Current Practice of Therapeutic Drug Monitoring of Biopharmaceuticals in Psoriasis Patients

Clinical pharmacokinetics and pharmacodynamics of oral systemic nonbiologic therapies for psoriasis patients

INTRODUCTION

Psoriasis is a chronic inflammatory immune condition. Treatments for psoriasis vary with disease severity, ranging from topicals to systemic biologic agents. The pharmacokinetic (PK) and pharmacodynamic (PD) properties of these therapies establish drug efficacy, toxicity, and optimal dosing to ensure therapeutic drug levels are sustained and adverse effects are minimized.

AREAS COVERED

A literature search was performed on PubMed, Google Scholar, and Ovid MEDLINE for PK and PD, efficacy, and safety data regarding oral systemic nonbiologic therapies utilized for moderate-to-severe plaque psoriasis. The findings were organized into sections for each drug: oral acitretin, methotrexate, cyclosporine, apremilast, tofacitinib, and deucravacitinib.

EXPERT OPINION

Some psoriasis patients may not respond to initial therapy. Ongoing research is evaluating genetic polymorphisms that may predict an improved response to specific medications. However, financial and insurance barriers, as well as limited genetic polymorphisms correlated with treatment response, may restrict the implementation of genetic testing necessary to personalize treatments. How well psoriasis patients adhere to treatment may contribute greatly to variation in response. Therapeutic drug monitoring may help patients adhere to treatment, improve clinical response, and sustain disease control.

Real-world use of ustekinumab therapeutic drug monitoring in moderate to severe psoriasis

Introduction

There is growing evidence that therapeutic drug monitoring of biologic therapy is beneficial in psoriatic patients. With respect to ustekinumab, the available evidence has not shown any relationship yet. The objective of this study is to identify correlations among ustekinumab trough concentrations, anti-ustekinumab antibodies and clinical response in moderate-to-severe plaque psoriasis patients, in a real-world setting.

Methods

Observational prospective follow-up study in psoriatic patients treated with ustekinumab. Patients were classified in optimal (PASI ≤ 3) and suboptimal responders (PASI > 3). Mann-Whitney U test and Spearman's rank correlation coefficient were used. Receiver-operator characteristic curve analysis was performed to identify ustekinumab concentration cut-off to achieve optimal response. A p-value < 0.05 was considered statistically significant.

Results

A total of 59 patients were included. Forty-eight patients (81.4%) corresponded to optimal responders and 11 (18.6%) to suboptimal responders. There was significant difference to ustekinumab concentrations: 0.7 μg/mL (range <0.1-1.8) vs. 0.4 μg/mL (range <0.1-0.8) respectively (p = 0.007). Positive correlation between ustekinumab concentration and psoriasis area and severity index (PASI) value was detected (p = 0.009). A cut-off value of 0.6 μg/mL ustekinumab concentration was found to achieve clinical response. Anti-ustekinumab antibodies were detected in 2 (3.4%) samples, both suboptimal responders.

Conclusion

A positive correlation exits between ustekinumab concentration and clinical response (optimal response PASI values ≤ 3) in blood draws performed before drug administration. The measurement of anti-ustekinumab antibodies could be considered in treatment failure.

The Evolving Role of Microsampling in Therapeutic Drug Monitoring of Monoclonal Antibodies in Inflammatory Diseases

Monoclonal antibodies (mAbs) have been extensively developed over the past few years, for the treatment of various inflammatory diseases. They are large molecules characterized by complex pharmacokinetic and pharmacodynamic properties. Therapeutic drug monitoring (TDM) is routinely implemented in the therapy with mAbs, to monitor patients’ treatment response and to further guide dose adjustments. Serum has been the matrix of choice in the TDM of mAbs and its sampling requires the visit of the patients to laboratories that are not always easily accessible. Therefore, dried blood spots (DBS) and various microsampling techniques have been suggested as an alternative. DBS is a sampling technique in which capillary blood is deposited on a special filter paper. It is a relatively simple procedure, and the patients can perform the home-sampling. The convenience it offers has enabled its use in the quantification of small-molecule drugs, whilst in the recent years, studies aimed to develop microsampling methods that will facilitate the TDM of mAbs. Nevertheless, hematocrit still remains an obstacle that hinders a more widespread implementation of DBS in clinical practice. The introduction of novel analytical techniques and contemporary microsampling devices can be considered the steppingstone to the attempts made addressing this issue.

