Protracted treatment with tegafur and low dose oral leucovorin in patients with advanced colorectal carcinoma

Randomised study of tegafur and oral leucovorin versus intravenous 5-fluorouracil and leucovorin in patients with advanced colorectal cancer

This randomised, open-label trial compared oral tegafur (FT)/leucovorin (LV) with the intravenous bolus 5-fluorouracil (5-FU)/LV as first-line chemotherapy for advanced colorectal cancer (CRC). Patients were randomised to receive oral FT 750 mg/m2/day for 21 days and LV 15 mg/m2 every 8 h in cycles repeated every 28 days (n=114), or intravenous LV 20 mg/m2 followed by 5-FU 425 mg/m2 daily for 5 days every 4 weeks for 2 cycles, and later every 5 weeks (n=123). Response rate was significantly higher in the FT/LV arm (27%, 95% CI 19-35) than in the 5-FU/LV arm (13%, 95% CI 7-19) (p<0.004). The median time to progression was 5.9 months (95% CI, 5.3-6.5; FT/LV arm) and 6.2 months (95% CI, 5.4-6.9; 5-FU/LV arm). Median overall survival was 12.4 months (95% CI, 10.3-14.5 months; FT/LV arm) and 12.2 months (95% CI, 8.9-15.7 months; 5-FU/LV arm) (p=n.s.; hazard ratio FT/LV:5-FU/LV=1.02). 5-FU/LV showed a higher incidence of grade 3/4 neutropenia (4.1 vs. 0%). Non-hematological toxicities showed similar incidences in the two treatment arms. Oral FT/LV was more active than IV 5-FU/LV in terms of objective response rate with similar overall survival, and with a favorable toxicity profile. This makes FT/LV a valid alternative to the IV 5-FU schedule in CRC patients.

A phase I study of raltitrexed (Tomudex) combined with carmofur in metastatic colorectal cancer

OBJECTIVES

The aim of the study was to define the maximum tolerated dose (MTD) of the combination of raltitrexed plus carmofur, and to evaluate the tolerability and efficacy of this combination in metastatic colorectal cancer.

METHODS

Twenty-eight patients (23 receiving first-line therapy, 5 receiving second-line therapy) entered the study; 16 were chemonaive. Raltitrexed (Tomudex) 1.5-3.0 mg/m(2) was given as a 15- to 30-min intravenous infusion on day 1 of a 21-day cycle followed by carmofur 300-400 mg/m(2) orally 3 times daily on days 2-14. Therapy was given until disease progression or dose-limiting toxicity (DLT) occurred.

RESULTS

A total of 170 cycles of therapy were administered. The MTD was reached at the raltitrexed dose of 3.0 mg/m(2) and the carmofur dose of 400 mg/m(2). DLTs included grade 3-4 diarrhea, fatigue, anorexia, mucositis, anemia, thrombocytopenia, neutropenia, neurological symptoms and febrile neutropenia. Eleven of the 22 evaluable first-line patients achieved a partial response (response rate 50%, 95% confidence interval 29-71%), 8 had stable disease and 3 had disease progression. One of the 5 patients who received second-line therapy responded.

CONCLUSIONS

The recommended dose of this combination therapy for further evaluation is raltitrexed 3.0 mg/m(2) plus carmofur 300 mg/m(2). This combination has unique but manageable toxicity and promising efficacy in metastatic colorectal cancer.

In vitro and preclinical studies of targeted alpha therapy (TAT) for colorectal cancer

INTRODUCTION

Effective targeted cancer therapy requires high selectivity and cytotoxicity of the labelled product. We report the preparation and testing of anticolorectal cancer monoclonal antibody c30.6 radioimmunoconjugates (RIC) labelled with alpha-emitting Bismuth-213 and positron emitting Terbium-152 using two chelators, viz. Cyclic dianhydride of diethylenetriaminepentacetic acid (DTPA) and CHX-A" (a DTPA derivative).

