Pharmacokinetics and pharmacodynamics of natalizumab in pediatric patients with RRMS

Therapeutic Advances in Pediatric Multiple Sclerosis

Pediatric-onset multiple sclerosis (POMS) is a chronic, immune-mediated disorder that affects the central nervous system in children and adolescents. Approximately 3-10% of MS patients have an onset that occurs before the age of 18. The vast majority of pediatric MS cases are characterized by a relapsing-remitting course with a high burden of disease activity. Pediatric MS patients were historically treated off-label with varying degrees of success. With the approval of many new therapies for adult-onset MS, alternative treatments in pediatric MS have rapidly started to emerge. In this narrative review, we will discuss therapeutic advancements in pediatric multiple sclerosis, including the seminal trials of PARADIGMS, which evaluated fingolimod use in pediatric MS patients, CONNECT (dimethyl fumarate), TERIKIDS (teriflunomide), OPERETTA I (ocrelizumab), and LEMKIDS (alemtuzumab). We will also review the safety and efficacy of different monoclonal antibodies that are commonly prescribed for multiple sclerosis. We will then examine induction versus escalation treatment strategies and conclude with discussions on treatment considerations in POMS patients.

Analysis of serum natalizumab concentrations obtained during routine clinical care in patients with multiple sclerosis: A cross-sectional study

BACKGROUND

Natalizumab is a humanized monoclonal antibody administered at a fixed dose of 300 mg intravenously or subcutaneously every 4-6 weeks to treat relapsing-remitting multiple sclerosis. In this prospective cross-sectional study, natalizumab serum concentrations obtained during routine healthcare were measured, and the relationships between different routes of administration, sampling times, body characteristics, changes in blood count, and presence of anti-natalizumab antibodies were evaluated.

METHODS

Ninety-two patients were included in this study. Blood samples were collected 0-48 days after administration, and natalizumab serum and anti-natalizumab antibody concentrations, as well as blood counts were measured. Subsequently, patients were divided into three groups according to the collection time after natalizumab administration.

RESULTS

During the entire monitored period, serum natalizumab concentrations ranged from 1.8 to 193.3 µg/mL and 1.8 to 100.3 µg/mL after intravenous and subcutaneous administrations, respectively. A significant inverse correlation was found between serum natalizumab concentrations and differential and absolute peripheral blood neutrophil counts, erythrocyte counts, and hemoglobin concentrations.

CONCLUSION

Although all patients were treated with the same dose, a 30-fold difference in serum natalizumab concentrations was observed. This wide inter-individual variability can potentially lead to an increased risk of natalizumab adverse events or, conversely, suboptimal therapeutic concentrations with the risk of further worsening of multiple sclerosis.

Old and New Strategies in the Treatment of Pediatric Multiple Sclerosis: A Personal View for a New Treatment Approach

Up to 10 years ago the most common approach to the treatment of pediatric MS (ped-MS) was to start with IFNB or GA (so-called first-line therapies or moderate-efficacy disease-modifying therapies [ME-DMTs]) and to switch to more aggressive treatments (or high-efficacy disease-modifying therapies [HE-DMTs]) in non-responder patients. The use of HE-DMTs as first choice was recommended in selected cases with an active, aggressive form of MS. Indications for the treatment of ped-MS were essentially derived from data of observational studies. Recently, results of three randomized clinical trials have been published as well as data from many observational studies evaluating the effect of new and more active DMTs, with clear evidence that HE-DMTs are more effective than ME-DMTs. Therefore, the paradigm of treatment for patients with MS onset before 18 years of age should be changed, offering treatment with HE-DMTs as first option, because of their superior effectiveness to prevent relapses and disease progression. HE-DMTs present an overall reassuring safety profile and obtain better adherence to treatment.

Early use of high efficacy therapies in pediatric forms of relapsing-remitting multiple sclerosis: A real-life observational study

BACKGROUND

Pediatric forms of multiple sclerosis are more active than those in adults. Yet, the effectiveness of different therapeutic approaches is not well studied in this population. Our objective was to compare the effectiveness of the early use of high efficacy therapies (HETs) with the effectiveness of moderate efficacy therapies (METs) in children with MS.

METHODS

This observational study included patients diagnosed with pediatric MS, at 4 hospital centers in France, during a 10-year period. METs included: interferon β-1a, glatiramer acetate, dimethyl fumarate, teriflunomide; HETs included: fingolimod, natalizumab, ocrelizumab, alemtuzumab. The primary endpoint was the occurrence of a new relapse, the secondary endpoint was EDSS worsening.

RESULTS

Sixty-four patients were included in the analysis (80% women; mean age 15.5 years, 81% treated with MET) with a median follow-up of 22.5 months. At baseline, 52 patients were on MET (interferon β-1a, glatiramer acetate, dimethyl fumarate, teriflunomide) and 12 patients were on HET (natalizumab, ocrelizumab). The cumulative probability of being relapse-free at 6.5 years was 23.3% on MET, vs 90.9% on HET (p = 0.013). The cumulative probability of no EDSS worsening did not differ between the 2 groups.

