The U.S. Food and Drug Administration (FDA) has approved the combination of lurbinectedin (Zepzelca®) and atezolizumab (Tecentriq®) or atezolizumab and hyaluronidase-tqjs (Tecentriq Hybreza®) as maintenance therapy for adults with extensive-stage small cell lung cancer (ES-SCLC) whose disease has not progressed after first-line induction therapy with atezolizumab, carboplatin, and etoposide. This approval, granted on October 2, 2025, marks the first combination treatment in this early maintenance setting and addresses an aggressive cancer with limited therapeutic options. The combination has also been included in the National Comprehensive Cancer Network (NCCN) guidelines for SCLC as a preferred regimen, underscoring its clinical relevance.
The approval is based on results from the Phase 3 IMforte study (NCT05091567), a randomized, multicenter, open-label trial involving 483 patients whose disease was stable after four cycles of induction therapy. From the time of randomization, the combination reduced the risk of disease progression or death by 46 percent and the risk of death by 27 percent compared to atezolizumab maintenance monotherapy. Median overall survival (OS) was 13.2 months in the combination arm versus 10.6 months in the monotherapy arm (stratified Hazard Ratio [HR] 0.73; 95% CI: 0.57–0.95; p=0.0174). Median progression-free survival (PFS) by independent assessment was 5.4 months versus 2.1 months (stratified HR 0.54; 95% CI: 0.43–0.67; p<0.0001). These data were presented at the American Society of Clinical Oncology (ASCO) 2025 Annual Meeting and simultaneously published in The Lancet.
Small cell lung cancer accounts for about 13 percent of all lung cancer cases in the U.S., with approximately 30,000 new diagnoses annually. It is the most aggressive form of lung cancer, metastasizing rapidly, particularly to the brain, liver, and bones. About 70 to 80 percent of cases occur in smokers or former smokers, but passive smoking, asbestos, chemical inhalations, radiation, and air pollution also increase the risk. Many patients initially respond well to therapies, but relapses are common, and the cancer becomes more resistant.
Lurbinectedin acts as an alkylating agent that binds to guanine residues in the DNA, thereby disrupting cell cycle activity, leading to a cascade of events that impair DNA repair pathways and potentially contribute to cell death. It received FDA accelerated approval in 2020 for patients with metastatic SCLC after failure of platinum-based chemotherapy. Atezolizumab, a PD-L1 inhibitor, is already standard in induction therapy. The new indication underscores advances in personalized oncology, where maintenance therapies can prolong remission duration.
Despite the benefits, the therapy carries significant risks. Common side effects (in ?30 percent of patients) include a decrease in lymphocytes, platelets, hemoglobin, leukocytes, and neutrophils, as well as nausea and fatigue/asthenia. Severe myelosuppression, including febrile neutropenia and sepsis, thrombocytopenia, and anemia, can be life-threatening. In the IMforte study, 84 percent of patients received primary prophylaxis with G-CSF; neutropenia (grade 3/4) occurred in 18 percent, with a median onset after 31 days. Hepatotoxicity, extravasation with tissue necrosis, rhabdomyolysis, and embryofetal toxicity require close monitoring. Therapy should only be initiated with adequate baseline laboratory values (neutrophils ?1,500/mm³, platelets ?100,000/mm³), with regular blood count monitoring and dose adjustments. Pregnant and lactating women require special protection; effective contraception is recommended for up to six months.
In elderly patients (?65 years, 51 percent in the study), efficacy was comparable, but severe side effects (grade 3/4) occurred more frequently (45 percent versus 31 percent in younger patients). In moderate hepatic impairment, dose reduction is necessary; in severe impairment, therapy should be avoided. Strong CYP3A inhibitors (e.g., grapefruit) should be avoided as they increase exposure; strong inducers reduce efficacy.
The approval marks a milestone in the treatment of ES-SCLC, where prognosis remains challenging despite advances. Experts see a shift in the treatment standard with the combination, which could reduce uncertainty after induction therapy and improve quality of life. Jazz Pharmaceuticals, which markets the drug Zepzelca, emphasizes a patient-centered approach and plans further research in oncology and neuroscience. Full prescribing information is available on the FDA website.
This development highlights the ongoing need for innovative therapies for rare and aggressive cancers to expand the limited options for those affected and sustainably increase survival rates.
