Immunogenicity assay development and validation for biological therapy as exemplified by ustekinumab.

Introduction of biotherapeutics has been a major milestone in the treatment of different chronic diseases. Nevertheless, the immune system can recognize the administered biological as non-self and respond with generation of anti-drug antibodies (ADA), including neutralizing ADA (nADA). Immunogenic responses may result in altered drug dynamics and kinetics leading to changes in safety and efficacy. However, there are several challenges with standard techniques for immunogenicity testing. Ustekinumab (UST), used in different inflammatory diseases, is a therapeutic antibody directed against the shared p40 subunit of interleukin (IL)-12 and IL-23, interfering in the pathogenically crucial T helper type 1 (Th1)/Th17 pathway. We established and validated different approaches for detection and quantitation of UST, UST-specific ADA and nADA. Addressing the obstacle of complex formation of UST with nADA, we developed an acidification assay to approach the total amount of nADA. Validated methods were based on surface plasmon resonance spectroscopy (SPR), enzyme-linked immunosorbent assay (ELISA) and a cell-based approach to characterize neutralizing capacity of nADA. Parameters assessed were determination and quantitation limits, linearity, range, precision, accuracy and selectivity. Quantitation of ADA and UST was feasible at lower concentrations using ELISA, whereas SPR showed a wider linear range for determination of ADA and UST. Accuracy, precision and linearity for quantitation were comparable using ELISA, SPR and the cell-based approach. All validated parameters fulfill the requirements of regulatory agencies. A combination of the testing approaches could address the increasing demand of precision medicine as it can be suitable for capturing the whole spectrum of immunogenicity and is transferable to other biologicals.

[Safety and efficacy of off-label use of biologic therapies in patients with inflammatory rheumatic diseases refractory to standard of care therapy : Data from a nationwide German registry (GRAID2)]. / Sicherheit und Wirksamkeitshinweise zum Off-label-Einsatz von Biologikatherapien nach Versagen konventioneller Therapien bei Patienten mit entzündlich rheumatischen Erkrankungen : Ergebnisse eines nationalen Registers (GRAID2).

BACKGROUND: The German Registry of Autoimmune Diseases 2 (GRAID2) is a retrospective, non-interventional, multicenter registry study collecting data from patients with inflammatory, mainly rheumatic diseases refractory to standard of care therapy and treated with an off-label biologic therapy. The retrospective documentation comprised case history, diagnosis, course of disease (including safety and global efficacy). The objective was to evaluate the global clinical outcome and safety of off-label biologic therapy in clinical practice. RESULTS: Data from 311 patients with an overall observation period of 338.5 patient-years were collected. The mean patients age was 47.8 years with 56.9% females. The most frequently documented diagnoses comprised rejection prophylaxis/therapy after renal transplantation (NTX, 18.3%), ANCA-vasculitides (17.4%), systemic lupus erythematosus (SLE, 10.3%), autoinflammatory fever syndromes (8.4%), autoimmune myositis (7.4%) and pemphigus (5.8%). Documented biologic therapies included rituximab (RTX, 70.1%), tocilizumab (TCZ, 9.3%), infliximab (IFX, 7.1%), anakinra (ANK, 5.5%), adalimumab (ADA, 3.5%), etanercept (ETA, 2.3%) and certolizumab (CTZ, 0.6%). After initiation of off-label biologic treatment, tolerability was assessed by the physicians as "very good"/"good" in 95.5%. Altogether, 275 adverse events were documented and of these, 104 were classified as serious adverse events and occurred in 62 patients. In 19 of these patients severe infections (30.6%) were documented, resulting in a rate of 5.6 severe infections per 100 patient years. A total of six deaths were documented, while five of these cases were rated as not related to the biologics treatment. Notably, the use of RTX in patients with small vessel vasculitides and of TCZ in patients with large vessel vasculitides prior to their approval support their relevance in clinical management of patients with severe diseases. CONCLUSION: The results of this registry together with data of GRAID1 provide evidence that use of off-label biologic therapies in patients with inflammatory rheumatic diseases refractory to conventional treatment did not result in any new safety signal already known for these compounds or subsequently shown by clinical trials in certain entities.

[Pharmacotherapy of psoriatic arthritis. Treatment recommendations against the background of limited evidence]. / Pharmakotherapie der Psoriasisarthritis. Behandlungsempfehlungen vor dem Hintergrund limitierter Evidenzen.

International treatment recommendations for assisting the choice of pharmaceutical treatment of psoriatic arthritis are currently available in two different versions. While the group for research and assessment of psoriasis and psoriatic arthritis (GRAPPA) recommendations mainly focus on both the description of treatment options for the different phenotypes of psoriatic arthritis and the listing of evidence grades, the European League against Rheumatism (EULAR) recommendations try to implement the knowledge about drugs into an algorithm for the different treatment steps. However, the presentation of a treatment algorithm suggests comparable evidence levels for the individual treatment steps, which is at present not the case for psoriatic arthritis. This should be borne in mind for each individual treatment option and treatment step when using a predetermined therapy algorithm and in view of the heterogeneous study results (or no study results available). Both recommendations are currently being revised and will allow the latest evidence trends to be included in the updated version.