What can we learn from a meta-analysis of trials testing the modulation of 5-FU by leucovorin? Advanced Colorectal Meta-analysis Project

The Optimal Duration of Adjuvant Chemotherapy in Colon Cancer

Adjuvant chemotherapy for colon cancer (UICC stage II and III) has been under investigation over the last 30 years, regarding treatment duration and regimens. In this review, choice of regimen, its duration, possible limitations and future perspectives are discussed. Monotherapy with 5-fluorouracil was followed by addition of oxaliplatin, resulting in improved 3-yr disease free survival (DFS) and overall survival (OS) rates, but also increased peripheral sensory neurotoxicity (PSN). The International Duration Evaluation of Adjuvant therapy (IDEA) collaboration demonstrated less toxicity, especially PSN, when shortening treatment duration to 3 months. However, formally, the anticipated non-inferiority of 3 months with fluoropyrimidine (FP)/oxaliplatin over 6 months (at 3-yr DFS) was not met for all patients groups, although subgroup analyses showed non-inferiority with capecitabine/oxaliplatin (CAPOX) rather than with FOLFOX, and also in relation to the prognostic information (e.g., clinical low-risk group, pT1-3 N0). In addition, first data of newer parameters like Immunoscore® and ctDNA show promising results as stratification parameters. Further investigations to better define clinical risk groups and prognostic factors are mandatory. Besides this, individual decision-making of treatment intensity (FP or FP/oxaliplatin) and duration should always consider patient characteristics and preferences, also given the absolute relatively small differences and their clinical relevance.

Contributions of meta-analyses based on individual patient data to therapeutic progress in colorectal cancer

Meta-analysis is the statistical process of combining information from several studies addressing the same question. Meta-analyses based on individual patient data are far more reliable and informative than those based on summary statistics obtained from the trialists or extracted from the published literature. Meta-analysis of randomized clinical trials may contribute to therapeutic progress through (1) establishing efficacy benefits beyond a reasonable doubt, (2) identifying sources of heterogeneity between trials, (3) studying subsets reliably, (4) confirming differences in toxicity profiles, (5) evaluating the cost-effectiveness of experimental therapies, (6) assessing surrogate endpoints, and (7) addressing ancillary questions. All of these potential contributions are illustrated with examples in early and advanced colorectal cancer.

Modelling and Simulation in the Development and use of Anti-Cancer Agents: An Underused Tool?

To help identify the role of modelling and simulation in the development of anti-cancer agents, their main advantages and the obstacles to their rational use, an expert meeting was organized by COST B15. This manuscript presents a synthesis of views expressed at that meeting and indicates future directions. The manuscript also shows some examples where modelling and simulation have proven to be of relevant value in the drug development process for anti-cancer agents.

Phase I and pharmacologic study of i.v. hydroxyurea infusion given with i.p. 5-fluoro-2'-deoxyuridine and leucovorin

Preclinical data suggests that the action of fluoropyrimidines may be enhanced by the addition of hydroxyurea. We developed a phase I trial to determine the maximum tolerated dose and pharmacokinetics of i.v. hydroxyurea (HU) in combination with i.p. 5-fluoro-2'-deoxyuridine (FUdR) and leucovorin (LV). Eligible patients had metastatic carcinoma confined mostly to the peritoneal cavity, and adequate hepatic, renal and bone marrow function. Patients were treated with a fixed dose of FUdR (3 g) and LV (640 mg) administered on days 1--3. HU was administered as a 72-h infusion starting simultaneously with i.p. therapy on day 1. The following dose levels were studied: 2.0, 2.5, 3.0 and 3.6 g/m(2)/day. Pharmacokinetics were studied in blood and peritoneal fluid. Twenty-eight patients were accrued. Steady-state plasma and peritoneal fluid HU levels increased with increasing dose, and steady state was achieved within 12 h of continuous dosing. The steady-state HU plasma:peritoneal fluid concentration ratio ranged from 1.06 x 10(3) to 1.25 x 10(3) and the plasma HU clearance ranged from 4.63 to 5.81 l/h/m(2). Peritoneal fluid AUC = 137,639 +/- 43,914 microg/ml x min, t(1/2) = 100.9 +/- 56.4 min and Cl = 25.29 +/- 10.88 ml/min. Neutropenia represented the dose-limiting toxicity. We conclude that i.p. FUdR and LV in combination with i.v. HU is well tolerated. The addition of systemic HU increased the incidence of myelosuppression.

