Improvements in fluorouracil chemotherapy?

High Dose Alpha-2B Interferon+Folinic Acid in the Modulation of 5-Fluorouracil. A Phase II Study in Advanced Colorectal Cancer with Evidence of An Unfavorable Cost/Benefit Ratio

The combination of folinic acid (FA) and 5-fluorouracil (5FU) is the most active systemic chemotherapy against advanced colorectal cancer. Experimental and clinical studies have suggested that the activity of 5FU can be improved by the addition of alpha-interferon (IFN). To evaluate the possibility of a double modulation of 5FU, a pilot study was conducted in the period July 1989-December 1989 with the following regimen: FA (200 mg/m2 i.v. bolus × 5 days) + 5FU (400 mg/m2 i.v. in 15 min × 5 days) + alpha-2b IFN (10 × 104 IU subcutaneously on alternate days). FA and 5FU administrations were repeated every 28 days; IFN was administered every week. In the 16 treated patients, 4 partial responses, 4 no changes, and 8 with progression of disease were observed, with an objective response rate of 25% (95% CI, 7.8%–55.1%). Median duration of response was 9.5 months, as was overall survival. Toxicity (fever, fatigue, neurotoxicity, stomatitis and diarrhea) was considerable and led to a reduction in IFN doses in 10/16 patients. Due to the unfavorable cost/benefit ratio, the study was closed and a new trial, with different doses and schedule of IFN, was started within the GISCAD (Italian Group for the Study of Digestive Tract Cancer).

A Feasibility Study of High-Dose Cisplatin and 5-Fluorouracil with Glutathione Protection in the Treatment of Advanced Colorectal Cancer

On the basis of previous studies supporting that glutathione (GSH) reduced cisplatin nephrotoxicity we have designed a new regimen in the treatment of advanced colorectal cancer, which included GSH as a modulator of cisplatin-induced toxicity. Eleven untreated patients with measurable metastatic colorectal cancer received 5-fluorouracil (750 mg/m2, daily continuous infusion for days 1-5) and cisplatin (40 mg/m2 1 hour-infusion for days 6-8) given every 4 weeks. Reduced glutathione (2.5 g) was delivered i.v. prior to each cisplatin infusion. Toxicity was minimal and reversible and included nausea/vomiting (11 cases), mild neurotoxicity (4 cases) and leukopenia (2 cases); only 2 patients showed moderate and transient increases of serum creatinine « 2 mg/dl) and BUN. Renal function impairment was also monitored by magnesemia levels and urinary marker enzymes indicating minimal cumulative nephrotoxicity. Out of 10 evaluable patients, only 2 partial responses were observed. The median survival was 9 months (range 5-26). The study was closed, since the preliminary results do not suggest any therapeutic advantage in adding cisplatin to 5-fluorouracil in the present schedule, even using an intensive regimen. Indirect evidence suggests that these disappointing results are not the consequence of interference of GSH on the cytotoxic efficacy of cisplatin. The lack of incidence of severe toxicity of this regimen supports the role of reduced glutathione as a potential protective against cisplatin nephrotoxicity. Although these preliminary results suggest that further studies with the present regimen in this disease are not warranted, in view of its safety this program deserves evaluation in the treatment of neoplastic diseases responsive to 5-fluorouracil/cisplatin.

Re-evaluation of cellular radiosensitization by 5-fluorouracil: high-dose, pulsed administration is effective and preferable to conventional low-dose, chronic administration

PURPOSE

It is widely believed that the anticancer drug 5- fluorouracil (5-FU) must be administered chronically and in low doses to maximize radiosensitization during chemoradiotherapy. The rationale is based upon cell experiments that assumed identical mechanisms of 5-FU action between low-dose chronic (LDC) and high-dose pulsed (HDP) exposures. Here we challenge the paradigm and demonstrate the effectiveness of HDP 5-FU as a radiosensitizer and the wide range of dose/time schedules that can be used to synergize with radiation as compared to the relatively restrictive protocols prescribed for current LDC administrations.

