Table 2

Survival times of SCID mice after immunoliposomal VCRa treatments

SCID mice (6–7/group) were injected i.v. with 5 million Namalwa cells in 0.2 ml PBS. After 24 h they were injected i.v. in the tail vein with a single bolus dose of 0.66 mg/kg as free VCR or liposomal VCR. Liposomes were composed of SM:Chol:mPEG-DSPE (55:40:5) or SM:Chol:mPEG-DSPE:Mal-PEG-DSPE (55:40:4:1). Liposomes targeted with mAbs had 66 μg αCD19/μmol PL (34 molecules of αCD19/liposome) or 52 μg αCD20/μmol PL (27 molecules of αCD20/liposome, respectively). The combination group had VCR-SM-SIL (αCD19) and VCR-SM-SIL (αCD20; total dose = 0.66 mg/kg) in equal parts.

GroupMean survival time ± SD (days)Percentage increase life spanLong-term survivors (>150 days)
Control (saline)25.4 ± 0.50/6
Free VCR38.7 ± 4.0530/6
VCR-SM-SL31.9 ± 3.0260/7
VCR-SM-SL + αCD2044.7 ± 5.9760/6
VCR-SM-SL + αCD1962.3 ± 8.81450/6
VCR-SM-SIL (αCD20)49.0 ± 4.6932/7
VCR-SM-SIL (αCD19)66.0 ± 13.11603/7
VCR-SM-SIL (αCD20) + VCR-SM-SIL (αCD19)77.0, 91.0203, 2585/7
  • a VCR, vincristine; SM, egg sphingomyelin; Chol, cholesterol; mPEG-DSPE, distearoyl phosphatidyl; Mal-PEG-DSPE, maleimide-derivatized PEG2000-DSPE; mAb, monoclonal antibody; PL, phospholipid; SIL, Stealth immunoliposomes.