FDA approves atezolizumab–lurbinectedin for ES-SCLC

The approval is based on the pivotal phase III IMforte study (n=483), which demonstrated that the atezolizumab–lurbinectedin regimen reduced the risk of disease progression or death by 46% (HR=0.54; 95% CI: 0.43–0.67; p<0.0001) and risk of death by 27% (HR=0.73; 95% CI: 0.57–0.95; p=0.0174) versus atezolizumab alone. Median overall survival reached 13.2 months compared with 10.6 months for atezolizumab monotherapy, while median progression-free survival improved to 5.4 months versus 2.1 months. Safety was consistent with established profiles for both agents.

Lurbinectedin is a DNA-binding synthetic derivative of trabectedin that inhibits oncogenic transcription, leading to DNA damage and tumour cell death, while also modulating the tumour microenvironment. Atezolizumab is a monoclonal antibody targeting PD-L1, reactivating T cells to recognise and attack tumour cells. Together, the combination targets both the tumour cells directly and the immune system, providing a complementary mechanism to delay disease progression.

The approval highlights a strategic licensing collaboration: Spanish biotech PharmaMar, the original developer of lurbinectedin, licensed U.S. and Canadian rights to Jazz Pharmaceuticals in December 2019 under a deal worth up to US$1bn in milestones and royalties. Roche partnered with Jazz to co-fund the IMforte study and combine lurbinectedin with its PD-L1 inhibitor atezolizumab, bringing the first-line maintenance regimen to patients. In 2026, Roche’s Japanese arm, Chugai, ended a licence agreement with PharmaMar.

From a clinical and market perspective, this approval introduces a complementary maintenance option for ES-SCLC, filling a previously unmet need following platinum-etoposide induction therapy. Compared with existing first-line maintenance therapies, the atezolizumab–lurbinectedin combination seems to nearly double median progression-free survival (5.4 months vs 2.1 months) and seems to extend median overall survival by 2.6 months (13.2 vs 10.6 months), positioning it as a potential standard of care in maintenance. While it does not replace induction regimens, it may capture a significant share of the post-induction maintenance market, providing an alternative to single-agent immunotherapy and potentially delaying the need for subsequent lines of cytotoxic chemotherapy.