Amgen and AstraZeneca combination cuts lung cancer death risk by 58% in Phase 3 trial

Amgen’s Imdelltra, combined with AstraZeneca’s Imfinzi, reduced the risk of death by 58% in patients with extensive-stage small cell lung cancer, according to results from a Phase 3 clinical trial, strengthening the evidence for using the treatment earlier in the disease pathway.

The DeLLphi-305 study found that patients receiving the combination had median overall survival of 21.1 months, compared with 12.7 months for those receiving Imfinzi alone. The findings were presented at the European Society for Medical Oncology (ESMO) Congress in Madrid on 24 October and published simultaneously in the New England Journal of Medicine.

The trial evaluated the combination as a first-line maintenance treatment for patients whose cancer had not progressed following initial treatment with Imfinzi, platinum-based chemotherapy and etoposide.

The results could have commercial implications for Amgen’s oncology portfolio if the combination secures the necessary regulatory approvals and enters routine clinical use in this setting.

Phase 3 trial demonstrates survival benefit

The DeLLphi-305 trial enrolled 563 patients with extensive-stage small cell lung cancer. Participants were assigned to receive either Imdelltra alongside Imfinzi or Imfinzi alone following initial chemoimmunotherapy.

The primary endpoint was overall survival, a measure of the time patients live following a specified point in a clinical study.

Median overall survival reached 21.1 months in the combination group, compared with 12.7 months in the control group. The results corresponded to a 58% reduction in the risk of death, based on a hazard ratio of 0.42.

At one year, approximately 79% of patients receiving the combination were alive, compared with 53% of those treated with Imfinzi alone.

The study also reported a benefit in progression-free survival, which measures the time patients live without their disease worsening. The combination reduced the risk of disease progression or death by 66%. Median progression-free survival was 7.4 months, compared with 1.9 months in the control group.

These findings indicate that the treatment improved both survival and disease control in the study population. However, individual patient outcomes can vary, and the trial results do not guarantee the same benefit for every patient.

Imdelltra targets cancer cells through immune-cell engagement

Imdelltra, also known as tarlatamab, is a bispecific T-cell engager designed to bring immune-system T cells into contact with cancer cells, helping direct an immune response against the tumour.

Imfinzi, whose generic name is durvalumab, is an immunotherapy that blocks the PD-L1 pathway, which cancers can use to evade immune-system activity.

The two medicines therefore act through different mechanisms. The trial investigated whether adding Imdelltra to an Imfinzi-based maintenance regimen could improve outcomes after the initial chemotherapy and immunotherapy treatment.

Small cell lung cancer is an aggressive form of the disease. Extensive-stage cases have spread beyond the area that can generally be treated as limited-stage disease, making long-term disease control particularly challenging.

The combination was studied in patients whose cancer had not progressed following initial treatment, rather than as a replacement for the entire initial treatment regimen.

Safety findings remain important

The survival results must be considered alongside the treatment’s safety profile.

According to the trial data reported by Reuters, serious treatment-related adverse events classified as Grade 3 or 4 occurred in approximately 20.9% of patients receiving the combination, compared with 10.8% of those receiving Imfinzi alone.

This difference is relevant to clinical decision-making because treatment benefits must be weighed against potential adverse effects, monitoring requirements and the overall impact on patients.

The published trial results and prescribing information will be important for clinicians assessing the combination’s suitability for individual patients. The reported safety figures should not be interpreted as covering every possible adverse event or as a direct measure of overall tolerability.

Commercial implications for Amgen and AstraZeneca

The trial could broaden the potential role of Imdelltra if regulators approve its use in the earlier maintenance setting.

Imdelltra is already approved in the United States for certain adults with extensive-stage small cell lung cancer whose disease has progressed during or after platinum-based chemotherapy. Evidence supporting its use in a maintenance combination could provide access to a different treatment stage, subject to regulatory review.

Reuters reported that Imdelltra’s US list price was approximately $30,000 per treatment cycle, with annual treatment costs exceeding $390,000 under the pricing assumptions cited in the report. These figures are list-price estimates rather than the net amount paid by patients, insurers or healthcare systems.

LSEG analyst estimates cited by Reuters projected annual sales of more than $2.5bn by 2030. That figure is a forecast, not reported revenue, and future sales will depend on regulatory decisions, clinical adoption, reimbursement, competition and the number of eligible patients.

For AstraZeneca, the results also reinforce the role of Imfinzi as the immunotherapy backbone in the studied treatment regimen. The companies will need to navigate the regulatory and commercial requirements associated with any expanded indication.

What the results mean for the lung cancer treatment market

The DeLLphi-305 findings provide evidence that combining a bispecific T-cell engager with an established immunotherapy can improve survival outcomes in extensive-stage small cell lung cancer when used as maintenance treatment following initial therapy.

For pharmaceutical companies, the study highlights the importance of clinical evidence in expanding the use of existing medicines into additional treatment settings. For healthcare providers and payers, the next questions include treatment costs, safety management, patient eligibility and the practicalities of delivering the combination.

The immediate milestone is regulatory review of the data. The trial results are significant, but the combination’s availability in this specific setting will depend on approval in the relevant markets.

For Amgen and AstraZeneca, the findings strengthen the clinical case for the combination. Its eventual commercial contribution will depend on whether the demonstrated benefit translates into approved use and adoption in routine care.

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