Safety and efficacy of cladribine tablets in patients with relapsing-remitting multiple sclerosis: Results from the randomized extension trial of the CLARITY study

Updates and advances in multiple sclerosis neurotherapeutics

The multiple sclerosis (MS) neurotherapeutic landscape is rapidly evolving. New disease-modifying therapies (DMTs) with improved efficacy and safety, in addition to an expanding pipeline of agents with novel mechanisms, provide more options for patients with MS. While treatment of MS neuroinflammation is well tailored in the existing DMT armamentarium, concerted efforts are currently underway for identifying neuropathological targets and drug discovery for progressive MS. There is also ongoing research to develop agents for remyelination and neuroprotection. Further insights are needed to guide DMT initiation and sequencing as well as to determine the role of autologous stem cell transplantation in relapsing and progressive MS. This review provides a summary of these updates.

Real-world experience of cladribine treatment in relapsing-remitting multiple sclerosis: A Danish nationwide study

BACKGROUND

Cladribine is a nucleoside analogue interfering with synthesis and repair of DNA. Treatment with cladribine leads to a preferential reduction in lymphocytes, resulting in profound depletion of B-cells with a rapid recovery of naïve B-cells, while T-cell show a lesser but long-lasting depletion It is approved for treatment of relapsing multiple sclerosis (MS). Cladribine tablets 3.5 mg/kg bodyweight are administered in two yearly treatment courses, each including two treatment series lasting 4 or 5 days, one at the start of the first month and the other at the start of the second month.

OBJECTIVE

To describe treatment patterns of cladribine in a real-world setting.

METHODS

Registry based observational cohort study with prospectively enrolled cases from December 2017 through June 2021. The data source is The Danish Multiple Sclerosis Registry, which is a near complete nationwide population-based registry. Outcomes were length of the treatment, preceding and following treatments, treatment response, and safety data.

RESULTS

In total 268 patients had started therapy with cladribine tablets, 89 men and 179 women, with a median age of 40 years (interquartile range (IQR) 32-48. The disease course was relapsing-remitting MS in 97.8% of the patients, and at treatment start the median time from disease onset was 8.1 years (IQR 4.2-14.5) and EDSS 2.5 (IQR 1.5-3.5). Thirty-four patients (12.7%) were treatment naïve while 56 (20.9%) had received one previous disease-modifying therapy (DMT), 67 (25.0%) two, and 111 (41.4%) three or more previous DMTs. In total, 214 (80.0%) patients had completed the full treatment of two courses of cladribine, while 54 (20.0%) had received only one course of cladribine tablets. The median follow-up time after cladribine initiation was 34.7 months (IQR 23.3-43.7). Compared with an annualized relapse rate (ARR) of 0.67 (95% CI [0.56, 0.79]) in the year prior to start of cladribine, ARR was reduced to 0.11 (95% CI [0.08, 0.15]) in year 0-2 after 3-month re-baseline with cladribine (84.8% reduction). Adverse events, reported in 44 (16.4%) of the patients, were mild or moderate, and herpes zoster was only reported in 2 patients. In total, 30 (11.2%) patients discontinued cladribine treatment, of whom 7 (2.6%) discontinued because of adverse effects and 12 (4.5%) discontinued because of disease activity.

CONCLUSION

In this nationwide review of all Danish patients starting therapy with cladribine tablets in a real-world setting, cladribine treatment was safe, and the therapeutic response was as expected from previous clinical trials. A prolonged observation period is necessary to assess the long-term benefit and risk of cladribine.

Cost-effectiveness of cladribine tablets and dimethyl fumarate in the treatment of relapsing remitting multiple sclerosis in Spain

Aim: To analyze the cost-effectiveness of treatment of relapsing remitting multiple sclerosis (RRMS) with cladribine tablets (CladT) and dimethyl fumarate (DMF) from the perspective of the Spanish National Health System (NHS). Methods: A probabilistic Markov model (second-order Monte Carlo simulation) with a 10-year time horizon and annual Markov cycles was performed. Results: CladT was the dominant treatment, with lower costs (-74,741 € [95% CI: -67,247; -85,661 €]) and greater effectiveness (0.1920 [95% CI: -0.1659; 0.2173] QALY) per patient, compared with DMF. CladT had a 95.1% probability of being cost-effective and a 94.1% chance of being dominant compared with DMF. Conclusion: CladT is the dominant treatment (lower costs, with more QALYs) compared with DMF in the treatment of RRMS in Spain.

Comparative effectiveness of cladribine tablets versus other oral disease-modifying treatments for multiple sclerosis: Results from MSBase registry

BACKGROUND

Effectiveness of cladribine tablets, an oral disease-modifying treatment (DMT) for multiple sclerosis (MS), was established in clinical trials and confirmed with real-world experience.

OBJECTIVES

Use real-world data to compare treatment patterns and clinical outcomes in people with MS (pwMS) treated with cladribine tablets versus other oral DMTs.

METHODS

Retrospective treatment comparisons were based on data from the international MSBase registry. Eligible pwMS started treatment with cladribine, fingolimod, dimethyl fumarate, or teriflunomide tablets from 2018 to mid-2021 and were censored at treatment discontinuation/switch, death, loss to follow-up, pregnancy, or study period end. Treatment persistence was evaluated as time to discontinuation/switch; relapse outcomes included time to first relapse and annualized relapse rate (ARR).

RESULTS

Cohorts included 633 pwMS receiving cladribine tablets, 1195 receiving fingolimod, 912 receiving dimethyl fumarate, and 735 receiving teriflunomide. Individuals treated with fingolimod, dimethyl fumarate, or teriflunomide switched treatment significantly more quickly than matched cladribine tablet cohorts (adjusted hazard ratio (95% confidence interval): 4.00 (2.54-6.32), 7.04 (4.16-11.93), and 6.52 (3.79-11.22), respectively). Cladribine tablet cohorts had significantly longer time-to-treatment discontinuation, time to first relapse, and lower ARR, compared with other oral DMT cohorts.

