Lurbinectedin (DNA-binding transcription inhibitor) + atezolizumab extends Q‑TWiST vs atezolizumab in ES‑SCLC maintenance

Lurbinectedin (a selective inhibitor of oncogenic transcription via DNA binding) plus the PD‑L1 inhibitor atezolizumab was evaluated as first-line maintenance in the Phase 3 IMforte trial (NCT05091567) in ES‑SCLC patients who were progression-free after induction atezolizumab/carboplatin/etoposide, randomizing 242 vs 241 patients to lurbi+atezo vs atezo. In this post hoc Q‑TWiST analysis (data cut July 29, 2024; median follow-up 15 months), mean Q‑TWiST improved to 12.2 vs 10.2 months (Δ 1.9 months; 14.9% relative gain at 26-month max follow-up), driven by longer mean TWiST (9.8 vs 6.4 months) with modestly more time in grade ≥3 toxicity pre-progression (TOX 0.7 vs 0.3 months) and less time post-progression (REL 4.4 vs 6.1 months). The accompanying restricted-mean survival estimates also favored the combination (mean PFS 10.5 vs 6.8 months; mean OS 14.8 vs 12.9 months), consistent with the IMforte primary results (stratified HR PFS 0.54; OS 0.73); clinically, this is an incremental but tangible gain over the current SOC of atezolizumab maintenance after chemo‑IO induction, where no prior Phase 3 maintenance intensification had shown OS benefit.