The first T-cell engager to improve survival in a common solid tumour, small-cell lung cancer.
Accelerated approval May 2024 (DeLLphi-301, ORR 40%); DeLLphi-304 phase 3 (2025) showed OS 13.6 vs 8.3 months versus chemotherapy in second-line SCLC, converting to full approval. First-line combination with PD-L1 (DeLLphi-305) and limited-stage trials ongoing. CRS in ~50% (mostly grade 1-2); step-up dosing with monitoring.
Backbone ribbon from PDB 1IGT. RCSB PDB 1IGT. The ribbon widens where the chain is folded into a regular pattern and narrows where it is a loose loop.
Tarlatamab is a half-life-extended BiTE; intact IgG shown as reference.
1.One arm binds DLL3 on the tumour cell
Source: US prescribing information (DailyMed). Doses are for orientation; the current label governs.
Given by infusion or injection in a clinic or hospital outpatient department, so it is a Part B drug: Medicare pays 80% after the Part B deductible and the patient owes 20% coinsurance, uncapped in Original Medicare unless a Medigap policy applies. Step-up dosing is often started in hospital (Part A) because of cytokine release syndrome monitoring, then continued in the outpatient setting. First DLL3 engager for small-cell lung cancer (2024).
Covered under the medical benefit with prior authorisation confirming diagnosis, biomarker status and line of therapy; site-of-care policies may steer infusions away from hospital outpatient departments.
20% Part B coinsurance on a high-cost infusion adds up quickly: Medigap Plan G or N, Medicare Advantage maximum out-of-pocket, Medicaid dual eligibility, or a charity fund are the usual buffers.
Sources: Medicare.gov: Chemotherapy · Medicare.gov: Prescription drugs (outpatient, Part B). Not medical or financial advice; verify with your plan.
Sources: NICE TA1091. Funding decisions are indication-specific and change monthly; verify with NICE and your treating team.
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Breakthrough Therapy designation, ES-SCLC after platinum source
Adult patients with extensive stage small cell lung cancer (ES-SCLC) with disease progression on or after platinum-based chemotherapy
Accelerated approval, ES-SCLC after platinum (DeLLphi-301) source
Phase 3 DeLLphi-304 OS benefit presented; conversion to full approval pursued source
Adult patients with extensive stage small cell lung cancer (ES-SCLC) with disease progression on or after platinum-based chemotherapy
Confirmed: the accelerated approval of 2024 converted to traditional approval 1.5 years after it was granted. source
Full approval based on DeLLphi-304 source
| Region | Year | Indication |
|---|---|---|
| US | 2024 | Extensive-stage SCLC after platinum chemotherapy |
| EU | 2026 | ES-SCLC after platinum-based chemotherapy; 29 May 2026 |
| England (NICE) | 2025 | Extensive-stage small-cell lung cancer progressing after two or more lines of treatment including platinum-based chemotherapy: not recommended · TA1091, published 20 August 2025, says tarlatamab should not be used in the NHS in England for this indication. |
| Adverse event | Any grade | Grade 3+ |
|---|---|---|
| Cytokine release syndrome DeLLphi-301, n=187 | 55% | 1.6% |
| Haemoglobin decreased DeLLphi-301, n=187 | 58% | 5% |
| Fatigue DeLLphi-301, n=187 | 51% | 10% |
| Dysgeusia DeLLphi-301, n=187 | 36% | 0% |
| Pyrexia DeLLphi-301, n=187 | 36% | 0% |
| Decreased appetite DeLLphi-301, n=187 | 34% | 2.7% |
| Musculoskeletal pain DeLLphi-301, n=187 | 30% | 1.1% |
| Constipation DeLLphi-301, n=187 | 30% | 0.5% |
| Nausea DeLLphi-301, n=187 | 22% | 1.6% |
| Neurologic toxicity incl. ICANS Boxed warning; ICANS in a minority, mostly grade 1-2 | - | - |
Rates read from the US prescribing information. Blank cells mean the figure was not sourced, not that it is zero.
| Country | Reimbursement | List price | Assistance |
|---|---|---|---|
| United States | Medicare Part B (physician-administered); commercial plans per formulary | not disclosed | amgensupportplus.com |
| United Kingdom | NICE: appraisal for ES-SCLC after platinum in progress (2026) | not disclosed | - |
List prices are manufacturer or Medicare figures where publicly disclosed; net prices after rebates are usually lower. Reimbursement changes; check the payer.
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Query for this drug: (TITLE:"Tarlatamab" OR ABSTRACT:"Tarlatamab" OR TITLE:"Imdelltra" OR ABSTRACT:"Imdelltra") AND (cancer OR tumor OR tumour OR oncology OR carcinoma OR lymphoma OR leukemia OR leukaemia OR myeloma OR sarcoma OR melanoma OR glioma). Results are unfiltered search hits about Tarlatamab, not a curated reading list.
Shares DLL3 expression, Charles M. Rudin, Subtype-directed therapy for SCLC (ASCL1 / NEUROD1 / POU2F3 / inflamed), Small cell lung cancer (KEGG map).
Shares Chemo-immunotherapy induction → maintenance intensification (SCLC), Limited-stage vs extensive-stage (small-cell lung cancer), Extrapulmonary neuroendocrine carcinoma, Neuroendocrine and small-cell prostate cancer.
Shares DLL3 expression, Charles M. Rudin, Notch signalling, Small cell lung cancer (KEGG map).
Shares Chemo-immunotherapy induction → maintenance intensification (SCLC), Small-cell lung cancer transcription-factor subtypes (SCLC-A, SCLC-N, SCLC-P, SCLC-I) and SLFN11, Lung cancer drugs in England: what NICE has recommended, Small cell lung cancer (KEGG map).
Shares Subtype-directed therapy for SCLC (ASCL1 / NEUROD1 / POU2F3 / inflamed), DeLLphi-301: tarlatamab, a DLL3-targeting T-cell engager, in previously treated small-cell lung cancer, DLL3, Limited-stage small-cell lung cancer.
Shares Sequencing DLL3 engager and B7-H3 ADC in relapsed SCLC, Small-cell lung cancer transcription-factor subtypes (SCLC-A, SCLC-N, SCLC-P, SCLC-I) and SLFN11, Small cell lung cancer (KEGG map), Neuroendocrine and small-cell prostate cancer.
Shares DeLLphi-304, Hospital Universitario 12 de Octubre, DeLLphi-301: tarlatamab, a DLL3-targeting T-cell engager, in previously treated small-cell lung cancer, Limited-stage small-cell lung cancer.
Shares Cancer stem cells & phenotypic plasticity, Extrapulmonary neuroendocrine carcinoma, Neuroendocrine and small-cell prostate cancer, Lineage plasticity & neuroendocrine transformation.