Despite promising trial data for Tarlatumab in first-line small cell lung cancer, its clear survival benefit as a second-line therapy makes clinicians reluctant to lose it as a reliable later-stage option. This creates a strategic dilemma about the optimal timing to deploy the most effective new therapies.
Post-approval, real-world data for Tarlatumab shows higher-than-expected rates of serious toxicities like ICANS. This has created a clinical need for a 'risk calculator' that uses patient variables like tumor burden and liver metastases to identify who is at high risk, allowing for proactive management like elective hospitalization.
If the Delphi-305 trial for the T-cell engager Tarlatumab is positive in the first-line maintenance setting for small cell lung cancer, it would likely eliminate any clinical role for Lurbinectedin, another therapy currently used in that space. This highlights how a single trial outcome can dramatically reshape treatment standards and render existing options obsolete.
Oncologists hypothesize that using the T-cell engager Tarlatumab after chemotherapy has reduced tumor volume may be a safer strategy. Real-world evidence suggests high tumor burden increases the risk of severe Cytokine Release Syndrome (CRS), so using chemotherapy to first cytoreduce the cancer could mitigate this toxicity.
For fast-progressing small cell lung cancer, the logistical delay of waiting for DLL3 biomarker test results is clinically unacceptable. Despite the test's potential to predict response to Tarlatumab, oncologists prioritize immediate treatment, accepting the small risk of treating a biomarker-negative patient over a guaranteed delay.