ABSTRACT
The safety and efficacy of rituximab have been retrospectively assessed in 17 children with Evans syndrome. Patients received 4 or 3 weekly doses of rituximab (375 mg/m(2) per dose) associated with prednisone, alone (14 patients) or associated with other immunosuppressive drugs. Complete or partial remission of at least one cytopenia was achieved in 13 out of the 17 patients (76%), and lasted in 11 of them with a mean follow-up of 2.4 years (range 0.5-7 years). Steroid therapy was stopped or tapered at 50-100% of the baseline dosage in all long-term responders. Moderate side effects and infection occurred only in 4 and 1 children respectively.
Subject(s)
Anemia, Hemolytic, Autoimmune/drug therapy , Antibodies, Monoclonal/administration & dosage , Immunologic Factors/administration & dosage , Purpura, Thrombocytopenic, Idiopathic/drug therapy , Adolescent , Anemia, Hemolytic, Autoimmune/complications , Anemia, Hemolytic, Autoimmune/mortality , Antibodies, Monoclonal/adverse effects , Antibodies, Monoclonal, Murine-Derived , Child , Child, Preschool , Disease-Free Survival , Female , Follow-Up Studies , France , Humans , Immunologic Factors/adverse effects , Infant , Infections/chemically induced , Infections/mortality , Male , Prednisolone/administration & dosage , Prednisolone/adverse effects , Purpura, Thrombocytopenic, Idiopathic/complications , Purpura, Thrombocytopenic, Idiopathic/mortality , Registries , Remission Induction , Rituximab , Survival Rate , SyndromeABSTRACT
Gatifloxacin (GAT) is a new 8-methoxy fluoroquinolone with enhanced activity against gram-positive cocci. Its activity was studied in an in vitro pharmacokinetic-pharmacodynamic model against five Staphylococcus aureus strains, either susceptible to ciprofloxacin or exhibiting various levels and mechanisms of ciprofloxacin (CIP) resistance: the ATCC 25923 reference strain (MICs of CIP and GAT: 0.5 and 0.1 microg/ml, respectively), its efflux mutant SA-1 (16 and 0.5 microg/ml; mutation in the norA promoter region), and three clinical strains, Sa2102 (2 and 0.2 microg/ml), Sa2667 (4 and 0.5 microg/ml), and Sa2669 (16 and 1 microg/ml), carrying mutations in the grlA (Ser80Tyr or Phe) and gyrA (Ser84Ala) quinolone resistance-determining regions (QRDRs) for Sa2669. Plasmatic pharmacokinetic profiles after daily 1-h perfusion of 400 mg for 48 h were accurately simulated. Thus, mean maximum concentration of drug in serum values for the two administration intervals were 5.36 and 5.80 microg/ml, respectively, and the corresponding half-life at beta-phase values were 8.68 and 7.80 h (goodness of fit coefficient, >0.98). Therapeutic concentrations of GAT allowed the complete eradication of the susceptible strain within 12 h (difference between the bacterial counts at the beginning of the treatment and at a defined time: -2.18 at the 1-h time point [t(1)] and -6.80 at t(24) and t(48); the bacterial killing and regrowth curve from 0 to 48 h was 30.2 h x log CFU/milliliter). However, mutants (M) with GAT MICs increased by 4- to 40-fold were selected from the other strains. They acquired mutations either supplementary (MSa2102 and MSa2667) or different (Ala84Val for MSa2669) in gyrA or in both gyrA and grlA QRDRs (MSA-1). MSa2667 additionally overproduced efflux system(s) without norA promoter modification. Thus, GAT properties should allow the total elimination of ciprofloxacin-susceptible S. aureus, but resistant mutants might emerge from strains showing reduced susceptibility to older fluoroquinolones independently of the first-step mutation(s).
