PARP1 and neoplasm: The heavily pre‐treated patient population, particularly at lower dose levels (median [range] prior chemotherapy regimen of 5 [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12] in the 2 ~ 20 mg/d groups and 2 [0–8] in the 40 ~ 240 mg/d groups), combined with tumor shrinkage observed from 20 mg/d and robust pharmacodynamic PARP inhibition from 10 mg/d, suggest the limitation of the classic 3 + 3 study design without backfill expansion at lower dose levels.