Emerging therapies and translational advances in small cell lung cancer: Overcoming resistance

Small-cell lung cancer (SCLC) is an aggressive neuroendocrine malignancy characterized by rapid proliferation, early metastasis, and poor prognosis. Although initially sensitive to chemotherapy and radiotherapy, most patients relapse rapidly, and long-term survival remains uncommon. Platinum-etoposide has long been the standard first-line therapy, and the recent incorporation of immune checkpoint inhibitors (ICIs) such as atezolizumab (IMpower133) and durvalumab (CASPIAN, ADRIATIC) has modestly improved survival, including a new role for durvalumab as a consolidation therapy in limited-stage SCLC. However, this benefit is restricted to a minority of patients, underscoring the need for novel therapeutic strategies. Emerging approaches include DLL3-directed bispecific T-cell engagers (BiTEs), such as tarlatamab and obrixtamig, which have shown promising efficacy in relapsed disease, and next-generation antibody-drug conjugates (ADCs) targeting DLL3, B7-H3, TROP2, and SEZ6. Additional modalities under investigation include chimeric antigen receptor (CAR) T-cell therapy and radioligand therapy (RLT), which aim to overcome the immunosuppressive tumor microenvironment and resistance to conventional treatments. Future therapeutic efforts will require biomarker-driven strategies that incorporate molecular subtyping (ASCL1, NEUROD1, POU2F3, and YAP1) and immune profiling to facilitate precise treatment selection. Combining ICIs, BiTEs, ADCs, and cellular or radioligand therapies in rational, evidence-based regimens represents a promising avenue to improve outcomes in this historically intractable disease.