colorectal cancer patients and their impact on the liver resection rates have not been considered. In this paper, we made a review of published randomized Phase II and III trials that reported the liver resection rates following upfront chemotherapy and linked this outcome to the pharmacological costs of drugs used. The costs are calculated based on the price at Pharmacy of our Hospital in Legnago (Italy), and as a measure of activity, we used the number of patients needed to treat to get one complete liver resection. Number needed to treat is highly variable among the different trials according to patient's characteristics, tumor biology and the efficacy of chemotherapy administered. The range of activity is greatly amplified when the costs are compared.

Neoadjuvant chemotherapy without radiotherapy for locally advanced rectal cancer

ABSTRACT 

Chemoradiotherapy or short-course radiotherapy followed by surgery is a standard treatment for locally advanced rectal cancer. This multimodality strategy has reduced the risk of local recurrence but failed to improve survival. Moreover, mid- and long-term side effects of radiotherapy have been reported. Alternative strategies have been investigated in an attempt to minimize treatment-related toxicities and improve outcome. Neoadjuvant chemotherapy without radiotherapy is an attractive therapeutic option that yields theoretical advantages. Moreover, if carefully selected, patients may be spared the effects of radiotherapy without compromising the oncology outcome. The authors review the available evidence on neoadjuvant chemotherapy without radiotherapy in locally advanced rectal cancer and try to anticipate potential algorithms of treatment selection to implement in clinical practice in the future.

Targeted therapies in metastatic colorectal cancer: a systematic review and assessment of currently available data

BACKGROUND

Survival of patients with metastatic colorectal cancer (mCRC) has been significantly improved with the introduction of the monoclonal antibodies targeting the vascular endothelial growth factor (VEGF) and the epidermal growth factor receptor (EGFR). Novel molecular-targeted agents such as aflibercept and regorafenib have recently been approved. The aim of this review is to summarize and assess the effects of molecular agents in mCRC based on the available phase II and III trials, pooled analyses, and meta-analyses/systematic reviews.

METHODS

A systematic literature search was conducted using the meta-database of the German Institute of Medical Documentation and Information. Criteria of the Scottish Intercollegiate Guidelines Network were used to assess the quality of the controlled trials and systematic reviews/meta-analyses.

RESULTS

Of the 806 retrieved records, 40 publications were included. For bevacizumab, efficacy in combination with fluoropyrimidine-based chemotherapy in first- and subsequent-line settings has been shown. The benefit of continued VEGF targeting has also been demonstrated with aflibercept and regorafenib. Cetuximab is effective with fluoropyrimidine, leucovorin, and irinotecan (FOLFIRI) in first-line settings and as a single agent in last-line settings. Efficacy for panitumumab has been shown with oxaliplatin with fluoropyrimidine in first-line settings, with FOLFIRI in second-line settings, and as monotherapy in last-line settings. Treatment of anti-EGFR antibodies is restricted to patients with tumors that do not harbor mutations in Kirsten rat sarcoma and in neuroblastoma RAS.

CONCLUSION

Among various therapeutic options, the future challenge will be a better selection of the population that will benefit the most from specific anti-VEGF or anti- EGFR treatment and a careful consideration of therapy sequence.

[Chemotherapy of metastatic colorectal cancer]

Increasing numbers of therapeutic options are becoming available for the systemic treatment of metastasized colorectal cancer (mCRC) which emphasizes the need for strategic decision making and planning across multiple lines of treatment. The choice of first-line therapy is influenced by clinical and molecular characteristics of patients and tumors, such as (K-)RAS gene mutations with respect to therapy guidance of epidermal growth factor receptor (EGFR) antibodies. First-line therapy is the major determinant of subsequent treatment regimens and can therefore be considered as the key decision in patients with mCRC. The German standard for first-line therapy in the majority of patients includes chemotherapy in combination with biological agents, with antibodies targeting EGFR possibly being the preferable option in patients with (K-)RAS wild-type tumors. The development of effective therapeutic strategies in patients with (K-)RAS mutant mCRC tumors must be promoted in the future and requires intensive research because the therapy options for this group of patients are very limited.

[Use of maintenance therapy and complete discontinuation for therapeutic management of non-resectable metastatic colorectal cancer]

Management of unresectable metastatic colorectal cancer dramatically changed over the past 20 years. News standards of care combine cytotoxic drugs like fluoropyrimidines, irinotecan and oxaliplatin, with targeted therapies such as anti-EGFR monoclonal antibodies and anti-angiogenic agents. Survival benefit results from these new options but correlates with more exposure to chemotherapy and cumulative toxicities. The main concern for these patients remains to find the optimal balance between efficacy, toxicity and quality of life. This article reviewed the main studies designed to evaluate the concept of maintenance therapy after induction chemotherapy and discontinuation strategy. Available therapeutic standards and options to shorten duration of chemotherapy and reduce toxicities are reported and discussed.

A feasibility study testing four hypotheses with phase II outcomes in advanced colorectal cancer (MRC FOCUS3): a model for randomised controlled trials in the era of personalised medicine?

BACKGROUND

Molecular characteristics of cancer vary between individuals. In future, most trials will require assessment of biomarkers to allocate patients into enriched populations in which targeted therapies are more likely to be effective. The MRC FOCUS3 trial is a feasibility study to assess key elements in the planning of such studies.

