# Subtype-directed therapy for SCLC (ASCL1 / NEUROD1 / POU2F3 / inflamed)

Source: https://onco.cc/ideas/idea-sclc-subtype-directed/  
OnCo record `idea-sclc-subtype-directed` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Small-cell lung cancer is at least four diseases under the microscope's uniform appearance. Treat each by its transcription-factor subtype.

## Summary

Small-cell lung cancer looks uniform under the microscope, but the Rudin and Gay classification splits it into transcription-factor subtypes: ASCL1-driven SCLC-A, which is DLL3-high and BCL-2 dependent, NEUROD1-driven SCLC-N, POU2F3-driven SCLC-P and the inflamed SCLC-I. The idea is to assign subtype prospectively by RNA or immunohistochemistry and treat each accordingly: tarlatamab for SCLC-A, immunotherapy for SCLC-I, Aurora kinase inhibitors for SCLC-N and PARP or ATR inhibitors for SCLC-P. The rationale is that these dependencies are reproducible in cell lines and xenografts, and a retrospective IMpower133 analysis suggested SCLC-I gained most from atezolizumab. The proposed test is a subtype-stratified umbrella trial in relapsed patients, and the evidence so far is preclinical.

## Fields

- Kind: Idea
- Last checked: 2026-09-07
- Hypothesis: Prospective subtype assignment (RNA or IHC) will predict benefit: DLL3 engagers in SCLC-A, immunotherapy in SCLC-I, Aurora kinase inhibitors in SCLC-N, and PARP/ATR inhibitors in SCLC-P.
- Rationale: Subtype-specific dependencies are reproducible in cell lines and PDX; DLL3 expression tracks ASCL1.
- Proposed test: Biomarker-stratified umbrella trial assigning relapsed patients by IHC subtype to tarlatamab, ATR inhibitor, Aurora A inhibitor, or chemo-immunotherapy.
- Maturity: preclinical-evidence

## Sources

- DeLLphi-301: tarlatamab, a DLL3-targeting T-cell engager, in previously treated small-cell lung cancer (New England Journal of Medicine 2023): https://doi.org/10.1056/NEJMoa2307980
- ClinicalTrials.gov NCT05740566: DeLLphi-304: https://clinicaltrials.gov/study/NCT05740566

## Connected records

- roadmaps: [Lung cancer roadmap: from Doll and Hill and the naming of tobacco, through the cytotoxic plateau, computed tomography screening, EGFR and ALK, immunotherapy by PD-L1, the perioperative trials and PACIFIC, to DLL3 in small-cell disease and a 2032 registry watch](https://onco.cc/roadmaps/lung-cancer-evidence-roadmap/)
- ideas: [Run small-cell lung cancer as one platform with shared controls and subtype stratification](https://onco.cc/ideas/idea-lung-small-cell-platform-with-shared-controls-and-subtypes/)
- cancers: [Extensive-stage small-cell lung cancer](https://onco.cc/cancers/extensive-stage-sclc/), [Limited-stage small-cell lung cancer](https://onco.cc/cancers/limited-stage-sclc/), [Small-cell lung cancer](https://onco.cc/cancers/sclc/)
- targets: [ATR](https://onco.cc/targets/atr/), [BCL-2](https://onco.cc/targets/bcl2/), [DLL3](https://onco.cc/targets/dll3/), [PARP](https://onco.cc/targets/parp/)
- drugs: [Tarlatamab](https://onco.cc/drugs/tarlatamab/)
- key papers: [DeLLphi-301: tarlatamab, a DLL3-targeting T-cell engager, in previously treated small-cell lung cancer](https://onco.cc/key-papers/paper-dellphi-301-nejm-2023/), [Efficacy and Safety of Rovalpituzumab Tesirine in Third-Line and Beyond Patients with DLL3-Expressing, Relapsed/Refractory Small-Cell Lung Cancer: Results From the Phase II TRINITY Study](https://onco.cc/key-papers/paper-dll3-sclc-clin-cancer-res-2019/), [Molecular subtypes of small cell lung cancer: a synthesis of human and mouse model data](https://onco.cc/key-papers/paper-rudin-sclc-molecular-subtypes-nat-rev-cancer-2019/), [Tarlatamab in Small-Cell Lung Cancer after Platinum-Based Chemotherapy](https://onco.cc/key-papers/paper-tarlatamab-sclc-n-engl-j-med-2025/)

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