How Lurbinectedin Works at the Molecular Level
Lurbinectedin binds covalently to DNA minor grooves, forming monoadducts that stall RNA polymerase II transcription.[1] This triggers DNA repair pathways, including nucleotide excision repair, leading to double-strand breaks and cell death, especially in rapidly dividing tumor cells.[2]
Primary Indications and Responsive Tumors
The FDA approved lurbinectedin (branded as Zepzelca) in 2020 for metastatic small cell lung cancer (SCLC) after platinum-based chemotherapy failure.[1] It shows activity in SCLC by targeting transcriptionally active cells, with response rates around 35% in pretreated patients.[3]
How It Differs from Other Chemotherapy Agents
Unlike platinum drugs that crosslink DNA, lurbinectedin specifically inhibits transcription elongation, sparing normal cells with lower transcriptional activity.[2] It outperforms topotecan in progression-free survival for relapsed SCLC (5.1 vs. 3.9 months in trials).[3]
Resistance Mechanisms and Clinical Limitations
Tumors can develop resistance via enhanced DNA repair (e.g., ERCC1 overexpression) or RNA polymerase II mutations.[4] Combination with doxorubicin improves outcomes but increases toxicity risks like myelosuppression.[3]
Ongoing Trials and Combination Strategies
Phase II/III trials test lurbinectedin with irinotecan or immunotherapy (e.g., atezolizumab) in SCLC and other solid tumors like ovarian cancer.[5] Early data suggest synergy by overcoming resistance in transcription-dependent cancers.
[1]: FDA Approval Summary for Zepzelca
[2]: Nature Reviews Drug Discovery - Lurbinectedin Mechanism
[3]: NEJM - Lurbinectedin vs. Topotecan in SCLC
[4]: Cancer Discovery - Resistance Pathways
[5]: ClinicalTrials.gov - Lurbinectedin Trials