FDA Cuts Monitoring Time for First Two Tarlatamab Doses

The FDA has approved an update to the prescribing information for tarlatamab (Imdelltra; Amgen), which reduces the required observation time for the first two doses from 22 to 24 hours to 6 to 8 hours. This change is aimed at making it easier for patients with extensive-stage small cell lung cancer (ES-SCLC) to receive treatment in community settings.

The update applies specifically to Cycle 1 Day 1 and Cycle 1 Day 8 doses, which now require 6 to 8 hours of observation in an appropriate healthcare setting. A follow-up assessment, including a vital signs check, is also added for the day after each of those two doses.

This change may allow more patients to begin tarlatamab closer to home rather than traveling to a tertiary center. The approval follows Amgen's recent report of positive overall survival data from the phase 3 DeLLphi-305 trial evaluating tarlatamab with Imfinzi (durvalumab; AstraZeneca) in first-line ES-SCLC.

The monitoring requirements are crucial because tarlatamab carries a boxed warning for cytokine release syndrome (CRS) and neurologic toxicity, including immune effector cell-associated neurotoxicity syndrome (ICANS). Patients should remain within 1 hour of an appropriate healthcare setting for a total of 48 hours after the Day 1 and Day 8 infusions, accompanied by a caregiver.