CONCLUSION

Cladribine tablets were associated with a significantly greater real-world treatment persistence and more favorable relapse outcomes than all oral DMT comparators.

The effect of cladribine on immunoglobulin levels compared to B cell targeting therapies in multiple sclerosis

Background

Cladribine is a useful therapeutic option in RRMS with moderate to high disease activity. Its oral formulation and tolerability make it a useful alternative to infusion therapies. Cladribine is known to deplete CD19⁺ B lymphocytes, but its effect on immunoglobulin subsets is unclear.

Objective

To identify whether cladribine therapy in pwMS reduces immunoglobulin subset levels as a surrogate marker of infection risk.

Methods

A 'real-world' retrospective analysis of 341 pwMS presenting to a single tertiary centre between March 2017 and July 2021. Differences in immunoglobulin levels between cladribine, other disease-modifying therapies and no active treatment were assessed using a univariate ANOVA.

Results

Three hundred and forty-one patients had immunoglobulin levels assessed, with 29 patients treated with cladribine. The mean IgG, IgM and IgA levels on cladribine therapy were 10.44 ± 0.40, 0.99 ± 0.09 and 2.04 ± 0.18 g/L respectively. These were not significantly different from patients not on active treatment. There was a statistically significant reduction in IgG and IgM levels for patients treated with ocrelizumab (9.37 ± 0.19 and 0.68 ± 0.04 g/L) and natalizumab (8.72 ± 0.53 and 0.69 ± 0.12 g/L) compared to patients not on treatment.

Conclusion

Cladribine therapy for RRMS was not associated with immunoglobulin subset deficiencies. This is contrasted to ocrelizumab and natalizumab which demonstrate significant reductions in both IgG and IgM levels.

DGKB mediates radioresistance by regulating DGAT1-dependent lipotoxicity in glioblastoma

Glioblastoma (GBM) currently has a dismal prognosis. GBM cells that survive radiotherapy contribute to tumor progression and recurrence with metabolic advantages. Here, we show that diacylglycerol kinase B (DGKB), a regulator of the intracellular concentration of diacylglycerol (DAG), is significantly downregulated in radioresistant GBM cells. The downregulation of DGKB increases DAG accumulation and decreases fatty acid oxidation, contributing to radioresistance by reducing mitochondrial lipotoxicity. Diacylglycerol acyltransferase 1 (DGAT1), which catalyzes the formation of triglycerides from DAG, is increased after ionizing radiation. Genetic inhibition of DGAT1 using short hairpin RNA (shRNA) or microRNA-3918 (miR-3918) mimic suppresses radioresistance. We discover that cladribine, a clinical drug, activates DGKB, inhibits DGAT1, and sensitizes GBM cells to radiotherapy in vitro and in vivo. Together, our study demonstrates that DGKB downregulation and DGAT1 upregulation confer radioresistance by reducing mitochondrial lipotoxicity and suggests DGKB and DGAT1 as therapeutic targets to overcome GBM radioresistance.

[New neuroimaging methods in assessing the activity of neuroinflammation in multiple sclerosis]

The review presents current data on the use of positron emission tomography and single-photon emission computed tomography in multiple sclerosis (MS) to assess the activity of the pathological process, including neuroinflammation, demyelination, activation of microglia, neurodegeneration and local blood flow disorders. These methodologies are a new approach for studying the mechanisms of action and evaluating the clinical effect of disease modifying therapy of MS, especially those capable of penetrating into brain tissue. Among them, the most attention is attracted by cladribine tablets acting on the mechanism of immune reconstitution therapy, most likely with the modulation of immune reactions directly in the brain tissue.

The therapeutic value of treatment for multiple sclerosis: analysis of health technology assessments of three European countries

In accordance with European regulation, medicines containing a new active substance to treat neurodegenerative diseases as well as autoimmune and other immune dysfunctions must be approved by the European Medicines Agency (EMA) through the centralized procedure before they can be marketed. However, after EMA approval, each country is responsible for national market access, following the assessment performed by health technology assessment (HTA) bodies with regard to the therapeutic value. This study aims to provide a comparative analysis of HTA recommendations issued by three EU countries (France, Germany, and Italy) for new drugs for multiple sclerosis (MS) following EMA approval. In the reference period, we identified 11 medicines authorized in Europe for MS, including relapsing forms of MS (RMS; n = 4), relapsing-remitting MS (RRMS; n = 6), secondary progressive MS (SPMS; n = 1), and the primary progressive form (PPMS; n = 1). We found no agreement on the therapeutic value (in particular, the "added value" compared to the standard of care) of the selected drugs. Most evaluations resulted in the lowest score ("additional benefit not proven/no clinical improvement"), underlining the need for new molecules with better efficacy and safety profiles for MS, especially for some forms and clinical settings.

Expert opinion on the long-term use of cladribine tablets for multiple sclerosis: Systematic literature review of real-world evidence

BACKGROUND

Treatment with cladribine tablets (CladT), an immune reconstitution therapy for relapsing multiple sclerosis (RMS), involves two short courses of treatment in Year 1 and Year 2. Most patients achieve sustained efficacy with CladT, but a small proportion may experience new disease activity (DA). Following completion of the indicated dose, physicians may have questions relating to the long-term management of these patients. Since the EU approval of CladT over 5 years ago, real-world evidence (RWE) is increasing and may provide some insights and guidance for clinical practice. We describe a systematic literature review (SLR) of RWE and provide expert opinions relating to six questions regarding the long-term use of CladT.

