For a patient with NSCLC harboring an EGFR or ALK mutation that transforms into SCLC, would you add immunotherapy to chemotherapy or avoid immunotherapy given the tumor's EGFR/ALK origin?

I typically avoid immunotherapy and continue the targeted therapy, such as osimertinib, with the chemotherapy.

Difficult question given limited data. Recent studies show that transformed SCLC is molecularly distinct from de novo SCLC. Molecular alterations associated with transformation are present prior to histologic transformation. CtDNA might help identify transformation early via the detection of epigene...

Transformation to SCLC is a recognized resistance mechanism in EGFR- or ALK-mutant NSCLC, occurring in up to 14% of EGFR-mutant cases and less commonly in ALK-positive disease. The prognosis after transformation is poor, with a median overall survival of 6–11 months.

Platinum and etoposide-based chem...