Elucidation of the statistical factors that influence anti-drug antibody cut point setting through a multi-laboratory study.

Appropriateness of anti-drug antibody (ADA) assay is critical for immunogenicity assessment of biopharmaceuticals. Although cut point setting in ADA assay has a large impact on the results, a standard statistical approach for its setting has not been well established. In this multi-laboratory study, to elucidate factors influencing the cut point setting, we compared the statistical approaches and calculated cut points for multiple datasets of ADA assays using the individual procedure employed at each laboratory.

Collaborative study using common samples to evaluate the performance of anti-drug antibody assays constructed by different companies.

This study was undertaken to evaluate the performance of anti-drug antibody (ADA) assays constructed by each participating company using common samples including ADA, drug and human serum. The ADA assays constructed by each company showed good sensitivity and precision for evaluation of ADA. Cut points for screening and confirmatory assays and assay selectivity were determined by various calculation methods.

Immunogenicity of therapeutic protein products: current considerations for anti-drug antibody assay in Japan.

Immunogenicity assessment is an important issue for ensuring the safety and efficacy of therapeutic protein products. Although the reliability of the anti-drug antibody (ADA) assay is one of the key points, there are some difficulties in assessing its validity because the analytes are polyclonal antibodies with variable and unknown characteristics. To elucidate the points to consider for the ADA assay, a Japanese research group was established that discusses the issues raised on the immunogenicity assessment.

Method development and validation of the simultaneous determination of a novel topoisomerase 1 inhibitor, the prodrug, and the active metabolite in human plasma using column-switching LC-MS/MS, and its application in a clinical trial.

A robust and sensitive method using liquid chromatography-tandem mass spectrometry was developed and validated for the simultaneous determination of a novel topoisomerase 1 inhibitor CH0793076 (3076), the prodrug CH4556300 (TP300), and the active metabolite CH0793011 (3011) in human plasma. All plasma analyzed with this method was acidified with 1M HCl and 46% citric acid solution in a ratio of 100:10:1 (v:v:v) to avoid the pH-based degradation of TP300 and to shift the equilibria of 3076 and 3011 between the lactone and carboxylate forms towards the lactone forms. After the plasma proteins were precipitated with methanol:acetonitrile:HCl 1M (50:50:1, v:v:v) containing stable isotopic internal standards, the analytes were trapped on an Xterra MS C18 column (10×2.

In vivo time-course of receptor binding in the parathyroid gland of the vitamin D analogue [(3)H]1,25-dihydroxy-22-oxavitamin D(3) compared with [(3)H]1,25-dihydroxyvitamin D(3), determined by micro-autoradiography.

1,25-Dihydroxy-22-oxavitamin D(3) (22-oxacalcitriol, OCT), is a new synthetic analogue of 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3), calcitriol), to be used in the treatment of secondary hyperparathyroidism. This study used receptor micro-autoradiography in the parathyroid gland to determine and compare the time-course of receptor binding between OCT and 1,25(OH)(2)D(3). Mice were injected with 4 microg/kg of [26-(3)H]OCT or [26,27-methyl-(3)H]1,25(OH)(2)D(3), and killed at 5, 15, 30 min, 1, 2, 4, 8, 12, and 24 h afterwards.