A phase II study of neoadjuvant bevacizumab plus capecitabine and concomitant radiotherapy in patients with locally advanced rectal cancer

Radiotherapy in the preoperative neoadjuvant treatment of locally advanced rectal cancer

Radiotherapy and chemotherapy are effective treatments for patients with locally advanced rectal cancer (LARC) and can significantly improve the likelihood of R0 resection. Radiotherapy can be used as a local treatment to reduce the size of the tumor, improve the success rate of surgery and reduce the residual cancer cells after surgery. Early chemotherapy can also downgrade the tumor and eliminate micrometastases throughout the body, reducing the risk of recurrence and metastasis. The advent of neoadjuvant concurrent radiotherapy (nCRT) and total neoadjuvant treatment (TNT) has brought substantial clinical benefits to patients with LARC. Even so, given increasing demand for organ preservation and quality of life and the disease becoming increasingly younger in its incidence profile, there is a need to further explore new neoadjuvant treatment options to further improve tumor remission rates and provide other opportunities for patients to choose watch-and-wait (W&W) strategies that avoid surgery. Targeted drugs and immunologic agents (ICIs) have shown good efficacy in patients with advanced rectal cancer but have not been commonly used in neoadjuvant therapy for patients with LARC. In this paper, we review several aspects of neoadjuvant therapy, including radiation therapy and chemotherapy drugs, immune drugs and targeted drugs used in combination with neoadjuvant therapy, with the aim of providing direction and thoughtful perspectives for LARC clinical treatment and research trials.

Angiogenesis as a hallmark of solid tumors - clinical perspectives

BACKGROUND

Angiogenesis is a key and early step in tumorigenesis, and is known as a hallmark of solid tumors and a key promoter of tumor recurrence. Unlike normal tissue vessels, the architecture of the tumor vasculature is abnormal, being leaky, tortuous, fragile and blind-ended. Perivascular cells are either detached or absent, causing reduction of vascular integrity, an increase in vessel immaturity, incoherent perfusion, defective functionality and enhanced tumor dissemination and metastasis. The abnormal tumor vasculature along with the defective tumor vessel functionality finally causes bouts of hypoxia and acidity in the tumor microenvironment (TME), further reinvigorating tumor aggression. Interstitial hypertension or high interstitial fluid pressure (IFP) is an outcome of tumor hyper-permeability. High IFP can be a barrier for either effective delivery of anti-cancer drugs toward the TME or accumulation of drugs within the tumor area, thus promoting tumor resistance to therapy. Some tumors do, however, not undergo angiogenesis but instead undergo vessel co-option or vascular mimicry, thereby adding another layer of complexity to cancer development and therapy.

CONCLUSIONS

Combination of anti-angiogenesis therapy with chemotherapy and particularly with immune checkpoint inhibitors (ICIs) is a promising strategy for a number of advanced cancers. Among the various approaches for targeting tumor angiogenesis, vascular normalization is considered as the most desired method, which allows effective penetration of chemotherapeutics into the tumor area, thus being an appropriate adjuvant to other cancer modalities.

The efficacy and safety of adding bevacizumab in neoadjuvant therapy for locally advanced rectal cancer patients: A systematic review and meta-analysis

Background

Patients with locally advanced rectal cancer (LARC) are more likely to suffer local recurrence and distant metastases, contributing to worse prognoses. Considering the provided dramatic reduction of local recurrences, neoadjuvant CRT (nCRT) followed by curative resection with total mesorectal excision (TME) and adjuvant chemotherapy has been established as standard therapy for LARC patients. However, the efficacy of adding bevacizumab in neoadjuvant therapy, especially in induction therapy-containing nCRT for LARC patients remains uncertain.

Materials

PubMed, Embase, and Web of Science were searched to retrieve records on the application of bevacizumab in a neoadjuvant setting for LARC patients. The endpoints of interest were pCR and the rates of patients suffering Grade 3/4 bevacizumab-specific adverse events, namely bleeding, wound healing complications, and gastrointestinal perforation.

Results

29 cohorts covering 1134 subjects were included in this systematic review. The pooled pCR rate for bevacizumab-relevant cohorts was 21% (95% confidence interval (95% CI), 17–25%; I² = 61.8%), the pooled estimates of Grade 3/4 bleeding, Grade 3/4 wound healing complication, Grade 3/4 gastrointestinal perforation were 1% (95% CI, 0–3%; I² = 0%), 2% (95% CI, 1–5%; I² = 4.7%), and 2% (95% CI, 0–5%; I² = 0%), respectively.

Conclusion

The addition of bevacizumab in the nCRT, especially in the TNT, for LARC patients provides promising efficacy and acceptable safety. However, the results should be interpreted cautiously due to the small amount of relevant data and need further confirmation by future studies.