METHODS

Selectivity and stability of the RIC were tested in vitro (flow cytometry) and in vivo (biodistribution, organ/tumour uptake and retention). Cytotoxicity assays were carried out using tritiated thymidine uptake (inhibition of DNA synthesis) and MTS assay.

RESULTS

High labelling efficiency (ranging between 89 and 91%) and stability over 2-5 half-lives of the isotopes were seen. Kidney retention was not seen in contrast to high uptake and retention of both conjugates in tumours. Flow cytometry studies showed high specificity of the antibody before and after labelling and this unchanged targeting behaviour was reflected in cytotoxicity assays. These assays showed that only alpha-labelled antibody could selectively kill the cancer cells for activities as low as 2-3 microCi. The study also revealed that free isotopes or isotopes bound to nonspecific antibodies did not kill cancer cells.

CONCLUSION

The stability of the RICs and outstanding cytotoxicity of the alpha emitter, together with no kidney retention and high tumour uptake and retention of the radiolabel, offers a new approach for the potential control of colorectal cancer.

In vitro and preclinical targeted alpha therapy for melanoma, breast, prostate and colorectal cancers

Targeted alpha therapy (TAT) can inhibit the growth of micrometastases by selectively killing isolated and preangiogenic clusters of cancer cells. The alpha emitting radioisotopes Tb-149 and Bi-213 were chelated to cancer specific monoclonal antibodies to form alpha-immunoconjugates (AIC) against melanoma, leukaemia, prostate and colorectal cancer, and to the plasminogen activator inhibitor type-2 (PAI2) to form alpha-PAI2 (API) against breast and prostate cancer. These conjugates were found to be highly stable, specific and cytotoxic in vitro. Melanoma and breast cancer tumour growth was observed in nude mouse models for untreated controls and non-specific AIC/API at 2 days post-subcutaneous inoculation of cancer cells. Complete inhibition of melanoma and breast cancer growth was found for local injections of AIC and API, respectively. Intra-lesional TAT of established melanoma showed that all melanomas regressed with 100 microCi injections of AIC. These results point to the potential application of local and systemic TAT in the management of metastatic cancer.

Cisplatin-5-fluorouracil therapy with remarkable effect and 5-year survival for paraaortic lymph node metastases of rectal carcinoma in females: a case report

A 68-year-old woman was admitted because of a rectal carcinoma with huge paraaortic lymph node metastases. Low anterior resection with regional lymph node dissection was performed, leaving the paraaortic mass. After the operation, cisplatin-5-fluorouracil therapy was used as supplemental chemotherapy. The metastatic lymph nodes shrank remarkably in response to anticancer drugs. We evaluated the effect of chemotherapy as a partial response. The physical condition of the patient was well controlled for more than 4 years until she was admitted again because of cardiac failure accompanied by relapse of abdominal lymph node swelling. She died of cardiac failure 5 years and 3 days after the operation.

Developments in fluoropyrimidine therapy for gastrointestinal cancer

The combination of 5-fluorouracil and leucovorin is the standard treatment in metastatic colorectal cancer and in Dukes' C colon cancer. There is, however, no agreement on the method for administration in metastatic colorectal cancer. Several new studies published in 1998 suggest that infusional 5-fluorouracil gives a higher response rate and better toxicity profile compared with a standard bolus 5-fluorouracil/leucovorin regimen. The median survival rate, however, is not different. Several new active drugs are being developed for advanced colorectal cancer. It has not yet been shown that these drugs as single agents are superior to an optimal 5-fluorouracil regimen. Combination trials of 5-fluorouracil/leucovorin with oxaliplatin, CPT-11 and raltitrexed are ongoing, and it can be expected that several of these combinations will be more active than 5-fluorouracil/leucovorin. The challenge for the future will be to show the most active combination and the best sequence of these combinations. The development of the orally administered fluoropyrimidines was rapid in 1998. Randomized studies comparing UFT, capecitabine, and eniluracil plus 5-fluorouracil with 5-fluorouracil/leucovorin are ongoing.