Irinotecan in the treatment of colorectal cancer: clinical overview.

PURPOSE AND METHODS: For more than three decades, the therapeutic options for patients with advanced colorectal cancer have almost exclusively been based on fluoropyrimidines. With the recognition that topoisomerase-I (TOP-I) is an important therapeutic target in cancer therapy, irinotecan, a semisynthetic TOP-I-interactive camptothecin derivative, has been clinically established in the treatment of colorectal cancer. RESULTS: Irinotecan was investigated as second-line chemotherapy after prior treatment with fluorouracil (FU)-based regimens in two large randomized phase III trials comparing irinotecan with either best supportive care or an infusional FU/leucovorin (LV) regimen. The outcomes of these trials established irinotecan as the standard therapy in the second-line treatment of colorectal cancer. The therapeutic value of irinotecan in the first-line treatment of metastatic colorectal cancer was investigated in two large randomized phase III trials comparing the combination of irinotecan and FU/LV with FU/LV alone. Both trials demonstrated significant superior efficacy for the combination of irinotecan and FU/LV in terms of response rate, median time to disease progression, and median survival time. Consequently, the combination of irinotecan and FU/LV has been approved as first-line chemotherapy for patients with metastatic colorectal cancer and constitutes the reference therapy against which other treatment options must be tested in the future. CONCLUSION: In this review, the clinical rationale and update of the present clinical status of irinotecan in the treatment of colorectal cancer and future prospects of irinotecan-based combinations are discussed.     

Integrating the anti-VEGF-A humanized monoclonal antibody bevacizumab with chemotherapy in advanced colorectal cancer

Recent advances in the treatment of colorectal cancer (CRC) include the incorporation of new drugs to treat a disease where only one drug was known to be active. Oxaliplatin and irinotecan have been incorporated into 5-fluorouracil (5-FU)-based regimens where they have increased response rates and survival. Targeted therapies against the epidermal growth factor pathway and the vascular endothelial growth factor (VEGF) pathway are also on the forefront of oncology research, and are beginning to play a role in the treatment of CRC. Current research efforts are trying to optimize the integration of targeted therapies into chemotherapy regimens such as IFL (irinotecan/bolus 5-FU/leucovorin [LV]), FOLFIRI (irinotecan/infusional 5-FU/LV), and FOLFOX (oxaliplatin/infusional 5-FU/LV). In this article, the incorporation of the monoclonal antibody bevacizumab into the IFL regimen will be reviewed in detail. Bevacizumab targets VEGF-A, an important angiogenesis signaling factor commonly expressed in metastatic CRC. The addition of bevacizumab to the IFL regimen significantly increased response rates, median time to progression, and overall survival in patients receiving first-line treatment for CRC, thus leading the Food and Drug Administration to approve bevacizumab for the treatment of CRC in combination with 5-FU-based regimens. Bevacizumab treatment is associated with an increased rate of hypertension. In addition, there may be slight (1%-2%) but relevant increased risks related to gastrointestinal perforations and cardiovascular events. A modest increased risk of wound healing complications was observed in patients who underwent surgery while still receiving, or shortly after receiving, bevacizumab. Bevacizumab plus 5-FU is also a highly active first-line regimen. The role of bevacizumab with other first-line combination regimens, as well as its activity in the second-line setting, is now being determined by ongoing clinical trials.     

