Key exclusions were active CNS metastases (except stable treated ones 4 weeks prior), prior anti-PD-L1 within 5 half-lives, MMAE-containing agent exposure, or ≥Grade 2 neuropathy per NCI CTCAE v5.0. Stratification occurred by tumor type (Parts A-E) and PD-L1 status.

In dose escalation, pts received doses of SGN-PDL1V from 0.5-1.75 mg/kg on days 1, and 8 of every 21-day cycle using adjusted ideal body weight. The primary objectives of this study are safety/tolerability and pharmacokinetics with antitumor activity as a secondary objective.

Safety evaluations included AE monitoring for up to 3 years, with specific focus on DLTs during the first treatment cycle, laboratory abnormalities, and immunogenicity (ADA incidence). PK parameters (AUC, Cmax, Ctrough) were assessed until last treatment plus 30-37 days.

Efficacy outcomes measured confirmed ORR, DOR, PFS, and OS per RECIST v1.1 over ~3 years across multiple solid tumors (NSCLC, HNSCC, TNBC, etc.), requiring PD-L1 expression (TPS/CPS ≥1 or <1) and prior therapy failure/refusal.