Recent advances in (chemo-)radiation therapy for rectal cancer: a comprehensive review

The role of radiation therapy in the treatment of (colo)-rectal cancer has changed dramatically over the past decades. Introduced with the aim of reducing the high rates of local recurrences after conventional surgery, major developments in imaging, surgical technique, systemic therapy and radiation delivery have now created a much more complex environment leading to a more personalized approach. Functional aspects including reduction of acute or late treatment-related side effects, sphincter or even organ-preservation and the unsolved problem of still high distant failure rates have become more important while local recurrence rates can be kept low in the vast majority of patients. This review summarizes the actual role of radiation therapy in different subgroups of patients with rectal cancer, including the current standard approach in different subgroups as well as recent developments focusing on neoadjuvant treatment intensification and/or non-operative treatment approaches aiming at organ-preservation.

Influence of concurrent capecitabine based chemoradiotherapy with bevacizumab on the survival rate, late toxicity and health-related quality of life in locally advanced rectal cancer: a prospective phase II CRAB trial

Background

Few studies reported early results on efficacy, toxicity of combined modality treatment for locally advanced rectal cancer (LARC) by adding bevacizumab to preoperative chemoradiotherapy, but long-term data on survival, and late complications are lacking. Further, none of the studies reported on the assessment of quality of life (QOL).

Patients and methods

After more than 5 years of follow-up, we updated the results of our previous phase II trial in 61 patients with LARC treated with neoadjuvant capecitabine, radiotherapy and bevacizumab (CRAB study) before surgery and adjuvant chemotherapy. Secondary endpoints of updated analysis were local control (LC), disease free (DFS) and overall survival (OS), late toxicity and longitudinal health related QOL (before starting the treatment and one year after the treatment) with questionnaire EORTC QLQ-C30 and EORTC QLQ-CR38.

Results

Median follow-up was 67 months. During the follow-up period, 16 patients (26.7%) died. The 5-year OS, DFS and LC rate were 72.2%, 70% and 92.4%. Patients with pathological positive nodes or pathological T3–4 tumors had significantly worse survival than patients with pathological negative nodes or T0–2 tumors. Nine patients (14.8%) developed grade ³3 late complications of combined modality treatment, first event 12 months and last 87 months after operation (median time 48 months). Based on EORTC QLQ-C30 scores one year after treatment there were no significant changes in global QOL and three symptoms (pain, insomnia and diarrhea), but physical and social functioning significantly decreased. Based on QLQ-CR38 scores body image scores significantly increase, problems with weight loss significantly decrease, but sexual dysfunction in men and chemotherapy side effects significantly increase.

Conclusions

Patients with LARC and high risk factors, such as positive pathological lymph nodes and high pathological T stage, deserve more aggressive treatment in the light of improving long-term survival results. Patients after multimodality treatment should be given greater attention to the regulation of individual aspects of quality of life and the occurrence of late side effects.

Methodological Development of Combination Drug and Radiotherapy in Basic and Clinical Research

Newer technical improvements in radiation oncology have been rapidly implemented in recent decades, allowing an improved therapeutic ratio. The development of strategies using local and systemic treatments concurrently, mainly targeted therapies, has however plateaued. Targeted molecular compounds and immunotherapy are increasingly being incorporated as the new standard of care for a wide array of cancers. A better understanding of possible prior methodology issues is therefore required and should be integrated into upcoming early clinical trials including individualized radiotherapy-drug combinations. The outcome of clinical trials is influenced by the validity of the preclinical proofs of concept, the impact on normal tissue, the robustness of biomarkers and the quality of the delivery of radiation. Herein, key methodological aspects are discussed with the aim of optimizing the design and implementation of future precision drug-radiotherapy trials.

Combination of novel systemic agents and radiotherapy for solid tumors - Part II: An AIRO (Italian association of radiotherapy and clinical oncology) overview focused on treatment toxicity

Clinical development and use of novel systemic agents in combination with radiotherapy (RT) is at nowadays most advanced in the field of treatment of solid tumors. Although for many of these substances preclinical studies provide sufficient evidences on their principal capability to enhance radiation effects, the majority of them have not been investigated in even phase I clinical trials for safety in the context of RT. In clinical practice, unexpected acute and late side effects may emerge especially in combination with RT. As a matter of fact, despite combined modality treatment holds potential for enhancing the therapeutic ratio, some concerns are raised from the lack of high-quality clinical data to guide the care of patients who are treated with novel compounds in conjunction with RT. The aim of this review is to provide, from a radio-oncological point of view, an overview of the most advanced combined treatment concepts for solid tumors focusing on treatment toxicity.

Combination of novel systemic agents and radiotherapy for solid tumors - part I: An AIRO (Italian association of radiotherapy and clinical oncology) overview focused on treatment efficacy

Over the past century, technologic advances have promoted the evolution of radiation therapy into a precise treatment modality allowing for the maximal administration of dose to tumors while sparing normal tissues. In parallel with this technological maturation, the rapid expansion in understanding the basic biology and heterogeneity of cancer has led to the development of several compounds that target specific pathways. Many of them are in advanced steps of clinical development for combination treatments with radiotherapy, and can be incorporated into radiation oncology practice for a personalized approach to maximize the therapeutic gain. This review describes the rationale for combining novel agents with radiation, and provides an overview of the current landscape focused on treatment efficacy.