New systemic frontline treatment for metastatic colorectal carcinoma

Options for first-line chemotherapy in patients with metastatic colorectal carcinoma have broadened considerably with the introduction of irinotecan and oxaliplatin. Furthermore, the oral fluoropyrimidine capecitabine has demonstrated efficacy in Phase III trials and recently was approved for first-line treatment in Europe and the United States. Capecitabine yielded similar median times to disease progression and median survival rates compared with bolus 5-fluorouracil (5-FU)/leucovorin (LV) (Mayo Clinic/North Central Cancer Treatment Group regimen), with superior and similar response rates, respectively. However, its role as a first-line, single-agent substitute for intermittent infusional 5-FU/LV remains to be defined. The addition of irinotecan or oxaliplatin to 5-FU/LV resulted in improved response rates and progression-free survival in large, randomized trials; moreover, irinotecan-containing regimens resulted in improved overall survival. Prevalent regimens of irinotecan/5-FU/LV and oxaliplatin/5-FU/LV have been compared in two randomized Phase III trials. One study demonstrated the statistical superiority of oxaliplatin/infusional 5-FU/LV over irinotecan/bolus 5-FU/LV in terms of response, time to disease progression, and median survival; however, those advantages may have been attributable to infusional administration or to major differences in second-line therapy. A randomized Phase III study comparing irinotecan and oxaliplatin in combination with the same infusional 5-FU/LV regimens and crossover in case of disease progression showed equivalent efficacy for both schedules in the first-line setting, but the irinotecan combination proved beneficial in terms of safety. New molecular targeted agents, such as angiogenesis-modulating compounds (e.g., bevacizumab) and epidermal growth factor receptor inhibitors (e.g., cetuximab), are under clinical investigation. This review updates current systemic frontline treatments and future perspectives for patients with advanced colorectal carcinoma.     

Oxaliplatin plus oral fluoropyrimidines in colorectal cancer

The medical treatment of colorectal cancer (CRC) has rapidly evolved in recent years with the introduction of novel cytotoxic drugs into clinical practice such as irinotecan, oxaliplatin, and capecitabine. Combination regimens using infusional 5-fluorouracil (5-FU)/leucovorin (LV) plus either oxaliplatin or irinotecan have demonstrated clinically meaningful, high efficacy in advanced CRC. Based on the results of the Intergroup trial N9741, FOLFOX4, a combination of infusional plus bolus 5-FU/LV and oxaliplatin, has emerged as the standard first-line therapy in the palliative setting. However, infusional 5-FU-based regimens carry the need for use of central venous lines and implantable ports to allow treatment on an outpatient basis and are thus inconvenient and expensive. The use of oral fluoropyrimidines (capecitabine or uracil/tegafur [UFT] plus LV) as substitutes for infusional 5-FU in combination protocols with oxaliplatin offers greater convenience, at the same time conceivably maintaining the high efficacy and tolerability observed with intravenous protocols. Various phase I/II trials have recently been reported that investigated oxaliplatin in combination with either capecitabine or UFT/LV in patients with advanced CRC. This review will detail the results of these trials focused on capecitabine-based combinations.     

Optimizing the use of irinotecan in colorectal cancer

The introduction of new agents with novel mechanisms of action has led to considerable changes in the management of colorectal cancer in recent years. One of these novel agents, irinotecan, has been shown to offer survival benefits in both the first- and second-line treatment of advanced/metastatic colorectal cancer. Irinotecan monotherapy improves survival compared with both best supportive care and infused 5-fluorouracil (5-FU) in patients with 5-FU-pretreated disease, without impacting negatively on patients' quality of life. As a result, irinotecan monotherapy is now considered to be the standard treatment in this setting. Irinotecan in combination with 5-FU/leucovorin (LV) was subsequently evaluated as first-line therapy for metastatic colorectal cancer in two randomized, phase III studies. Both trials confirmed that irinotecan plus infused or bolus 5-FU/leucovorin LV provide a modest survival benefit without compromising patients' quality of life. Combined irinotecan/5-FU/LV represents a new standard in the first-line treatment of metastatic colorectal cancer. In an attempt to further improve efficacy and tolerability, recent studies have investigated irinotecan in combination with capecitabine as first-line treatment for colorectal cancer. The replacement of infused 5-FU with oral capecitabine provides a more convenient treatment option. A phase I study was conducted to establish the maximum tolerated dose, and demonstrated encouraging antitumor activity and a manageable safety profile with the combination. This article provides a brief overview of the pivotal clinical trial data for irinotecan and discusses how irinotecan-based therapy may be improved in the future. It also discusses potential optimization of irinotecan use through identification of patient subpopulations most likely to benefit from combination or sequential strategies, and the potential of new, oral agents such as capecitabine to replace i.v. 5-FU as a combination partner for irinotecan.     