MATERIALS AND METHODS

Clonogenic survival of human glioblastoma and colon cancer cell lines, U87MG-VIII and HCT-116, respectively, was used to assess temporal and dose effects of 5-FU on radiosensitivity and in split-dose experiments to characterize changes in sublethal damage repair.

RESULTS

We show that HDP 5-FU administration does indeed radiosensitize both the highly radioresistant U87MG-VIII and HCT-116. Additionally, we show that this radiosensitization lasts for at least 24 h if cells are pre-irradiated with 2 Gy immediately after HDP 5-FU exposure as a result of a decrease in sublethal damage repair capacity for subsequent irradiations, suggesting the ideal combination of 5-FU bolus injection with fractionation radiotherapy schemes.

CONCLUSIONS

5-FU bolus administration protocols combined with radiation would not only help improve treatment outcomes and reduce development of 5-FU resistance, but it would greatly benefit patients by shortening clinical stays and lowering overall therapeutic costs.

Phase III study of cyclophosphamide, doxorubicin, and fluorouracil (CAF) plus leucovorin versus CAF for metastatic breast cancer: Cancer and Leukemia Group B 9140

PURPOSE

To determine whether biochemical modulation with LV (leucovorin) enhances the efficacy of CAF (cyclophosphamide, doxorubicin, and fluorouracil) against metastatic breast cancer.

PATIENTS AND METHODS

Women with histologically confirmed stage IV breast cancer, Cancer and Leukemia Group B (CALGB) performance status 0 to 2, and no prior chemotherapy for metastatic disease were randomly assigned to receive CAF (cyclophosphamide 500 mg/m2 day 1, doxorubicin 40 mg/m2 day 1, and fluorouracil [FU] 200 mg/m2 intravenous bolus days 1 to 5) with or without LV (LV 200 mg/m2 over 30 minutes days 1 to 5 given 1 hour before FU).

RESULTS

Two hundred forty-two patients were randomly assigned to treatment; 124 patients had visceral crisis and 40 patients had a CALGB performance status score of 2. The median follow-up was 6 years. The two study arms were similar with regard to serious adverse events; four patients died from treatment-related causes, two patients on each study arm. Predictive variables for time to treatment failure and survival were visceral disease and performance status. The overall response rate was 29% for CAF versus 28% for CAF plus LV. The median time to treatment failure (9 months) and median survival (1.7 years) did not differ by treatment arm.

CONCLUSION

Modulation of CAF with LV improved neither response rates nor survival among women with metastatic breast cancer, compared with CAF alone. Multivariate analyses confirmed the prognostic importance of performance status and visceral crisis. However, the overall and complete response rates, response durations, time to treatment failure, and survival were the same in the two treatment arms.

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.

Sequential biochemical modulation of fluorouracil with folinic acid, N-phosphonacetyl-L-aspartic acid, and interferon alfa-2a in advanced colorectal cancer

PURPOSE

Several agents have been evaluated for their effect as biochemical modulators of fluorouracil (5-FU) in the treatment of metastatic colorectal carcinoma. In this study, we used folinic acid (FA), N-phosphonacetyl-L-aspartic acid (PALA), and recombinant interferon alfa-2a (IFNalpha-2a) in a sequential order to assess the efficacy of this approach in patients with metastatic colorectal carcinoma.

PATIENTS AND METHODS

Forty-four patients with metastatic colorectal carcinoma were enrolled onto the study. The treatment course consisted of three cycles: (cycle 1) FA 20 mg/m(2) followed by 5-FU 425 mg/m(2) on days 1 to 5; (cycle 2) PALA 250 mg/m(2) on days 29, 36, 43, and 50 and 5-FU 2,600 mg/m(2) as a 24-hour infusion on days 30, 37, 44, and 51; and (cycle 3) IFNalpha-2a 9 million units (MU) three times a week for 5 weeks beginning on day 57, with a continuous infusion of 5-FU 750 mg/m(2) on days 57 to 61, and then weekly bolus of 5-FU 750 mg/m(2)/wk on days 71, 78, and 85. Response was determined after cycle 3.