The efficacy of adding targeted agents to neoadjuvant therapy for locally advanced rectal cancer patients: a meta-analysis

Patients with locally advanced rectal cancer (LARC) are at tremendous risk of metastatic diseases. To improve the prognoses of LARC patients, the efficacy of adding targeted agents to neoadjuvant therapy has been investigated by many researchers but remains controversial. A literature search of relevant databases was conducted through December 2016, 804 studies were identified and 32 investigations were ultimately included. A total of 1196 patients from 31 cohorts of 29 studies were eligible for quantitative synthesis in this single‐arm setting meta‐analysis. As pathologic complete response (pCR) shows promise as a prognosis indicator, we focused on pCR rates to evaluate whether adding targeted agents to neoadjuvant therapies improves the outcome of LARC patients. In our study, we revealed pooled estimates of pCR of 27% (95%CI, 21–34%) and 14% (95%CI, 9–21%) for bevacizumab‐relevant cohorts and cetuximab‐relevant cohorts, respectively. The safety of adding targeted agents to neoadjuvant therapy was also evaluated by pooling the data of Grade 3/4 toxicity. In conclusion, our study revealed that adding bevacizumab to the neoadjuvant therapy regimens provides appreciable pCR for LARC patients. Meanwhile, the efficacy of cetuximab remains inconclusive, RCTs with larger scale and better study design that stress more on mutational status are needed.

Phase 2 Neoadjuvant Treatment Intensification Trials in Rectal Cancer: A Systematic Review

PURPOSE

Multiple phase 2 trials of neoadjuvant treatment intensification in locally advanced rectal cancer have reported promising efficacy signals, but these have not translated into improved cancer outcomes in phase 3 trials. Improvements in phase 2 trial design are needed to reduce these false-positive signals. This systematic review evaluated the design of phase 2 trials of neoadjuvant long-course radiation or chemoradiation therapy treatment intensification in locally advanced rectal cancer.

METHODS AND MATERIALS

The PubMed, EMBASE, MEDLINE, and Cochrane Library databases were searched for published phase 2 trials of neoadjuvant treatment intensification from 2004 to 2016. Trial clinical design and outcomes were assessed, with statistical design and compliance rated using a previously published system. Multivariable meta-regression analysis of pathologic complete response (pCR) was conducted.

RESULTS

We identified 92 eligible trials. Patients with American Joint Committee on Cancer stage II and III equivalent disease were eligible in 87 trials (94.6%). In 43 trials (46.7%), local staging on magnetic resonance imaging was mandated. Only 12 trials (13.0%) were randomized, with 8 having a standard-treatment control arm. Just 51 trials (55.4%) described their statistical design, with 21 trials (22.8%) failing to report their sample size derivation. Most trials (n=84, 91.3%) defined a primary endpoint, but 15 different primary endpoints were used. All trials reported pCR rates. Only 38 trials (41.3%) adequately reported trial statistical design and compliance. Meta-analysis revealed a pooled pCR rate of 17.5% (95% confidence interval, 15.7%-19.4%) across treatment arms of neoadjuvant long-course radiation or chemoradiation therapy treatment intensification and substantial heterogeneity among the reported effect sizes (I² = 55.3%, P<.001). Multivariable meta-regression analysis suggested increased pCR rates with higher radiation therapy doses (adjusted P=.025).

CONCLUSIONS

Improvement in the design of future phase 2 rectal cancer trials is urgently required. A significant increase in randomized trials is essential to overcome selection bias and determine novel schedules suitable for phase 3 testing. This systematic review provides key recommendations to guide future treatment intensification trial design in rectal cancer.

The Addition of Target Therapy to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer: A Review

Currently, neoadjuvant fluoropyrimidine-based chemoradiotherapy (CRT) is standard practice in the management of locally advanced rectal cancer (LARC). In the last decade there has been a lively interest in the improvement of clinical outcomes by modifying this standard regimen by the addition of further agents. We review combinations of targeted therapies and conventional CRT currently under investigation in LARC patients.

A Dose-finding and Biomarker Evaluation Phase Ib Study of Everolimus in Association With 5-Fluorouracil and Pelvic Radiotherapy as Neoadjuvant Treatment of Locally Advanced Rectal Cancer (E-LARC Study)

BACKGROUND

During the past 20 years, considerable improvement has occurred in the treatment of patients with locally advanced rectal cancer (LARC). With the introduction of multimodal treatment, refinements in preclinical staging and improvements in surgical skills, local relapse is no longer the major problem for patients with LARC. However, many patients die of metastatic disease. The present phase Ib study aimed to establish the maximum tolerated dose of everolimus combined with 5-fluorouracil and radiotherapy in patients with LARC.

