A double-blind placebo-controlled randomized phase III trial of 5-fluorouracil and leucovorin, plus or minus trimetrexate, in previously untreated patients with advanced colorectal cancer

Magnitude of advantage in tumor response contributes to a better correlation between treatment effects on overall survival and progression-free survival: a literature-based meta-analysis of clinical trials in patients with metastatic colorectal cancer

BACKGROUND

Although it is suggested that the endpoints originated from the concept of tumor shrinkage dynamics, such as early tumor shrinkage and depth of response, are strongly associated with overall survival (OS) in patients with metastatic colorectal cancer (mCRC), they are yet to be validated as a single surrogate endpoint of OS by themselves. This study aimed to investigate the impact of advantage in tumor response on the correlation between treatment effects on progression-free survival (PFS) and OS in mCRC patients.

METHODS

Based on an electronic search, we identified randomized controlled trials of first-line therapy for mCRC. The impact of advantage in objective response rate (ORR) on the correlation between treatment effects on PFS and OS was evaluated based on Spearman correlation coefficients (r_s).

RESULTS

Forty-seven trials with a total of 24,018 patients were identified. The hazard ratio for PFS showed a relatively higher correlation with that for OS (r_s = 0.63) when the trials were limited to those that demonstrated a larger difference in ORR, compared to the case for trials that demonstrated a smaller difference (r_s = 0.32). This tendency was also observed in the subgroup analysis stratified by the types of treatment agents (targeted or non-targeted).

CONCLUSIONS

The magnitude of advantage in tumor response was suggested to contribute to a better prediction of OS benefit based on PFS in patients with mCRC. The accuracy of OS estimation in mCRC is expected to be improved by considering the degree of tumor shrinkage in conjunction with PFS.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Network meta-analysis of the efficacy of first-line chemotherapy regimens in patients with advanced colorectal cancer

This network meta-analysis compared the short-term and long-term efficacies of first-line chemotherapy regimens in patients with advanced colorectal cancer (CRC). The 10 regimens included folinic acid + 5-fluorouracil + oxaliplatin (FOLFOX), folinic acid + 5-fluorouracil + irinotecan (FOLFIRI), folinic acid + 5-fluorouracil + gemcitabine (FFG), folinic acid + 5-fluorouracil + trimetrexate (FFT), folinic acid + 5-fluorouracil (FF), irinotecan + oxaliplatin (IROX), raltitrexed + oxaliplatin (TOMOX), folinic acid + tegafur-uracil (FTU), raltitrexed, and capecitabine. Electronic searches were performed in the Cochrane Library, PubMed and Embase databases from inception to June 2017. Network meta-analysis combined direct and indirect evidence to obtain odds ratios (ORs) and surface under the cumulative ranking curves (SUCRA) of different chemotherapy regimens for advanced CRC. Fourteen randomized controlled trails (RCTs) covering 4,383 patients with advanced CRC were included. The results revealed that FOLFOX, FOLFIRI, IROX, and TOMOX all showed higher overall response rates (ORRs) than FF or raltitrexed. Compared with raltitrexed, the aforementioned four regimens also had higher 1-year progression-free survival (PFS) rates. In addition, FOLFOX and FOLFIRI exhibited higher disease control rates (DCRs) and 1-year PFS rates than FF or raltitrexed. Cluster analysis revealed that FOLFOX, FOLFIRI, and TOMOX had better short-term and long-term efficacies. These findings suggest FOLFOX, FOLFIRI, and TOMOX are superior to other regimens for advanced CRC. These three regimens are therefore recommended for clinical treatment of advanced CRC.

New small-molecule inhibitors of dihydrofolate reductase inhibit Streptococcus mutans

Streptococcus mutans is a major aetiological agent of dental caries. Formation of biofilms is a key virulence factor of S. mutans. Drugs that inhibit S. mutans biofilms may have therapeutic potential. Dihydrofolate reductase (DHFR) plays a critical role in regulating the metabolism of folate. DHFR inhibitors are thus potent drugs and have been explored as anticancer and antimicrobial agents. In this study, a library of analogues based on a DHFR inhibitor, trimetrexate (TMQ), an FDA-approved drug, was screened and three new analogues that selectively inhibited S. mutans were identified. The most potent inhibitor had a 50% inhibitory concentration (IC50) of 454.0±10.2nM for the biofilm and 8.7±1.9nM for DHFR of S. mutans. In contrast, the IC50 of this compound for human DHFR was ca. 1000nM, a >100-fold decrease in its potency, demonstrating the high selectivity of the analogue. An analogue that exhibited the least potency for the S. mutans biofilm also had the lowest activity towards inhibiting S. mutans DHFR, further indicating that inhibition of biofilms is related to reduced DHFR activity. These data, along with docking of the most potent analogue to the modelled DHFR structure, suggested that the TMQ analogues indeed selectively inhibited S. mutans through targeting DHFR. These potent and selective small molecules are thus promising lead compounds to develop new effective therapeutics to prevent and treat dental caries.