METHODS

Pertinent clinical questions were developed by a steering committee (SC) of 14 international multiple sclerosis (MS) experts regarding breakthrough DA in Year 1, new DA after 2 years or more of treatment, long-term management of stable patients, and whether additional courses of CladT may be required or safe. An SLR was performed in EMBASE and PubMed using the population, intervention, comparators, outcomes, study design (PICOS) framework to identify relevant studies within the last 15 years. Searches of key congress proceedings for the last 2-3 years were also performed. Following review of the results and RWE, the SC drafted and agreed on expert opinion statements for each question.

RESULTS

A total of 35 publications reporting RWE for CladT were included in this review. In the real world, breakthrough DA in Year 1 is of low incidence (1.1-21.9%) but can occur, particularly in patients switching from anti-lymphocyte trafficking agents. In most patients, this DA did not lead to treatment discontinuation. Reported rates of DA after the full therapeutic effect of CladT has been achieved (end of Year 2, 3 or 4) range from 12.0 to 18.7% in the few studies identified. No RWE was identified to support management decisions for stable patients in Year 5 or later. Views among the group were also diverse on this question and voting on expert opinion statements was required. Only two studies reported the administration of additional courses of CladT, but detailed safety outcomes were not provided.

CONCLUSIONS

RWE for the long-term use of CladT in the treatment of RMS is increasing, however, gaps in knowledge remain. Where possible, the RWE identified through the SLR informed expert statements, but, where RWE is still lacking, these were based solely on experiences and opinion, providing some guidance on topics and questions that occur in daily clinical practice. More real-world studies with longer-term follow-up periods are needed and highly anticipated.

Multiple sclerosis and migraine: Links, management and implications

Multiple sclerosis (MS) is a chronic inflammatory disease leading to multifocal neuronal demyelination and axonal damage in the central nervous system (CNS). MS symptoms vary widely but typically do not include headaches. A large spectrum of headaches manifestations was reported as comorbidities in MS and results in additional disability. Migraine, tension-type headache and cluster headache are the most frequently reported primary headache syndromes in patients with MS (pwMS). Secondary causes of headache should be excluded (cerebral vein thrombosis, CNS or systemic infection, cervical and/or cranial trauma, headaches associated with psychiatric disorders, medication overuse headache, etc.) in this particular population. A careful medical history and general and neurological examinations and sometimes further investigations may be needed to rule out secondary headache syndromes. In pwMS, the headache could be an adverse effect of the disease-modifying therapies or a complication of pain medication overuse prescribed to relieve other causes of pain related to MS (neuropathic pain, mechanical pain, pain associated with spasticity, etc.). Migraine-type headache occurs in pwMS more frequently than in the general population. It can precede the disease onset, be associated with relapses, or appear during the MS course. A predominance of brainstem inflammatory lesions is described on magnetic resonance imaging (MRI) in MS patients with migraine. The relationship between both conditions remains unclear. Migraine and MS occur in the same demographic groups with similar background factors, including gender, hormonal status, and psychological features (anxiety, depression, stress). An early diagnosis and adequate treatment of migraine in MS patients are important to improve their quality of life. In this review, we focus on the relationship between MS and Migraine, discuss the differential diagnoses of migraine in pwMS, and describe its management in this particular context.

Comparing switch to ocrelizumab, cladribine or natalizumab after fingolimod treatment cessation in multiple sclerosis

BACKGROUND

To compare the effectiveness and treatment persistence of ocrelizumab, cladribine and natalizumab in patients with relapsing-remitting multiple sclerosis switching from fingolimod.

METHODS

Using data from MSBase registry, this multicentre cohort study included subjects who had used fingolimod for ≥6 months and then switched to ocrelizumab, cladribine or natalizumab within 3 months after fingolimod discontinuation. We analysed relapse and disability outcomes after balancing covariates using an inverse-probability-treatment-weighting method. Propensity scores for the three treatments were obtained using multinomial-logistic regression. Due to the smaller number of cladribine users, comparisons of disability outcomes were limited to natalizumab and ocrelizumab.

RESULTS

Overall, 1045 patients switched to ocrelizumab (n=445), cladribine (n=76) or natalizumab (n=524) after fingolimod. The annualised relapse rate (ARR) for ocrelizumab was 0.07, natalizumab 0.11 and cladribine 0.25. Compared with natalizumab, the ARR ratio (95% confidence interval [CI]) was 0.67 (0.47 to 0.96) for ocrelizumab and 2.31 (1.30 to 4.10) for cladribine; the hazard ratio (95% CI) for time to first relapse was 0.57 (0.40 to 0.83) for ocrelizumab and 1.18 (0.47 to 2.93) for cladribine. Ocrelizumab users had an 89% lower discontinuation rate (95% CI, 0.07 to 0.20) than natalizumab, but also a 51% lower probability of confirmed disability improvement (95% CI, 0.32 to 0.73). There was no difference in disability accumulation.

CONCLUSION

After fingolimod cessation, ocrelizumab and natalizumab were more effective in reducing relapses than cladribine. Due to the low ARRs in all three treatment groups, additional observation time is required to determine if statistical difference in ARRs results in long-term disability differences.

High persistence and low adverse events burden in cladribine treated MS patients from Argentina

BACKGROUND

Early initiation with high efficacy therapies seems to be better than an escalation approach in terms of disability prevention in patients with relapsing-remitting MS (RRMS). Although efficacy and safety of cladribine tablets have been shown in clinical trials, real-world evidence (RWE) studies from Latin America are scarce.