PATIENTS AND METHODS

Patients were sequentially assigned to 4 cohorts with an increasing dose of everolimus, starting from 14 days before 5-fluorouracil and radiotherapy and continuing throughout concomitant treatment. The secondary endpoints were the Dworak tumor regression grade, pathologic complete response rate, neoadjuvant rectal score, biomarker assessment (phosphorylated mTOR [mammalian target of rapamycin] protein and phosphorylated-p70S6K protein).

RESULTS

At the time of this report, 12 patients had been treated, and no dose-limiting toxicity was recorded. The most frequently reported acute toxicities were rectal tenesmus, skin rash, diarrhea, and dysuria. All 12 patients underwent curative R0 resection. Two patients had Dworak tumor regression grade 4 (pathologic complete response). No everolimus-related postoperative complications were observed. No relationship was found between biomarker expression and the clinicopathologic outcomes.

CONCLUSION

Although the addition of everolimus did not appear to worsen the toxicity of chemoradiation in patients with LARC, evaluation of its activity deserves further investigation in larger clinical trials.

Reengineering the Tumor Microenvironment to Alleviate Hypoxia and Overcome Cancer Heterogeneity

Solid tumors consist of cancer cells and stromal cells, including resident and transiting immune cells-all ensconced in an extracellular matrix (ECM)-nourished by blood vessels and drained by lymphatic vessels. The microenvironment constituents are abnormal and heterogeneous in morphology, phenotype, and physiology. Such irregularities include an inefficient tumor vascular network comprised of leaky and compressed vessels, which impair blood flow and oxygen delivery. Low oxygenation in certain tumor regions-or focal hypoxia-is a mediator of cancer progression, metastasis, immunosuppression, and treatment resistance. Thus, repairing an abnormal and heterogeneous microenvironment-and hypoxia in particular-can significantly improve treatments of solid tumors. Here, we summarize two strategies to reengineer the tumor microenvironment (TME)-vessel normalization and decompression-that can alleviate hypoxia. In addition, we discuss how these two strategies alone and in combination with each other-or other therapeutic strategies-may overcome the challenges posed by cancer heterogeneity.

Critical role of bevacizumab scheduling in combination with pre-surgical chemo-radiotherapy in MRI-defined high-risk locally advanced rectal cancer: Results of the BRANCH trial

BACKGROUND

We have previously shown that an intensified preoperative regimen including oxaliplatin plus raltitrexed and 5-fluorouracil/folinic acid (OXATOM/FUFA) during preoperative pelvic radiotherapy produced promising results in locally advanced rectal cancer (LARC). Preclinical evidence suggests that the scheduling of bevacizumab may be crucial to optimize its combination with chemo-radiotherapy.

PATIENTS AND METHODS

This non-randomized, non-comparative, phase II study was conducted in MRI-defined high-risk LARC. Patients received three biweekly cycles of OXATOM/FUFA during RT. Bevacizumab was given 2 weeks before the start of chemo-radiotherapy, and on the same day of chemotherapy for 3 cycles (concomitant-schedule A) or 4 days prior to the first and second cycle of chemotherapy (sequential-schedule B). Primary end point was pathological complete tumor regression (TRG1) rate.

RESULTS

The accrual for the concomitant-schedule was early terminated because the number of TRG1 (2 out of 16 patients) was statistically inconsistent with the hypothesis of activity (30%) to be tested. Conversely, the endpoint was reached with the sequential-schedule and the final TRG1 rate among 46 enrolled patients was 50% (95% CI 35%-65%). Neutropenia was the most common grade ≥ 3 toxicity with both schedules, but it was less pronounced with the sequential than concomitant-schedule (30% vs. 44%). Postoperative complications occurred in 8/15 (53%) and 13/46 (28%) patients in schedule A and B, respectively. At 5 year follow-up the probability of PFS and OS was 80% (95%CI, 66%-89%) and 85% (95%CI, 69%-93%), respectively, for the sequential-schedule.

CONCLUSIONS

These results highlights the relevance of bevacizumab scheduling to optimize its combination with preoperative chemo-radiotherapy in the management of LARC.

Targeted agents in GI radiotherapy: Clinical efficacy and side effects

Approximately 50% of all patients with cancer receive radiotherapy (RT) at some point during their treatment. Despite the advent of modern imaging and advances in planning and delivering highly-conformal and precise RT, further dose escalation to improve clinical outcome is often limited by the potential side-effects to adjacent tissues. Addition of chemotherapy to radiotherapy (CRT) has led to significant clinical improvements in many gastrointestinal malignancies but at the expense of increased toxicity as most chemotherapy drugs lack specificity. Targeted agents modulate specific biological pathways and can potentially enhance RT efficacy. However, so far, the majority of clinical studies incorporating targeted agents into RT and CRT have produced disappointing results in gastrointestinal malignancies. Also, we lack validated biomarkers and methods for monitoring and predicting the efficacy of these agents when combined with RT/CRT. In the present article, we will review the most important targeted therapies, and examine the efficacy and toxicity of these agents when combined with RT/CRT in gastrointestinal malignancies. The shortcomings as well as future challenges and perspectives for the successful use of these compounds with RT/CRT in future trials will also be outlined.