晚期结直肠癌内科治疗进展

晚期转移性结直肠癌的5年生存率低于10％。5-FU／LV方案治疗的中位生存期大约12个月。最近化疗方案的更新延长了患者的中位生存期。研究发现奥沙利铂、伊立替康联合5-FU／LV或者卡培他滨等化疗方案使中位生存期延长到20个月。奥沙利铂，伊立替康联合5-FU／LV比传统的单药5-FU／LV使生活质量改善时间延长。目前转移性结直肠癌标准的一线治疗方案为FOLFOX和FOLFIRI。正在进行的研究关注新的分子靶向药物（molecular targeted therapy）联合化疗治疗转移性结直肠癌，且部分试验取得了较好的疗效。本文将对5-FU、新一代化疗药物以及分子靶向药物在转移性结肠癌治疗的演进及新进展作一综述。     

Advances in the treatment of metastatic colorectal cancer

The overall 5-year survival rate for patients with metastatic colorectal cancer (CRC) is less than 10%. Median survival with 5-fluorouracil (5-FU)/leucovorin (LV) therapy is approximately 12 months. Recent additions to the chemotherapy armamentarium for this disease have begun to prolong median survival times. In trials in which patients are exposed to all three approved chemotherapy agents, oxaliplatin, irinotecan, and 5-FU/LV, or capecitabine during the course of their disease, median survival has reached 20 months. The addition of oxaliplatin and irinotecan to 5-FU/LV regimens has also led to the maintenance of quality of life for longer intervals than were traditionally observed with 5-FU/LV alone. Current standard first-line regimens for metastatic CRC are FOLFOX (infusional 5-FU/LV with oxaliplatin) and FOLFIRI (infusional 5-FU/LV with irinotecan). The addition of bevacizumab to a two-drug regimen (irinotecan with 5-FU/LV) prolongs median survival to 20 months, with a modest amount of additional toxicity. Improvements in this median survival have not yet been realized with modifications to the current standard regimens; however, the oral agent capecitabine appears to be a reasonable substitute for infusional 5-FU/LV in combination regimens or as a single agent, with the advantage of reducing the inconvenience of the long infusion time. Ongoing investigations will identify a place for capecitabine, epidermal growth factor inhibitors, and new cytotoxics in the treatment of metastatic CRC.     

Systemic therapy for metastatic colorectal cancer: current options, current evidence.

Combination chemotherapy regimens including irinotecan and oxaliplatin markedly improve response rate and prolong median survival over fluorouracil with leucovorin (FU/LV), and have supplanted FU/LV as the standard systemic approach for metastatic colorectal cancer. The recent availability of five active chemotherapeutic agents has doubled the median overall survival for metastatic colorectal cancer from 10 to 20 months, and though the optimal strategy for incorporation of all drugs is still unclear, current data support the use of chemotherapy doublets in first-line rather than sequential single-agent therapy. Multidrug regimens increase both response rate and the proportion of patients able to undergo potentially curative resection. In addition, as many as 20% to 30% of patients never receive second-line chemotherapy. When used as single agents, bolus and infusional FU/LV and capecitabine are similarly effective but have differing toxicity. Chemotherapy combinations that incorporate infusion of FU are less toxic and more effective than those using bolus FU dosing. Capecitabine is under study as an alternative dosing method for use in combination regimens; however, the optimal dose has not been defined and final safety and efficacy outcomes are being addressed in ongoing phase II and III investigations. Three combinations have shown excellent first-line efficacy in phase III trials--IFL with bevacizumab, FOLFOX, and FOLFIRI--but neither of these combinations is clearly superior. Sound clinical judgment must continue to guide treatment decisions while we await data regarding the optimal combination and sequence of fluorouracil, irinotecan, oxaliplatin, bevacizumab, and cetuximab.     

Mortality associated with daily bolus 5-fluorouracil/leucovorin administered in combination with either irinotecan or oxaliplatin: results from Intergroup Trial N9741