RESULTS

All patients had a Zubrod performance status >/= 2, measurable disease, and had received no prior chemotherapy for their metastatic disease. A total of 212 cycles were given. Thirty-six patients were assessable for response. No complete responses were seen. Seven patients had a partial response, eight had stable disease, and 15 had progressive disease. The median duration of response was 25 weeks, and the median survival was 53 weeks. Grade 3 and 4 toxic effects included granulocytopenia, stomatitis, diarrhea, rash, nausea, and fatigue.

CONCLUSION

This trial provided no evidence that sequential biochemical modulation of 5-FU in patients with metastatic colorectal carcinoma had any therapeutic advantage over conventional treatment regimens of 5-FU plus FA.

Management of hepatic metastases from colorectal cancer: systemic chemotherapy

The current phase III studies of chemotherapy in advanced colorectal cancer include 60% to 85% of patients with the liver as a site of metastatic disease. Within the past 10 years, various modulatory combinations of 5-fluorouracil (5-FU) with agents such as leucovorin, interferon, N-(phosphonacetyl)-L-aspartate (PALA), and methotrexate have produced higher response rates than 5-FU alone. A major seven-arm study, conducted by the Southwestern Oncology Group and reported in 1995, suggested that single-agent, continuous-infusion 5-FU demonstrated the most encouraging results. Nine of 12 reported randomized studies comparing the combination of 5-FU and leucovorin with 5-FU alone report significant increases in response rates; two studies reported significant increases in survival. The meta-analysis project involving 1381 patients confirmed the increase in response rate with the combination (23%) vs. 5-FU alone (11%) but did not demonstrate any significant difference in median survival. The current issues involving 5-FU administration largely concentrate on the best approach (modulation vs. scheduling) and comprehensive evaluation of end points (quality of life, survival, and pharmacoeconomics). The current literature examining quality-of-life issues suggests that 5-FU and low-dose leucovorin produce the best overall improvement in symptoms. Others argue that continuous-infusion scheduling is also associated with a very good quality of life (although the increased cost and morbidity of continuous-infusion administration has to be factored into this consideration). An important phase III study is currently being conducted by the National Cancer Institute of Canada comparing immediate vs. delayed (until symptomatic) chemotherapy in patients with advanced colorectal cancer. Of the new approaches to therapy, perhaps the most immediately applicable are the new thymidylate synthase inhibitors (in particular, Tomudex, which produces a response rate equivalent to that of 5-FU plus leucovorin with less toxicity and a more convenient schedule).

A phase II study of 5-fluorouracil, leucovorin, adriamycin, and cisplatin (FLAP) for metastatic gastric and gastroesophageal junction adenocarcinoma. A Penn Cancer Clinical Trial Group and Roswell Park Cancer Institute Community Oncology Research Program Trial

A Phase II study was performed to evaluate the activity and toxicity of 5-fluorouracil, leucovorin, Adriamycin, and cisplatin combination chemotherapy (FLAP) in patients with previously untreated advanced gastric and gastroesophageal (GE) junction adenocarcinoma. Forty-two consecutive patients were enrolled to received FLAP in this multi-institutional trial. Response, toxicity, and survival data were noted. Fifteen of 42 (36%) patients demonstrated objective responses, with two complete responses (5%) and 13 partial responses (31%). The median time to disease progression was 17 weeks, and the overall survival duration was 30 weeks. Myelosuppression was significant, requiring dose modifications, but there were no treatment-related deaths. FLAP is an active regimen in the treatment of advanced gastric and GE junction adenocarcinoma. We are presently using this regimen in the neoadjuvant setting in patients with gastric and GE junction cancers.

