Larotrectinib is a drug used to treat certain types of cancer. It is important to ensure that the drug is pure and free from any impurities that could affect its safety or efficacy. Larotrectinib impurities refer to any unwanted substances that may be present in the drug, either as a result of the manufacturing process or due to external factors. These impurities can be harmful to patients, and therefore it is essential to monitor and control their levels during the drug's production and use.