The development of a maturing T-cell-mediated immune response was characterized in Parkinson's disease subjects receiving recombinant human glial-derived neurotrophic factor (r-metHuGDNF) via continuous bilateral intraputaminal infusion. Eighteen of 34 subjects tested positive for anti-r-metHuGDNF-binding antibodies. Four subjects developed neutralizing activity, three of which demonstrated classic immunoglobulin class switching from IgM to IgG. An increase of anti-r-metHuGDNF IgG-binding antibodies correlated with the development of neutralizing activity. All serum samples from two subjects with neutralizing activity were characterized for IgG subclasses. These data revealed an initial anti-r-metHuGDNF IgG population where IgG1 >> IgG2 >> IgG4, and IgG3 concentrations were negligible. However, continued antigenic stimulation resulted in concentration changes where IgG4 > IgG1> IgG2, indicating a mature immune response. In addition, using in silico techniques, two immunodominant MHC class II T-cell epitopes were predicted for the native GDNF sequence. These data demonstrate development of a mature T-cell-mediated immune response in these subjects.

No abstract

No abstract

All therapeutic proteins have the potential to induce anti-drug antibodies (ADA). Clinically relevant ADA can impact efficacy and/or safety of a biological therapeutic. Immunogenicity assessment strategy evaluates binding and neutralizing ADA, and the need for additional characterization (e.g., epitope, titer and so on) is determined using a risk-based approach. The choice of characterization assays depends on the type, application and immunogenicity of the therapeutic. ADA characterization can impact the interpretation of the risk profile of a given therapeutic, and offers insight into opportunities for risk mitigation and management. This article describes common ADA characterization methods. Strategic assessment and characterization of clinically relevant ADA are discussed, in order to support clinical options for safe and effective patient care and disease management.

No abstract

e18637 Background: Pegfilgrastim-cbqv, a pegfilgrastim biosimilar, is administered 24-72 h after myelosuppressive chemotherapy to prevent febrile neutropenia. Pegfilgrastim delivery via an on-body injector (OBI) applied on the day of chemotherapy eliminates the need for a second healthcare visit. This study evaluated the pharmacokinetic (PK), pharmacodynamic (PD) bioequivalence (BE), and the safety of pegfilgrastim-cbqv administered via OBI vs prefilled syringe. Methods: In this open-label, 2-period crossover study, healthy adult male participants were randomized 1:1 to 2 treatment sequences to receive a 6-mg subcutaneous (SC) injection of pegfilgrastim-cbqv via OBI or prefilled syringe in period 1 and an injection via the other method in period 2 (after a 6- to 8-wk washout). Primary endpoints (PK) were area under the concentration-time curve from time 0 to infinity (AUC0-inf), the AUC from time 0 to the last quantifiable concentration (AUC0-last), and the maximum plasma concentration (Cmax). Secondary endpoints (PD) were area under the absolute neutrophil count (ANC)-time curve from time 0 to the last quantifiable ANC (ANC AUC0-last) and maximum ANC (ANCmax). PK/PD BE was established if the 90% CI for the geometric mean ratios (GMRs) fell within 80-125%. Safety and immunogenicity were also assessed. Results: The 90% CIs of the GMRs for PK and PD endpoints in healthy participants fell within the predetermined range (Table). Treatment-emergent adverse events (TEAEs) occurred in 87.8% (OBI) vs 75.8% (prefilled syringe) of participants. Most TEAEs were musculoskeletal effects and mild in severity. The most common injection site–related TEAE was erythema (OBI 34.1%; prefilled syringe 2.5%). The injection site erythema reactions were mild in severity and self-limiting. The incidence of treatment-emergent antidrug antibodies (ADAs) in period 1 was similar with OBI (40.0%) vs prefilled syringe (36.6%); ADA titers were low, transient, and primarily directed to the polyethylene glycol (PEG) moiety of pegfilgrastim-cbqv. The ADAs had no apparent impact on PK, PD, or safety. Neutralizing antibodies were not detected in any participant. Conclusions: This study demonstrated PK and PD BE of pegfilgrastim-cbqv administered via OBI vs prefilled syringe in healthy adult males. OBI and prefilled syringe administration had similar safety and immunogenicity profiles. No unexpected safety signals were identified.[Table: see text]

We designed a three-step statistical approach to transfer bioanalytical assays (ELISA and Biacore) which evaluates the (1) average equivalence between the two labs (2) concordance in individual sample results between the two labs, and (3) long-term stability of assay performance. Each experimental design evaluated the contribution of four critical variables to the overall variability. Two lots of each variable were examined in a controlled experiment. The variables tested for ELISA were analyst, plate washer, biotinylated-therapeutic protein, and streptavidin-horseradish peroxidase; and for Biacore were analyst, instrument, chip lot, and conjugation chemistry reagent lots. Equivalence in the mean signal to noise (S/N) or mean relative units (RU) between the two labs was established through statistical evaluation of the assay performance characteristics across multiple assay variables. Concordance between the two labs in the individual sample results was subsequently verified both quantitatively and qualitatively. The long-term maintenance of assay stability was monitored by performance testing of a predefined set of samples which were prepared in sufficient quantities to last several years. The process of method validation for biomarker testing in clinical trials is to analyze the variability of the assay performance. However, different factors contribute to this variability and need to be evaluated when the method is transferred to another site/lab. Lack of understanding the critical variables can potentially result in unexpected problems and delays. The three-step statistical approach of assay transfer provides a robust process for transferring complex biological assays.

No abstract