BACKGROUND: Intergroup Trial N9741 evaluated 5-fluorouracil (5-FU)/leucovorin (LV) administered in conjunction with either irinotecan or oxaliplatin in the first-line treatment of advanced colorectal carcinoma (CRC). The current report describes two treatment arms that were withdrawn from the protocol due to unexpected treatment-related toxicities and a high mortality rate. The complications observed in these arms highlight the importance of aggressive and immediate supportive care in the management of digestive toxicity. METHODS: In Trial N9741, patients were randomly assigned to receive one of the following six regimens: 1) irinotecan plus bolus 5-FU/LV (Arm A); 2) sequential irinotecan plus bolus 5-FU/LV (Arm B); 3) bolus 5-FU/LV only (Mayo Clinic regimen; Arm D); 4) oxaliplatin plus bolus 5-FU/LV (Arm E); 5) oxaliplatin plus infusional 5-FU/LV (Arm F); or 6) oxaliplatin plus irinotecan (Arm G). In the current study, the authors investigated treatment-related toxicity in patients who received either of the two combination regimens containing daily bolus 5-FU (i.e., patients in Arm B or Arm E). RESULTS: Sixty-one and 47 patients were enrolled in Arm B and Arm E, respectively. Diarrhea and neutropenia were the most common toxicities in both groups. Five patients in Arm B (8.2%) and 4 patients in Arm E (8.5%) died within 60 days of study entry. All fatal toxicities occurred within 15 days of treatment administration, and all deaths were associated with the simultaneous occurrence of multiple symptoms, which were dominated by Grade > or = 3 diarrhea. CONCLUSIONS: Combination regimens containing daily bolus 5-FU/LV and oxaliplatin or irinotecan can be associated with severe gastrointestinal toxicity and high mortality rates. Therefore, the authors recommend the use of more tolerable infusional 5-FU-based regimens in the treatment of metastatic CRC.     

Irinotecan-based regimens in the adjuvant therapy of colorectal cancer

Irinotecan is a cornerstone drug in the management of metastatic colorectal cancer, as demonstrated by several randomized studies proving a survival benefit for the first time. In the adjuvant setting, FOLFOX (infusional 5-fluorouracil [5-FU]/leucovorin [LV] in combination with oxaliplatin) has improved 3-year disease-free survival in stage II/III colorectal cancer in the MOSAIC trial. Because 5-FU/LV-based combination therapy with oxaliplatin or irinotecan has similar efficacy in metastatic disease in the first-line setting, the impact of irinotecan in the adjuvant setting deserves further randomized clinical trials. Six such trials are ongoing or have already been closed to accrual, the results of which will be reported shortly. Five of these trials presently accruing patients or already closed combine irinotecan with an infusional regimen of 5-FU, based on a better tolerance and efficacy profile established in the metastatic setting according to clinical trials conducted principally in Europe. The results of 2 main randomized trials in the adjuvant therapy of stage III colon cancer will be presented at the 41st Annual Meeting of the American Society of Clinical Oncology in 2005 and are eagerly awaited. These results should provide important new insights as to how to manage stage II/III colon cancer.     

Cetuximab plus XELIRI or XELOX for first-line therapy of metastatic colorectal cancer

Modern chemotherapy combinations for metastatic colorectal cancer (mCRC) comprise infusional 5-fluorouracil (5-FU), leucovorin, and irinotecan or oxaliplatin. The fluoropyrimidine derivative capecitabine is at least as effective as 5-FU plus leucovorin bolus regimens. It displays a favorable toxicity profile and offers the advantages of oral administration. The epidermal growth factor receptor antibody cetuximab induces synergistic antitumor activity when combined with chemotherapy. In pretreated patients, cetuximab can restore the sensitivity to irinotecan and, therefore, has been registered in this setting. Several phase I/II trials have investigated the combination of cetuximab with irinotecan-based or oxaliplatin-based chemotherapy for the first-line treatment of mCRC. These combinations have been proven to be safe and have provided promising efficacy data. A recent phase III trial confirmed improved progression-free survival, response rates, and a particularly significant increase of secondary resection rates for the combination of FOLFIRI (infusional 5-FU/leucovorin/irinotecan) plus cetuximab compared with FOLFIRI alone. In this review, we discuss the background of combining XELIRI (capecitabine/irinotecan) or XELOX (capecit-abine/oxaliplatin) with cetuximab for the first-line treatment of mCRC and present available data of these combined cytotoxic and targeted treatment approaches.     