Balancing efficacy of and host immune responses to cancer therapy: the yin and yang effects

Local and systemic treatments for cancer include surgery, radiation, chemotherapy, hormonal therapy, molecularly targeted therapies, antiangiogenic therapy, and immunotherapy. Many of these therapies can be curative in patients with early stage disease, but much less frequently is this the case when they are used to treat advanced-stage metastatic disease. In the latter setting, innate and/or acquired resistance are among the reasons for reduced responsiveness or nonresponsiveness to therapy, or for tumour relapse after an initial response. Most studies of resistance or reduced responsiveness focus on 'driver' genetic (or epigenetic) changes in the tumour-cell population. Several studies have highlighted the contribution of therapy-induced physiological changes in host tissues and cells that can reduce or even nullify the desired antitumour effects of therapy. These unwanted host effects can promote tumour-cell proliferation (repopulation) and even malignant aggressiveness. These effects occur as a result of systemic release of numerous cytokines, and mobilization of various host accessory cells, which can invade the treated tumour microenvironment. In short, the desired tumour-targeting effects of therapy (the 'yin') can be offset by a reactive host response (the 'yang'); proactively preventing or actively suppressing the latter represents a possible new approach to improving the efficacy of both local and systemic cancer therapies.

Phase I study of pre-operative continuous 5-FU and sorafenib with external radiation therapy in locally advanced rectal adenocarcinoma

PURPOSE

The standard of care in locally advanced rectal cancer is preoperative treatment with fluoropyrimidine-based chemoradiotherapy. Sorafenib works synergistically with radiation and inhibits Ras/Raf, PDFGR, and VEGFR. This phase I study evaluated the safety and efficacy of sorafenib with infusional 5-fluorouracil (5-FU) and radiation in patients with locally advanced rectal cancer.

METHODS AND MATERIALS

Patients with confirmed stage II or III rectal cancer were recruited in 4 cohorts of 3 patients per dose level, with an expansion cohort at the maximum tolerated dose. A 3+3 dose escalation design was used. Radiation was given in 28 fractions at 1.8 Gy (50.4 Gy) day 1-5 at all dose levels. Initial dose of sorafenib was 200mg qd and titrated up to 400mg BID to determine the MTD. Standard dose of infusional 5-FU was used (225 mg/m(2)/24h). Patients underwent surgery 6-10 weeks after neoadjuvant therapy.

RESULTS

Between August 2011 and August 2014, 17 patients (median age of 54 years) were enrolled. After toxicities requiring dose interruptions were observed in cohort 1 (2 patients with grade 2 (G2) and grade 3 (G3) hand foot skin reaction and 1 patient with G2 mucositis), the protocol was amended, changing administration of chemotherapy and sorafenib from daily to days 1-5 only. With the amended protocol, the primary G3 toxicity was hypertension in 2 patients at the 200-mg adjusted dose level (day1-5) and 1 patient at the 400-mg twice daily dose level. One patient had G3 ALT elevation at 400mg, and no grade IV toxicities were observed. G1 and G2 toxicities included hand-foot skin reaction, diarrhea, mucositis, nausea, fatigue, and proctitis. No perioperative complications were seen. Two patients refused to undergo surgery. The pathological complete remission (pCR) rate was 33%, and downstaging was observed in 85.7% of patients. Median neoadjuvant rectal cancer score was 8.7.

CONCLUSIONS

With the changed dosing schedule, this regimen was very well tolerated. The tumor pCR and downstaging rates are encouraging and support further clinical investigation of this regimen.

Role of vascular density and normalization in response to neoadjuvant bevacizumab and chemotherapy in breast cancer patients

Preoperative bevacizumab and chemotherapy may benefit a subset of breast cancer (BC) patients. To explore potential mechanisms of this benefit, we conducted a phase II study of neoadjuvant bevacizumab (single dose) followed by combined bevacizumab and adriamycin/cyclophosphamide/paclitaxel chemotherapy in HER2-negative BC. The regimen was well-tolerated and showed a higher rate of pathologic complete response (pCR) in triple-negative (TN)BC (11/21 patients or 52%, [95% confidence interval (CI): 30,74]) than in hormone receptor-positive (HR)BC [5/78 patients or 6% (95%CI: 2,14)]. Within the HRBCs, basal-like subtype was significantly associated with pCR (P = 0.007; Fisher exact test). We assessed interstitial fluid pressure (IFP) and tissue biopsies before and after bevacizumab monotherapy and circulating plasma biomarkers at baseline and before and after combination therapy. Bevacizumab alone lowered IFP, but to a smaller extent than previously observed in other tumor types. Pathologic response to therapy correlated with sVEGFR1 postbevacizumab alone in TNBC (Spearman correlation 0.610, P = 0.0033) and pretreatment microvascular density (MVD) in all patients (Spearman correlation 0.465, P = 0.0005). Moreover, increased pericyte-covered MVD, a marker of extent of vascular normalization, after bevacizumab monotherapy was associated with improved pathologic response to treatment, especially in patients with a high pretreatment MVD. These data suggest that bevacizumab prunes vessels while normalizing those remaining, and thus is beneficial only when sufficient numbers of vessels are initially present. This study implicates pretreatment MVD as a potential predictive biomarker of response to bevacizumab in BC and suggests that new therapies are needed to normalize vessels without pruning.

