Etravirine in treatment-experienced, HIV-1-infected children and adolescents: 48-week safety, efficacy and resistance analysis of the phase II PIANO study.

OBJECTIVES: PIANO (Paediatric study of Intelence As an NNRTI Option; TMC125-C213; NCT00665847) assessed the safety/tolerability, antiviral activity and pharmacokinetics of etravirine plus an optimized background regimen (OBR) in treatment-experienced, HIV-1-infected children (≥ 6 to < 12 years) and adolescents (≥ 12 to < 18 years) over 48 weeks. METHODS: In a phase II, open-label, single-arm study, 101 treatment-experienced patients (41 children; 60 adolescents) with screening viral load (VL) ≥ 500 HIV-1 RNA copies/mL received etravirine 5.2 mg/kg (maximum dose 200 mg) twice a day (bid) plus OBR. RESULTS: Sixty-seven per cent of patients had previously used efavirenz or nevirapine. At week 48, the most common treatment-related grade ≥ 2 adverse event (AE) was rash (13%); 12% experienced grade 3 AEs. Only two grade 4 AEs occurred (both thrombocytopaenia, not etravirine related). At week 48, 56% of patients (68% children; 48% adolescents) achieved a virological response (VL<50 copies/mL; intent-to-treat, noncompleter=failure). Factors predictive of response were adherence > 95%, male sex, low baseline etravirine weighted genotypic score and high etravirine trough concentration (C0h ). Seventy-six patients (75%) completed the trial; most discontinuations occurred because of protocol noncompliance or AEs (8% each). Sixty-five per cent of patients were > 95% adherent by questionnaire and 39% by pill count. Forty-one patients experienced virological failure (VF; time-to-loss-of-virological-response non-VF-censored algorithm) (29 nonresponders; 12 rebounders). Of 30 patients with VF with paired baseline/endpoint genotypes, 18 (60%) developed nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations, most commonly Y181C. Mean etravirine area under the plasma concentration-time curve over 12 h (AUC0-12h ; 5216 ng h/mL) and C0h (346 ng/mL) were comparable to adult target values. CONCLUSIONS: Results with etravirine 5.2 mg/kg bid (with OBR) in this treatment-experienced paediatric population and etravirine 200 mg bid in treatment-experienced adults were comparable. Etravirine is an NNRTI option for treatment-experienced paediatric patients.

Expression and purification of monospecific and bispecific recombinant antibody fragments derived from antibodies that block the CD80/CD86-CD28 costimulatory pathway.

The development of recombinant techniques for rapid cloning, expression, and characterization of cDNAs encoding antibody (Ab) subunits has revolutionized the field of antibody engineering. By fusion to heterologous protein domains, chain shuffling, or inclusion of self-assembly motifs, novel molecules such as bispecific Abs can be generated that possess the subset of functional properties designed to fit the intended application. We describe the engineering of Ab fragments produced in bacteria for blocking the CD28-CD80/CD86 costimulatory interaction in order to induce tolerance against transplanted organs. We designed single-chain Fv antibodies, monospecific and bispecific diabodies, and a bispecific tetravalent antibody (BiTAb) molecule directed against the CD80 and/or CD86 costimulatory molecules. These recombinant Ab molecules were expressed in Escherichia coli, followed by purification and evaluation for specific interaction with their respective antigen in an enzyme-linked immunosorbent assay (ELISA). A specific sandwich ELISA confirmed the bispecificity of the bispecific diabodies and the BiTAb.