A small-molecule induces apoptosis and suppresses metastasis in pancreatic cancer cells

Pancreatic cancer is one of the most malignant tumor diseases with the characters of aggressive growth and metastasis. With the inefficiency of the current therapeutics, new potential targets and new therapeutic agents for healing of pancreatic cancer are critically needed. We have previously found a small molecule, named 4-tert-butyl-2-[(cyclohexylamino) methyl]-6-methylphenol (TBMMP, NSC number: 48160), which can freeze the intermediate of Ras-GTP hydrolysis in the open non-signaling conformation with high affinity and high specificity in silico. In this work, we studied the effect and mechanism of TBMMP on two pancreatic cancer cell lines, CFPAC-1 and BxPC-3. The results showed that TBMMP could restrain the growth of the pancreatic cancer cells with IC(50) value 84.3 μM for CPFAC-1 and 94.5 μM for BxPC-3, respectively. Additionally, TBMMP increased cytochrome c release, reduced mitochondrial membrane potential, activated caspase-3, -9, elevated ROS and increased expression of the Bax in the pancreatic cancer cell lines. The results indicated that TBMMP induced the apoptosis of pancreatic cancer cells through the mitochondrial pathway. Further, we also found that TBMMP could suppress the metastasis of both pancreatic cancer cells in vitro. Taken together, we proposed that TBMMP might be a therapeutic potential lead for treating patients with pancreatic cancer.

Evaluation of progression-free survival as a surrogate endpoint for survival in chemotherapy and targeted agent metastatic colorectal cancer trials

Pooled analyses of chemotherapy trials in metastatic colorectal cancer (mCRC) have suggested that progression-free survival (PFS) is a surrogate endpoint for overall survival (OS). However, this has not been evaluated under current standard-of-care regimens of chemotherapy in combination with targeted therapies. We conducted an analysis of published mCRC trials of chemotherapy and targeted therapies from 2000 to evaluate the surrogacy of PFS and response rate (RR) for OS. Study-level data was pooled from 24 randomized mCRC trials that evaluated fluoropyrimidine-based regimens and included trials conducted with targeted agents (panitumumab, cetuximab, bevacizumab, and aflibercept). A total of 69 treatment arms with a sample size of 20,438 patients was included. Linear regression analysis was carried out to estimate the correlation of PFS and RR with OS. The correlation coefficient between PFS HRs and OS HRs was 0.86 for all trials, 0.89 for 12 phase III trials of targeted agents in combination with chemotherapy, 0.95 for 8 first-line phase III trials of targeted agents, and 0.83 for 9 trials of anti-EGFR-targeted agents. In all cases, correlation coefficients between RR and OS HRs were lower than those between PFS HRs and OS HRs (range, 0.42-0.81). In this study-level analysis of randomized mCRC trials of chemotherapy and targeted agents, improvements in PFS are strongly correlated with improvements in OS. This suggests that PFS remains a valid surrogate endpoint for OS with current treatment regimens in the mCRC setting.

S9511: a Southwest Oncology Group phase II study of trimetrexate, 5-fluorouracil, and leucovorin in unresectable or metastatic adenocarcinoma of the stomach

OBJECTIVE

The primary objective of this trial was to evaluate the response rate for trimetrexate in conjunction with 5-FU and leucovorin (LV) (= TFL) in the treatment of advanced gastric cancer in a phase II, cooperative group setting.

METHODS

Patients with locally advanced, unresectable, or metastatic adenocarcinoma of the stomach received trimetrexate 110 mg/m IV over 60 minutes day 1, followed by 5-FU 500 mg/m IV bolus and LV 200 mg/m IV over 60 minutes day 2, followed by oral LV 15 mg every 6 hours x 7 doses, all weekly for 6 weeks followed by 2 weeks of rest, continued until progression.

