AbbVie acquired South San Francisco-based Stemcentrx for ~$5.8B (approximately $2B cash + $3.8B AbbVie stock) plus up to $4B in success-based milestones (~$9.8B total). Lead asset Rova-T was an anti-DLL3 ADC in registrational trials for SCLC. Acquisition recorded $4B impairment in 2018-2020 after Phase 3 failures; program ultimately terminated.