9291 complete designation AZD9291, also known as ositinib, is a third-generation targeted drug for the treatment of lung cancer. Ossitinib resistance may result in symptoms such as coughing, chest tightness, breath-holding, and added pain at the lesion. Ocitinib is prone to drug resistance, and prolonged use may lead to symptoms such as cough, chest tightness, breathlessness, additional pain at the lesion, and additional metastasis. Brain metastases cause patients to experience headaches and dizziness, nausea and vomiting, and bone metastases cause patients to experience symptoms such as sore and swollen bones. Ocitinib-resistant patients need to be combined with changes in body sensation, resistance time and other comprehensive judgment of the specific treatment. Patients with short-term drug resistance can follow the doctor’s instructions to choose to replace the anti-tumor drugs, biological immunotherapy, such as replacement for the targeting drug Anrotinib hydrochloride capsules, trametinib tablets and other immunosuppressant therapy. Patients with recurrent drug resistance can choose systemic intravenous chemotherapy and other treatment methods. Patients with symptoms of ositinib resistance should consult a doctor in time for proper treatment under the guidance of the doctor.