RESULTS

Characteristics for 37 eligible patients: median age 63 (range: 23-83); male/female: 69% of 31%; performance status 0/1/2 15/20/1. The confirmed response rate was 19%, and median overall survival was 6 months. Two patients died as a result of therapy, 1 because of infection without significant neutropenia, and 1 due to perforation of a responding gastric lesion. Seventy-two percent experienced grades 3 and 4 toxicity, most commonly diarrhea, fatigue, and lymphopenia.

CONCLUSIONS

This regimen achieves response rates comparable to other 5-FU-based regimens, when used in treatment of incurable gastric cancer. Toxicity appears manageable.

The impact of chemotherapy on overall survival and quality of life of patients with metastatic colorectal cancer: a review of phase III trials

The treatment aims for advanced colorectal cancer (ACRC) patients are to prolong overall survival and to improve or maintain quality of life. Phase III studies published between 1997 and 2006 comparing different first or subsequent lines of treatment regimens were collected in order to evaluate the impact of these regimens on the overall survival and quality of life of ACRC patients. Our review shows that a first-line polychemotherapy regimen including oxaliplatin or irinotecan, in comparison with monochemotherapy, can improve overall survival. Second-line therapy and/or a cross-over between the first-line treatment arms can further modify the disease course. Hence, from the very beginning the treatment of ACRC patients must embrace a strategic approach taking into account all new agents available. Quality of life (QoL) was assessed in 52.3% of the first-line studies, while this was done in the whole group of studies evaluating pre-treated patients. QoL appears to be unrelated to the toxicity profile.

A systematic review of the use of quality of life measures in colorectal cancer research with attention to outcomes in elderly patients

PURPOSE

Quality of life (QOL) measures are critical to the evaluation of new cancer treatments, particularly for elderly patients. Our intent was to assess patterns of use of QOL endpoints in colorectal cancer (CRC) treatment research and to summarize current knowledge about how CRC treatment affects elderly patients.

PATIENTS AND METHODS

We searched MEDLINE for English-language, human trials published from 1995 to 2005 that met the following criteria: reported on patients with CRC, were not surgery-only cohorts, and included a QOL or functional endpoints. Trials specifically reporting data on elderly patients were reviewed in depth and summarized.

RESULTS

One hundred twenty-one eligible studies and 10 trials with elderly-specific data were found. The median number of trials published annually increased from 5 (range, 4-8 trials) between 1995 and 1999 to 14.5 (range, 11-22 trials) between 2000 and 2005. Chemotherapy was the most commonly studied treatment (55%), and metastatic CRC (55%) was the most commonly studied population. The European Organization for Research and Treatment of Cancer C30, with or without C38, was the most frequently used instrument (49%). Studies reporting on elderly patients showed that many patients experience a decline in physical function immediately after surgery and have increased need for supportive services. Little information is available on the effect of chemotherapy in elderly patients. Use of QOL and functional measures in treatment-related CRC research has increased; however, it continues to be hampered by a lack of dissemination and methodologic problems.

CONCLUSION

Missing data from patient attrition, limitations of assessment methods, and a small number of patients treated with chemotherapy in the trials reporting on elderly patients seriously limit our ability to draw conclusions from this survey about how treatment affects QOL or function in CRC.

Surrogate end points for median overall survival in metastatic colorectal cancer: literature-based analysis from 39 randomized controlled trials of first-line chemotherapy

PURPOSE

Our aims were to determine the correlations between progression-free survival (PFS), time to progression (TTP), and response rate (RR) with overall survival (OS) in the first-line treatment of metastatic colorectal cancer (MCRC), and to identify a potential surrogate for OS.

METHODS

Randomized trials of first-line chemotherapy in MCRC were identified, and statistical analyses were undertaken to evaluate the correlations between the end points.

RESULTS

Thirty-nine randomized controlled trials were identified containing a total of 87 treatment arms. Among trials, the nonparametric Spearman rank correlation coefficient (r(s)) between differences (Delta) in surrogate end points (DeltaPFS, DeltaTTP, and DeltaRR) and DeltaOS were 0.74 (95% CI, 0.47 to 0.88), 0.52 (95% CI, 0.004 to 0.81), 0.39 (95% CI, 0.08 to 0.63), respectively. The r(s) for DeltaPFS was not significantly different from the r(s) DeltaTTP (P = .28). Linear regression analysis was performed using hazard ratios for PFS and OS. There was a strong relationship between hazard ratios for PFS and OS; the slope of the regression line was 0.54 +/- 0.10, indicating that a novel therapy producing a 10% risk reduction for PFS will yield an estimated 5.4% +/- 1% risk reduction for OS.