PATIENTS AND METHODS

Patients with advanced colorectal cancer were registered from 24 centres between February 2010 and April 2011. With their consent, patients' tumour samples were analysed for KRAS/BRAF oncogene mutation status and topoisomerase 1 (topo-1) immunohistochemistry. Patients were then classified into one of four molecular strata; within each strata patients were randomised to one of two hypothesis-driven experimental therapies or a common control arm (FOLFIRI chemotherapy). A 4-stage suite of patient information sheets (PISs) was developed to avoid patient overload.

RESULTS

A total of 332 patients were registered, 244 randomised. Among randomised patients, biomarker results were provided within 10 working days (w.d.) in 71%, 15 w.d. in 91% and 20 w.d. in 99%. DNA mutation analysis was 100% concordant between two laboratories. Over 90% of participants reported excellent understanding of all aspects of the trial. In this randomised phase II setting, omission of irinotecan in the low topo-1 group was associated with increased response rate and addition of cetuximab in the KRAS, BRAF wild-type cohort was associated with longer progression-free survival.

CONCLUSIONS

Patient samples can be collected and analysed within workable time frames and with reproducible mutation results. Complex multi-arm designs are acceptable to patients with good PIS. Randomisation within each cohort provides outcome data that can inform clinical practice.

Survival of patients with initially unresectable colorectal liver metastases treated with FOLFOX/cetuximab or FOLFIRI/cetuximab in a multidisciplinary concept (CELIM study)

BACKGROUND

Initially, unresectable colorectal liver metastases can be resected after response to chemotherapy. While cetuximab has been shown to increase response and resection rates, the survival outcome for this conversion strategy needs further evaluation.

PATIENTS AND METHODS

Patients with technically unresectable and/or ≥5 liver metastases were treated with FOLFOX/cetuximab (arm A) or FOLFIRI/cetuximab (arm B) and evaluated with regard to resectability every 2 months. Tumour response and secondary resection data have been reported previously. A final analysis of overall survival (OS) and progression-free survival (PFS) was carried out in December 2012.

RESULTS

Between December 2004 and March 2008, 56 patients were randomised to arm A, 55 to arm B. The median OS was 35.7 [95% confidence interval (CI) 27.2-44.2] months [arm A: 35.8 (95% CI 28.1-43.6), arm B: 29.0 (95% CI 16.0-41.9) months, HR 1.03 (95% CI 0.66-1.61), P = 0.9]. The median PFS was 10.8 (95% CI 9.3-12.2) months [arm A: 11.2 (95% CI 7.2-15.3), arm B: 10.5 (95% CI 8.9-12.2) months, HR 1.18 (95% CI 0.79-1.74), P = 0.4]. Patients who underwent R0 resection (n = 36) achieved a better median OS [53.9 (95% CI 35.9-71.9) months] than those who did not [21.9 (95% CI 17.1-26.7) months, P < 0.001]. The median disease-free survival for R0 resected patients was 9.9 (95% CI 5.8-14.0) months, and the 5-year OS rate was 46.2% (95% CI 29.5% to 62.9%).

CONCLUSIONS

This study confirms a favourable long-term survival for patients with initially sub-optimal or unresectable colorectal liver metastases who respond to conversion therapy and undergo secondary resection. Both FOLFOX/FOLFIRI plus cetuximab, appear to be appropriate regimens for 'conversion' treatment in patients with K-RAS codon 12/13/61 wild-type tumours. Thus, liver surgery can be considered curative or alternatively as an additional 'line of therapy' in those patients who are not cured.

CLINICAL TRIAL NUMBER

NCT00153998, www.clinicaltrials.gov.

Selected gastrointestinal cancer presentations from the American Society of Clinical Oncology annual meeting 2013 in review: it is not about the destination, it is about the journey

INTRODUCTION

In the GI tumors area, key findings from the American Society of Clinical Oncology 2013 annual meeting were long awaited, particularly in colorectal, gastric and pancreatic cancer.

AREAS COVERED

The following pages briefly present and comment on a selection of those studies considered most relevant for clinical practice and future research planning. The following trials were then reviewed: the FIRE-3, Triplet + beva (TRIBE), new EPOC, CAIRO-3 and SAKK in colorectal cancer, the TRIO-013/LOGIC and COUGAR-02 in gastric cancer and the metastatic adenocarcinoma of the pancreas (MPACT) and LAP07 in pancreatic cancer.

EXPERT OPINION

Although the proportion of clinical questions that these trials were able to answer was almost exactly paralleled by the introduction of new questions to be responded in the next (hopefully) few years, globally they represented a significant improvement in our knowledge about colorectal cancer and pancreatic tumors.

Conference Scene: Annual Meeting of the American Society of Clinical Oncology

Annual Meeting of the American Society of Clinical Oncology, Chicago, IL, USA, 31 May–4 June 2013

Every year the American Society of Clinical Oncology Annual Meeting is one of the most awaited events for medical oncologists all around the world. This report briefly summarizes some of the most relevant news in the treatment of metastatic colorectal cancer patients with special regard to notable results from randomized trials in first-line treatment and the maintenance setting, and to new data regarding molecular determinants that will shortly enter the daily clinical practice.