A pilot trial of 5-FU, leucovorin, and cisplatin with or without adriamycin in advanced cancer

In a pilot trial, we treated patients with solid tumors with 5-FU (5-fluorouracil), leucovorin (LV), and cisplatin (FLP) with Adriamycin in selected patients (FLAP). 5-FU/LV were administered weekly for 6 weeks, with cisplatin at two dose levels (and Adriamycin in some patients) at weeks 1 and 4. Nine patients received FLP; 11 received FLAP.FLP was able to be administered with a cisplatin dose of 75 mg/m2; the maximum-tolerated dose of FLAP included a cisplatin dose of 60 mg/m2. Significant toxicities included granulocytopenia, thrombocytopenia, and diarrhea. Preliminary activity was demonstrated with FLAP in patients with adenocarcinomas of the stomach and gastroesophageal (GE) junction. Ongoing trials of FLAP are underway in patients with gastric and GE junction carcinomas in the neoadjuvant and advanced disease settings.

Different intravenous administration techniques for 5-fluorouracil. Pharmacokinetics and pharmacodynamic effects

The pharmacokinetics after 20 min intravenous infusion or a 2 min bolus (push) injection of 5-fluorouracil (500 mg/m2) were studied in 14 colorectal cancer patients. Treatment effects and toxicity related to the administration technique of 5-fluorouracil were retrospectively analysed in 198 colorectal cancer patients. The AUC after bolus injection was 6158 +/- 874 micromol/l*min compared to 3355 +/- 428 micromol/l*min after short-time infusion of 5-fluorouracil (p < 0.01). The mean peak-level after bolus injection was 341 +/- 34 microM versus 161 +/- 17 microM after a short-time infusion (p < 0.01). Patients receiving bolus injections had significantly better treatment result (32% partial remission) than patients receiving infusion (10% partial remissions, p < 0.001). Toxic side-effects were more frequently encountered after bolus injection but subjective improvement was also more frequently experienced by these patients. Bolus 5-fluorouracil push injection rather than a short-time infusion appears to be the more efficient administration technique.

Adjuvant treatment of colon and rectal cancer: impact of chemotherapy, radiotherapy, and immunotherapy on routine postsurgical patient management. Forschungsgruppe Onkologie Gastrointestinaler Tumoren (FOGT)

Colon cancer patients with UICC stage III or T4 N0 M0 stage II should receive postoperative adjuvant therapy, since relapse rates are high and surgical outcome has been improved by adjuvant treatment. The standard treatment is 5-fluourouracil plus levamisole; an alternative option is the combination of 5-fluourouracil and folinic acid. Stage II (T3 N0 M0) colon cancer patients should not receive adjuvant treatment outside of studies. Rectal cancer patients of stage II or III should receive postoperative radiochemotherapy with 45-54.4 Gy and 5-fluourouracil as standard treatment. Patients not eligible for radiotherapy may receive adjuvant chemotherapy only. Studies need to be conducted to improve adjuvant therapy in colorectal cancer. All qualified patients should be treated within these studies requiring sufficient patient numbers, as well as comparable surgical procedures, proper patient selection and stratification criteria, drug and dose intensities. Intraportal infusion may be as effective as systemic adjuvant treatment; the tumor type and stage for which benefit from this kind of treatment is consistently significant needs to be defined, since intraportal infusion of all resectable colorectal cancers is overtreatment. Both surgery and histopathological staging may be improved in some centers, and these require standardization and quality control.

ZD1694 (Tomudex): a new thymidylate synthase inhibitor with activity in colorectal cancer

ZD1694 (Tomudex) is a new antifolate which is a specific inhibitor of thymidylate synthase (TS). Evidence suggests that ZD1694 has a spectrum of activity that only partially overlaps with 5-fluorouracil (modulated with leucovorin) against colon tumours in vitro. Potent cytotoxic activity is dependent upon active uptake into cells via the reduced folate/methotrexate cell membrane carrier (RFC) and subsequent metabolism to polyglutamated forms (tri, tetra and pentaglutamates). These polyglutamates are approximately 60-fold more active as TS inhibitors and are not effluxed readily from cells. Extensive polyglutamation also occurs in various mouse tissues (e.g. small intestinal epithelium, liver and kidney), resulting in high tissue/plasma drug ratios which persist for a prolonged period. ZD1694 has antitumour activity in mice, although the high plasma thymidine in this species complicates: (1) the interpretation of therapeutic index; (2) tumour types in which activity is likely to be observed; and (3) translation of doses and schedules for clinical evaluation. ZD1694 entered clinical study and has completed Phase I and II evaluation, with activity observed in several tumour types. Appreciable activity in the Phase II colorectal study (29% objective response rate on interim analysis) led to the current Phase III study, randomised against 5-fluorouracil/leucovorin.