CONCLUSION

In first-line chemotherapy trials for MCRC, improvements in PFS are strongly associated with improvements in OS. In this patient population, PFS may be an appropriate surrogate for OS. As a clinical end point, PFS offers increased statistical power at a given time of analysis and a significant lead time advantage compared with OS.

Applying Fong's CRS Liver Score in Patients with Colorectal Liver Metastases Treated by Cryotherapy

BACKGROUND

A significant proportion of patients with liver metastases from colorectal cancer have unresectable disease and we have used cytoablative treatment such as cryotherapy in some of these patients. We retrospectively reviewed patients who underwent hepatic cryotherapy for colorectal metastases and studied the effect of the clinical risk score (CRS) reported by Fong et al, which can predict survival following liver resection.

METHODS

A retrospective study was performed on patients who underwent hepatic cryotherapy between 1990 and 2000 in St George Hospital. There were 61 patients in this study and they were stratified into prognostic groups based on five preoperative CRS parameters: primary node positive, disease-free interval from primary to metastases < 12 months, number of hepatic tumours > 1, largest hepatic tumour > 5 cm and carcinoembryonic antigen level > 200 ng/mL. The median follow-up was 25 months.

RESULTS

The median survival was 26 months and the 3-year survival rate was 37%. Median survivals for patients with CRS scores 1 (13%), 2 (25%), 3 (53%), 4 (6%) and 5 (4%) were 37, 25, 30, 21 and 15 months, respectively (R2 = 0.81).

CONCLUSION

The CRS score can be used to predict outcome of hepatic cryotherapy, but the difference in survival between CRS 2, 3 and 4 is modest.

Quality of life versus prolongation of life in patients treated with chemotherapy in advanced colorectal cancer: A review of randomized controlled clinical trials

Oncologists disagree if chemotherapy in advanced cancer can improve quality of life (QoL), to prolong duration of life, or both. The objective of this study was to clarify the main treatment intention of palliative chemotherapy (PCT): the prolongation of life (PoL); or QoL. Randomized controlled clinical trials of PCT in advanced colorectal cancer that included HRQoL assessment were selected from PubMed and reviewed. Authors' conclusions were based on both PoL- and QoL-related outcomes. However, if PoL and QoL outcomes of the experimental arm were opposite, which was the case in 13 out of 28 trials, the authors generally based their conclusion on PoL outcomes. Authors' conclusions focused mainly on PoL-related outcomes, while QoL-related outcomes were of overriding importance in only 1/28 case. QoL can therefore not be considered as the main outcome of PCT. The review shows that in the context of chemotherapy in advanced colorectal cancer, 'palliative' refers to a life-prolonging intention, whereas within palliative care it refers to an improvement in QoL.

A Phase I/II Study of Trimetrexate and Capecitabine in Patients With Advanced Refractory Colorectal Cancer

OBJECTIVE

We tested the hypothesis that the combination of trimetrexate (TMTX) and capecitabine (CAP) would be active in patients with previously treated metastatic colorectal cancer (CRC). Because the optimum dose of this combination was unknown, we used a phase I/II design.

METHODS

In the phase I cohort, patients received 110 mg/m2 TMTX intravenously weekly x6 and CAP starting at 750 mg/m2 orally twice daily from days 2 to 15 and 23 to 36 (one cycle). Cycles were repeated every 8 weeks. The phase II doses were 110 mg/m2 TMTX and 1000 mg/m2 CAP orally twice daily.

RESULTS

Thirty-two patients were entered. All patients had prior 5-fluorouracil therapy and 94% had prior exposure to irinotecan. Grade 3/4 toxicities included abdominal pain in 4 patients (12.5%) and vomiting in 3 patients (9.4%). Twenty-seven patients were evaluable for response: one patient each had a complete response and a partial response for an overall response rate of 7.4%. The median time to progression was 3.3 months (95% confidence interval [CI], 1.6-3.7 months) and the median overall survival was 5.9 months (95% CI, 5.2-10.2 months).

CONCLUSIONS

The combination of TMTX and CAP is well tolerated. However, recent studies have shown more active regimens in the second- and third-line metastatic setting.