Current status of second-line therapy for metastatic colorectal cancer

Decisions regarding the optimal systemic therapy for patients with metastatic colorectal cancer (CRC) have become more complex with the identification and development of multiple effective agents for this disease. Multiple treatment options are now available in the second-line setting for patients with metastatic CRC who have progressed despite prior chemotherapy. The exact choice of second-line therapy depends on the first-line treatment that was administered. Irinotecan as a salvage therapy for patients with metastatic CRC who have progression following front-line 5-fluorouracil (5-FU)-based therapies was confirmed in a number of phase II/III studies. Many patients who received irinotecan/5-FU-based therapy as first-line treatment benefit from the combination of oxaliplatin and 5-FU/leucovorin (FOLFOX) in terms of response, time to progression, and relief of tumor-related symptoms. Other considerations include the integration of targeted therapies into chemotherapy regimens. The results of a randomized phase II trial have demonstrated that the addition of cetuximab to irinotecan in patients with irinotecan-resistant tumors represents another active treatment option for these patients. The activity of bevacizumab as part of second-line therapy is currently under investigation and results from phase III trials are expected within the next year. In summary, the availability of 5 drugs that are active in CRC provides us, for the first time, with choice--and dilemma--regarding optimal second-line therapy in patients with metastatic CRC.     

Chemotherapy intensification

Today the treatment of metastatic colorectal cancer is based on several treatment options incorporating chemotherapy, targeted agents, and the surgery of metastases, and a median survival of almost 2 years has been reached. Despite these advances and the availability of multiple lines of treatment, the choice of the first-line chemotherapy indeed still matters, and the development of chemotherapy regimens associated with improved efficacy is a key question in the “biologics era.” This review discusses the development of the triple drug combination FOLFOXIRI (irinotecan [CPT-11], oxaliplatin, and 5-fluorouracil [5FU]/leucovorin [LV]). Several phase II trials demonstrated the feasibility of this combination and, more importantly, a phase III trial demonstrated that the triplet FOLFOXIRI is the first studied combination that significantly increases response rate, complete tumor resection of metastases, progression-free survival, and overall survival compared with an infusional 5FU containing doublet, such as FOLFIRI (5FU/LV and CPT-11). Therefore, FOLFOXIRI represents a new first-line option of care for patients with metastatic colorectal cancer.     

Bevacizumab in combination with irinotecan, 5-fluorouracil, and leucovorin (FOLFIRI) in patients with metastatic colorectal cancer who were previously treated with oxaliplatin-containing regimens: a multicenter observational cohort study (TCTG 2nd-BV study)

The efficacy of bevacizumab combined with infusional 5-fluorouracil/leucovorin (5-FU/LV) plus irinotecan (FOLFIRI) as the second-line treatment for metastatic colorectal cancer (mCRC) has not been fully clarified, although bevacizumab combined with infusional 5-FU/LV plus oxaliplatin (FOLFOX) in the second-line setting has demonstrated a survival benefit. We investigated the efficacy of bevacizumab plus FOLFIRI in mCRC patients who failed oxaliplatin-containing regimens without bevacizumab. Patients who received bevacizumab plus FOLFIRI or bevacizumab plus FOLFOX as second-line chemotherapy between July 2007 and March 2008 were registered (trial registration: UMIN000001547). Patient background data and progression-free survival (PFS), overall survival (OS), response, and bevacizumab-related adverse events were prospectively collected every 6?months. A total of 195 patients were enrolled from 26 institutions. Among them, 115 patients received bevacizumab plus FOLFIRI after failure of oxaliplatin and fluoropyrimidine (FOLFIRI+BV after OX/FU group), and 45 patients received bevacizumab plus FOLFOX after failure of irinotecan and fluoropyrimidine (FOLFOX+BV after IRI/FU group). Median PFS was 8.3?months (95% confidence interval [CI], 6.7-9.9) for the FOLFIRI+BV after OX/FU group and 7.8?months (95% CI, 5.8-9.7) for the FOLFOX+BV after IRI/FU group. Median OS was 21.6?months (95% CI, 17.6-25.6) and 16.5?months (95% CI, 11.8-21.2), respectively. Overall response rates were 25 and 29%, respectively. The most common grade ≥3 bevacizumab-related adverse events were hypertension (5.0%) and bleeding (3.8%). FOLFIRI+BV after OX/FU showed comparable efficacy to FOLFOX+BV after IRI/FU.     

