Therapeutic activity of L19-IL2, rIL-2, and rituximab in mono- and combination therapy against localized DoHH-2 lymphoma xenografts. SCID mice bearing established sc DoHH-2 lymphoma xenografts were dosed IV with control saline (×), 6.6 μg nontargeted rIL-2 + SIP(L19) (▵), 20 μg L19-IL2 (□), 200 μg rituximab (●), 200 μg rituximab + 6.6 μg rIL-2 + SIP(L19) (▴), or 200 μg rituximab + 20 μg L19-IL2 (■). The administration of L19-IL2 in combination with rituximab led to complete lymphoma eradications in all cases and was significantly more effective than equivalent doses of nontargeted rIL-2 (plus free L19) in combination with rituximab (P < .05). Data represent mean tumor volumes (± SE). Arrows, days of treatment.