SMS 201.995 (Sandostatin) enhances in-vitro effects of 5-fluorouracil in colorectal cancer

5-fluorouracil (5-FU) is still the most effective cytotoxic agent for the treatment of human colorectal cancer. Response rates, however, vary between 5-20%. One attempt to improve the effect of 5-FU is through biomodulation. We have previously found the somatostatin analogue, SMS 201.995 (Sandostatin, Sandoz), to inhibit both the in-vitro and in-vivo growth of some human colon cancer cell lines. It may act specifically by means of receptors on the surface of tumour cells, or by reducing the concentration of some growth factors. We report that, when 5-FU at 0.125 and 0.25 micrograms/ml was combined with SMS 201.995 at 10(-12) x 2 to 10(-8) x 2M, an enhanced inhibition of in-vitro growth of two human colorectal cancer cell lines (C170 and LIM 1215) was achieved. Effects were measured using [3H]-thymidine uptake and by a colorimetric assay of cellular respiration (MTT, Promega, Sydney). SMS 201.995 alone has minimal inhibitory effects, whilst 5-FU alone shows inhibition as low as 39.6% of control. When 5-FU was then combined with SMS 201.995, a 10-30% inhibition occurred compared to the 5-FU control. The combination of 5-FU and SMS 201.995 may be a useful method of improving response to human colorectal cancer therapy.

Phase II trial of intravenous melphalan in advanced colorectal carcinoma

BACKGROUND

Relatively few studies have examined the activity of alkylating agents in the treatment of advanced colorectal adenocarcinoma. Recent reports have suggested possible therapeutic activity for high-dose intravenous melphalan administered with autologous bone marrow transplantation (BMT) support. We conducted a phase II study to determine the efficacy of administering intravenous melphalan at doses that do not require BMT support in patients with advanced colorectal adenocarcinoma.

PATIENTS AND METHODS

Fifteen patients with histologically proven, bidimensionally measurable disease were treated. The starting dose of melphalan was 30 mg/m2, with dose escalation permitted.

RESULTS

No objective responses were observed. Toxic effects were primarily reversible granulocytopenia and thrombocytopenia. There were no treatment-associated deaths.

CONCLUSION

Melphalan's lack of efficacy at the doses administered does not disprove the steep chemotherapy dose-response relationship postulated for many solid tumors. However, we feel that it is unlikely that repetitive courses of high dose melphalan with autologous BMT support will be a practical approach to the management of advanced colorectal adenocarcinoma.

Nonsurgical management of recurrent colorectal cancer

Most patients with colorectal carcinoma undergo attempts at curative surgery. However, some present with metastatic disease and many others ultimately relapse. Most recurrences of colorectal cancer are not resectable and require nonsurgical approaches such as chemotherapy and radiation therapy directed against local recurrences, hepatic metastases, and widely disseminated disease. Nonsurgical therapy for locoregional recurrence of rectal cancer can offer significant palliation. Intraarterial chemotherapy for liver metastases increases the likelihood of response compared to systemic treatments, but has little effect on survival. Extrahepatic progression and hepatic toxicity are important limitations to this regional therapy. 5-fluorouracil (5-FU) is the mainstay of systemic chemotherapy, and efforts to modulate biochemically the cytotoxic effects of 5-FU with folinic acid, phosphonacetyl-L-aspartate, interferon, and other agents have resulted in promising response rates. The different approaches to biochemical modulation are being studied in ongoing cooperative group trials. Novel approaches, including monoclonal antibody therapy, biologic modifier therapy, and gene therapy, are under investigation.

