Phase II evaluation of recombinant alpha-2a-interferon and continuous infusion fluorouracil in previously untreated metastatic colorectal adenocarcinoma

Medical Management of Colorectal Carcinomas

Current information on the medical treatment of colorectal cancer was reviewed after a search of the literature through Medline. Publications from 1984 to present were surveyed. Appropriate adjuvant therapy increases overall survival and disease-free intervals. The treatment modalities of unresectable or metastatic tumors are disappointing, with at best 40% of patients experiencing short-lasting responses. Whenever possible, patients with advanced colorectal cancer should be enrolled in clinical trials.

Surgical adjuvant therapy of rectal carcinoma: a controlled evaluation of leucovorin, 5-fluorouracil and radiation therapy with or without interferon-alpha2b

BACKGROUND

The aim of this study was to determine whether the efficacy of the combination of 5-fluorouracil (5-FU), leucovorin (LV) and radiation therapy (RT) could be improved by the addition of interferon-alpha2b (IFN-alpha) in patients who have had a 'curative' resection, for rectal adenocarcinoma (Dukes' B2/C; T3 N0, T4 N0, N1-3).

PATIENTS AND METHODS

A total of 207 eligible patients with a performance status of 0 or 1 were randomized postoperatively between days 21 and 70 to one of the two treatment groups: group A, LV 20 mg/m2 i.v. bolus and 5-FU 425 mg/m2 i.v. days 1-5 and 29-33, LV 20 mg/m2 and 5-FU 400 mg/m2 days 57-60 and 85-88, LV 20 mg/m2 and 5-FU 380 mg/m2 days 1-5 and 29-33 with the second day 1 occurring 28 days after the completion of RT (45 Gy); group B, LV, 5-FU and RT as in group A, and IFN-alpha 5 x 10(6) IU s.c. three times during each week chemotherapy is given.

RESULTS

104 patients were randomized into group A and 103 into group B. There was no statistically significant difference in either disease-free survival or overall survival between the two groups. Toxicity was also the same, except for the flu-like syndrome associated with the IFN-alpha administration.

CONCLUSIONS

There was no difference in efficacy between the two combinations. Toxicity was greater with the LV + 5-FU + IFN-alpha regimen because of the flu-like syndrome.

Biomodulation with sequential intravenous IFN-alpha2b and 5-fluorouracil as second-line treatment in patients with advanced colorectal cancer

A phase II trial was carried out by the Grupo Oncologico Cooperativo del Sur (G.O.C.S.) to assess the efficacy and toxicity of a biochemical modulation of 5-fluorouracil (5-FU) by i.v. pretreatment with interferon (IFN)-alpha2b in patients with advanced colorectal carcinoma refractory to previous therapy with 5-FU modulated by methotrexate (MTX) or leucovorin (LV) or both. Between January 1993 and October 1995, 34 patients were entered on the study. The treatment was IFN-alpha2b 5 x 10(6)/m2 IU in a 1-h i.v. infusion, followed immediately by 5-FU 600 mg/m2 i.v. bolus injection. Courses were repeated weekly until observation of progressive disease or severe toxicity. One patient could not be assessed for response. Objective regression was observed in 2 of 33 patients (6%, 95% confidence interval, 0%-14%). No patient achieved a complete response. Two patients had partial responses (6%). No change was recorded in 14 patients (41%), and progressive disease occurred in 17 (52%). The median time to treatment failure was 3 months, and the median survival was 5 months. Toxicity was within acceptable limits. The main side effects were mucositis and diarrhea. Four episodes of grade 2 stomatitis were observed, causing dosage modifications. The most frequent toxic effects attributable to IFN-alpha2b were mild fatigue and fever. In conclusion, second-line therapy with i.v. IFN-alpha2b preceding 5-FU has shown an interesting profile of activity in a patient population with clearly unfavorable characteristics. From this perspective, further appropriately designed studies are needed to identify the greatest potential of IFN-alpha2b as a modulator of 5-FU.