Combining bevacizumab and chemoradiation in rectal cancer. Translational results of the AXEBeam trial

Background:

This study characterises molecular effect of bevacizumab, and explores the relation of molecular and genetic markers with response to bevacizumab combined with chemoradiotherapy (CRT).

Methods:

From a subset of 59 patients of 84 rectal cancer patients included in a phase II study combining bevacizumab with CRT, tumour and blood samples were collected before and during treatment, offering the possibility to evaluate changes induced by one dose of bevacizumab. We performed cDNA microarrays, stains for CD31/CD34 combined with α-SMA and CA-IX, as well as enzyme-linked immunosorbent assay (ELISA) for circulating angiogenic proteins. Markers were related with the pathological response of patients.

Results:

One dose of bevacizumab changed the expression of 14 genes and led to a significant decrease in microvessel density and in the proportion of pericyte-covered blood vessels, and a small but nonsignificant increase in hypoxia. Alterations in angiogenic processes after bevacizumab delivery were only detected in responding tumours. Lower PDGFA expression and PDGF-BB levels, less pericyte-covered blood vessels and higher CA-IX expression were found after bevacizumab treatment only in patients with pathological complete response.

Conclusions:

We could not support the ‘normalization hypothesis' and suggest a role for PDGFA, PDGF-BB, CA-IX and α-SMA. Validation in larger patient groups is needed.

Phase II study of preoperative bevacizumab, capecitabine and radiotherapy for resectable locally-advanced rectal cancer

Background

To evaluate whether the addition of bevacizumab (BVZ) to capecitabine-based chemoradiotherapy in the preoperative treatment of locally advanced rectal cancer (LARC) improves efficacy measured by the pathological complete response (pCR) rate.

Methods

A phase II two-step design was performed. Patients received four cycles of therapy consisting of: BVZ 10 mg/kg in first infusion on day 1 and 5 mg/kg on days 15, 29, 43, capecitabine 1800 mg/m²/day 5 days per week during radiotherapy, which consisted of external-beam irradiation (45 Gy in 1.8 Gy dose per session over 5 sessions/week for 5 weeks). Six to eight weeks after completion of all therapies surgery was undergone. To profile the biological behaviour during BVZ treatment we measured molecular biomarkers before treatment, during BVZ monotherapy, and during and after combination therapy. Microvessel density (MVD) was measured after surgery.

Results

Forty-three patients were assessed and 41 were included in the study. Three patients achieved a pathological complete response (3/40: 7.5%) and 27 (67.5%) had a pathological partial response, (overall pathological response rate of 75%). A further 8 patients (20%) had stable disease, giving a disease control rate of 95%. Downstaging occurred in 31 (31/40: 77.5%) of the patients evaluated. This treatment resulted in an actuarial 4-year disease-free and overall survival of 85.4 and 92.7% respectively. BVZ with chemoradiotherapy showed acceptable toxicity. No correlations were observed between biomarker results and efficacy variables.

Conclusion

BVZ with capecitabine and radiotherapy seem safe and active and produce promising survival results in LARC.

Trial registration

ClinicalTrials.gov Identifier NCT00847119. Trial registration date: February 18, 2009.

The emerging quest for the optimal angiostatic combination therapy

Angiostatic therapies are now routinely embedded in the daily clinical management of cancer. Although these agents clearly benefit patient survival rates, the effect is only moderate with sometimes considerable side effects. A major cause of failure in this respect is the induction of resistance and tolerability against these drugs. Most angiostatic drugs are tyrosine kinase inhibitors that aim to inhibit or neutralize the activity of tumour-produced growth factors. Frustrating the tumour cells in this way results in genetic adaptations in the cells, turning them into mutants that are dependent on other growth mechanisms. It may therefore be necessary to shift to another class of drugs that directly target the tumour vasculature. It is evident that improvement of future angiogenesis inhibitors can only arise from two efforts. First, through the identification of better targets, preferably specifically expressed in the tumour vasculature. Secondly, through the development of combination therapies. The present review highlights the current efforts and challenges in trying to develop effective angiostatic combination therapies.

Phase II trial evaluating the feasibility of interdigitating folfox with chemoradiotherapy in locally advanced and metastatic rectal cancer

BACKGROUND

Patients (pts) with metastatic rectal cancer and symptomatic primary, require local and systemic control. Chemotherapy used during chemoradiotherapy (CRT) is adequate for radiosensitisation, but suboptimal for systemic control. The aim of this phase II study was to assess tolerability, local/systemic benefits, of a novel regimen delivering interdigitating intensive chemotherapy with radical CRT.