Combination chemotherapy with tauromustine (TCNU), 5-fluorouracil and leucovorin in advanced colorectal carcinoma: a dose-finding study

BACKGROUND

In preparation for a phase II trial we performed a dose-finding study involving tauromustine (TCNU), fluorouracil (5-FU) and leucovorin (LV), applied in patients with colon cancer. To prevent TCNU/5-FU antagonism, a phenomenon recently demonstrated in vitro, special attention was paid to the sequencing of these agents.

PATIENTS AND METHODS

In 25 patients with advanced colorectal carcinoma (13 M, 12 F, median age 51 yrs), four dose levels of TCNU (25, 30, 35 or 40 mg/m2) were investigated. The agent was administered orally once per week in weeks 1 through 4, in combination with fixed i.v. doses of 400 mg/m2 5-FU and 80 mg/m2 LV, once a week, weeks 1 through 8. Unless progression occurred, two 8-week cycles were applied. TCNU was administered at least 24 hours prior to 5-FU, because recent in vitro studies suggested that such an interval is required to obtain additive cytotoxicity.

RESULTS

All 25 patients were evaluable for toxicity; 23 patients received at least one full 8-week course, and 13 were eligible for second cycles. Significant haematologic toxicity, predominantly thrombocytopenia WHO grade 3 or 4, was mainly encountered at the 35 and 40 mg/m2 dose levels. Although occasionally severe, myelosuppression did not result in toxic deaths; spontaneous haemorrhage was never observed, and platelet transfusions were not required. Additional toxicity, also related to the two higher dose levels, consisted of diarrhea (WHO grade 3) and the 'hand and foot syndrome', both occurring in a single patient; two patients developed fever of undetermined origin, but only one of them required hospitalization and antibiotic treatment. The overall response rate was 20% (7 partial responses in 25 evaluable patients).

CONCLUSIONS

For phase II studies, we recommend a weekly oral dose of 40 mg/m2 TCNU, weeks 1 through 4, in combination with 400 mg/m2 5-FU and 80 mg/m2 LV (IV), once a week, weeks 1 through 8.

A phase I trial of protracted 5-fluorouracil infusion and oral calcium leucovorin

This phase I study of 36 patients was performed to identify the maximal tolerated dose of oral calcium leucovorin (CLV) that could be concomitantly administered with protracted 5-fluorouracil (5-FU) infusion (greater than 30 days). Administration of CLV in very small doses (5 mg p.o. q8h) with 5-FU, 200-300 mg/m2/day, resulted in excessive toxicity requiring treatment interruption in all patients. Subsequent reduction in the dose of 5-FU to 100 mg/m2/day with simultaneous administration of CLV, 5 mg p.o. q8h, decreased the toxicity and allowed for protracted administration of the combination. In subsequent patients the dose of oral CLV was increased to 22.5 mg p.o. q8h, which resulted in treatment-limiting toxicity in the majority of patients. Toxicity consisted almost exclusively of mucositis. No myelosuppression or significant organ toxicity was observed. We conclude that even low doses of oral CLV potentiate the biological effect of infusion 5-FU. If the combination is to be given on a protracted basis, 5-FU must be administered at a much smaller dosage than has been traditionally utilized.

Phase II study of gemcitabine in advanced colorectal adenocarcinoma

A phase II trial of gemcitabine (difluorodeoxycytidine) was conducted in 14 patients with advanced colorectal adenocarcinoma. Gemcitabine was administered intravenously over 30 minutes at weekly intervals for 3 consecutive weeks each month. The starting dose was 800 mg/m2, with dose escalation as tolerated. No complete or partial response were observed. Ten patients experienced progressive disease while on therapy. Toxic effects were primarily hematologic in nature. Grade 3 toxicities included leukopenia (one patient at 1000 mg/m2), granulocytopenia (two patients at 800 mg/m2), anemia (two patients at 800 mg/m2), and myalgia (one patient at 800 mg/m2). No grade 4 toxic effects or treatment-associated deaths were observed. Gemcitabine, at the doses and schedule used in this study, did not demonstrate activity against advanced colorectal adenocarcinoma.

