On May 16, the U.S. Food and Drug Administration (FDA) granted accelerated approval to intravenous Imdelltra^™ (tarlatamab) for the treatment of adults with relapsed/refractory extensive stage small cell lung cancer (RR ES-SCLC) with disease progression on or after platinum-based chemotherapy.¹ Tarlatamab is an immunotherapy drug that may be administered in the outpatient setting.²  This novel delta-like ligand 3 (DLL3)-targeting bispecific T-cell engager (BiTE) therapy activates the patient’s own T cells to attack DLL3-expressing tumor cells.⁴ 

The FDA approval was supported by the Phase 2 DeLLphi-301 trial which evaluated 99 patients with RR ES-SCLC after platinum-based chemotherapy.^1,2 Efficacy endpoints were overall response rate (40%; 2% complete response; 38% partial responses) and median duration of response (9.7 months; range, 2.7, 20.7+).^3,4 Among responders, 68% had a response lasting at least 6 months and 40% had a response lasting at least 12 months.² Biomarker testing for DLL3 is not required to initiate tarlatamab.⁵

About 30,000 Americans are diagnosed with small cell lung cancer each year and 85% of these cases overexpress DLL3. ^4,7,8 Nearly 60% of all cases are metastatic at diagnosis and cigarette smoking is the cause of nearly all SCLC cases.⁶ Unfortunately, less than 3% of patients with ES-SCLC live longer than five years.⁶ Current systemic therapy options such as chemotherapy and checkpoint inhibitors like Keytruda® (pembrolizumab) add about two months to a patient’s life.⁸ However, treatment resistance and progression are common.⁴