Information contributed by meta-analysis in exposure–response modeling: application to phase 2 dose selection of guselkumab in patients with moderate-to-severe psoriasis

Ustekinumab, a human immunoglobulin G1 kappa (IgG1κ) monoclonal antibody that binds with high affinity to human interleukin (IL)-12 and IL-23, has been approved to treat patients with psoriasis. Guselkumab is a related human IgG1 monoclonal antibody in clinical development which specifically blocks IL-23. The objective of this study was to study the exposure–response relationship of guselkumab to guide dose selection for a Phase 2 study in patients with moderate-to-severe psoriasis. Data were available from a Phase 1 study of 47 healthy subjects and 24 patients with psoriasis who received various doses of guselkumab. Disease severity was assessed using Psoriasis Area and Severity Index (PASI) scores in all studies. Individual pharmacokinetic parameters were derived from population pharmacokinetics modeling for the purpose of exposure–response modeling to guide dosing regimen selection. A population mechanism-based exposure–response model of guselkumab was developed to evaluate the association of guselkumab dosing with PASI scores using a Type I indirect response model, with placebo effect empirically modeled. The model was subsequently updated, first by incorporating data from psoriasis patients who received placebo (n = 765) and from patients actively treated with ustekinumab 45 or 90 mg (n = 1,230) in two ustekinumab Phase 3 trials. Inclusion of this additional ustekinumab data and the consequent contributions to specific model components substantially reduced uncertainties in all model components except for one parameter. Additional sensitivity analyses showed that the dose selection decision was robust to this remaining uncertainty. The described approach underscores the importance of utilizing all available sources of information in dose selection decisions, along with the importance of effective development team interaction.     

Cancer risk of immunosuppressants in manufacturing

During the chemical and pharmaceutical production of active pharmaceutical substances which are intended for immunosuppressive therapy, the employees may be exposed to these substances via inhalation. Immunosuppressants are linked to development of certain types of cancers e.g., lymphoma or skin cancer in transplant patients. The development of these cancers in patients is linked to the level of immunosuppression needed for transplantation in order to avoid organ rejection. Below these levels, with the immune system functioning uninhibited, cancer is unlikely to develop.     

A new efficient tool for non-invasive diagnosis of fetomaternal platelet antigen incompatibility

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is the consequence of platelet destruction by maternal alloantibodies against fetal human platelet antigens (HPA). This may result in intracranial haemorrhages (ICH) or even fetal death. Currently, fetal HPA genotyping is performed using invasive procedures. Here, we carried out a proof-of-concept study for non-invasive prenatal diagnosis of fetal platelet genotyping in four HPA systems (HPA-1, -3, -5 and-15) by droplet digital polymerase chain reaction (ddPCR) using cell-free DNA extracts from the plasma of 47 pregnant women with suspected, or history of, FNAIT. Results showed that 74% (35/47) of pregnant women presented incompatibility in at least one HPA system, and 38% (18/47) of cases presented HPA-1 incompatibility, including nine women with multiple incompatibilities. ICH occurred in one case of profound fetal thrombocytopenia with HPA-15 incompatibility, confirming the need for non-invasive prenatal genotyping in systems other than HPA-1. Fetal HPA genotypes predicted by ddPCR were confirmed in all FNAIT cases after amniocentesis or delivery. Fetal HPA genotyping on maternal plasma based on ddPCR is a fast, safe and reliable non-invasive method. This technique will be useful for the early identification of pregnancies at high risk of FNAIT requiring antenatal management to minimize the risk of fetal/neonatal haemorrhage.     

Are the Effects of High-Intensity Exercise Training Different in Patients with COPD Versus COPD+Asthma Overlap?

Purpose

This study aimed to investigate whether patients with chronic obstructive pulmonary disease (COPD) presenting asthma overlap (ACO) benefit similarly in comparison to patients with only COPD after a 12-week high-intensity exercise training (ET) program.

Methods

Subjects with a diagnosis of COPD alone or ACO were evaluated and compared before and after a high-intensity ET program composed of walking and cycling plus strengthening exercises of the upper and lower limbs (3 days/week, 3 months, 36 sessions). Assessments included spirometry, bioelectrical impedance, 6-min walk test (6MWT), London Chest Activity of Daily Living Scale (LCADL), Hospital anxiety and depression Scale, modified Medical Research Council Scale (mMRC), Saint George Respiratory Questionnaire (SGRQ), and respiratory and peripheral muscle strength [manovacuometry and 1-repetition maximum test (quadriceps femoris, biceps and triceps brachialis), respectively]. ACO was defined according to Sin et al. (Eur Respir J 48(3):664-673, 2016).

Results

The sample was composed of 74 subjects (57% male, age 67 ± 8 years, BMI 26 (21–32) kg/m², FEV₁ 47 ± 17%predicted), and 12 (16%) of them were classified as presenting ACO. Both groups improved pulmonary function, 6MWT, peripheral and inspiratory muscle strength, LCADL, and SGRQ after ET (p < 0.005 for all). There were no significant interactions between ACO and COPD on ET effects (p > 0.05 for all). Likewise, there was no difference in the proportion of patients achieving the minimum clinical important difference for 6MWT and mMRC.

Conclusion

High-intensity exercise training generates similar benefits in patients with COPD regardless of whether presenting asthma overlap or not.

     

The activation pattern of macrophages in giant cell (temporal) arteritis and primary angiitis of the central nervous system

To determine if the pattern of macrophage activation reflects differences in the pathogenesis and clinical presentation of giant cell arteritis and primary angiitis of the central nervous system, specimens of 10 patients with giant cell arteritis and five with primary angiitis of the central nervous system were immunohistochemically studied and the expression of the macrophage activation markers 27E10, MRP14, MRP8 and 25F9 was determined in the vasculitic infiltrates. Thus, a partly different expression pattern of macrophage activation markers in giant cell arteritis and primary angiitis of the central nervous system was observed. The group comparison revealed that giant cell arteritis cases had significantly higher numbers of acute activated MRP14‐positive macrophages, whereas primary angiitis of the central nervous system is characterized by a tendency toward more MRP8‐positive intermediate/late activated macrophages. Furthermore, in giant cell arteritis comparably fewer CD8‐positive lymphocytes were observed. These observations suggest, that despite their histopathological similarities, giant cell arteritis and primary angiitis of the central nervous system appear to represent either distinct entities within the spectrum of granulomatous vasculitides or different stages of similar disease processes. Their discrete clinical presentation is reflected by different activation patterns of macrophages, which may characterize giant cell arteritis as a more acute process and primary angiitis of the central nervous system as a more advanced inflammatory process.