Study Finds Blood Test Predicts Tarlatamab Benefit in Small Cell Lung Cancer

Published in Cancer Discovery, researchers report high accuracy in a 20-patient cohort, with prospective validation needed before clinical use.

Overview

In a Mass General Brigham–led study, DLL3 detected on circulating tumor cells predicted durable benefit from tarlatamab with 85% sensitivity and 100% specificity.
About half of the 20 patients had abundant DLL3-positive cells in blood, and those patients were the ones who showed clinical benefit.
The liquid-biopsy approach uses an advanced circulating tumor cell enrichment platform developed at Mass General Brigham and licensed to TellBio.
Findings challenge assumptions of uniform DLL3 expression in small cell lung cancer and could inform development of other DLL3-directed therapies.
Researchers identified resistance patterns involving DLL3 loss or T-cell dysfunction and stressed that larger prospective trials are needed before the test guides care, which could also help avoid unnecessary risks such as early-dose hospitalization for cytokine release syndrome.