Biomodulation of Fluorouracil in colorectal cancer

5-Fluorouracil (5-FU) remains the agent of choice for the treatment of colorectal cancer. Research has focused on the biomodulation of 5-FU in order to attempt to improve the cytotoxity and therapeutic effectiveness of this drug in the treatment of advanced colorectal cancer. Modulation of 5-FU by methotrexate (MTX), trimetrexate (TMTX), interferon-alpha (IFN-alpha), leucovorin (LV), or N-(phosphonacetyl)-L-asparte acid (PALA) has produced higher response rates than those observed with 5-FU alone. Methotrexate may improve the durability of response to or survival with 5-FU, but with inferior results compared with those in trials of 5-FU and leucovorin. Trimetrexate produces a number of responses, and further phase III trials are in progress to confirm the results of promising phase II trials with this drug. IFN-alpha has shown therapeutic efficiency when combined with 5-FU alone or with 5-FU and leucovorin, but latest studies with these combinations have shown increased toxicity. Initial single-institution phase I trials with 5-FU and PALA reported promising responses, but the latter responses with PALA were not substantiated in randomized multicenter trials. Leucovorin enhances the cytotoxic activity of 5-FU in vitro and in vivo, and several clinical trials have shown improved response rates and possible trends in improved survival when such therapy is compared with the use of 5-FU as a single-agent. More recent randomized trials have focused their attention on determining the optimal dose and schedule with this combination for producing a better clinical response with minimal toxicity. Schedules using infusional 5-FU appear to be the most active regimens when 5-FU is used as a single agent, as demonstrated by recent randomized trials. The Southwest Oncology Group (SWOG) and the Eastern Cooperative Oncology Group (ECOG) have performed separate randomized trials and have shown that the optimal regimens employ infusional 5-FU as a single agent, and that these are the least toxic regimens, perhaps more effective, and associated with a better quality of life. Future studies will focus on infusional regimens involving either short-term, high-dose protracted or long-term, low-dose protracted infusion of 5-FU, since these regimens have shown the most favorable toxicity spectrum and produced the longest survival times. Future research will also focus on the evaluation of various methods of delivery of 5-FU, including oral administration of the drug in combination with compounds that can modify its catabolism.

Continuous infusion of chemotherapy: focus on 5-fluorouracil and fluorodeoxyuridine

Continuous infusion of chemotherapy is one of the developments to try to improve the treatment of metastatic cancer. There is a sound theoretical rationale to deliver cytotoxic drugs as a continuous infusion. Furthermore, the development of reliable venous access devices and portable infusion pumps enables patients to be treated in an ambulatory setting. This review focuses on the continuous infusion of the most frequently used drugs: 5-fluorouracil (5-FU) and fluorodeoxyuridine (FUDR). An overview is given of both preclinical studies and studies in humans. Continuous infusion of 5-FU and FUDR has proven to be feasible in all studies. However, the results (response rate and especially survival) are rather disappointing. So far, continuous infusion of cytostatic drugs can still be considered as an experimental procedure. Whether protracted, intermittent of circadian modulated continuous infusion is the optimal treatment schedule has still to be proven in future studies. Furthermore, studies are needed to demonstrate whether dose intensity for most tumours is important for treatment outcome. Also, studies are needed to investigate quality of life and economic issues.

A phase II randomised trial of 5-fluorouracil with or without interferon alpha-2a in advanced colorectal cancer

With the association of 5-fluorouracil (5-FU) and alpha-interferon (IFN), objective responses as high as 26 63% have been reported in untreated patients with advanced colorectal cancer. However, grade 3-4 toxicity has also been reported. We have conducted a prospective phase II randomised study comparing 5-FU to 5-FU + IFN, to investigate whether the addition of IFN to a weekly 5-FU regimen devoid of significant toxicity used at our institutions could improve the effectiveness of 5-FU while maintaining acceptable toxicity. Patients with histologically proven advanced colorectal carcinoma were randomised to receive 5-FU 500 mg m-2 intravenous (i.v.) bolus on days 1-5 followed by 5-FU 500 mg m-2 i.v. bolus weekly from day 15, with or without IFN alpha-2a intramuscularly (i.m.) 1.5 mU daily on days 6-12 and 3 mU i.m. daily thereafter. The treatment was administered on an outpatient basis. Response was evaluated every 3 months, and treatment continued until progression or after two consecutive judgements of stable disease. Response rate was the main end point of the study. Of 141 patients eligible, 72 were randomised to 5-FU alone (arm A) and 69 to 5-FU + IFN (arm B). Responses were 9/72 (12.5%) in arm A and 6/69 (8.7%) in arm B; complete responses were three in arm A and two in arm B. Progression-free survival (median 4 months) and survival (median 12 months) were identical in the two arms. Toxicity was almost absent in arm A and moderate in arm B, represented mainly by haematological toxicity (usually leucopenia). In conclusion, overall survival was good in both arms of treatment and toxicity was moderate. While the response rate with 5-FU alone was in accord with the literature data, response to 5-FU + IFN was lower than expected. At least at this dosage and schedule, the association of 5-FU and IFN is no better than 5-FU alone and is of no clinical interest.

5-Fluorouracil versus 5-fluorouracil plus alpha-interferon as treatment of metastatic colorectal carcinoma. A randomized study

BACKGROUND

In 1989, S. Wadler reported very promising results (76% response rate) with a combination of 5-fluorouracil (5-FU) plus alpha-2a interferon (IFN) in the treatment of metastatic colorectal carcinoma (MCRC). In vitro, there are several potential explanations for synergism between the two agents. We therefore decided in 1989 to start a randomized study comparing 5-FU alone with 5-FU plus IFN.