METHODS

Eligible pts had untreated synchronous symptomatic primary/metastatic rectal cancer. A total of 12 weeks of treatment with split-course pelvic CRT (total 50.4 Gy with concurrent oxaliplatin and 5-FU infusion) alternating with FOLFOX chemotherapy. All pts staged with CT, MRI and FDG-PET pre and post treatment.

RESULTS

Twenty-six pts were treated. Rectal primary MRI stage: T3 81% and T4 15%. Liver metastases in 81%. Twenty-four pts (92%) completed the 12-week regimen. All patients received planned RT dose, and for both agents over 88% of patients achieved a relative dose intensity of >75%. Grade 3 toxicities: neutropenia 23%, diarrhoea 15%, and radiation skin reaction 12%. Grade 4 toxicity: neutropenia 15%. FDG-PET metabolic response rate for rectal primary 96%, and for metastatic disease 60%.

CONCLUSIONS

Delivery of interdigitating chemotherapy with radical CRT was feasible to treat both primary and metastatic rectal cancer. High completion and response rates were encouraging.

Neoadjuvant capecitabine, bevacizumab and radiotherapy for locally advanced rectal cancer: results of a single-institute Phase I study

The aim of this Phase I clinical trial was to assess the feasibility and safety of capecitabine-based preoperative chemoradiotherapy (CRT) combined with bevacizumab and to determine the optimal capecitabine dose for Japanese patients with locally advanced rectal cancer. Patients with cT3/T4 rectal cancer were eligible. Bevacizumab was administered at 5 mg/kg intravenously on Days 1, 15 and 29. Capecitabine was administered on weekdays concurrently with pelvic radiotherapy at a daily dose of 1.8 Gy, totally to 50.4 Gy. Capecitabine was initiated at 825 mg/m(2) twice daily at Dose Level 1, with a planned escalation to 900 mg/m(2) twice daily at Dose Level 2. Within 6.1-10.3 (median, 9.4) weeks after the completion of the CRT, surgery was performed. Three patients were enrolled at each dose level. Regarding the CRT-related acute toxicities, all of the adverse events were limited to Grade 1. There was no Grade 2 or greater toxicity. No patient needed attenuation or interruption of bevacizumab, capecitabine or radiation. All of the patients received the scheduled dose of CRT. All of the patients underwent R0 resection. Two (33.3%) of the six patients had a pathological complete response, and five (83.3%) patients experienced downstaging. In total, three patients (50%) developed postoperative complications. One patient developed an intrapelvic abscess and healed with incisional drainage. The other two patients healed following conservative treatment. This regimen was safely performed as preoperative CRT for Japanese patients with locally advanced rectal cancer. The recommended capecitabine dose is 900 mg/m(2) twice daily.

Phase II study of preoperative concurrent chemoradiotherapy with S-1 plus bevacizumab for locally advanced resectable rectal adenocarcinoma

OBJECTIVE

A single-arm phase II clinical trial was conducted to evaluate the safety and efficacy of preoperative chemoradiotherapy (CRT) with concurrent S-1, bevacizumab, and radiation in patients with locally advanced rectal cancer (LARC).

METHODS

Fifty-two patients with LARC were enrolled. A total dose of 45 Gy was delivered in 25 fractions over 5 weeks, S-1 was administered orally twice a day on days 1-14 and 22-35, and bevacizumab was administered on days 1, 15, and 29. Surgical resection was scheduled 8 weeks (6-10 weeks) after completing the CRT.

RESULTS

All 52 patients underwent R0 radical surgery. Sphincter preservation was possible in 38 (73.1%) patients. A pathologic complete response was obtained in 10 (19.2%) patients, a pathologic downstaging was achieved in 37 (71.2%) patients, and the tumor shrinkage rate was 77.1%. The only grade 3 adverse events were leukopenia and rash in 1 (1.9%) patient. The rate of postoperative complications was 28.8%. Anastomotic leakage occurred in 9 (23.7%) of the 38 patients who underwent sphincter-preserving surgery. Perineal wound dehiscence developed in 2 (14.3%) of the 14 patients who received an abdominoperineal resection.

CONCLUSIONS

Adding bevacizumab to S-1 clearly increased the incidence of wound-related complications, with no distinct enhancement of tumor response.

Bevacizumab in the pre-operative treatment of locally advanced rectal cancer: A systematic review

Despite advances in the management of patients with locally advanced, non-metastatic rectal adenocarcinoma (LARC), prognosis remains largely unsatisfactory due to a high rate of distant relapse. In fact, currently available neoadjuvant protocols, represented by fluoropyrimidine-based chemo-radiotherapy (CT-RT) or short-course RT, together with improved surgical techniques, have largely reduced the risk of local relapse, with limited impact on distant recurrence. Available results of phase III trials with additional cytotoxic agents combined with standard CT-RT are disappointing, as no significant reduction in the risk of recurrence has been demonstrated. In order to improve the control of micrometastatic disease, integrating targeted agents into neoadjuvant treatment protocols thus offers a rational approach. In particular, the antiangiogenic agent bevacizumab has demonstrated synergistic activity with both CT and RT in pre-clinical and clinical models, and thus may represent a suitable companion in the neoadjuvant treatment of LARC. Preliminary results of phase I-II clinical studies are promising and suggest potential clinical parameters and molecular predictive biomarkers useful for patient selection: treatment personalization is indeed the key in order to maximize the benefit while reducing the risk of more complex neoadjuvant treatment schedules.