Level of evidence of irinotecan clinical trials and recent data in colorectal cancer

Combination chemotherapy based on bolus or infusional 5-fluorouracil (5-FU), folinic acid (FA), together with either irinotecan or oxaliplatin has become the standard of care for the first-line treatment of metastatic colorectal cancer. The practice of combining 5-FU/FA with irinotecan or oxaliplatin is based on data from randomised clinical trials, and these are complicated by the variety of endpoints used, including overall survival, progression-free survival and response rate. An evidence-based system has been developed by the United States National Cancer Institute, whereby oncology clinical trials are ranked according to the trial design and the endpoints assessed. According to this system, the highest levels of evidence for the benefit of first-line combination therapy on overall survival are achieved with the combination of irinotecan and bolus and/or infusional 5-FU/FA. Thus, if evidence-based medicine is to be our aim, the combination of 5-FU/FA plus irinotecan should be the standard of care for the first-line treatment of metastatic colorectal cancer.     

Targeted therapies for patients with advanced colorectal cancer: focus on cetuximab

Colorectal cancer (CRC) is the fourth most common cancer in men and the third in women worldwide. Combinations of 5-fluorouracil (5-FU)/folinic acid (FA) with irinotecan or oxaliplatin form the standard treatment approaches for metastatic disease. The introduction of targeted agents has presented the opportunity to improve on the efficacy of current treatments without exacerbating the associated toxicity. Cetuximab (Erbitux®) is an IgG1 monoclonal antibody (MAb) that specifically targets the epidermal growth factor receptor (EGFR) with high affinity and competitively inhibits endogenous ligand binding. Cetuximab has shown good efficacy in combination with irinotecan in CRC that had previously progressed on irinotecan-based therapy. Cetuximab plus irinotecan and various schedules of 5-FU/FA have shown efficacy in a first-line setting. The activity of cetuximab and oxaliplatin-based regimens is being investigated in both first- and subsequent-line settings. Cetuximab is well tolerated and does not increase the side effect profile of agents it is combined with. Other EGFR inhibitors, including the tyrosine kinase inhibitors, gefitinib and erlotinib, and the MAbs, panitumumab and matuzumab, are also being investigated in a number of solid tumors. The vascular endothelial growth factor (VEGF) inhibitor, bevacizumab, although apparently inactive as a single agent, has demonstrated survival benefits when combined with bolus 5-FU/FA and irinotecan in a first-line setting and with 5-FU/FA and oxaliplatin in the second-line treatment of metastatic CRC. In this paper we discuss the use of targeted therapies in the treatment of metastatic CRC, with a focus on cetuximab.     

IFL

An IFL regimen combining irinotecan, a bolus administration of 5-fluorouracil (5-FU) and leucovorin (LV) was associated with a significantly better response rate, progression-free survival and median overall survival, compared to 5-FU/LV against metastatic colorectal cancer. Despite a favorable initial report, randomized trials have suggested that triple therapy may be more toxic (severe neutropenia, diarrhea), leading to unacceptably high rates of early treatment-related mortality. On the other hand,a survival benefit for the oxaliplatin-containing regimen (FOLFOX 4) compared to bolus IFL, has been shown from INT trial 9741, and a European trial (V 308) suggests similar efficacy for combinations of irinotecan or oxaliplatin with short-term infusional 5-FU/LV (FOLFIRI or FOLFOX 6). Overall, FOLFIRI or FOLFOX regimen is now a standard option for first-line treatment of metastatic CRC.     

Capecitabine plus oxaliplatin for the treatment of colorectal cancer

Based on improved safety and efficacy results, advanced colorectal cancer (CRC) treatment has recently shifted from intravenous bolus 5-fluorouracil (5-FU) monotherapy to standard combinations of prolonged intravenous 5-FU infusion with either oxaliplatin (FOLFOX) or irinotecan (FOLFIRI). Capecitabine, a rationally designed oral fluoropyrimidine that is converted into 5-FU preferentially at the tumor site, could replace infusional 5-FU as the mainstay of combined chemotherapy treatment for metastatic CRC. Evidently, oral medication obviates the drawbacks of prolonged intravenous infusion. The combination of capecitabine and oxaliplatin is especially attractive owing to its favorable tolerability profile, good activity and convenient administration schedule. Phase III trials comparing capecitabine/oxaliplatin with infusional regimens of 5-FU +/- LV and oxaliplatin in advanced CRC show similar toxicity and efficacy outcomes with both regimens. Capecitabine has the potential to replace 5-FU/LV as the optimal combination partner for oxaliplatin at a higher cost. Capecitabine and oxaliplatin concomitantly with radiation therapy has been evaluated before surgery in rectal cancer treatment. The combination of capecitabine and oxaliplatin, with or without bevacizumab, a monoclonal antibody blocking VEGF, is also being evaluated in early stage colon cancer.     