PATIENTS AND METHODS

105 non-pretreated patients with measurable metastatic colorectal carcinoma entered into this study. The patients were randomly allocated either in arm A (n = 49) with 5-FU: 750 mg/m2 i.v. CI d1-d5 followed by 750 mg/m2 i.v. bolus once a week, or in arm B (n = 56) with 5-FU as in arm A plus IFN 9 x 10(6) IU sub-cutaneously three times a week.

RESULTS

After two months of treatment we observed 1 CR and 2 PR in arm A (response rate 6.1%), 3 CR and 8 PR in arm B (response rate 19.6%), i.e., a significant difference (P = 0.05). Event-free survival was significantly higher in arm B (6 months) than in arm A (2 months) (P < 0.01), while median survival was slightly higher in arm B (12 months) than in arm A (10 months) (P < 0.05). For overall survival the difference was not significant after adjustment on center treatment and baseline Karnofsky status (P = 0.13). Toxicity was also greater in arm B. Sixteen percent of patients in arm A and 36% in arm B experienced certain grade 3-4 side effects (P < 0.05).

CONCLUSION

5-FU plus IFN is more effective than 5-FU alone in terms of response rate, event free survival but not of overall survival. 5-FU plus IFN is more toxic. As IFN has no demonstrated efficacy in MCRC as a single agent, this study suggests that IFN is acting as a 5-FU modulatory agent. The response rate observed (19.6%) is similar to the results obtained elsewhere with 5-FU plus leucovorin.

Current treatment modalities in advanced colorectal carcinoma

Several biochemical and immunological substances are currently being tested for their efficacy in the treatment of advanced colorectal cancer, the second-most malignant disease in the western world. Presently, a combination of 5-fluorouracil (FU) and the biochemical modulator folinic acid is considered to be the standard treatment for this malignancy, with a median response rate of 30%. A recent multi-analysis of phase III trials with methotrexate and FU versus FU alone has demonstrated a statistically significant doubling of the response rate as well as a significant survival advantage for the combination. So far, other biochemical or immunological modulators of FU have not shown a significant advantage regarding response or survival. Several new drugs such as tegafur, thymidilate synthase inhibitors, trimetrexate, or topoisomerase-I-inhibitors have been tested with promising results in preclinical and early clinical settings. While local treatment such as hepatic artery infusion has become safer, it is still more toxic than systemic treatment and showed a significant improvement of response but no survival advantage. Since all treatment strategies in advanced colorectal cancer are still palliative, quality of life is a more important endpoint in clinical trials.

A clinical and pharmacological study of 5-fluorouracil, leucovorin and interferon alfa in advanced colorectal cancer

Modulation of 5-fluorouracil (FUra) using leucovorin (LV) is a standard treatment approach in patients with metastatic colorectal cancer. Modulation of FUra with interferon alfa has also shown some promise. Laboratory data have demonstrated increased cytotoxicity when FUra is combined with both LV and interferon. The current study examined the effects of double modulation of FUra using LV and interferon. Patients with measurable advanced colorectal cancer received bolus FUra 375 mg/m2 plus LV 20 mg/m2 daily for 5 days, repeated every 28 days. Recombinant human interferon alfa-2a, 3 million IU/m2 subcutaneously, was given daily on the days of chemotherapy then three times weekly. There was one complete response and nine partial responses (10/41) seen for an overall response rate of 24% (95% CI 12.0-40.0%). Overall, 70% of patients experienced one or more episodes of nonhematologic toxicity of grade 3 or more. Weight loss was common, with a mean decrease of 2.9 kg over the first two months (P < 0.0001). Improvements in tumor-related symptoms were balanced by increased fatigue and a deterioration in body weight and performance status. There was no evidence of progressive changes in FUra metabolism from interferon usage.

Rolling review: gastrointestinal malignancy

The chemotherapy of gastrointestinal malignancies remain mostly investigational, although several adjuvant protocols in colorectal cancer and anal cancer are beginning to be accepted as standards against which newer regimens are to be compared. Chemotherapy regimens are best understood and appreciated with a basic understanding of cancer biology, tumour cell kinetics, and drug toxicities. An appreciation of chemotherapy-induced toxicity and an awareness of their management will help the gastroenterologist be an active participant in the multidisciplinary team caring for the patient with gastrointestinal malignancies.

The role of interferons in the treatment of colorectal cancer

There is a substantial body of evidence suggesting in vivo synergy between fluorouracil (FU) and interferons (IFNs). The mechanism(s) which is implicated in the expression of synergy with the combination of FU and IFNs is unknown. Although phase I studies have demonstrated a pharmacokinetic advantage for this combination, subsequent phase II studies in patients with advanced colorectal cancer showed that only one-third of the patients responded partially to this treatment. Double modulation of FU with leucovorin and IFN does not appear to add any survival benefit to these patients compared to single modulation of FU by IFN. In conclusion, the role of IFNs in the treatment of colorectal cancer has not been defined yet. It is hoped that phase III trials which currently are in progress will clarify this issue.