The FDA has approved uridine triacetate (Vistogard), a first-of-its-kind rescue drug for overdose toxicity of the chemotherapy drugs 5-fluorouracil or capecitabine.
Such overdoses, which are rare but can be fatal, may happen if a patient receives the drug at a dose or rate greater than intended or if a patient has genetic variations, impaired clearance, or other factors that increase susceptibility to the drug’s toxicities. Uridine triacetate blocks cell damage and cell death caused by the chemotherapy.
Two trials examined efficacy and safety of 135 adults and pediatric cancer patients; 117 had received an overdose of fluorouracil or capecitabine by rate (1.3 to 720 times the infusion rate), by dose, or by both dose and rate. The remaining 18 had early-onset, unusually severe, or life-threatening toxicities within 96 hours of receiving fluorouracil. The toxicities involved the central nervous system (such as acute mental status change), cardiovascular system, gastrointestinal system (eg, mucositis), and bone marrow.
The studies’ main measure was survival at 30 days or resumption of chemotherapy before 30 days. Patients received a single course of 10 grams orally every 6 hours for 20 doses (dose was adjusted for patients aged 1 to 7 years).
Five patients died of fluorouracil or capecitabine toxicity. Of those treated for overdose, 97% were still alive at 30 days. Of those treated for early-onset toxicity, 89% were alive at 30 days. In both studies, 33% of patients resumed chemotherapy in fewer than 30 days. By contrast, in retrospective historical reports, 84% of 25 patients who received only supportive care for 5-FU overdose (all overdosed with 1.9 to 64 times the planned infusion rate) died.
Uridine triacetate is not recommended for treating nonemergency adverse effects (AEs) associated with fluorouracil or capecitabine, because it could lessen their effectiveness. The most common AEs of treatment with uridine triacetate were diarrhea, vomiting, and nausea.
Sources: U.S. Food and Drug Administration. FDA approves first emergency treatment for overdose of certain types of chemotherapy [news release]. Silver Springs, MD: U.S. Food and Drug Administration Website. http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm476919.htm. Updated December 11, 2015. Accessed January 28, 2016.
Vistogard [package insert]. Gaithersburg, MD: Wellstat Therapeutics; 2015.