OBJECTIVE

To describe the baseline characteristics of patients enrolled in the Argentina Patient Support Program (PSP) for cladribine tablets (Adveva®), with at least 1 treatment course, evaluate treatment persistence, adverse event reports from PSP patients and reported relapses characterization.

METHODS

Anonymized data routinely collected by Adveva® team of patients that received the first dose of cladribine from April 16th 2018 to March 31st 2021 were analyzed. Treatment persistence was defined as the percentage of patients that initiated year 2 (Y2) from the population of patients with elapsed time since year 1 (Y1) cladribine tablet initiation of at least 18 months. In addition, using the pharmacovigilance data, reported adverse events and the time elapsed from treatment initiation to relapse were analyzed.

RESULTS

The present analysis included 269 patients (mean age: 41.7 ± 16 years) that had initiated Y1 of cladribine tablets treatment between April 16th 2018 and March 31st 2021. Although only 29.4% (79/269) of our population was treatment naïve, the ratio of naïve/switch patients that initiated cladribine tablets increased from April 2018-March 2019 to April 2020-March 2021. From the 110 patients with elapsed time since treatment initiation ≥18 months, 101 patients initiated Y2 indicating a persistence level of 91.8%. During follow-up, 425 adverse events were reported, mainly MS relapse (8.9%, 38/425), fatigue (3.8%, 16/425) and headache (3.5%, 15/425). Lymphopenia and infections were rarely reported by RRMS patients treated with cladribine tablets. MS relapse was more frequently reported in patients switching from a previous treatment (87.5%, 27/32) than in the naïve cohort (12.5%, 5/32).

CONCLUSIONS

The first real life experience in RRMS patients from Latin America demonstrated that the Adveva® enrolled support program patients have a high persistence level to oral treatment with cladribine tablets. Our results also confirmed the known safety profile of cladribine tablets, with a low incidence of lymphopenia and infections.

Real-Life Experience of the Effects of Cladribine Tablets on Lymphocyte Subsets and Serum Neurofilament Light Chain Levels in Relapsing Multiple Sclerosis Patients

Although cladribine induces sustained reductions in peripheral T and B lymphocytes, little is known about its effect on axonal damage reduction in multiple sclerosis (MS), which could be demonstrated by assessing the serum neurofilament light chain (sNfL) levels. We investigated the reduction/reconstitution of different lymphocyte subsets (LS) by verifying the correlation with no evidence of disease activity (NEDA) and the variation in sNfL levels during cladribine treatment. We analysed 33 highly active relapsing MS patients and followed them up for 12 ± 3.3 months; blood samples were collected at treatment start (W0) and after 8, 24 and 48 weeks. Seventeen patients (60.7%) showed NEDA during the first treatment. At week 8, we observed a significant decrease in B memory cells, B regulatory 1 CD19+/CD38+ and B regulatory 2 CD19+/CD25+, a significant increase in T regulatory CD4+/CD25+, a slight increase in T cytotoxic CD3+/CD8+ and a non-significant decrease in T helper CD3+/CD4+. Starting from week 24, the B subsets recovered; however, at week 48, CD19+/CD38+ and CD19+/CD25+ reached values near the baseline, while the Bmem were significantly lower. The T cell subsets remained unchanged except for CD4+/CD25+, which increased compared to W0. The LS changes were not predictive of NEDA achievement. The sNfL levels were significantly lower at week 24 (p = 0.046) vs. baseline. These results could demonstrate how cladribine, by inflammatory activity depletion, can also reduce axonal damage, according to the sNfL levels.

Treatment with Cladribine Tablets Beyond Year 4: A Position Statement by Southeast European Multiple Sclerosis Centers

Based on the results of the pivotal CLARITY study, cladribine tablets were approved for use in the European Union in 2017 as a high-efficacy therapy for highly active relapsing-remitting multiple sclerosis (MS). Cladribine tablets are used as an induction therapy: half of the total dose is given in year 1 and the other half in year 2. In the CLARITY Extension trials, repeating the dose routinely in years 3 and 4, was not associated with significantly improved disease control. However, there is very limited evidence on how to manage people with MS (pwMS) beyond year 4, which is increasingly important because more and more patients are now ≥ 4 years after cladribine treatment. Overall, postapproval data show that treatment with two cladribine cycles effectively controls disease activity in the long term. However, there is general agreement that some pwMS with suboptimal response could benefit from retreatment. This study reviews the practical aspects of using cladribine tablets, summarizes the evidence from clinical trials and real-world studies on the safety and efficacy of cladribine, and proposes a treatment algorithm developed by expert consensus for pwMS previously treated with cladribine. In brief, we propose that additional courses of cladribine tablets should be considered in patients with minimal (no relapses, 1-2 new lesions) or moderate (1 relapse, 3-4 new lesions) disease activity, while significant disease activity (> 1 relapse, > 3 new lesions) or progression should warrant a switch to another high-efficacy treatment (HET). More evidence is needed to improve the treatment guidelines for pwMS who previously received cladribine.

Cladribine treatment for highly active multiple sclerosis: Real-world clinical outcomes for years 3 and 4

INTRODUCTION

Cladribine is an effective immunomodulatory treatment used for relapsing forms of multiple sclerosis (MS).

OBJECTIVES

To describe the clinical outcomes and rates of no evidence of disease activity (NEDA) in patients with highly-active disease treated with 2 years cumulative dose of cladribine, for years 3 and 4.

METHODS

We used the Sheba Multiple Sclerosis computerized data registry to retrospectively evaluate year-3 and year-4 clinical outcomes and NEDA-2 rates in highly active RRMS patients who completed the 2-dose 2-year cladribine treatment protocol (3.5 mg/kg cumulative dose over 2 years). The first week of treatment in year 1 was considered as baseline. Data analyses were performed using Python (version 3.0) and SAS® (version 9.4 SAS Institute, Cary, NC).