Fluorouracil-alone versus high-dose folinic acid and fluorouracil in advanced colorectal cancer: a randomized trial of the Italian Oncology Group for Clinical Research (GOIRC)

One hundred eighty-one patients with measurable recurrent or metastatic colorectal cancer, who had not received prior chemotherapy, were randomized in a prospective controlled trial to receive 5-fluorouracil (5FU), 13.5 mg/kg, for five days (arm A) or high-dose folinic acid [Cyanamid-Lederle, Italy] (FA), 200 mg/m2, for five days and 5FU, 400 mg/m2 for five days (arm B). The treatments were repeated every four weeks. One hundred fifty-five patients were evaluable for response. The two arms were balanced for all potential prognostic factors studied. The response rate (CR+PR) was 18% in the 5FU arm and 16% in the 5FU plus FA arm. Median duration of response was 56 weeks for 5FU alone and 42 weeks for the combination (p = 0.48). Median time to failure (TTF) was 20 weeks for arm A and 21 for arm B (p = 0.62). Median survival was 62 weeks on the 5FU arm and 53 weeks on the FA plus 5FU arm (p = 0.14). Dose intensity (DI) delivered was the same in both arms. Diarrhea and mucositis were the most frequent adverse reactions in arm B; 20% of the patients in arm A and 38% of those in arm B experienced diarrhea (p = 0.008). Mucositis occurred in 34% of patients in arm A and 42% in arm B (p = 0.04). In general nausea and vomiting were moderate. Hematological toxicity was more severe in patients treated with 5FU alone: 31% in arm A and 14% in arm B developed leukopenia (p = 0.015). In the combination arm one patient died due to gastrointestinal and hematological toxicity after the seventh cycle. This study indicates that, in advanced colorectal cancer, the combination of high-dose FA and 5FU is not superior to 5FU alone when utilized at standard high-dose intensity.

A phase I trial of 5-fluorouracil, folinic acid, and alpha-2a-interferon in patients with metastatic colorectal carcinoma

The mechanisms of biochemical modulation of 5-fluorouracil (5-FU) cytotoxicity by folinic acid (FA) have been elucidated, and the clinical use of this combination has improved response rates and survival in patients with metastatic colorectal cancer. Recently, Phase II trials also showed potential synergism between alpha-2a-interferon (rHuIFN-alpha 2a) and 5-FU. Therefore, a Phase I trial of these three agents 5-FU, FA, and rHuIFN-alpha 2a was conducted in patients with metastatic colorectal cancer. The drugs were given over 5 days, with dose escalation of either rHuIFN-alpha 2a or 5-FU. Fifty-five eligible patients were treated at eight dosing levels. The maximal tolerated dose (MTD) was as follows: 5-FU 430 mg/m2/d intravenously (IV) on days 1 to 5, FA 200 mg/m2 IV on days 1 to 5, and rHuIFN-alpha 2a 4.0 x 10(6) U/m2/d subcutaneously on days 1 to 5. The dose-limiting toxicities were mucositis and neutropenia. Objective responses were seen at most dosing levels, and overall 15 of 55 patients (27%; 95% confidence interval, 16% to 41%) responded (median duration, 6.5 months). A Phase II trial using the MTD is ongoing.

Randomised comparison of weekly bolus 5-fluorouracil with or without leucovorin in metastatic colorectal carcinoma

148 patients with advanced untreated colorectal cancer were randomised to receive a weekly bolus of 5-fluorouracil (5-FU) 600 mg/m2 alone, with or without leucovorin (LV) 500 mg/m2. 5-FU plus LV produced a higher response rate than 5-FU alone: 23% (5 complete response, 11 partial response) vs. 8% (2 complete response, 4 partial response) (P = 0.03) out of 70 and 72 evaluable patients, respectively. Median survival was 11 months in both groups and median time to progression was not significantly different (P = 0.08). The combined regimen was more toxic than 5-FU alone, as evidenced by (a) a higher percentage of grade 3-4 diarrhoea, 19.5% vs. 8.5% (P = 0.045) and conjunctivitis, 26.5% vs. 5.6% (P = 0.0025); (b) the recording of one toxic death in the combined arm; and (c) the reduction of the median dose intensity of 5-FU actually delivered during the first 2 months of treatment. We conclude that 5-FU plus LV at a price of a higher toxicity is more active than 5-FU alone without improving survival and progression-free survival.

