1. Steady-State Serum IgG Trough Levels Are Adequate for Pharmacokinetic Assessment in Patients with Immunodeficiencies Receiving Subcutaneous Immune Globulin
- Author
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Barbara McCoy, Werner Engl, Zhaoyang Li, and Leman Yel
- Subjects
medicine.medical_specialty ,Cuvitru ,Primary Immunodeficiency Diseases ,Immunology ,Immunoglobulins ,subcutaneous immunoglobulin ,Trough (economics) ,Gastroenterology ,Immunoglobulin G ,Clinical Trials, Phase II as Topic ,Pharmacokinetics ,Clinical Research ,intravenous immunoglobulin ,Internal medicine ,medicine ,Humans ,Multicenter Studies as Topic ,Immunology and Allergy ,Clinical Trials ,In patient ,Prospective Studies ,Retrospective Studies ,biology ,business.industry ,Phase II as Topic ,Immunologic Deficiency Syndromes ,Immunoglobulins, Intravenous ,medicine.disease ,Phase III as Topic ,Clinical Trials, Phase III as Topic ,Primary immunodeficiency ,biology.protein ,Trough level ,Original Article ,Steady state (chemistry) ,Antibody ,Intravenous ,primary immunodeficiency diseases ,business - Abstract
Patients with primary immunodeficiency diseases often require lifelong immunoglobulin (IG) therapy. Most clinical trials investigating IG therapies characterize serum immunoglobulin G (IgG) pharmacokinetic (PK) profiles by serially assessing serum IgG levels. This retrospective analysis evaluated whether steady-state serum IgG trough level measurement alone is adequate for PK assessment. Based on individual patient serum IgG trough levels from two pivotal trials (phase 2/3 European [NCT01412385] and North American [NCT01218438]) of weekly 20% subcutaneous IG (SCIG; Cuvitru, Ig20Gly), trough level-predicted IgG AUC (AUCτ,tp) were calculated and compared with the reported AUC calculated from serum IgG concentration-time profiles (AUCτ). In both studies, mean AUCτ,tpvalues for Ig20Gly were essentially equivalent to AUCτwith point estimates of geometric mean ratio (GMR) of AUCτ,tp/AUCτnear 1.0 and 90% CIs within 0.80–1.25. In contrast, for IVIG, 10%, mean AUCτ,tpvalues were lower than AUCτby >20%, (GMR [90% CI]: 0.74 [0.70–0.78] and 0.77 [0.73–0.81] for the two studies, respectively). Mean AUCτ,tpvalues calculated for 4 other SCIG products (based on mean IgG trough levels reported in the literature/labels) were also essentially equivalent to the reported AUCτ(differences 20%. In conclusion, steady-state serum IgG levels following weekly SCIG remain stable, allowing for reliable prediction of AUC over the dosing interval using trough IgG levels. These findings indicate that measuring steady-state serum IgG trough levels alone may be adequate for PK assessment of weekly SCIG.
- Published
- 2021