RESULTS

Among 128 patients with highly-active MS that received cladribine treatment, 61 patients, 43 females, were studied for year-3 clinical outcomes, and 35 patients, 23 females, also for year-4. At the initiation of cladribine treatment, the mean ± SD age was 39.6 ± 10.74 years (45.9% of the patients were between 18 and 40 years), disease duration 12.7 ± 9.08 years, Expanded Disability Status Scale (EDSS) 3.7 ± 1.86 (54% had EDSS score > 3.0), and the annual relapse rate was 1.6 ± 0.9. The annual relapse rate decreased to 0.36 in year-3 and was 0.17 in year-4; 68.9% (42/61) of the patients were relapse-free in year-3, and 82.9% (29/35) were relapse-free in year-4. Disability at year-3 was 3.1 ± 2.07; 83.6% (51/61) of the patients remained neurologically stable (33, 54.1%) or improved (18, 29.5%). In year-4, EDSS was 3.2 ± 1.91, and 85.7% (30/35) of the patients remained stable (20, 57.1%) or improved (10, 28.6%). NEDA-2 was achieved for 59.0% (36/61) of patients in year-3, and for 74.3% (26/35) in year-4 of cladribine treatment.

CONCLUSIONS

In the real-world cladribine proved to be clinically effective in year-3 and year-4 of treatment in the majority of highly active RRMS patients.

Cladribine treatment improves cortical network functionality in a mouse model of autoimmune encephalomyelitis

Background

Cladribine is a synthetic purine analogue that interferes with DNA synthesis and repair next to disrupting cellular proliferation in actively dividing lymphocytes. The compound is approved for the treatment of multiple sclerosis (MS). Cladribine can cross the blood–brain barrier, suggesting a potential effect on central nervous system (CNS) resident cells. Here, we explored compartment-specific immunosuppressive as well as potential direct neuroprotective effects of oral cladribine treatment in experimental autoimmune encephalomyelitis (EAE) mice.

Methods

In the current study, we compare immune cell frequencies and phenotypes in the periphery and CNS of EAE mice with distinct grey and white matter lesions (combined active and focal EAE) either orally treated with cladribine or vehicle, using flow cytometry. To evaluate potential direct neuroprotective effects, we assessed the integrity of the primary auditory cortex neuronal network by studying neuronal activity and spontaneous synaptic activity with electrophysiological techniques ex vivo.

Results

Oral cladribine treatment significantly attenuated clinical deficits in EAE mice. Ex vivo flow cytometry showed that cladribine administration led to peripheral immune cell depletion in a compartment-specific manner and reduced immune cell infiltration into the CNS. Histological evaluations revealed no significant differences for inflammatory lesion load following cladribine treatment compared to vehicle control. Single cell electrophysiology in acute brain slices was performed and showed an impact of cladribine treatment on intrinsic cellular firing patterns and spontaneous synaptic transmission in neurons of the primary auditory cortex. Here, cladribine administration in vivo partially restored cortical neuronal network function, reducing action potential firing. Both, the effect on immune cells and neuronal activity were transient.

Conclusions

Our results indicate that cladribine exerts a neuroprotective effect after crossing the blood–brain barrier independently of its peripheral immunosuppressant action.

Impact of histone modifier-induced protection against autoimmune encephalomyelitis on multiple sclerosis treatment

Multiple sclerosis is a progressive demyelinating central nervous system disorder with unknown etiology. The condition has heterogeneous presentations, including relapsing-remitting multiple sclerosis and secondary and primary progressive multiple sclerosis. The genetic and epigenetic mechanisms underlying these various forms of multiple sclerosis remain elusive. Many disease-modifying therapies approved for multiple sclerosis are broad-spectrum immunomodulatory drugs that reduce relapses but do not halt the disease progression or neuroaxonal damage. Some are also associated with many severe side effects, including fatalities. Improvements in disease-modifying treatments especially for primary progressive multiple sclerosis remain an unmet need. Several experimental animal models are available to decipher the mechanisms involved in multiple sclerosis. These models help us decipher the advantages and limitations of novel disease-modifying therapies for multiple sclerosis.

Cladribine Reduces Trans-Endothelial Migration of Memory T Cells across an In Vitro Blood–Brain Barrier

Multiple sclerosis (MS) is a chronic, demyelinating disease of the central nervous system (CNS) induced by immune dysregulation. Cladribine has been championed for its clinical efficacy with relatively minor side effects in treating MS. Although it is proposed that cladribine exerts an anti-migratory effect on lymphocytes at the blood–brain barrier (BBB) in addition to its lymphocyte-depleting and modulating effects, this has not been properly studied. Here, we aimed to determine if cladribine treatment influences trans-endothelial migration of T cell subsets across an inflamed BBB. Human brain endothelial cells stimulated with pro-inflammatory cytokines were used to mimic the BBB. Peripheral blood mononuclear cells were obtained from healthy controls, untreated and cladribine-treated MS patients. The trans-endothelial migration of CD4⁺ effector memory T (T^EM) and CD8⁺ central memory T (T^CM) cells was reduced in cladribine-treated MS patients. CD28 expression was decreased on both CD4⁺ T^EM and CD8⁺ T^CM cells, suggesting lowered peripheral activation of these cells thereby maintaining the integrity of the BBB. In addition, these cells have likely reconstituted following cladribine treatment, revealing a long-term anti-migratory effect. These results highlight new mechanisms by which cladribine acts to control MS pathogenesis.

