Durvalumab monotherapy as a third-line treatment for extensive-stage small-cell lung cancer: a case report

The global incidence and mortality rates of lung cancer are the highest of any cancer. Smallcell lung cancer (SCLC) is an undifferentiated carcinoma which accounts for 15-20% of all lung cancers. Compared with the other major lung cancer type, non-small cell lung cancer, SCLC exhibits worse biological behavior, has a higher degree of malignancy, and develops more rapidly. The majority of SCLC present with extensive-stage disease, and the prognosis for these patients remains poor. Recently, immunotherapy has been demonstrated clinical activity in extensive-stage SCLC (ES-SCLC); however, the efficacy and safety of immunotherapy in ES-SCLC needs further confirmation. Durvalumab, a selective, high-affinity human IgG1 monoclonal antibody that blocks PD-L1 binding to PD-1 and CD80, showed durable clinical activity and a manageable safety profile in patients with pretreated ES-SCLC as a first-line treatment. Here, we report the case of an ES-SCLC patient who achieved complete remission (CR) of local lesions after receiving durvalumab monotherapy as a third-line treatment, experiencing no obvious immune-related side effects, such as rash, diarrhea, fatigue, myelosuppression, or thyroid dysfunction. No immune-related pulmonary or hepatorenal toxicities occurred. The case suggests that immunotherapy can be selected for third-line or multi-line treatment of ES-SCLC, and anti-PD-L1 antibody may be the better choice for patients who have poor performance status (PS) scores.