The role of meta-analyses in assessing cancer treatments

The results of individual phase III cancer clinical trials are often inconclusive due to the overly optimistic size of treatment differences that are sought. Increased power and precision can generally be obtained if the data from several different trials studying the same or similar questions are analysed together. Individual patient data meta-analyses, which combine together the quantitative results from all properly randomised studies, provide an overall estimate of the size of treatment differences. Individual patient data meta-analyses have played an especially important role in breast and gastrointestinal tract cancers where many important questions have been addressed. Although meta-analyses have been subject to considerable criticism, individual patient data meta-analyses provide the best overall evidence of treatment effect in the absence of large-scale trials and have been instrumental in providing objective data that can be used in the design of new studies.

The addition of low-dose leucovorin to the combination of 5-fluorouracil- levamisole does not improve survival in the adjuvant treatment of Dukes' C colon cancer. IKN Colon Trial Group

PURPOSE

To assess the effect of the addition of leucovorin to the combination of 5-fluorouracil (5-FU)-levamisole on recurrence risk and overall survival in patients after a resection with curative intent of a Dukes' C colon cancer.

PATIENTS AND METHODS

Five hundred patients with Dukes' C colon cancer were randomly assigned to adjuvant treatment for one year with 5-fluorouracil (450 mg/m2 i.v. weekly) and levamisole (150 mg p.o. every two weeks), the C-group or with leucovorin (20 mg/m2 i.v.), 5-fluorouracil and levamisole, the L-group. The median follow-up for patients still alive is 36 months. Four patients were ineligible because of advanced disease at the time of randomisation.

RESULTS

Sixty percent of the patients have completed all courses of chemotherapy. Of the remaining 40% of the patients who did not complete one-year treatment with chemotherapy, 46% discontinued because of toxic and/or emotional reasons. They were equally divided over both treatment arms. The addition of leucovorin increased toxicity (especially mucositis and conjunctivitis) without a significant increase in treatment withdrawal. Five-year disease-free interval (C-group: 49%, L-group: 46%; log-rank test, P = 0.86) and overall survival (C-group: 55%, L-group: 59%, log-rank test: P = 0.96) were very similar in both treatment arms.

CONCLUSIONS

The addition of low dose leucovorin to the combination of 5-fluorouracil and levamisole in a 12-month adjuvant therapy for curatively resected Dukes' C colon cancer patients does not improve disease-free interval nor overall survival. The addition of leucovorin to the combination of 5-FU levamisole increases toxicity. Therefore leucovorin 5-FU levamisole is not recommended in a 12 months adjuvant regime of Dukes' C colon cancer.

[Role of first-line palliative chemotherapy in metastatic colorectal cancer]

The prognosis of metastatic colorectal cancer remains poor. The 5-year survival rate is indeed 0 to 7%. The median survival duration is 8 months in patients without disease-related symptoms, and 6 months in patients with disease-related symptoms. The true benefit of palliative chemotherapy to increase the overall survival, and the symptom-free survival, has been largely discussed. In patients with disease-related symptoms, combinations of 5 fluoro-uracil (5-FU) and a biomodulator (leucovorin or methotrexate) have demonstrated a benefit on overall survival. In patients with asymptomatic disease, the advantage of systematic chemotherapy is more debatable. Two randomized studies have recently demonstrated that early chemotherapy yielded increased overall survival, disease-free symptom survival, and quality of life. Consequently, in patients with metastatic colorectal cancer, palliative chemotherapy must be performed even at early stages, before the onset of disease-related symptoms. Several regimens can be used as first line chemotherapy. In patients with good general status, and patients in whom a further resection of metastatic tumors could be possible, intensive regimens seem to be more appropriate. In the other patients, 5-FU-based regimens or raltitrexed can be proposed. Generally, the "standard" first line regimen seems to currently be LV5FU2 (bolus and continuous infusion of 5FU and leucovorin).

Prognostic variable in patients with advanced colorectal cancer treated with fluorouracil and leucovorin-based chemotherapy

Possible prognostic variables for tumor response, time to progression (TTP), and survival in 141 patients with advanced colorectal cancer treated with fluorouracil and leucovorin-based chemotherapy were analyzed. None of the variables examined for their possible influence on tumor response attained significance in the stepwise logistic regression. In the univariate analysis, variables found to be strongly associated with TTP were performance status (PS) (P = 0.0301), liver involvement (P = 0.030), and the initial values of WBC (P = 0.0319), lactic dehydrogenase (LDH; P = 0.0053), gamma-glutamyl-transpeptidase (gamma-GT; P = 0.0013), alkaline phosphatase (ALP; P = 0.0186), albumin (P = 0.0004), and carcinoembryonic antigen (CEA; P = 0.0014). In the Cox analysis, liver involvement (P = 0.0553), albumin (P = 0.0181), PS (P = 0.484), and ALP (P = 0.0553) were retained as independently significant variables. When only patients with liver metastases were included in the analysis, then only albumin (P < 0.001) demonstrated a prognostic significance. Also, in the univariate analysis, variables predicting survival were PS (P = 0.0230), grade (P = 0.00600), liver involvement (P = 0.0002), LDH (P = 0.0001), gamma-GT (P < 0.001), ALP (P = 0.0006), albumin (P = 0.0309), and CEA (P = 0.005). With the multivariate analysis, gamma-GT (P = 0.0004), albumin (P = 0.0634), and CEA (P = 0.0804) were selected as significant. In those patients who presented with liver involvement, variables predicted survival were gamma-GT (P = 0.0041), albumin (P = 0.0442), and the percentage of involved liver parenchyma (P = 0.0690). These results could be helpful for the stratification of future trials in advanced colorectal cancer.

