Reversible severe fatty liver induced by capecitabine: A case report

Review of the fluoropyrimidine antidote uridine triacetate

In 2015, the United States Food and Drug Administration (FDA) approved uridine triacetate to treat overdose and severe toxicity of the fluoropyrimidine chemotherapy agents 5-fluorouracil (5-FU) and its oral prodrug capecitabine. Uridine triacetate is as an oral prodrug of uridine that competes with cytotoxic fluoropyrimidine metabolites for incorporation into nucleotides. Two million people worldwide start fluoropyrimidine chemotherapy each year, with 20-30% developing severe or life-threatening adverse effects, often attributable to a genetic predisposition such as dihydropyrimidine dehydrogenase deficiency. Whilst genetic prescreening is recommended prior to starting fluoropyrimidine agents, this only prevents 20-30% of early-onset life-threatening toxicity and so does not obviate the need for an antidote. Initial in-human studies established that uridine triacetate more than doubles the maximum tolerated weekly 5-FU bolus dose. A lack of clinical equipoise meant a placebo-controlled phase III trial was not ethical and so the phase III trials used historical controls. These found that uridine triacetate improved survival in those with fluoropyrimidine overdose and severe toxicity from 16% to 94%, with 34% able to resume chemotherapy within 30 days. Five case reports of delayed fluoropyrimidine toxicity demonstrate improvement following uridine triacetate treatment 120-504 h after last fluoropyrimidine administration, suggesting efficacy beyond the FDA licencing indications. Mechanistically uridine triacetate would be expected to be effective for overdose and severe toxicity of tegafur (a 5-FU prodrug), but there are no published case reports describing this. Uridine triacetate is available internationally through an expanded access scheme and has been available in the UK since 2019 on a named patient basis.

Drug-Induced Liver Injury Caused by Capecitabine: A Case Report and a Literature Review

Chemotherapy is widely used in cancer treatment, and the drug Capecitabine is often used in treatment of breast cancer and usually well-tolerated. Toxicity from Capecitabine typically involves hand-foot syndrome, fatigue, nausea, reduced appetite, and diarrhea, while severe liver toxicity is rarely seen. We present a case of a 63-year-old female with metastatic breast cancer, without liver metastasis, who developed a severe drug-induced liver injury (DILI) with critically elevated liver enzyme levels as reaction to Capecitabine treatment with seemingly no evident explanation as to why. The patient had a RUCAM score of 7 and a Naranjo score of 6 implying that this association between Capecitabine and the liver injury falls into the "probable" category. The patient recovered completely and was then successfully treated with other cytotoxic drugs without any sign of liver engagement. An in-depth literature search based on Pubmed database was performed to obtain information about Capecitabine, liver injury, and chemotherapy-associated acute hepatic toxicity. The following keywords were used: Capecitabine, chemotherapy, liver toxicity, and hepatic toxicity. Five studies were found showing some similarities to this case documenting hepatic injury after Capecitabine treatment including hepatic steatosis and moderately elevated liver enzymes. However, no studies were found reporting a severe DILI with highly elevated enzyme levels as immediate response to Capecitabine treatment. No reason could be identified as for why the patient developed an acute toxic liver reaction to Capecitabine. This case calls for more attention to the potential severe liver toxicity of an otherwise well-tolerated drug.

One-Carbon Metabolism in Fatty Liver Disease and Fibrosis: One-Carbon to Rule Them All

Nonalcoholic fatty liver disease (NAFLD) is a term used to characterize a range of disease states that involve the accumulation of fat in the liver but are not associated with excessive alcohol consumption. NAFLD is a prevalent disease that can progress to organ damage like liver cirrhosis and hepatocellular carcinoma. Many animal models have demonstrated that one-carbon metabolism is strongly associated with NAFLD. Phosphatidylcholine is an important phospholipid that affects hepatic lipid homeostasis and de novo synthesis of this phospholipid is associated with NAFLD. However, one-carbon metabolism serves to support all cellular methylation reactions and catabolism of methionine, serine, glycine, choline, betaine, tryptophan, and histidine. Several different pathways within one-carbon metabolism that play important roles in regulating energy metabolism and immune function have received less attention in the study of fatty liver disease and fibrosis. This review examines what we have learned about hepatic lipid metabolism and liver damage from the study of one-carbon metabolism thus far and highlights unexplored opportunities for future research.