CONCLUSION

Patients starting with METs had much higher clinical disease activity than those starting early with HETs. Rapid initiation of more aggressive treatment may allow better disease control; however, the data on EDSS worsening are not conclusive.

Current Status of Pharmacokinetic Research in Children: A Systematic Review of Clinical Trial Records

BACKGROUND

Many medications have different pharmacokinetics in children than in adults. Knowledge about the safety and efficacy of medications in children requires research into the pharmacokinetic profiles of children's medicines. By analysing registered clinical trial records, this study determined how frequently pharmacokinetic data is gathered in paediatric drug trials.

METHODS

We searched for the pharmacokinetic data from clinical trial records for preterm infants and children up to the age of 16 from January 2011 to April 2022. The records of trials involving one or more drugs in preterm infants and children up to the age of 16 were examined for evidence that pharmacokinetic data would be collected.

RESULTS

In a total of 1483 records of interventional clinical trials, 136 (9.17%) pharmacokinetic data involved adults. Of those 136 records, 60 (44.1%) records were pharmacokinetics trials involving one or more medicines in children up to the age of 16.20 (33.3%) in America, followed by 19 (31.6%) in Europe. Most trials researched medicines in the field of infection or parasitic diseases 20 (33.3%). 27 (48.2%) and 26 (46.4%) trials investigated medicines that were indicated as essential medicine.

CONCLUSION

The pharmacokinetic characteristics of children's drugs need to be better understood. The current state of pharmacokinetic research appears to address the knowledge gap in this area adequately. Despite slow progress, paediatric clinical trials have experienced a renaissance as the significance of paediatric trials has gained international attention. The outcome of paediatric trials will have an impact on children's health in the future. In recent years, the need for greater availability and access to safe child-size pharmaceuticals has received a lot of attention.

Effect of natalizumab treatment on the rate of No Evidence of Disease Activity in young adults with multiple sclerosis in relation to pubertal stage

Approximately 40% of young-onset multiple sclerosis (MS) patients experience breakthrough disease, which carries a high risk for long-term disability, and requires using therapies beyond traditional first-line agents. Despite the increasing use of newer disease-modifying treatments (DMTs) in this population, data are not available to guide the need for escalating DMTs and there is a scarcity of data on the effects of natalizumab in children and young adults with active disease. We performed a retrospective analysis of the rate of No Evidence of Disease Activity (NEDA), tolerability, and safety of natalizumab in a multi-center cohort of 36 children and young adults with highly active MS. All patients had active disease and initiated treatment with natalizumab. The primary endpoint was the rate of achieving NEDA-3 status, within two years of natalizumab treatment. To examine a possible effect of age on the outcome of treatment, outcomes were also analyzed by pre-pubertal (n = 13 children aged 9-13 years) and pubertal subgroups (n = 23 young adolescents aged 14-20 years). The NEDA-3 status of the pre-pubertal group was 92% in the first and second year and in the pubertal group - 96% in the first year and 92% in the second year. Natalizumab reduced the number and volume of brain lesions in both pre-pubertal and pubertal groups. Treatment was well-tolerated, only 8 patients (22.2%) had adverse events during the 2-year study period. Our analysis shows that natalizumab is effective and well-tolerated in pre-pubertal and pubertal MS patients.

Multiple Sclerosis in Children: Differential Diagnosis, Prognosis, and Disease-Modifying Treatment

Pediatric-onset multiple sclerosis (POMS) is a rare neuroinflammatory and neurodegenerative disease that has a significant impact on long-term physical and cognitive patient outcomes. A small percentage of multiple sclerosis (MS) diagnoses occur before the age of 18 years. Before treatment initiation, a careful differential diagnosis and exclusion of other similar acquired demyelinating syndromes such as anti-aquaporin-4-associated neuromyelitis optica spectrum disorder (AQP4-NMOSD) and myelin oligodendrocyte glycoprotein antibody spectrum disorder (MOGSD) is warranted. The recent 2017 changes to the McDonald criteria can successfully predict up to 71% of MS diagnoses and have good specificity of 95% and sensitivity of 71%. Additional measures such as the presence of T1-weighted hypointense lesions and/or contrast-enhancing lesions significantly increase the accuracy of diagnosis. In adults, early use of disease-modifying therapies (DMTs) is instrumental to a better long-term prognosis, including lower rates of relapse and disability worsening, and numerous FDA-approved therapies for adult-onset MS are available. However, unlike their adult counterparts, the development, testing, and regulatory approval of POMS treatments have been significantly slower and hindered by logistic and/or ethical considerations. Currently, only two MS DMTs (fingolimod and teriflunomide) have been tested in large phase III trials and approved by regulatory agencies for use in POMS. First-line therapies not approved by the FDA for use in children (interferon-β and glatiramer acetate) are also commonly used and result in a significant reduction in inflammatory activity when compared with non-treated POMS patients. An increasing number of POMS patients are now treated with moderate efficacy therapies such as dimethyl fumarate and high-efficacy therapies such as natalizumab, anti-CD20 monoclonal antibodies, anti-CD52 monoclonal antibodies, and/or autologous hematopoietic stem cell transplantation. These high-efficacy DMTs generally provide additional reduction in inflammatory activity when compared with the first-line medications (up to 62% of relapse-rate reduction). Therefore, a number of phase II and III trials are currently investigating their efficacy and safety in POMS patients. In this review, we discuss potential changes in the regulatory approval process for POMS patients that are recommended for DMTs already approved for the adult MS population, including smaller sample size for pharmacokinetic/pharmacodynamic studies, MRI-centered primary outcomes, and/or inclusion of teenagers in the adult trials.