Economic evaluation of cladribine tablets in high disease activity (HDA) relapsing multiple sclerosis (RMS) patients in Lebanon

BACKGROUND

Cladribine tablets are a newly launched short course oral treatment approved for high disease activity (HDA) relapsing multiple sclerosis (RMS). The current analysis assessed the cost-utility and budgetary impact of introducing cladribine tablets in HDA-RMS patients compared with other HDA-RMS therapies in Lebanon.

METHODS

The global cost-utility and budget impact models were adapted from Lebanese National Social Security Fund (NSSF) perspective. The data for the models' adaptation were retrieved from the literature and validated by Lebanese experts. The comparators considered in the cost-utility model were alemtuzumab, fingolimod, and natalizumab while budget impact analysis additionally considered dimethyl fumarate. A sensitivity analysis was also performed to assess the uncertainty in the analysis.

RESULTS

The cost-utility results showed that cladribine tablets are an economically dominant therapeutic strategy (i.e., less costly and better quality-adjusted life year [QALY]) compared to all comparators. The cost saving was driven by drug acquisition, administration, and monitoring costs; while incremental QALY gain was driven by differences in delayed Expanded Disability Status Scale progression. Sensitivity analysis showed that cladribine tablets have a high probability (99.3-100%) of being dominant at a threshold of 22,000 United States Dollars (approximately three times of gross domestic product) per QALY gained against different comparators. The budget impact analysis showed that the introduction of cladribine tablets would result in 5.0% to 21.5% savings in the overall budget over a period of five years.

CONCLUSIONS

Cladribine tablets are a cost-effective and a budget-saving treatment option for the treatment of HDA-RMS patients in Lebanon from the NSSF perspective.

Cytokine Secretion Dynamics of Isolated PBMC after Cladribine Exposure in RRMS Patients

Cladribine (CLD) treats multiple sclerosis (MS) by selectively and transiently depleting B and T cells with a secondary long-term reconstruction of the immune system. This study provides evidence of CLD’s immunomodulatory role in peripheral blood mononuclear cells (PBMCs) harvested from 40 patients with untreated relapsing-remitting MS (RRMS) exposed to CLD. We quantified cytokine secretion from PBMCs isolated by density gradient centrifugation with Ficoll−Paque using xMAP technology on a FlexMap 3D analyzer with a highly sensitive multiplex immunoassay kit. The PBMC secretory profile was evaluated with and without CLD exposure. PBMCs isolated from patients with RRMS for ≤12 months had significantly higher IL-4 but significantly lower IFN-γ and TNF-α secretion after CLD exposure. PBMCs isolated from patients with RRMS for >12 months had altered inflammatory ratios toward an anti-inflammatory profile and increased IL-4 but decreased TNF-α secretion after CLD exposure. CLD induced nonsignificant changes in IL-17 secretion in both RRMS groups. Our findings reaffirm CLD’s immunomodulatory effect that induces an anti-inflammatory phenotype.

Expert-Agreed Practical Recommendations on the Use of Cladribine

Cladribine is a disease-modifying selective immune reconstitution oral therapy for adult patients with highly active relapsing multiple sclerosis (RMS). It was approved in the USA in 2019 and in Europe in 2017, thus there are still gaps in existing guidelines for using cladribine tablets in clinical practice. Nine experts with extensive experience in managing patients with multiple sclerosis in Spain identified some of the unanswered questions related to the real-life use of cladribine tablets. They reviewed the available clinical trial data and real-world evidence, including their own experiences of using cladribine, over the course of three virtual meetings held between November 2020 and January 2021. This article gathers their practical recommendations to aid treatment decision-making and optimise the use of cladribine tablets in patients with RMS. The consensus recommendations cover the following areas: candidate patient profiles, switching strategies (to and from cladribine), managing response to cladribine and safety considerations.

Long-term management of multiple sclerosis patients treated with cladribine tablets beyond year 4

INTRODUCTION

Oral cladribine is a highly effective pulsed selective immune reconstitution therapy licensed for relapsing multiple sclerosis (RMS) since 2017. A full treatment course comprises two treatment cycles given 1 year apart, followed by two treatment-free years. The management of cladribine-treated patients beyond year 4 needs to be addressed as patients have now passed the initial 4 years since European Medical Agency approval.

AREAS COVERED

A panel of neurologists and a neuroradiologist experienced in MS treatment/monitoring evaluated clinical trial data and real-world evidence and proposed recommendations for the management of cladribine-treated patients beyond year 4.

EXPERT OPINION

Continuous monitoring of disease activity during the treatment-free period is important. Subsequent management depends on the presence or absence of inflammatory disease activity, determined in the absence of consistent guidelines via practice-driven neurological decision criteria. Persisting or newly occurring inflammatory disease activity is an indication for further treatment, i.e. either re-initiation of cladribine or switching to another highly effective disease-modifying therapy. The decision to retreat or switch should be based on clinical and radiological evaluation considering disease course, treatment history, and safety aspects. In the absence of disease activity, either retreatment can be offered, or the treatment-free period can be extended under structured monitoring.

Predicting disease activity in patients with multiple sclerosis: An explainable machine‐learning approach in the Mavenclad trials

Multiple sclerosis (MS) is among the most common autoimmune disabling neurological conditions of young adults and affects more than 2.3 million people worldwide. Predicting future disease activity in patients with MS based on their pathophysiology and current treatment is pivotal to orientate future treatment. In this respect, we used machine learning to predict disease activity status in patients with MS and identify the most predictive covariates of this activity. The analysis is conducted on a pooled population of 1935 patients enrolled in three cladribine tablets clinical trials with different outcomes: relapsing–remitting MS (from CLARITY and CLARITY‐Extension trials) and patients experiencing a first demyelinating event (from the ORACLE‐MS trial). We applied gradient‐boosting (from XgBoost library) and Shapley Additive Explanations (SHAP) methods to identify patients' covariates that predict disease activity 3 and 6 months before their clinical observation, including patient baseline characteristics, longitudinal magnetic resonance imaging readouts, and neurological and laboratory measures. The most predictive covariates for early identification of disease activity in patients were found to be treatment duration, higher number of new combined unique active lesion count, higher number of new T1 hypointense black holes, and higher age‐related MS severity score. The outcome of this analysis improves our understanding of the mechanism of onset of disease activity in patients with MS by allowing their early identification in clinical settings and prompting preventive measures, therapeutic interventions, or more frequent patient monitoring.

