Tarceva, generically known as erlotinib, is a prescription medication used in the treatment of non-small cell lung cancer (NSCLC) and pancreatic cancer. It belongs to a class of drugs known as tyrosine kinase inhibitors, which work by blocking the action of a protein that signals cancer cells to multiply. This helps to stop or slow the growth of cancer cells. Tarceva is specifically designed for use in patients with certain types of genetic mutations that make their cancer responsive to this treatment. It is often prescribed after other cancer medicines have been tried without successful treatment of the cancer. Tarceva is taken orally, in the form of a pill, and its use and dosage depend on the specific condition being treated, the patient's overall health, and how well they respond to the therapy.