A phase I study evaluating the pharmacokinetics, safety and tolerability of an antibody-based tissue factor antagonist in subjects with acute lung injury or acute respiratory distress syndrome.

BACKGROUND: The tissue factor (TF)-dependent extrinsic pathway has been suggested to be a central mechanism by which the coagulation cascade is locally activated in the lungs of patients with acute lung injury and acute respiratory distress syndrome (ALI/ARDS) and thus represents an attractive target for therapeutic intervention. This study was designed to determine the pharmacokinetic and safety profiles of ALT-836, an anti-TF antibody, in patients with ALI/ARDS. METHODS: This was a prospective, randomized, placebo-controlled, dose-escalation Phase I clinical trial in adult patients who had suspected or proven infection, were receiving mechanical ventilation and had ALI/ARDS (PaO(2)/FiO(2) ≤ 300 mm). Eighteen patients (6 per cohort) were randomized in a 5:1 ratio to receive ALT-836 or placebo, and were treated within 48 hours after meeting screening criteria. Cohorts of patients were administered a single intravenously dose of 0.06, 0.08 or 0.1 mg/kg ALT-836 or placebo. Blood samples were taken for pharmacokinetic and immunogenicity measurements. Safety was assessed by adverse events, vital signs, ECGs, laboratory, coagulation and pulmonary function parameters. RESULTS: Pharmacokinetic analysis showed a dose dependent exposure to ALT-836 across the infusion range of 0.06 to 0.1 mg/kg. No anti-ALT-836 antibody response was observed in the study population during the trial. No major bleeding episodes were reported in the ALT-836 treated patients. The most frequent adverse events were anemia, observed in both placebo and ALT-836 treated patients, and ALT-836 dose dependent, self-resolved hematuria, which suggested 0.08 mg/kg as an acceptable dose level of ALT-836 in this patient population. CONCLUSIONS: Overall, this study showed that ALT-836 could be safely administered to patients with sepsis-induced ALI/ARDS. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01438853.

Immunogenicity assessment of tbo-filgrastim in cancer patients receiving chemotherapy.

AIM: This integrated analysis examined the immunogenicity of tbo-filgrastim and its potential clinical impact in three Phase III randomized studies in patients with breast cancer, lung cancer and non-Hodgkin lymphoma receiving chemotherapy. RESULTS: Treatment-emergent antidrug antibodies (ADA) occurred in 3/213 (1.4%) breast cancer patients, 2/160 (1.3%) lung cancer patients and 1/63 (1.6%) patients with non-Hodgkin lymphoma. None of the treatment-emergent ADA showed cross-reactivity toward native granulocyte-colony stimulating factors or exhibited neutralizing activity against tbo-filgrastim. Among patients with treatment-emergent ADA, there was no treatment-related hypersensitivity or anaphylaxis and no evidence of loss of clinical efficacy. CONCLUSION: Tbo-filgrastim has demonstrated low immunogenicity in cancer patients receiving chemotherapy and ADA response does not impact safety and efficacy in the patients.

Method establishment for discerned immunogenicity assessment of a recombinant glycoprotein containing nonhuman sialic acid Neu5Gc residues.

AIM: Recombinant glycoprotein produced in nonhuman mammalian cell lines can be modified with the immunogenic nonhuman sialic N-glycolylneuraminic acid (Neu5Gc). We describe here a validated method for detection of antidrug antibodies against both protein and Neu5Gc-containing glycan epitopes. RESULTS: An electrochemiluminescent method was established with drug conjugates as capture and detection reagents. Rabbit antidrug polyclonal antibodies were used as the positive control for protein moiety-specific antibodies, while chicken anti-Neu5Gc polyclonal antibodies were used as the positive control for antibodies against Neu5Gc glycan epitope. Specificity to Neu5Gc was verified by signal inhibition with bovine γ-globulin that contains Neu5Gc. CONCLUSION: The assay illustrated here discerns the immunogenicity of the protein backbone and the sialic acid Neu5Gc glycan moiety of a recombinant protein containing Neu5Gc.

