Pharmacology Which of the following antitumor agents works by impairing de novo purine synthesis? A Acyloguanosine B 5-Fluorouracil C Methotrexate (antifolate) D Allopurinol 💡 Explanation Which of the following antitumor agents works by impairing de novo purine synthesis? ✓ Correct Answer: C. Methotrexate (antifolate)