Monitoring fluoropyrimidine metabolism in solid tumors with in vivo (19)F magnetic resonance spectroscopy

(19)Fluorine magnetic resonance spectroscopy ((19)F MRS) offers unique possibilities for monitoring the pharmacokinetics of fluoropyrimidines in vivo in tumors and normal tissue in a non-invasive way, both in animals and in patients. This method may therefore be useful for predicting response to fluoropyrimidine-based therapy with or without the effects of modulating agents, and this may be of value for the individualization of anticancer therapy and the strategic development of new anticancer drugs. (19)F MRS has been very valuable in elucidating the basic aspects of fluoropyrimidine metabolism, especially in animal studies. Studies in humans have indicated its clinical potential, but widespread application has been hampered by the relatively low detection sensitivity of the method. The recent introduction of clinical MR scanners with magnetic fields above 1.5 T may stimulate increased clinical use of (19)F MRS.

Double modulation of 5-fluorouracil by trimetrexate and leucovorin in patients with advanced colorectal carcinoma

The purpose of this report is to evaluate the efficacy and toxicity (Tx) of a double modulation of 5-fluorouracil (5-FU) by trimetrexate (TMTX) and leucovorin (LV) in patients with advanced recurrent (inoperable) or metastatic colorectal cancer (ACC). Between December 1997 and August 2000, 36 patients were entered in this phase II study. Median age was 61 years, and 18 patients (50%) were female. Median performance status was 0 (range: 0-1), whereas primary tumor location was colon in 21 patients (58%) and rectum in 15 patients (42%). The number of metastatic sites was 1:29 patients (81%); 2:6 patients (17%) and 3:1 patient (3%). Hepatic involvement was observed in 33 patients (92%). Treatment consisted of TMTX 110 mg/m2 IV over 1 hour at hour (H) 0; LV 50 mg/m2 IV over 2 hours IV infusion starting at H 18; and 5-FU 900 mg/m2 IV bolus at H 20. LV (rescue) 15 mg/m2 orally was administered every 6 hours (total 6 doses) beginning at H 24. Cycles were repeated every 2 weeks until progressive disease (PD) or severe Tx. Thirty-four patients are assessable for response (R) (two patients refused further treatment after the first course of therapy), whereas all patients were assessable for Tx. Complete response: 1 patient (3%); partial response: 4 patients (12%), with an overall objective response rate of 15% (95% CI, 1%-25%); no change: 12 patients (35%); and progressive disease: 17 patients (50%). The median time to treatment failure was 4 months and median survival was 11 months. Tx was within acceptable limits. The dose-limiting side effect was mucositis. Eight episodes of grade II or III stomatitis were observed and were responsible for dosage modifications of TMTX and 5-FU. Leukopenia was observed in 16 patients (44%); neutropenia was registered in 19 patients (53%); anemia was seen in 18 patients (50%); emesis in 22 patients (61%); and dermatitis in 3 patients (8%). There were no therapy-related deaths. The double modulation of 5-FU by TMTX and LV showed modest antitumoral activity with mild to moderate Tx.

Methodological issues in assessing health-related quality of life of colorectal cancer patients in randomised controlled trials

Although health-related quality of life (HRQOL) is increasingly reported as an important endpoint in cancer clinical trials, questions still remain about the quality of its reporting. The aim of this study was to evaluate the level of reporting of HRQOL in randomised controlled trials (RCTs) of colorectal cancer (CRC). A systematic literature search from 1980 to March 2003 was undertaken on a number of databases. Identified eligible studies were selected and then evaluated on a broad set of HRQOL predetermined criteria by four reviewers. Thirty-one randomised controlled trials involving 9683 colorectal cancer patients were identified. Nearly all studies dealt with metastatic patients and principally compared different chemotherapy regimens. The HRQOL tool most often used was the European Organisation for Research and Treatment of Cancer, Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30), which was used in 48% of the studies. Some methodological limitations were identified: 39% of the RCTs did not report HRQOL compliance at baseline and 52% did not give details on missing data. A rationale for using a specific HRQOL measure was given in only 10% of the studies. Whilst HRQOL assessment is a potential valuable source of information in understanding the impact of colorectal cancer, a number of methodological shortcomings have to be further addressed in future studies.

