Pseudoprogression Associated With T-cell Infiltration During Tarlatamab Therapy for Small-Cell Lung Cancer: A Case Report
Abstract
Tarlatamab is a bispecific T-cell engager immunotherapy that targets delta-like ligand 3 and CD3. We report a case of pseudoprogression (PsPD) in a patient with small-cell lung cancer treated with tarlatamab. Due to its mechanism, tarlatamab is known to induce T-cell infiltration into tumors. In PsPD, the tumor transiently enlarges because of massive T-cell accumulation within the tumor. In this case, the peripheral blood lymphocyte count decreased, and the interleukin-6 level was markedly elevated, which was thought to reflect T-cell accumulation in the tumor. These trends in the blood tests may be useful in easily differentiating PsPD from true progressive disease during tarlatamab treatment.
Fields of Study & Subjects
Cancer Immunotherapy and Biomarkers
Lung Cancer Research Studies
Lung Cancer Treatments and Mutations
Publication details
- Journal / source
- Cureus
- Volume
- 18
- Issue
- 2
- Pages
- e103393–e103393
- Publication date
- 10 February 2026
- Language
- EN