Trifluorothymidine and 5-fluorouracil: antiproliferative activity in tissue culture

The antiproliferative activity of trifluorothymidine (F3TDR) and 5-fluorouracil (5-FU), two cell-cycle-phase-specific antimetabolites, was compared in a tissue culture model of human scleral fibroblasts and rabbit corneal epithelial cells. The mean concentrations required to inhibit human scleral fibroblast proliferation to 50% of the control rate (ID50) after 5 days of exposure were 8.50 micrograms/mL for F3TDR and 0.43 microgram/mL for 5-FU. The corresponding ID50 levels for rabbit corneal epithelial cells were 0.24 microgram/mL and 0.42 microgram/mL. The ID50 of F3TDR was significantly higher than that of 5-FU in human scleral fibroblasts (p less than 0.001) but not in rabbit corneal epithelial cells. F3TDR appears to have no clinical advantage over 5-FU in minimizing corneal epithelial toxicity when given to prevent fibroblast proliferation after glaucoma filtering surgery.