Dermatologists on the medical need for therapeutic drug monitoring of biologics in psoriasis: results of a structured survey

BACKGROUND

Therapeutic drug monitoring (TDM) may lead to more rational use of biologics. Still, TDM is largely underexplored in psoriasis. Little is known about the dosing behavior of biologics by dermatologists, and their attitude toward TDM.

OBJECTIVE

Exploration of the awareness and need for the concept of TDM in psoriasis amongst (inter)national dermatologists.

METHOD

A survey was distributed at the Belgian Dermatology Days 2019 and Skin Inflammation & Psoriasis International Network (SPIN) Congress 2019. Next, an online survey version was launched amongst the SPIN Scientific Committee members. We collected physician's characteristics, prescription behavior of biologics, data regarding clinical response to biologics and attitude toward TDM.

RESULTS

A total of 107 surveys were included for analysis. Most dermatologists were Belgium-based (54.2%), others from European (23.4%) or non-European countries (19.6%). Seventy percent performed either dose increase (64.8%), time interval shortening (74.6%), dose lowering (16.9%) or time interval extension (33.8%). The majority who performed dose adaptations acknowledged the need for TDM.

CONCLUSION

This study showed most dermatologists perform dose adaptations empirically. The need for TDM was indicated by the majority, implying the need for effective communication regarding availability, utility and implementation of TDM assays in daily dermatology practice.

Development and validation of immunoassays for monitoring of guselkumab and anti-guselkumab antibodies in patients with moderate-to-severe psoriasis

Therapeutic drug monitoring, which is the measurement of drug concentrations in the blood, is a useful tool to guide clinical decision-making and treatment adjustments, on the condition that drug concentrations are correlated with treatment response. For guselkumab, an anti-IL-23 monoclonal antibody for the treatment of moderate-to-severe psoriasis, such a concentration-response relationship could not yet be determined as no commercial assays for the quantification of this drug or antibodies against this drug are available. Therefore, the aim of this study was to develop and validate immunoassays for the quantification of guselkumab and anti-guselkumab antibodies according to the guidelines of the European Medicines Agency (EMA). A diverse panel of 20 highly specific anti-guselkumab monoclonal antibodies (MA-GUS) was generated of which eight revealed a neutralizing capacity of ≥65 %. At least seven different antibody clusters were identified based on their epitope binning profile. Using MA-GUS9F6 as the capture antibody and MA-GUS12G12 as the detection antibody, an ELISA was developed with a dose-response curve ranging from 0.08 to 5 ng/mL. The assay was specific, selective and could accurately and precisely quantify guselkumab concentrations in spiked healthy control serum and serum from guselkumab-treated psoriasis patients with a cut-off for quantification of 0.014 μg/mL. The presence of IL-23 in physiological concentrations or of non-neutralizing antibodies did not impact the quantification of guselkumab, while the presence of neutralizing antibodies did. Using MA-GUS12A9 as a calibrator, two anti-guselkumab antibody assays were developed to detect anti-guselkumab antibodies, which differ in the threshold for detection and quantification and the tolerance to the presence of guselkumab. Together, these validated immunoassays are essential to establish a concentration-response relationship and will allow the future implementation of therapeutic drug monitoring in moderate-to-severe psoriasis patients receiving guselkumab treatment.