Treatment principles in advanced colorectal cancer

BACKGROUND

Colorectal cancer is an important disease in the Australian community. Whilst there has been much discussion about the appropriate management of local disease, particularly with respect to the issue of adjuvant therapy, there has been relatively little local discussion of treatment options in metastatic colorectal cancer.

METHODS

The critical principles underlying treatment in this setting are briefly outlined in the present article, indicating wherever possible what options could be considered standard, and based on the available literature, which approaches must still be considered experimental at this time.

RESULTS

Overall, the results of treatment in this group of patients remain poor.

CONCLUSION

Further clinical trials are required to address the issues affecting patients with metastatic colorectal cancer.

Treatment of advanced colorectal cancer with 5-fluorouracil and interferon-alpha: an overview of clinical trials

5-Fluorouracil (5-FU) is the most active single agent for treatment of advanced colorectal cancer, although objective responses occur in only 20% of patients, and there seems to be no impact on overall survival. Experimental findings suggesting that interferon-alpha (IFN-alpha) enhances 5-FU cytotoxicity have stimulated an increasing number of clinical trials to evaluate the therapeutic potential of this combination. This article summarises the possible mechanisms of interaction of 5-FU and IFN-alpha, and provides an overview of the current status of this approach in advanced colorectal cancer. A computerised (Medline) and manual search were performed to identify all trials using 5-FU and IFN-alpha for the treatment of advanced colorectal cancer published in the English literature between 1960 and 1994. Information abstracted included treatment regimen, number of patients, pretreatment status, complete and partial remissions, remission duration, overall survival, and toxicity. A total of 417 patients were enrolled in 16 trials using different regimens of 5-FU and IFN-alpha, and double modulation of 5-FU with leucovorin (LV) and IFN-alpha was investigated in nine trials involving 332 patients. The mean overall response rate in these phase II trials was only 31% (range 3-76) and 35% (range 0-54), respectively. Early results of six prospectively randomised studies of 5-FU or 5-FU/LV +/- IFN-alpha also did not suggest a significant enhancement of the antitumour effectiveness with the addition of IFN-alpha. There is increasing evidence, however, that administration of IFN-alpha along with 5-FU enhances toxicity. Because of their modest therapeutic index, currently employed regimens of 5-FU +/- LV plus IFN-alpha cannot be recommended for routine use at the present time. The combination of 5-FU plus LV represents an equally effective and less expensive alternative. Nevertheless, there is still hope that further attempts to elucidate the complex mechanisms of this potentially synergistic drug combination will allow the rational design of regimens with a superior therapeutic index.

A phase II study of advanced colorectal cancer patients treated with combination 5-fluorouracil plus leucovorin and subcutaneous interleukin-2 plus alpha interferon

Twenty-one patients with advanced, pretreated colorectal cancer in disease progression were entered in a phase II study to investigate the use of 5-fluorouracil (5FU) + leucovorin with subcutaneous Interleukin-2 + alpha interferon (alpha-IFN). Eighteen of these patients were evaluable for response to treatment: 1 partial response (PR) (duration 8 months), 9 stable disease (SD) (median duration of 6.5 months, range 2-15) and 8 progressive disease (PD). The PR patient survived for 15 months, the SD patients for a median of 11 months and 8 months for PD patients. Toxicity evaluated in the 21 patients reached grade 4 for mucositis in two cases. Grade 3 toxicity was observed more frequently for fever (52.3%) and diarrhea (33.3%) and was most probably the result of the combined side-effect of chemotherapy and the biological response modifiers (BRMs). Treatment was, for the most part, carried out on an out-patient basis as originally planned. In 15 patients tests were carried out to verify whether any immuno-activation had taken place. Significant increases were found during the course of therapy regarding cluster of differentiation activation (HLA-DR, CD71, CS25). Different curves were observed during the course of treatment with respect to the CD8 value, which proved higher in SD patients than in PD patients. Our study would seem to suggest that the addition of BRMs to 5FU + leucovorin could increase survival. The next step, however, must be to determine lower doses of IL-2 for subcutaneous administration in order to reduce toxicity but maintain the same immunostimulation.