There is a high unmet need to find more effective treatments for liver cancer. Currently, treatment options for patients often only increase life expectancy by 3 to 4 months.
An accidental discovery by researchers at the University of Pittsburgh has shed light on a potential new therapeutic option for those who have undergone a liver transplant as a result of the disease. The treatment itself has actually been tried before, but not for the correct patients. The story of this discovery also reinforces the need for precision medicine– which basically means making sure the correct drug is given to the correct patient. The approach is based on the understanding that each individual is unique and therefore, their most effective treatment regime will be unique as well.
Researchers at the University of Pittsburgh stumbled across the fact that cells with a mutation in β-catenin produced high levels of a protein called mTOR. They believe high levels of this protein could cause progression in liver cancer, even in patients who have had a liver transplant.
To investigate, they began a trial of a mTOR inhibitor in mice called rapamycin. This anti-rejection drug already has analogs approved for other cancers such as HER2-negative breast cancer and renal cell carcinoma. Mice in the study had mutations in β-catenin genes as well as MET genes. The tumors were representative of the types of tumors in 20% of liver cancer patients.
Mice who were given rapamycin clearly indicated a reduction in tumor size. Mice who were given rapamycin as well as a MET inhibitor had their tumors almost completely disappear.
Previous trials using mTOR inhibitors have not had positive results. For instance, three years ago a trial of 525 patients showed that the mTOR inhibitor called sirolimus did not have a significant impact when compared to a different kind of anti-rejection treatment. Researchers believe that the results from their recent study with mice indicate that mTOR inhibitors will be most effective for patients who have β-catenin gene mutation, in addition to an addiction to the protein mTOR.
Researchers hope that this new understanding of rapamycin will help the drug be prescribed to the right patients. However, they understand that more research is still needed. They are planning on developing a clinical trial of rapamycin specifically for liver cancer patients who have undergone a liver transplant.
Results from their study investigating rapamycin in mice were reported here, in Cell Metabolism.
You can also read a summary of their investigation as well as their plan for future research in liver cancer here.