The CLARION study design and status update: a long-term, registry-based study evaluating adverse events of special interest in patients with relapsing multiple sclerosis newly started on cladribine tablets

OBJECTIVE

To describe the design of the CLARION post-approval safety study (EU PAS Register number, EUPAS24484) and provide a status update, including characteristics of patients included up to 1 May 2021.

METHODS

CLARION aims to further evaluate adverse events of special interest in patients who are newly initiating treatment with cladribine tablets for relapsing multiple sclerosis (MS). The study population consists of two cohorts: patients newly initiating cladribine tablets (cladribine cohort) and patients newly initiating oral fingolimod tablets (comparator fingolimod cohort), with an aim to include 8000 patients (4000 patients per cohort). The study relies on secondary use of data from pre-existing MS registries/data sources (except in Germany, where primary data collection is performed). The study is projected to last 15 years, with an anticipated 5-year inclusion period. Study outcomes are: malignancies; severe infections; tuberculosis; progressive multifocal leukoencephalopathy; other opportunistic infections; herpes zoster; severe lymphopenia (Grade ≥ 3); and treatment discontinuation.

RESULTS

As of 1 May 2021, 2393 patients were included in CLARION from seven participating MS registries/data sources (cladribine cohort, n = 1266; fingolimod cohort, n = 1127). The majority of patients are female (cladribine cohort, 72.5%; fingolimod cohort, 68.0%), with mean age at onset of MS of 31.5 years for the cladribine cohort and 30.9 years for the fingolimod cohort. The majority of patients in both cohorts had relapsing MS (cladribine cohort, 92.1%; fingolimod cohort, 93.5%).

CONCLUSION

By providing further information on adverse events of special interest during long-term follow-up, CLARION will assist neurologists and patients regarding treatment decision-making for management of relapsing MS.

Cladribine Treatment for MS Preserves the Differentiative Capacity of Subsequently Generated Monocytes, Whereas Its Administration In Vitro Acutely Influences Monocyte Differentiation but Not Microglial Activation

Cladribine (2-chlorodeoxyadenosine, 2CdA) is one of the most effective disease-modifying drugs for multiple sclerosis (MS). Cladribine is a synthetic purine nucleoside analog that induces cell death of lymphocytes and oral cladribine treatment leads to a long-lasting disease stabilization, potentially attributable to immune reconstitution. In addition to its effects on lymphocytes, cladribine has been shown to have immunomodulatory effects on innate immune cells, including dendritic cells and monocytes, which could also contribute to its therapeutic efficacy. However, whether cladribine can modulate human macrophage/microglial activation or monocyte differentiation is currently unknown. The aim of this study was to determine the immunomodulatory effects of cladribine upon monocytes, monocyte-derived macrophages (MDMs) and microglia. We analyzed the phenotype and differentiation of monocytes from MS patients receiving their first course of oral cladribine both before and three weeks after the start of treatment. Flow cytometric analysis of monocytes from MS patients undergoing cladribine treatment revealed that the number and composition of CD14/CD16 monocyte subsets remained unchanged after treatment. Furthermore, after differentiation with M-CSF, such MDMs from treated MS patients showed no difference in gene expression of the inflammatory markers compared to baseline. We further investigated the direct effects of cladribine in vitro using human adult primary MDMs and microglia. GM-CSF-derived MDMs were more sensitive to cell death than M-CSF-derived MDMs. In addition, MDMs treated with cladribine showed increased expression of costimulatory molecules CD80 and CD40, as well as expression of anti-inflammatory, pro-trophic genes IL10 and MERTK, depending on the differentiation condition. Cladribine treatment in vitro did not modulate the expression of activation markers in human microglia. Our study shows that cladribine treatment in vitro affects the differentiation of monocytes into macrophages by modulating the expression of activation markers, which might occur similarly in tissue after their infiltration in the CNS during MS.

Predictors of Cladribine Effectiveness and Safety in Multiple Sclerosis: A Real-World, Multicenter, 2-Year Follow-Up Study

Introduction

Cladribine administration has been approved for the treatment of relapsing–remitting multiple sclerosis (MS) in 2017; thus, data on cladribine in a real-world setting are still emerging.

Methods

We report on cladribine effectiveness, safety profile, and treatment response predictors in 243 patients with MS followed at eight tertiary MS centers. Study outcomes were: (1) No Evidence of Disease Activity-3 (NEDA-3) status and its components (absence of clinical relapses, MRI activity, and sustained disability worsening); (2) development of grade III/IV lymphopenia. The relationship between baseline features and the selected outcomes was tested via multivariate logistic models.

Results

Of the 243 subjects included in the study (66.5% female, age 34.2 ± 10 years, disease duration 6.6 ± 9.6 years), 64% showed NEDA-3 at median follow-up (22 months). Patients with higher number of previous treatments had lower probability to retain NEDA-3 [odds ratio (OR) 0.64, 95% confidence interval (CI) 0.41–0.98, p = 0.04] and were more prone to experience clinical relapses (OR 1.6, 95% CI 1–2.6, p = 0.04). The presence of active lesions at baseline was associated with follow-up magnetic resonance imaging (MRI) activity (OR 1.92, 95% CI 1.04–3.55, p = 0.04). Patients with higher rate of relapses in the year prior to cladribine start were at higher risk of developing sustained disability worsening (OR 2.95% CI 1–4.2, p = 0.04). Lymphopenia grade III/IV over the follow-up was associated with baseline lymphocyte count (OR 0.998, 95% CI 0.997–0.999, p = 0.01).

