BIOCHEMISTRY, BIOMEDICINE & PHARMACEUTICS

Introduction to Anti Drug-Antibody Assay The total anti-drug antibody(TAb) assays detect the antibodies that are specific to the therapeutic molecules. These assays do not distinguish specific isotypes and detect all classes of antibodies present in the samples. The different platforms have been used for the detection of total antibodies such as bridging antibody assays, indirect ELISA assays, SPR assays, Immuno-PCR assay and most recently mass spectrometric assay.  Although the detection system varies with different platforms, the detection still relies on the ADA and therapeutic molecules binding and interactions. A tier-based approach is utilized for detection of ADA that includes a) Screening Assay b) Confirmation Assay c) Titer Assay a) Screening Assay : The screening assay is designed to detect and distinguish the presence or absence of anti-drug antibodies in the samples. The screening assays involve the incubation of samples with capture and detection reagents. Th...

Case Presentation A 62-year-old man with a 10-year history of type 2 diabetes mellitus visited the hospital with complaints of swelling in his lower extremities. The patients' had a co-incidence of diabetes mellitus and hypertension. The clinical laboratory report showed the following observations: Biochemical Parameters Results Serum Glucose 250 mg/dL Serum Albumin 2.5g/dL Serum Creatinine 1.5 mg/dL Blood Urea itrogen 25mg/dL Serum Sodium 130 mEq/L Serum Potassium 4.3 mEq/L Serum Total Cholesterol 275 mg/dL Serum Anti-ANA antibodies Negative Serum Rheumatoid factors Negative Serum Cryoglobulins Negative Urine examinations Urinary proteins: 5.0 gm/dL Urinary glucose: ++ Provisional diagnosis: Diabetic kidney disease with hypoalbuminemia, massive protein loss( nephrotic syndrome), hypercholesterolemia. Nephroti...

Anti-drug antibody (ADA) assays are developed to detect and characterize an antibody response generated against bio-therapeutic products. The total antibody (TAb) assay (TAb) detects the total antibodies generated against the therapeutic proteins. The total antibody assay positive samples that are positive for total ADA are tested for the neutralizing capacity. These TAb-positive samples may be subjected to isotype characterization as necessary. These assays are performed in three tiers : a) screening assay, b) confirmation assay, c) titer assay  Assay cut points are established with three basic assumptions The cut points are usually a statistically determined cut off value above which the samples are considered positive. During pre-study validation, the cut points are established by analyzing a set of approximately fifty drug-naïve healthy individual samples. The cut points are established with the following basic assumptions: a) No prior exposure to the drug b) No preexisting...