Amgen's Imdelltra to Initiate Phase 3 Trial to Evaluate Efficacy in First-Line Extensive-Stage Small Cell Lung Cancer
Imdelltra Embarks on DeLLphi-312 Phase 3 Trial for First-Line Treatment
Amgen (AMGN) has initiated the DeLLphi-312 (NCT07005128) Phase 3 trial for Imdelltra (tarlatamab), a DLL3-targeting bispecific T-cell engager (BiTE), to evaluate its efficacy in patients with first-line extensive-stage small cell lung cancer (ES-SCLC). This trial will assess the efficacy and overall survival (OS) improvement of a four-drug combination therapy consisting of Imdelltra in addition to the standard of care: durvalumab and carboplatin + etoposide. Imdelltra has already demonstrated clinical efficacy, having received FDA accelerated approval as a second-line treatment in May 2024 and securing full approval in November 2025. Its advancement to the first-line treatment setting is considered a critical milestone for diversifying the company's oncology portfolio and driving revenue growth.
Innovative Four-Drug Combination Therapy with Immuno-Oncology and Bispecific Antibodies
Imdelltra uniquely connects DLL3 proteins on tumor cells with CD3 receptors on T cells, enabling the patient's immune system to destroy cancer cells. This design effectively targets the biological characteristic that DLL3 is overexpressed in over 85% of small cell lung cancer (SCLC) patients. The combination with durvalumab, a PD-L1 inhibitor, aims to synergistically block the tumor's immune evasion mechanisms. This first-in-class four-drug therapy, combining cytotoxic chemotherapy, immune checkpoint inhibitors, and a bispecific T-cell engager (BiTE), is expected to usher in a new treatment paradigm in the field of highly treatment-resistant small cell lung cancer.
Competitive Landscape and Potential of the Small Cell Lung Cancer Treatment Market
The global small cell lung cancer market is currently estimated at approximately $15 billion in 2025, with significant unmet medical needs, ensuring rapid growth upon the entry of new drugs. AstraZeneca's Imfinzi and Roche's Tecentriq, which have established themselves as first-line standard therapies, currently lead the market, but patient prognosis remains poor. In the second-line market, Jazz Pharmaceuticals' Zepzelca (lurbinectedin) has established a unique position, but there is still room for improvement in efficacy. If Imdelltra demonstrates superior clinical benefits compared to the existing three-drug therapy in this Phase 3 trial and becomes a first-line standard treatment, it could secure a dominant market position and become a global blockbuster with annual sales of up to $2.8 billion to $3.8 billion.
Amgen's Financial Growth Driver and Significance from a Global Investment Perspective
Imdelltra has rapidly become a key financial driver for Amgen, recording global sales of $627 million in 2025. In the first quarter of 2026, sales surged 219% year-over-year to $258 million, demonstrating strong market demand and high physician confidence. The success of the DeLLphi-312 trial will be crucial in maximizing the value of Imdelltra by expanding its reach to earlier patient populations and mitigating the revenue gap from existing products nearing patent expiration. From an investor perspective, the patient enrollment rate in the Phase 3 trial and the safety and efficacy data to be released in the interim analysis will be key indicators in determining Amgen's medium- to long-term valuation.
Amgen's (AMGN) initiation of the Phase 3 DeLLphi-312 trial for Imdelltra, a DLL3-targeting T-cell engager, to advance its potential as a first-line treatment for extensive-stage small cell lung cancer (ES-SCLC) represents a pivotal inflection point for enhancing its mid- to long-term pipeline value. With the global small cell lung cancer market projected to reach up to $9.6 billion in 2025, the primary objective of the trial is to demonstrate superior survival benefits compared to the current standard of care, AstraZeneca's (AstraZeneca) Imfinzi three-drug regimen. Imdelltra, which generated $627 million in sales in 2025, is expected to potentially reach peak sales of up to $3.8 billion by 2035 if it expands to the first-line treatment setting, garnering significant investor interest. The first-in-class Phase 3 trial combining immune checkpoint inhibitors and T-cell engagers offers researchers a mechanistic synergy for improving small cell lung cancer cure rates and provides an opportunity to establish a distinct clinical advantage over competing pipelines. Success in this trial will lead to a complete overhaul of the first-line standard guidelines for small cell lung cancer, allowing Amgen to secure market dominance and drive value appreciation in its subsequent DLL3 pipeline assets.
Source: ClinicalTrials.gov (api_ct)