Extended dosing of monoclonal antibodies in multiple sclerosis

Over the past two decades, treatment options for patients with multiple sclerosis (MS) have increased exponentially. In the current therapeutic landscape, "no evidence of MS disease activity" is within reach in many of our patients. Minimizing risks of complications, improving treatment convenience, and decreasing health care costs are goals that are yet to be reached. One way to optimize MS therapy is to implement personalized or extended interval dosing. Monoclonal antibodies are suitable candidates for personalized dosing (by therapeutic drug monitoring) or extended interval dosing. An increasing number of studies are performed and underway reporting on altered dosing intervals of anti-α₄β₁-integrin treatment (natalizumab) and anti-CD20 treatment (ocrelizumab, rituximab, and ofatumumab) in MS. In this review, current available evidence regarding personalized and extended interval dosing of monoclonal antibodies in MS is discussed with recommendations for future research and clinical practice.

Therapy of Pediatric-Onset Multiple Sclerosis: State of the Art, Challenges, and Opportunities

Treatment of pediatric-onset multiple sclerosis (POMS) has been tailored after observational studies and data obtained from clinical trials in adult-onset multiple sclerosis (AOMS) patients. There are an increasing number of new therapeutic agents for AOMS, and many will be formally studied for use also in POMS. However, there are important efficacy and safety concerns regarding the use of these therapies in children and young adults. This review will discuss the current state of the art of POMS therapy and will focus on the newer therapies (oral and infusion disease-modifying drugs) and on those still currently under investigation.

Early Predictors of 9-Year Disability in Pediatric Multiple Sclerosis

OBJECTIVE

The purpose of this study was to assess early predictors of 9-year disability in pediatric patients with multiple sclerosis.

METHODS

Clinical and magnetic resonance imaging (MRI) assessments of 123 pediatric patients with multiple sclerosis were obtained at disease onset and after 1 and 2 years. A 9-year clinical follow-up was also performed. Cox proportional hazard and multivariable regression models were used to assess independent predictors of time to first relapse and 9-year outcomes.

RESULTS

Time to first relapse was predicted by optic nerve lesions (hazard ratio [HR] = 2.10, p = 0.02) and high-efficacy treatment exposure (HR = 0.31, p = 0.005). Predictors of annualized relapse rate were: at baseline, presence of cerebellar (β = -0.15, p < 0.001), cervical cord lesions (β = 0.16, p = 0.003), and high-efficacy treatment exposure (β = -0.14, p = 0.01); considering also 1-year variables, number of relapses (β = 0.14, p = 0.002), and the previous baseline predictors; considering 2-year variables, time to first relapse (2-year: β = -0.12, p = 0.01) entered, whereas high-efficacy treatment exposure exited the model. Predictors of 9-year disability worsening were: at baseline, presence of optic nerve lesions (odds ratio [OR] = 6.45, p = 0.01); considering 1-year and 2-year variables, Expanded Disability Status Scale (EDSS) changes (1-year: OR = 26.05, p < 0.001; 2-year: OR = 16.38, p = 0.02), and ≥ 2 new T2-lesions in 2 years (2-year: OR = 4.91, p = 0.02). Predictors of higher 9-year EDSS score were: at baseline, EDSS score (β = 0.58, p < 0.001), presence of brainstem lesions (β = 0.31, p = 0.04), and number of cervical cord lesions (β = 0.22, p = 0.05); considering 1-year and 2-year variables, EDSS changes (1-year: β = 0.79, p < 0.001; 2-year: β = 0.55, p < 0.001), and ≥ 2 new T2-lesions (1-year: β = 0.28, p = 0.03; 2-year: β = 0.35, p = 0.01).

INTERPRETATION

A complete baseline MRI assessment and an accurate clinical and MRI monitoring during the first 2 years of disease contribute to predict 9-year prognosis in pediatric patients with multiple sclerosis. ANN NEUROL 2021;89:1011-1022.

The introduction of new medications in pediatric multiple sclerosis: Open issues and challenges

Disease-modifying drugs (DMDs) for multiple sclerosis (MS) have been evaluated in pediatric patients in observational studies demonstrating a similar, even better clinical effect compared to adults, with a similar safety. Only fingolimod has been tested in a randomized controlled trial (RCT) and is approved for pediatric multiple sclerosis (ped-MS). Numerous methodological, practical, and ethical issues underline that RCTs are difficult to conduct in ped-MS. This also creates a lack of safety information. To facilitate the availability of new agents in ped-MS, we encourage to develop a different approach based on pharmacokinetic/pharmacodynamic studies to yield information on optimal doses and implementation of obligatory registries to obtain information on safety as primary endpoint.