A team of researchers led by UCL Great Ormond Street Institute of Child Health (ICH) and Great Ormond Street Hospital (GOSH) has found that metformin—a drug commonly used to treat Type 2 diabetes—can successfully reduce symptoms associated with tuberous sclerosis complex (TSC), including reduction in the frequency of seizures and the size of brain tumors.
The study, which also included teams from Royal United Hospitals Bath NHS Foundation Trust (RUH) and University Hospitals Bristol and Weston NHS Foundation Trust, recruited 51 patients with TSC who were randomly assigned a placebo or metformin for one year on a dose similar to that given for Type 2 diabetes.
TSC is a genetic disorder characterized by the development of benign tumors due to loss of inhibitory regulation of the mTOR (mechanistic Target of Rapamycin) intracellular growth pathway. As a result, people with the condition may develop tumors (hamartomas) throughout the body that can affect the heart, kidneys, brain, skin and nails. Although some with the condition may experience few issues, for others it can be disfiguring or even have life threatening complications. As tumors can form in the brain, 75% of people with TSC will have epilepsy, which can lead to daily seizures.
Throughout the study, the research team wanted to see if metformin, which inhibits the mTOR (cellular growth) pathway, could limit the tumor growth and epilepsy associated with TSC. All patients involved in the study had tumors in the kidney known as renal angiomyolipomas (AML). Of the 51 who took part, 27 patients had tumors in the brain called subependymal giant cell astrocytomas (SEGA) and 21 of them were under assessment for seizure frequency.
Over the course of the year, the team found a 21% reduction in the size of brain tumors of those who were given metformin, compared to a 3% increase in tumor volume for those taking the placebo. Patients with epilepsy and taking metformin saw a 44% drop in the frequency of their seizures, compared to a drop of only 3% for those on the placebo.
Metformin has been gaining attention in cancer research, with large population studies starting to show reduced rates of cancers in those regularly taking it. Metformin is also used to treat polycystic ovary syndrome.