Background: Lurbinectedin (L), an inhibitor of active transcription, has shown activity in second-line (2L) small cell lung cancer (SCLC) (ASCO 2019). Topotecan (T) is the only approved drug in 2L SCLC and is also used in platinum resistant ovarian cancer (PROC). Methods: This pooled safety analysis includes data from 554 patients (pts) treated with L at 3.2 mg/m² Day 1 q3wk 1-h (no primary prophylaxis with G-CSF required): 335 with selected solid tumors (9 indications, including 105 pts with SCLC) from a phase II Basket study and 219 with PROC in the phase III CORAIL study. An indirect exploratory comparison (pooled data from CORAIL + Basket) and a direct comparison (data from CORAIL) of L vs. T are presented. Results: Most common adverse events with L were grade 1/2 fatigue, nausea and vomiting. Treatment-related (L/T): dose reductions: 22.9/48.3%, delays: 25.8/52.9%, grade ≥3 serious adverse events (SAEs): 15.0/32.2%, discontinuations: 3.2/5.7%, deaths: 1.3/1.5%, G-CSF use: 23.8/70.1%, and transfusions: 15.9/52.9%. Conclusions: Lurbinectedin has a predictable and manageable safety profile. A significant safety advantage was observed when lurbinectedin was compared with topotecan in the CORAIL trial in terms of hematological toxicities. With the limitations of indirect comparisons, in the pooled safety analysis, fewer lurbinectedin-treated pts had severe hematological toxicities, SAEs, dose adjustments, treatment discontinuations and use of supportive treatments than topotecan-treated pts. Clinical trial information: NCT02421588 and NCT02454972.

^a Primary G-CSF prophylaxis allowed.