Kaplan-Meier estimates of PFS and OS by rituximab exposure in cycle 1 (AUC₁). Patients with AUC₁ ≥9400 mg × h per liter had significantly better (A) 4-year PFS (83% vs 62%; log-rank P = .011) and (B) 4-year OS (94% vs 69%; log-rank P = .0016) than those with AUC₁ <9400 mg × h per liter.