Small molecules under development for psoriasis: on the road to the individualized therapies

Psoriasis is an incurable cutaneous illness characterized by the presence of well-delimited reddish plaques and silvery-white dry scales. So far, there is a limited understanding of its pathogenesis, though recent discoveries on the immunological, genetic and molecular aspects of this disease have significantly contributed to the identification of new targets and the development of novel drugs. Despite these advances, many patients are still dissatisfied, so to improve patient satisfaction, reliability, and clinical outcomes, the individualization of the treatments for this disease becomes a necessity. This review summarizes recent findings related to psoriasis pathogenesis and describes new small molecules and targets recently identified as promising for treatments. Additionally, the current status, challenges and the future directions for achieving individualized therapy for this disease and the need for more collaborative studies are discussed. The individualization of treatments for psoriasis, rather than a goal, is analyzed as a process where a dynamic integration between the needs and characteristics of the patients, the pharmacological progress, and the clinical decisions takes place.

Association between infliximab concentrations and clinical response in psoriasis: a prospective cohort study

BACKGROUND

Infliximab (IFX) trough concentrations (C_min) have been linked to treatment efficacy in psoriatic patients. Inter-individual IFX C_min variability and factors influencing IFX pharmacokinetics could explain differences in treatment response.

OBJECTIVE

To evaluate the association between IFX C_min and clinical outcomes in psoriatic patients.

METHODS

Prospective study of 33 patients with moderate to severe psoriasis receiving IFX at Bellvitge University Hospital, between October 2013 and November 2016. IFX C_min and antibodies toward infliximab (ATI) were measured.

RESULTS

We collected 155 IFX C_min and ATI values (mean age, 46 (14) years; 11 (33.3%) women). Mean IFX C_min was 2.5 (2.4) mg/L and ATIs were detected in six patients, resulting in undetectable IFX C_min. IFX C_min was significantly associated with ATI and body mass index (BMI) (β -2.51, 95% CI -3.56 to -1.4 and β -0.05, 95% CI -0.09 to -0.01). PASI score and PASI 90/100 response were significantly associated with IFX C_min (IRR 0.80, 95% CI 0.70 to 0.92; OR 1.79, 95% CI 1.18 to 2.71 and OR 1.79, 95% CI 1.14 to 2.81).

CONCLUSION

IFX C_min significantly influences PASI 90/100 response rates. IFX C_min wa significantly associated with ATI and BMI. The observed inter-individual variability in IFX C_min supports the need for IFX drug monitoring.

Clinical response correlates with 4-week postinjection ustekinumab concentrations in patients with moderate-to-severe psoriasis

Background

Cost‐effective use of biologicals is important. As drug concentrations have been linked to clinical outcomes, monitoring drug concentrations is a valuable tool to guide clinical decision‐making. A concentration–response relationship for ustekinumab at trough is uncertain owing to the contradictory results reported.

Objectives

To investigate the relationship between 4‐week postinjection ustekinumab concentrations and clinical response in patients with psoriasis.

Methods

Forty‐nine patients with moderate‐to‐severe psoriasis treated with 45 mg or 90 mg ustekinumab every 12 weeks for ≥ 16 weeks were included. Ustekinumab serum concentrations and anti‐ustekinumab antibodies were measured at week 4 after injection and disease severity was assessed by Psoriasis Area and Severity Index (PASI).

Results

At week 4 after injection, a significantly negative correlation was observed between ustekinumab concentrations and absolute PASI score up to 5·9 μg mL⁻¹ (ρ = –0·357, P = 0·032). Ustekinumab concentrations were higher in optimal responders (PASI ≤ 2) than in suboptimal responders (PASI > 2) (4·0 vs 2·8 μg mL⁻¹, P = 0·036). The ustekinumab concentration threshold associated with optimal response was determined to be 3·6 μg mL⁻¹ (area under the curve 0·71, sensitivity 86%, specificity 63%). Only one patient (2%) had anti‐ustekinumab antibodies. Psoriatic arthritis was identified as an independent predictor of higher PASI scores and higher ustekinumab concentrations (P = 0·003 and P = 0·048, respectively).

Conclusions

A concentration–response relationship at week 4 after injection was observed for patients with psoriasis treated with ustekinumab. Monitoring 4‐week postinjection ustekinumab concentrations could timely identify underexposed patients who might benefit from treatment optimization.

What's already known about this topic?