Treatment of Advanced Colorectal Cancer with Mitoxantrone, High Dose Folinic ACID and Fluorouracil

A new combination chemotherapy including mitoxantrone 10 mg/m2 i.v. on day 1 and 5-fluorouracil 400 mg/m2 i.v. plus folinic acid 200 mg/m2 i.v. on days 1-5 was administered every 28 days to 13 patients with locally advanced or metastatic colon (1 case), rectosigmoid colon (4 cases), or rectum (8 cases) carcinoma. The median number of cycles performed was 3 (range, 1-9). No patient achieved complete or partial remission with this regimen, whereas 5 showed a stable disease lasting 3-8 months. Acute toxicity was mild/moderate in intensity and comparable to that reported with the standard 5-fluorouracil + folinic acid combination. Since we observed no major responses in our 13 consecutive patients, we consider that the overall activity of our regimen, at the doses and schedule utilized, was only moderately effective in advanced colorectal carcinoma.

Fluorouracil and recombinant interferon alfa-2a in advanced gastrointestinal neoplasms

Based on preclinical studies which demonstrated synergy between recombinant interferon alfa-2a (rIFN alpha-2a) and 5-fluorouracil (5FU), clinical studies have been initiated to investigate this combination. The initial study conducted by investigators from the Albert Einstein Cancer Center reported a response rate of 76% with 13/17 patients with advanced colorectal carcinoma responding. To further evaluate this regimen, two clinical trials have been conducted in previously untreated advanced colorectal carcinoma patients with measurable disease. The regimen consisted of 5FU administered as a continuous infusion, 750 mg/m2/d for 5 consecutive days. Intravenous bolus administration of 5FU 750 mg/m2 was given weekly for 7 weeks starting 1 week after completion of the continuous infusion. rIFN alpha-2a, 9 MU, was administered subcutaneously three times weekly. In The University of Texas M.D. Anderson Cancer Center trial, 15/45 evaluable patients experienced partial response, and one patient achieved a complete response for an overall response rate of 35%. Another trial of this regimen conducted by Memorial Sloan-Kettering has reported a 26% response rate with 9/34 evaluable patients experiencing a partial response. Current randomized trials comparing this schedule of 5FU with rIFN alpha-2a to 5FU plus folinic acid or single-agent 5FU may clarify its role in the treatment of advanced colorectal carcinomas.

Modification of 5-fluorouracil activity by high-dose methotrexate or leucovorin in advanced colorectal carcinoma

21 patients with advanced colorectal carcinoma were entered into a phase II study to evaluate efficacy and toxicity of methotrexate (MTX), 1500 mg/m2 rapid infusion on day 1, combined with continuous infusion of 5-fluorouracil (5-FU), 600 mg/m2 per 24 h on days 1-4. 12 patients who had progressive disease during this regimen subsequently received high-dose leucovorin, 200 mg/m2 bolus injection on days 1-4, combined with 4 days' continuous infusion of 5-FU. In the MTX/5-FU group 1 pathologically proven complete remission and 3 partial remissions were seen (response rate 20%). The median progression-free interval was 30 weeks. In 12 patients with progressive disease leucovorin/5-FU stabilized disease in 2 (17%). Toxicity in both regimens was tolerable, gastro-intestinal side-effects being most frequent. There were no treatment-related deaths. Median survival time was 10 months. Serum levels of carcinoembryonic antigen before treatment or doubling-time during progression did not correlate with survival.