results we rarely saw five years ago. (avo) in a clinical trial, significantly more patients lived longer and saw their tumors shrink than on chemotherapy alone. (dr. kloecker) it's changed my approach to treating patients. (avo) keytruda may be used with certain chemotherapies as your first treatment if you have advanced nonsquamous, non-small cell lung cancer and you do not have an abnormal "egfr" or "alk" gene. keytruda helps your immune system fight cancer, but can also cause your immune system to attack healthy parts of your body. this can happen during or after treatment and may be severe and lead to death. see your doctor right away if you have new or worse cough, chest pain, shortness of breath, diarrhea, severe stomach pain or tenderness, nausea or vomiting, rapid heartbeat, increased hunger or thirst, constipation, dizziness or fainting, changes in urine or eyesight, muscle pain or weakness, joint pain, confusion or memory problems, fever, rash, itching, or flushing. these are not all the possible side effects. tell your doctor about all your medical conditions, including immune system problems, if you've had an organ transplant, had or plan to have a stem cell transplant,