Publication Date:
2020-07-18
Description:
Background Li-Fraumeni Syndrome (LFS) is a highly penetrant autosomal dominant cancer predisposition disorder caused by germline TP53 pathogenic variants. Patients with LFS have increased oxidative phosphorylation capacity in skeletal muscle and oxidative stress in blood. Metformin inhibits oxidative phosphorylation, reducing available energy for cancer cell proliferation, and decreasing production of reactive oxygen species that cause DNA damage. Thus, metformin may provide pharmacologic risk reduction for cancer in patients with LFS, but its safety in non-diabetic patients with germline TP53 pathogenic variants has not been documented. Methods This study assessed safety and tolerability of metformin in non-diabetic LFS patients and measured changes in metabolic profiles. Adult patients with LFS and germline TP53 variant received 14 weeks of metformin. Blood samples were obtained for measurement of serum IGF-1, insulin, and IGFBP3. Hepatic mitochondrial function was assessed with fasting exhaled CO2 after ingestion of 13C-labeled methionine. Changes in serum metabolome were measured. All statistical tests were two-sided. Results We enrolled 26 subjects: 20 females and 6 males. The most common adverse events were diarrhea (50.0%) and nausea (46.2%). Lactic acidosis did not occur, and there were no changes in fasting glucose. Cumulative mean 13C exhalation was statistically significantly suppressed by metformin (p=.001). Mean levels of IGFBP-3 and IGF-I were statistically significantly lowered (p=.02). Lipid metabolites and branched chain amino acids accumulated. Conclusions Metformin was safe and tolerable in patients with LFS. It suppressed hepatic mitochondrial function as expected in these individuals. This study adds to the rationale for development of a pharmacologic risk reduction clinical trial of metformin in LFS.
Electronic ISSN:
2515-5091
Topics:
Chemistry and Pharmacology
,
Medicine
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