Monitoring drug concentrations is a valuable tool that can guide clinical decision‐making when drug concentrations are linked to clinical outcomes.

The presence of a concentration–response relationship for ustekinumab at trough is still debated owing to the contradictory results reported.

What does this study add?

A concentration–response relationship at week 4 after injection for ustekinumab‐treated patients with psoriasis was demonstrated.

Monitoring 4‐week postinjection ustekinumab concentrations could timely identify underexposed patients who might benefit from treatment optimization.

Based on the findings of this study, a treatment algorithm for patients with a suboptimal response is proposed.

Linked Comment: https://doi.org/10.1111/bjd.18709.

https://doi.org/10.1111/bjd.18709 available online

Biopharmaceuticals: Reference Products and Biosimilars to Treat Inflammatory Diseases

Biopharmaceuticals are primarily therapeutic proteins developed to perform specific functions by acting on the disease pathophysiology. Compared with low-molecular chemically synthesized drugs, production of biopharmaceuticals is much more complex and routes of administration and pharmacokinetics differ. Biopharmaceuticals are blockbusters in the treatment of inflammatory diseases, such as psoriasis, multiple sclerosis, rheumatic diseases, and inflammatory bowel diseases, and the introduction of these drugs has revolutionized treatment. Disadvantages include their high costs and the fact that they can evoke antidrug antibodies leading to decreased efficacy. Treatment can be optimized through the development of dosing algorithms and cost can be reduced by biosimilars, after a comparable biological activity, safety, and efficacy have been demonstrated.

Current Practice for Therapeutic Drug Monitoring of Biopharmaceuticals in Rheumatoid Arthritis

The treatment of rheumatoid arthritis (RA) has largely improved in the biopharmaceutical era. These compounds, primarily tumor necrosis factor (TNF) inhibitors, are effective, but some patients may show poor response, sometimes because of the presence of antidrug antibodies (ADAs). In some instances, clinicians may increase or taper the dose depending on the clinical response. Besides the current clinical-based practice, a tailored strategy based on drug monitoring has emerged as a way to improve the use of these drugs. However, the relevance of this therapeutic drug monitoring (TDM) of biopharmaceuticals in RA is still unknown. In this literature review, we examine the most relevant articles dealing with the concentration-response relationship, ADA detection and pharmacokinetics in RA patients receiving biopharmaceuticals. A concentration-response relationship was clearly established for TNF inhibitors. Moreover, ADA positivity was associated with low drug concentrations, poor clinical outcome, and reduced drug survival for TNF-inhibitor monoclonal antibodies. Concomitant use of disease-modifying antirheumatic drugs, especially methotrexate, is associated with good clinical outcome, increased drug concentrations, and reduced immunogenicity. Strategies based on TDM of TNF inhibitors seem promising for RA, but randomized controlled trials are required to support this. A concentration-response relationship may exist with tocilizumab, and immunogenicity seems rare. Finally, the relevance of TDM for RA patients receiving rituximab and abatacept remains unclear.

Practical recommendations for the use of therapeutic drug monitoring of biopharmaceuticals in inflammatory diseases

Biopharmaceuticals directed against tumor necrosis factor-alpha, integrins, interleukins, interferons and their receptors have become key agents for the management of inflammatory diseases in the fields of gastroenterology, rheumatology, dermatology and neurology. However, response to these treatments is far from optimal. Therapeutic failure has been attributed in part to inadequate serum concentrations of the drug and the formation of antidrug antibodies (ADA). Therapeutic drug monitoring (TDM) based on drug concentrations and ADA represents a pharmacologically sound tool for guiding dosage adjustments to optimize exposure. Although becoming standard practice in tertiary care centers, the widespread accessibility and recognition of TDM is hindered by several hurdles, including a lack of education of health care providers on TDM. In this paper, the Monitoring of monoclonal Antibodies Group in Europe (MAGE) provides an introduction on the fundamental principles of the concept of TDM, aiming to educate clinicians and assist them in the process of implementing TDM of anti-inflammatory biopharmaceuticals.