Small cell lung cancer is one of oncology's hardest problems — fast-growing, quick to relapse, and for decades almost untouched by the targeted-therapy and immunotherapy revolutions happening next door in non-small cell disease. ASCO 2026 was the year that changed in the data. One asset, one target, accounts for the steepest growth curve in the entire meeting.
Eighteen-fold in two years
Tarlatamab — a bispecific T-cell engager that links a patient's T-cells (via CD3) to the SCLC-defining surface antigen DLL3 — appeared in just 2 ASCO studies in 2024. In 2025 it was 12. At ASCO 2026 it reached 37. No other single drug in the program grew that fast.
The growth is not happening in a vacuum: the broader SCLC field is also more active (33 → 50 → 49 studies), but tarlatamab is now its organizing asset — the drug the rest of the field's combination, sequencing, and real-world questions revolve around.
The result behind the curve: DeLLphi-304
Study momentum follows hard clinical data, and tarlatamab's data is the real thing. In the pivotal Phase 3 DeLLphi-304 trial, 509 patients with previously treated SCLC were randomized to tarlatamab or standard second-line chemotherapy (topotecan, lurbinectedin, or amrubicin). Tarlatamab delivered a median overall survival of 13.6 months versus 8.3 months for chemotherapy — a hazard ratio of 0.60, a 40% reduction in the risk of death. Twelve-month survival was 53% versus 37%. This was the first global Phase 3 trial to show a survival benefit over chemotherapy in relapsed SCLC, and it carried tarlatamab to NCCN Category 1 status and full FDA approval. That is the clinical engine under the study curve.
| DeLLphi-304 endpoint (2L SCLC) | Tarlatamab (n=254) | Chemotherapy (n=255) | Hazard ratio |
|---|---|---|---|
| Median overall survival | 13.6 months | 8.3 months | 0.60 |
| 12-month survival | 53% | 37% | — |
| 6-month survival | 76% | 62% | — |
| Median progression-free survival | 4.2 months | 3.2 months | 0.72 |
At ASCO 2026 specifically, the radar shows the franchise broadening rather than just repeating: new studies cover tarlatamab's intracranial efficacy in patients with brain metastases (a critical question in SCLC, where CNS spread is common), real-world analyses of cytokine-release-syndrome and neurotoxicity management, and use across multiple lines of therapy.
DLL3 is becoming a target, not just an SCLC drug
The most forward-looking signal in the data is where tarlatamab is starting to appear outside small cell lung cancer.
The first studies in DLL3-positive advanced prostate cancer and B-cell lymphoma are small in number but large in meaning: DLL3 expression is not unique to SCLC, and a validated DLL3 engager is a platform that can travel. This is the same pan-target logic reshaping the ADC and bispecific fields generally — once a target is clinically validated, the franchise expands to every tumor that expresses it.
The commercialization read
For BD teams: DLL3 is now a validated, franchise-grade target with an approved first mover. That makes the next questions competitive: second-generation DLL3 engagers, DLL3 ADCs and CAR-Ts, and DLL3 beyond SCLC are all live white-space opportunities the radar can scope. For investors: the combination of a definitive survival win, an approval, and the first cross-tumor studies is the classic signature of a forming franchise — the same pattern that preceded the HER2 and BCMA franchises.
Explore the underlying data
Every number above is live and pivotable on the Knitify ASCO Radar — analyze the 7,222 studies in the ASCO 2026 program by drug, indication, sponsor, or trial-in-progress status, and compare year over year against 2025 and 2024. Filter the board to tarlatamab or small cell lung cancer to reproduce every count in this article. The radar links to each study on the official ASCO program; it does not reproduce copyrighted text.
Methodology & scope: figures in this article are structured signals the Knitify ASCO Radar derives from the publicly released ASCO 2026 scientific program (7,222 studies presented; 6,511 in 2025; 5,885 in 2024) — counting how many studies reference a given drug, indication, or modality class. They quantify research attention and momentum, not clinical efficacy or market share. Named trial results are quoted from public company press releases, the ASCO press program, and peer-reviewed journals (cited below). The radar does not reproduce any copyrighted text — it links to each study on the official ASCO program. This is editorial commentary on public data — not investment, legal, regulatory, or medical advice.