Patients with newly diagnosed extensive-stage small cell lung cancer (ES-SCLC) typically receive platinum-doublet chemotherapy plus an anti-PD-L1 antibody. Nonetheless, most patients will have rapid disease progression, indicating a need for more intensive maintenance therapy. Now, data from the phase Ib DeLLphi-303 trial demonstrate the feasibility and safety, as well as promising signs of efficacy, of the anti-delta-like ligand 3 T cell-engaging antibody tarlatamab as additional maintenance therapy.

In this trial, a total of 88 patients with previously untreated ES-SCLC without disease progression following 4–6 cycles of chemotherapy plus an anti-PD-L1 antibody received maintenance therapy with tarlatamab, with continuation of the anti-PD-L1 antibody until disease progression. Safety was the primary end point.