A clinical trial of biochemical modulation of 5-fluorouracil with N-phosphonoacetyl-L-aspartate and thymidine in advanced gastric and anaplastic colorectal cancer.
A novel sequential administration schedule of PALA (N-phosphonoacetyl-L-aspartate) and thymidine to enhance the cytotoxic effect of 5-fluorouracil (5FU) was tested in 36 patients with advanced gastric cancer and 21 patients with advanced poorly differentiated (anaplastic) colorectal cancer. The potency of 5FU was dramatically increased as indicated by the observation of dose-limiting leukopenia at less than one tenth the maximum tolerated dose of 5FU when given as a single agent by intravenous bolus technique. Twenty-five percent of gastric cancer patients and 33% of colorectal cancer patients experienced an objective tumor response, including three patients with complete response. However, response duration was brief (median, 6 months), and there were four treatment-related fatalities due to severe and unpredictable leukopenia leading to sepsis. Survival was short with a median of 6 months for gastric cancer patients and 3 1/2 months for colorectal cancer patients. We conclude that therapeutic index of 5FU was not improved by the addition of PALA and thymidine in this patient population based on considerations of objective tumor response rate, patient survival, and toxicity.
St. Cloud Clinic of Internal Medicine, Ltd., MN.
H E
HE
Windschitl
M J
MJ
O'Connell
H S
HS
Wieand
J E
JE
Krook
J
J
Rubin
C G
CG
Moertel
J W
JW
Kugler
D M
DM
Pfeifle
R M
RM
Goldberg
J A
JA
Laurie
D000328:Adult; D000368:Aged; D001224:Aspartic Acid / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D002986:Clinical Trials as Topic; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000401:mortality; D004341:Drug Evaluation; D004357:Drug Synergism; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010746:Phosphonoacetic Acid / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000401:mortality; D013936:Thymidine / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use
D001224:Aspartic Acid; C013195:sparfosic acid; D010746:Phosphonoacetic Acid; D005472:Fluorouracil; D013936:Thymidine