Mutant EGFR inhibitors are primarily used in the treatment of non-small cell lung cancer (NSCLC), particularly in patients with specific EGFR mutations. These inhibitors target and block the activity of mutated EGFR proteins, which are often responsible for uncontrolled cell growth in cancer. By inhibiting these mutant proteins, the drug helps to slow down or stop the progression of the cancer. It is especially effective in cases where traditional chemotherapy has not been successful. Additionally, these inhibitors are often used as a first-line treatment for patients with advanced NSCLC who test positive for EGFR mutations. The targeted approach of these inhibitors generally results in fewer side effects compared to conventional chemotherapy, improving the quality of life for patients during treatment. Ongoing research is exploring their potential in other cancers with similar genetic mutations.