Results from the global phase 3 IMforte trial (NCT05091567) found that maintenance therapy with a combination of lurbinectedin (Zepzelca™; Jazz Pharmaceuticals / PharmaMar) and atezolizumab (Tecentriq®; Genentech/Roche) helped some patients with extensive-stage small cell lung cancer (ES-SCLC) live longer compared to maintenance therapy with atezolizumab alone. [1]
The research will be presented at the annual meeting of the American Society of Clinical Oncology, held May 30 through June 3, 2025 in Chicago, Illinois.
Difficult to treat
“While the introduction of immunotherapy in first-line treatment has improved outcomes, advanced small cell lung cancer remains difficult to treat,” explained lead study author Luis G. Paz Ares, MD, PhD, 12 de Octubre University Hospital in Madrid, Spain.
The IMforte trial included 660 patients with previously untreated ES-SCLC, no history of metastases to the brain or spinal cord, and good performance status. All patients enrolled in the study received standard-of-care (SoC) induction therapy of atezolizumab, carboplatin, and etoposide in 4 cycles.
After induction therapy, participating patients were eligible to continue in the study if they had an ongoing tumor response or stable disease after 4 cycles. There were 483 patients who went on to receive maintenance therapy. Participating patients were randomly assigned to receive either lurbinectedin and atezolizumab (242 patients) or atezolizumab alone (241 patients). The participants were from 91 study sites in 13 different countries. Approximately 82% were White, 13% were Asian, and 5% had another racial origin. Around 7% were Hispanic or Latino. The median age of the participants was 66 years, and approximately 63% of the patients were men.
“The phase 3 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,” Paz Ares added
Study Findings
- After a median follow-up of 15 months, the median progression-free survival (PFS) was 5.4 months in the lurbinectedin and atezolizumab arm versus 2.1 months in the atezolizumab alone arm.
- Patients treated with lurbinectedin and atezolizumab had a 46% lower risk of cancer progression than those treated with atezolizumab alone.
- The median overall survival was 13.2 months for patients treated with lurbinectedin and atezolizumab and 10.6 months for patients treated with atezolizumab alone.
- Patients treated with lurbinectedin and atezolizumab had a 27% lower risk of death than those treated with atezolizumab alone.
- The median treatment duration was 4.1 months on lurbinectedin and 4.2 months on atezolizumab in the lurbinectedin and atezolizumab arm. In the atezolizumab alone arm, it was 2.1 months. A longer treatment duration can often provide greater benefit as more doses of the drug are tolerated.
Adverse events
There was a noted difference in adverse events between the two groups. Treatment-related adverse events occurred in 83.5% of patients in the lurbinectedin and atezolizumab arm, compared to 40% in the atezolizumab alone arm.
In the lurbinectedin and atezolizumab arm, 25.6% of patients experienced a grade 3 or 4 adverse event and 0.8% experienced a grade 5 adverse event. In the atezolizumab alone arm, 5.8% experienced a grade 3 or 4 adverse event and 0.4% experienced a grade 5 adverse event. In the lurbinectedin and atezolizumab arm, 6.2% of patients stopped treatment due to side effects compared to 3.3% in the atezolizumab alone arm.
Next Steps
The IMforte study is ongoing. Researchers will continue to follow enrolled patients. They are also considering other settings in which to use this treatment combination, such as first-line therapy.
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Clinical trials
A Phase 3, Open-Label Study of Maintenance Lurbinectedin in Combination With Atezolizumab Compared With Atezolizumab in Participants With Extensive-Stage Small-Cell Lung Cancer (IMforte) – ClinicalTrials.gov ID NCT05091567
Highlights of prescribing information
Lurbinectedin (Zepzelca™; Jazz Pharmaceuticals / PharmaMar)[Prescribing Information]
Atezolizumab (Tecentriq®; Genentech/Roche)[Prescribing Information]
Reference
[1] Luis Paz-Ares, Hossein Borghaei, Stephen Liu, Roy Herbst, Katarzyna Stencel, Margarita Majem, Grzegorz Czyżewicz, Reyes Bernabe Caro, Ki Hyeong Lee, Melissa Johnson, Nuri Karadurmus, Christian Grohe, Vaikunth Cuchelkar, Vilma Graupner, Monika Kaul, Ya-Chen Lin, Debasis Chakrabarti, Kamalnayan Bhatt, Martin Reck, Solange Peters
Lurbinectedin (lurbi) + atezolizumab (atezo) as first-line (1L) maintenance treatment (tx) in patients (pts) with extensive-stage small cell lung cancer (ES-SCLC): Primary results of the phase 3 IMforte trial. 10.1200/JCO.2025.43.16_suppl.8006
Featured Image: Lung radiography | Doctor examining a lung radiography. Photo courtesy: © 2018 – 2025 Fotolia/Adobe. Used with permission
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