STABILITY TESTING OF ANTI-VACCINE ANTIBODIES IN HUMAN SERUM

Background: To generate exhaustive data on the stability of human anti-vaccine or anti-drug antibodies, we designed a GLP study using anti-vaccine antibodies (AVA) samples collected from over 100 different subjects. Samples were selected from various time points after vaccination to cover the heterogeneity of the polyclonal human immune response. Samples were analyzed shortly after serum collection using specific ELISAs and re-analyzed after long-term storage or multiple cycles of freeze-thaw (FT). The general acceptance criteria for incurred sample reanalysis (ISR) for ligand binding assays (LBA) were applied, as well as some alternative stricter acceptance criteria promoted by various white papers. Results: Anti-vaccine antibodies are stable in undiluted serum for at least three cycles of freeze-thaw and at least 3.5 years storage at a nominal temperature of -80°C. Conclusion: The nature of the humoral immune response allows extending the conclusion of this study to all anti-vaccine and anti-drug antibodies, making it unnecessary to test long-term stability for each new biological therapeutics or vaccine program

STABILITY OF ANTI-IMMUNOTHERAPEUTIC ANTIBODIES IN FROZEN HUMAN SERUM SAMPLES

Background: To generate exhaustive data on the stability of human anti-vaccine or anti-drug antibodies, we designed a GLP study using anti-vaccine antibodies (AVA) samples collected from over 100 different subjects. Samples were selected from various time points after vaccination to cover the heterogeneity of the polyclonal human immune response. Samples were analyzed shortly after serum collection using specific ELISAs and re-analyzed after long-term storage or multiple cycles of freeze-thaw (FT). The general acceptance criteria for incurred sample reanalysis (ISR) for ligand binding assays (LBA) were applied, as well as some alternative stricter acceptance criteria promoted by various white papers. Results: Anti-vaccine antibodies are stable in undiluted serum for at least three cycles of freeze-thaw and 3.5 years storage at a nominal temperature of -80°C. Conclusion: The nature of the humoral immune response allows extending the conclusion of this study to all anti-vaccine and anti-drug antibodies, making it unnecessary to test long-term stability for each new biological therapeutics or vaccine program

Unexpected Hepatotoxicity in a Phase I Study of TAS266, a Novel Tetravalent Agonistic Monoclonal Nanobody® Targeting the DR5 Receptor

ABSTRACT Purpose: TAS266 is a novel agonistic tetravalent Nanobody® targeting the DR5 receptor. In preclinical studies, TAS266 was more potent than a cross-linked DR5 antibody or TRAIL. This first-in-human study was designed to evaluate the safety and tolerability, maximum tolerated dose, pharmacokinetics, pharmacodynamics, immunogenicity and preliminary efficacy of TAS266. Methods: Adult patients with advanced solid tumors were to receive assigned doses of TAS266 (3, 10, 15, or 20 mg/kg) intravenously on days 1, 8, 15, and 22 of a 28-day treatment cycle. Results: Grade ≥3 elevations in aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) levels, occurring during cycle 1 in 3 of 4 patients at the 3 mg/kg dose level, were attributed to TAS266 and led to early study termination. Liver enzyme levels quickly returned to grade ≤1 following TAS266 discontinuation. Evidence of pre-existing antibodies able to bind to TAS266 was found in the 3 patients who experienced these dose-limiting toxicities. Immunogenic responses remained elevated and strengthened at end-of-treatment (EOT). In the 1 patient who did not develop hepatotoxicity, no evidence of immunogenicity was observed at baseline or following administration of 4 TAS266 doses; however, incipient positive immunogenicity was observed at the EOT visit. Conclusion: TAS266 was associated with unexpected, significant but reversible hepatotoxicity. Although the underlying mechanism is not fully elucidated, factors including the molecule’s high potency, immunogenicity to TAS266 and possibly increased DR5 expression on hepatocytes further enhancing the activity of the Nanobody®, may have contributed to enhanced DR5 clustering and activation of hepatocyte apoptosis

Unexpected Hepatotoxicity in a Phase I Study of TAS266, a Novel Tetravalent Agonistic Monoclonal Nanobody® Targeting the DR5 Receptor

SUMMARY Purpose: This first-in-human study was designed to evaluate the safety and tolerability, maximum tolerated dose, pharmacokinetics, pharmacodynamics, immunogenicity, and preliminary efficacy of TAS266, a novel agonistic tetravalent Nanobody® targeting the DR5 receptor. Experimental design: Adult patients with advanced solid tumors were to receive assigned doses of TAS266 (3, 10, 15, or 20 mg/kg) intravenously on days 1, 8, 15, and 22 of a 28-day treatment cycle. Results: Grade ≥ 3 elevations in aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) levels occurring during cycle 1 in 3 of 4 patients enrolled at the 3 mg/kg dose level were attributed to TAS266 and led to early study termination. Liver enzyme levels quickly returned to grade ≤ 1 following TAS266 discontinuation. Evidence of antidrug antibodies, indicating pre-existing immunogenicity to TAS266, was found in the 3 patients who experienced these dose-limiting toxicities (DLTs). Immunogenic responses remained elevated and strengthened at the end of treatment. In the 1 patient who did not develop hepatotoxicity, no evidence of immunogenicity was observed at baseline or following administration of 4 doses of TAS266; however, incipient positive immunogenicity was observed at the end of treatment visit. TAS266 had a mean total systemic clearance of 0.47 L/hr and a median terminal phase half-life of 14.29 hours. Conclusion: TAS266 was associated with unexpected, significant but reversible hepatotoxicity. Although the underlying mechanism is not fully elucidated, immunogenicity to TAS266 may have contributed to enhanced DR5 clustering and activation of hepatocyte apoptosis