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

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

The status of targeted agents in the setting of neoadjuvant radiation therapy in locally advanced rectal cancers

Radiotherapy has a longstanding and well-defined role in the treatment of resectable rectal cancer to reduce the historically high risk of local recurrence. In more advanced borderline or unresectable cases, where the circumferential resection margin (CRM) is breached or threatened according to magnetic resonance imaging (MRI), despite optimized local multimodality treatment and the gains achieved by modern high quality total mesorectal excision (TME), at least half the patients fail to achieve sufficient downstaging with current schedules. Many do not achieve an R0 resection. In less locally advanced cases, even if local control is achieved, this confers only a small impact on distant metastases and a significant proportion of patients (30-40%) still subsequently develop metastatic disease. In fact, distant metastases have now become the predominant cause of failure in rectal cancer. Therefore, increasing the intensity and efficacy of chemotherapy and chemoradiotherapy by integrating additional cytotoxics and biologically targetted agents seems an appealing strategy to explore-with the aim of enhancing curative resection rates and improving distant control and survival. However, to date, we lack validated biomarkers for these biological agents apart from wild-type KRAS. For cetuximab, the appearance of an acneiform rash is associated with response, but low levels of magnesium appear more controversial. There are no molecular biomarkers for bevacizumab. Although some less invasive clinical markers have been proposed for bevacizumab, such as circulating endothelial cells (CECS), circulating levels of VEGF and the development of overt hypertension, these biomarkers have not been validated and are observed to emerge only after a trial of the agent. We also lack a simple method of ongoing monitoring of 'on target' effects of these biological agents, which could determine and pre-empt the development of resistance, prior to radiological and clinical assessessments or even molecular imaging. These shortcomings probably explain our current relative lack of success in the arena of combining these agents with chemoradiation.

Design and conduct of early-phase radiotherapy trials with targeted therapeutics: lessons from the PRAVO experience

New strategies to facilitate the improvement of physical and integrated biological optimization of high-precision treatment protocols are an important priority for modern radiation oncology. From a clinical perspective, as knowledge accumulates from molecular radiobiology, there is a complex and exciting opportunity to investigate novel approaches to rational patient treatment stratification based on actionable tumor targets, together with the appropriate design of next-generation early-phase radiotherapy trials utilizing targeted therapeutics, to formally evaluate relevant clinical and biomarker endpoints. A unique aspect in the development pathway of systemic agents with presumed radiosensitizing activity will also be the need for special attention on patient eligibility and the rigorous definition of radiation dose-volume relationships and potential dose-limiting toxicities. Based on recent experience from systematically investigating histone deacetylase inhibitors as radiosensitizing agents, from initial studies in preclinical tumor models through the conduct of a phase I clinical study to evaluate tumor activity of the targeted agent as well as patient safety and tumor response to the combined treatment modality, this communication will summarize principles relating to early clinical evaluation of combining radiotherapy and targeted therapeutics.

Antiangiogenic therapy of colorectal cancer: state of the art, challenges and new approaches

Advanced colorectal cancer is the first tumor type for which an antiangiogenic agent, namely bevacizumab, has been approved by the Food and Drug Administration for therapy in humans; it has been in use since February 2004. This review paper summarizes and discusses the results obtained with this agent and highlights the main open or controversial issues on antiangiogenic therapy, taking into account that the clinical results obtained are below the expectations, particularly in the adjuvant setting.

Progress in rectal cancer treatment

The dramatic improvement in local control of rectal cancer observed during the last decades is to be attributed to attention to surgical technique and to the introduction of neoadjuvant therapy regimens. Nevertheless, systemic relapse remains frequent and is currently insufficiently addressed. Intensification of neoadjuvant therapy by incorporating chemotherapy with or without targeted agents before the start of (chemo)radiation or during the waiting period to surgery may present an opportunity to improve overall survival. An increasing number of patients can nowadays undergo sphincter preserving surgery. In selected patients, local excision or even a "wait and see" approach may be feasible following active neoadjuvant therapy. Molecular and genetic biomarkers as well as innovative imaging techniques may in the future allow better selection of patients for this treatment option. Controversy persists concerning the selection of patients for adjuvant chemotherapy and/or targeted therapy after neoadjuvant regimens. The currently available evidence suggests that in complete pathological responders long-term outcome is excellent and adjuvant therapy may be omitted. The results of ongoing trials will help to establish the ideal tailored approach in resectable rectal cancer.