Addition of bevacizumab to bolus fluorouracil and leucovorin in first-line metastatic colorectal cancer: results of a randomized phase II trial.

PURPOSE: Bevacizumab, a monoclonal antibody against vascular endothelial growth factor, increases survival when combined with irinotecan-based chemotherapy in first-line treatment of metastatic colorectal cancer (CRC). This randomized, phase II trial compared bevacizumab plus fluorouracil and leucovorin (FU/LV) versus placebo plus FU/LV as first-line therapy in patients considered nonoptimal candidates for first-line irinotecan. PATIENTS AND METHODS: Patients had metastatic CRC and one of the following characteristics: age > or = 65 years, Eastern Cooperative Oncology Group performance status 1 or 2, serum albumin < or = 3.5 g/dL, or prior abdominal/pelvic radiotherapy. Patients were randomly assigned to FU/LV/placebo (n = 105) or FU/LV/bevacizumab (n = 104). The primary end point was overall survival. Secondary end points were progression-free survival, response rate, response duration, and quality of life. Safety was also assessed. RESULTS: Median survival was 16.6 months for the FU/LV/bevacizumab group and 12.9 months for the FU/LV/placebo group (hazard ratio, 0.79; P = .16). Median progression-free survival was 9.2 months (FU/LV/bevacizumab) and 5.5 months (FU/LV/placebo); hazard ratio was 0.50; P = .0002. Response rates were 26.0% (FU/LV/bevacizumab) and 15.2% (FU/LV/placebo) (P = .055); duration of response was 9.2 months (FU/LV/bevacizumab) and 6.8 months (FU/LV/placebo); hazard ratio was 0.42; P = .088. Grade 3 hypertension was more common with bevacizumab treatment (16% v 3%) but was controlled with oral medication and did not cause study drug discontinuation. CONCLUSION: Addition of bevacizumab to FU/LV as first-line therapy in CRC patients who were not considered optimal candidates for first-line irinotecan treatment provided clinically significant patient benefit, including statistically significant improvement in progression-free survival.     

Current status of clinical studies for colorectal cancer in Taiwan

The incidence and age-adjusted mortality of colorectal cancer (CRC) has drastically increased in the past 2 decades in Taiwan. Fortunately, chemotherapy for metastatic CRC also showed improvement in terms of tumor response rate and survival in the corresponding time period. For its low toxicity profile and high objective response rate (17.5%-31.9% in patients who received low-dose 5-fluorouracil [5-FU] that failed and 53.3%-61.5% in patients who were chemotherapy-naive), weekly 24-hour infusion of high-dose 5-FU and leucovorin (LV) has been a favorable regimen for advanced CRC for medical oncologists in Taiwan. Investigators also put their effort in exploring the mechanisms of high efficacy and low toxicity profile of this regimen, as well as the prognostic factors in predicting tumor response to this regimen. With the emergence of new, active compounds for metastatic CRC, a simple 2-hour infusion of oxaliplatin plus 46-hour infusion of 5-FU/LV every 2 weeks has become a favorable regimen, with an overall response rate (ORR) of 40%-50% and overall survival of 18.2 months in chemotherapy-naive patients. Conversely, there were also studies to suggest that biweekly oxaliplatin plus weekly or biweekly bolus 5-FU/LV was shown to achieve a comparable tumor response and survival in 5-FU-refractory metastatic CRC. In patients who had been treated with oxaliplatin plus infusional 5-FU/LV that failed, salvage biweekly irinotecan plus bolus and infusional 5-FU/LV could achieve an ORR of 22.2% with a median duration of response of 8 months. As for oral fluoropyrimidine analogues, oral tegafur/uracil and capecitabine are available in Taiwan. In addition, a clinical trial of dendritic cell-based immunotherapy for chemotherapy-refractory metastatic CRC has also been initiated and is in progress.