Dose Optimization and Efficacy Assessment of a Fluoropyrimidine Antidote

Fluoropyrimidines (FLU) are drugs widely used in chemotherapy for various tumors, such as breast, colon, rectal, and gastric cancers. FLU is a drug that inhibits thymine synthesis and, consequently, DNA synthesis, leading to tumor cell death. However, up to 30% of patients treated with FLU experience severe toxicities, depending on the dose and regimen received. The most common symptoms include mucositis, vomiting, nausea, diarrhea, and neutropenia.

The enzyme dihydropyrimidine dehydrogenase (DPD) plays a key role in FLU metabolism. Patients with mutations in the DPYD gene (which encodes DPD) are at high risk of experiencing severe toxicities from FLU. Uridine triacetate (UT) is a drug that can be used as an antidote for 5-FU in patients who develop severe toxicities. However, despite its efficacy, it is expensive and not commercially available in Brazil.

Currently, the Brazilian population has no access to an antidote for the treatment of FLU-related toxicities. This Phase I/II study will evaluate the dose, safety, and efficacy of compound the association of two molecules as an antidote for grade 3 or higher toxicities resulting from the use of FLU.