ASCO 2025: Lurbinectedin-atezolizumab combination boosts ESCLC survival
The IMforte trial shows an increase in long-term survival for ESCLC patients on combined maintenance therapy of lurbinectedin and atezolizumab.
Findings from Phase III IMforte trial, due to be presented at the ASCO Annual Meeting (30 May–3 June, IL, USA), show that previously treated patients who received a combined maintenance therapy of Zepzelca® (lurbinectedin) and atezolizumab lived months longer than those on atezolizumab alone.
Overall, 13–15% of lung cancer diagnoses are classed as small cell lung cancer (SCLC) with 70% having metastatic versions termed extensive-stage small cell lung cancer (ESCLC). Although there have been some advances in treatment since 2019, the 5-year relative survival rate still sits at 3% and median survival time at 1 year.
Current treatment plans include a combined immunotherapy and chemotherapy approach with patients being on maintenance with immunotherapy thereafter. The immunotherapy notably used is Tecentriq® (atezolizuma). Lurbinectedin, a drug approved for use in the treatment of SCLC, is an alkylating agent with a mechanism of action whereby it damages the DNA of cancer cells to hinder proliferation.
The IMforte trial recruited 660 patients, from 91 study sites in 13 different countries, diagnosed with non-metastatic ES-SCLC who were administered the standard induction therapy and continued to suffer from the disease or experience re-lapse following the first line of treatment. Of the 660 patients initially recruited, 483 received maintenance therapy.
The study consisted with mainly white patients, making up 82% of the cohort, followed by 13% Asians and the rest being other racial origins. Overall, 242 patients were randomly assigned to lurbinectedin and atezolizumab combined therapy approach and the other half received atezolizumab alone (241 patients).
Luis G. Paz Ares (12 de Octubre University Hospital in Madrid, Spain) stated: “The Phase III IMforte trial shows that the new treatment combination of lurbinectedin and atezolizumab given as maintenance therapy after first-line treatment helps people live longer and reduces the risk of disease progression or death. This outcome represents a major milestone and could provide a much-needed option for advancing the treatment of this aggressive disease.”
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Key trial results show that the median progression-free survival – after a median follow up of 15 months – was 5.4 months in the lurbinectedin and atezolizumab group. This is more that double that of atezolizumab alone.
The combination therapy also reduced the risk of cancer progression by 46% compared to atezolizumab alone. Additionally, the dual treatment extended median overall survival to 13.2 months, compared to 10.6 months with single-agent therapy. Patients on the combination regimen experienced a 27% reduction in mortality risk versus those receiving atezolizumab alone.
Despite these promising initial results, it was noted that 83.5% of patients in the combined therapy of lurbinectedin and atezolizumab, faced treatment-related adverse effects. This is significantly higher than the 40% seen in the atezolizumab alone group.
The IMforte trial is ongoing with considerations being given to the idea of using the combined therapy approach as a first-line treatment option.