Immunogenicity Assessment of Lipegfilgrastim in Patients with Breast Cancer Receiving Chemotherapy.

Lipegfilgrastim is a long-acting, once-per-cycle, glycopegylated recombinant granulocyte colony-stimulating factor (G-CSF) used to prevent neutropenia in patients receiving myelosuppressive chemotherapy. This integrated analysis examined the immunogenicity of lipegfilgrastim and its potential clinical impact in two double-blind randomized studies (phases II and III) of patients with breast cancer receiving chemotherapy. Serum samples were analyzed using sequential assays for screening, confirmation, antibody titer, and characterization of antidrug antibodies (ADA). Neutropenia-related efficacy measures were reviewed for each ADA-positive patient. Among 255 patients receiving lipegfilgrastim (154 in phase II, 101 in phase III) and 155 patients receiving pegfilgrastim (54 in phase II, 101 in phase III), the incidence of treatment-emergent ADA was low and similar between the lipegfilgrastim (phase II: 1.3%; phase III: 1.0%) and pegfilgrastim (phase II: 1.9%; phase III: 1.0%) arms. None of the treatment-emergent ADA-positive samples exhibited neutralizing activity against lipegfilgrastim, pegfilgrastim, or glycosylated G-CSF in a cell-based neutralizing antibody assay. No changes were observed in neutropenia-related efficacy measures among ADA-positive patients, and no treatment-related hypersensitivity or anaphylaxis occurred. These results indicate that there is no apparent impact of ADA on lipegfilgrastim efficacy and safety.

Differential sensitivity of lipegfilgrastim and pegfilgrastim to neutrophil elastase correlates with differences in clinical pharmacokinetic profile.

To assess the basis of the different half-lives of long-acting human granulocyte colony-stimulating factor (G-CSF) drugs, the effect of neutrophil elastase on lipegfilgrastim and pegfilgrastim was investigated. Sensitivity to human neutrophil elastase (HNE) was evaluated by incubating the drugs with HNE followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Drugs were also incubated with isolated human neutrophils followed by Western blot analysis. Lipegfilgrastim was more resistant to degradation with HNE or neutrophils than pegfilgrastim and appeared more intact on SDS-PAGE gels and Western blots. Lipegfilgrastim retained more functional activity than pegfilgrastim after incubation with HNE (67% vs ∼ 9%, respectively) or neutrophils (80% vs ∼ 4%, respectively) as assessed in an NFS-60 cell-based [(3) H]-thymidine incorporation assay. The binding and affinity of untreated lipegfilgrastim and pegfilgrastim for G-CSF receptors were evaluated using an NFS-60 competitive G-CSF receptor-binding assay and surface plasmon resonance. Untreated drugs were also evaluated in the functional NFS-60 thymidine incorporation assay. G-CSF receptor binding, receptor affinity, and functional activity were comparable between untreated drugs. The results showed a greater resistance to neutrophil elastase degradation and concomitant retention of functional activity of lipegfilgrastim compared with pegfilgrastim, which potentially explains the clinical observations of a longer half-life of lipegfilgrastim versus pegfilgrastim.

Comparative immunogenicity assessment: a critical consideration for biosimilar development.

An appropriate assessment strategy with validated anti-drug antibody (ADA) assays is critical for comparative evaluation of immunogenicity between a proposed biosimilar and its reference product. The strategy should aim to identify potential differences in immune responses between these products. While an ADA assay employing the proposed biosimilar product as the detecting reagent has been generally recommended for such evaluation, a product-specific assay using the product of interest may be of use as it offers a capability of detecting antibodies against specific epitopes from the respective product. Regardless of assay strategy, the performance of the assay must be fully assessed and method needs to be validated to meet the comparative purpose of immunogenicity assessment.