Novel antifolate drugs

Antimetabolites are active chemotherapeutic agents for many solid tumor and hematologic malignancies. Folate antagonists, purine analogues, and pyrimidine analogues are the three main categories of antimetabolites. Methotrexate, the most studied folate antagonist, is effective in many malignancies. Methotrexate inhibits dihydrofolate reductase, which leads to accumulation of polyglutamated folates, causing further inhibition of thymidylate synthase and glycinamide ribonucleotide formyltransferase. Subsequently, the lack of reduced folate substrates impairs synthesis of purine nucleotides, thymidylate, and certain amino acids, which can lead to cell death. However, methotrexate resistance develops through several mechanisms, including decreased folate carrier-mediated membrane transport, dihydrofolate reductase gene amplification, specific transcription-translational modifications, and downregulation of intracellular methotrexate polyglutamation. Antifolate drug development has focused on agents designed to overcome different aspects of methotrexate resistance. This article reviews the enzymatic targets for antifolates, describes the known mechanisms of antifolate resistance, and summarizes the current development of novel antifolate agents. Discussed specifically are trimetrexate, edatrexate, raltitrexed, pemetrexed, ZD9331, lometrexol, LY309887, GW1843, OSI-7904(L), and nolatrexed, all of which have unique clinical pharmacology and are in various stages of development. The toxicity of antifolates has been sporadic and difficult to predict clinically. Supplementation with folic acid and vitamin B(12) has been shown to reduce the toxicity of pemetrexed without affecting efficacy and has increased the therapeutic index for this novel agent.

Trimetrexate as biochemical modulator of 5-fluorouracil/leucovorin in advanced colorectal cancer: final results of a randomised European study

BACKGROUND

Trimetrexate (TMTX) is a biochemical modulator of 5-fluorouracil (5-FU) and leucovorin (LV). Phase II trials have shown promising activity of 5-FU/LV/TMTX in patients with advanced colorectal cancer (ACC). This trial evaluated the effect of TMTX in combination with 5-FU/LV as first-line treatment in ACC.

PATIENTS AND METHODS

Patients with ACC were randomised to receive either intravenous LV 200 mg/m2/5-FU 600 mg/m2 or TMTX 110 mg/m2 followed 24 h later by LV 200 mg/m2/5-FU 500 mg/m2 plus oral LV rescue. Both schedules were given weekly for 6 weeks every 8 weeks. Patients were evaluated for progression-free survival (PFS), overall survival (OS), tumour response, quality of life (QoL) and toxicity.

RESULTS

A total of 365 patients were randomised. A statistically significant prolongation of median PFS was seen in patients treated with TMTX/5-FU/LV compared with 5-FU/LV (5.4 months versus 4.1 months, respectively; P = 0.03), and a trend towards a significant benefit for OS (13.4 months versus 10.5 months, respectively; P = 0.08). Tumour response, QoL and toxicity were comparable between the two arms. Diarrhoea was the most frequently occurring grade 3 or 4 toxicity (22% and 30%, respectively).

CONCLUSIONS

The addition of TMTX to a weekly regimen of 5-FU/LV results in a small but significant improvement in PFS without adding toxicity or worsening QoL in patients with ACC.

Integrated analysis of overall survival in two randomised studies comparing 5-fluorouracil/leucovorin with or without trimetrexate in advanced colorectal cancer

BACKGROUND

Two randomised studies were performed with trimetrexate (TMTX) as a biochemical modulator of 5-fluorouracil (5-FU)/leucovorin (LV) in advanced colorectal cancer (ACC), one in Europe and one in the United States. Both studies were similarly designed to detect a statistically significant difference in progression-free survival (PFS). Overall survival (OS), however, was later adopted as the primary outcome measure for approvability of agents for first-line treatment of ACC. Therefore, an integrated analysis of survival data from the European and USA trials was performed to detect a clinically relevant difference in survival.

PATIENTS AND METHODS

The experimental arm was identical in both studies and consisted of TMTX 110 mg/m2 intravenously (i.v.) followed 24 h later by i.v. LV 200 mg/m2/5-FU 500 mg/m2 plus oral LV rescue. The 5-FU dose in the control arm was 600 mg/m2 in the European study and 500 mg/m2 in the USA study, and the USA study was placebo-controlled. Treatment was given weekly for 6 weeks every 8 weeks.

RESULTS

A total of 746 patients were analysed. Median OS was 13.0 months for 5-FU/LV and 14.6 months for TMTX/5-FU/LV (P = 0.15; Wilcoxon). Median PFS was 4.4 months and 5.4 months, respectively (P = 0.07; Wilcoxon).

CONCLUSIONS

The addition of TMTX to a weekly regimen of 5-FU/LV does not improve the outcome for patients with ACC.