Outpatient Tarlatamab Administration Feasible in Relapsed SCLC With Close Monitoring

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Outpatient tarlatamab administration for relapsed small cell lung cancer was feasible and safe with proper monitoring, according to findings presented at ASCO.

An abstract presented at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting described the feasibility and safety of administering tarlatamab in an outpatient setting for patients with small cell lung cancer (SCLC).

Tarlatamab, a bispecific T-cell engager targeting delta-like ligand 3 (DLL3), received FDA approval in May 2024 for the treatment of relapsed SCLC. Due to the risks for cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome (ICANS), the first two doses of tarlatamab require 24-hour observation.

“We developed an outpatient program to administer tarlatamab at the Winship Cancer Institute and describe the initial experience in this report,” wrote Jennifer Carlisle, MD, and colleagues.

Between June 2024 and January 2025, 29 patients with relapsed SCLC were treated with tarlatamab. Twenty-seven patients completed at least two treatment cycles and were included in the safety and efficacy analysis. Treatment was administered at an outpatient infusion center, followed by 24-hour observation at an onsite immediate care center staffed by advanced practice providers.

Monitoring included vital signs and Immune Effector Cell-Associated Encephalopathy (ICE) scores. Per protocol, patients were admitted to inpatient care for cytokine release syndrome of grade 2 or more or ICANS of grade 1 or more, as graded using the American Society for Transplantation and Cellular Therapy consensus criteria.

Four patients were admitted prophylactically due to factors such as limited home support, travel distance, or administration logistics. An additional six patients required admission to the immediate care center during the first two cycles: one with cytokine release syndrome, one with ICANS, and four with both. One patient was admitted 48 hours after cycle 1, day 8, for grade 1 cytokine release syndrome and nausea.

Cytokine release syndrome occurred in 14 of the 27 evaluated patients, with the following distribution: grade 1 in seven patients, grade 2 in four patients, and grade 3 in three patients. ICANS occurred in 10 patients: grade 1 in three, grade 2 in four, and grade 3 in three. Eight patients experienced dose holds due to toxicities, and two of these patients restarted treatment using a step-up dosing approach.

Investigator-assessed radiographic responses included nine patients with partial response, seven with stable disease, six with progressive disease, and five patients who were not evaluable. At a median follow-up of 133 days (95% CI, 91–168), the estimated median progression-free survival (PFS) was 101 days (95% CI, 78–not available).

“Outpatient administration of tarlatamab is safe and feasible with appropriate monitoring, including for patients with an ECOG performance status of 2,” Dr. Carlisle and colleagues said.