Conclusion

In this large cohort, we confirm previous data about cladribine effectiveness on disease activity and disability worsening and provide information on response predictors that might inform therapeutic choices.

Cladribine Tablets for Relapsing-Remitting Multiple Sclerosis: A Clinician's Review

Multiple sclerosis (MS) is a chronic neurodegenerative disease characterized by inflammation and demyelination for which there is currently no cure; therefore, the aim of therapy is to reduce the risk of relapse and disability progression. The treatment options for MS have increased greatly in recent years with the development of several disease-modifying therapies (DMTs) and the advent of immune reconstitution therapy (IRT). IRTs are administered in short-dosing periods to produce long-term effects on the immune system. Treatment with an IRT is based on the 3Rs: reduction, repopulation, and reconstitution of lymphocytes, which leads to restoration of immune effector functions. Cladribine tablets represent a selective, high-efficacy, oral form of IRT for patients with MS that targets lymphocytes and spares innate immune cells. Patients require only two weekly treatment courses, with each course comprising two treatment weeks, in Years 1 and 2; therefore, cladribine tablets are associated with a lower monitoring burden than many other DMTs, while short dosing periods can help to improve adherence. This review provides an overview of IRT and offers the clinician's perspective on the current MS treatment landscape, with a focus on practical advice for the management of patients undergoing treatment with cladribine tablets based on the most recent evidence available, including risks associated with COVID-19 and recommendations for vaccination in patients with MS.

Multiple Sclerosis: Therapeutic Strategies on the Horizon

Multiple sclerosis (MS) is a chronic disease affecting the brain and the spinal cord. It is a chronic inflammatory demyelinating disease of the central nervous system. It is the leading cause of non-traumatic disability in young adults. The clinical course of the disease is quite variable, ranging from stable chronic disease to rapidly evolving debilitating disease. The pathogenesis of MS is not fully understood. Still, there has been a rapid shift in understanding the immune pathology of MS away from pure T cell-mediated disease to B cells and microglia/astrocytes having a vital role in the pathogenesis of MS. This has helped in the emergence of new therapies for management. Effective treatment of MS requires a multidisciplinary approach to manage acute attacks, prevent relapses and disease progression and treat the disabling symptoms associated with the disease. In this review, we discuss the pathogenesis of MS, management of acute relapses, disease-modifying therapies in MS, new drugs and drugs currently in trial for MS and the symptomatic treatment of MS.  All language search was conducted on Google Scholar, PubMed, MEDLINE, and Embase till February 2022. The following search strings and medical subheadings (MeSH) were used: "Multiple Sclerosis", "Pathogenesis of MS", and "Disease-modifying therapies in MS". We explored literature on the pathogenic mechanisms behind MS, management of acute relapses, disease-modifying therapies in MS and symptomatic management.

How to choose initial treatment in multiple sclerosis patients: a case-based approach

BACKGROUND

Immunotherapy dramatically changed the natural history of multiple sclerosis (MS), which was classically associated with severe disability. Treatment strategies advocate that early control of disease activity is crucial to avoid progressive disability, and the use of high efficacy drugs may be beneficial, but safety is a concern. Choosing the disease-modifying therapy is challenging in clinical practice and should be further discussed.

OBJECTIVE

To discuss the state of art of selecting the initial therapy for relapsing MS patients.

METHODS

We used a case-based approach followed by clinical discussion, exploring therapeutic options in different MS settings.

RESULTS

We presented clinical cases profile compatible with the use of MS therapies, classified into moderate and high efficacy. In the moderate efficacy group, we discussed interferons, glatiramer acetate, teriflunomide and dimethyl fumarate, while in the high efficacy group we discussed fingolimod, cladribine, natalizumab, ocrelizumab, alemtuzumab and ofatumumab.

CONCLUSION

Advances in MS treatment are remarkable. Strong evidence supports the use of early high efficacy therapy. However, biomarkers, clinical and radiologic prognostic factors, as well as patients' individual issues, should be valued and considered for a personalized treatment decision.

Real-world evidence for cladribine tablets in multiple sclerosis: further insights into efficacy and safety

Cladribine (CLAD) is a purine nucleoside analog approved in tablet form to treat highly active multiple sclerosis (MS). CLAD tablets are the first oral therapy with an infrequent dosing schedule, administered in two annual treatment courses, each divided into two treatment cycles comprising 4–5 days of treatment. The efficacy and safety of CLAD tablets have been verified in randomized controlled clinical trials. Clinical observational studies are performed in more representative populations and over more extended periods, and thus provide valuable complementary insights. Here, we summarize the available evidence for CLAD tablets from post-marketing trials, including two observational, four long-term extensions, and two comparative studies. The patients in the post-marketing setting differed from the cohort recruited in the pivotal phase III trials regarding demographics and MS-related disability. The limited number of studies with small cohorts corroborate the disease-modifying capacity of oral CLAD and report on a durable benefit after active treatment periods. Skin-related adverse events were common in the studies focusing on safety aspects. In addition, single cases of CLAD-associated autoimmune events have been reported. Lastly, CLAD tablets appear safe regarding COVID-19 concerns, and patients mount a robust humoral immune response to SARS-CoV‑2 vaccination. We conclude that the current real-world evidence for CLAD tablets as immune reconstitution therapy for treatment of MS is based on a small number of studies and a population distinct from the cohorts randomized in the pivotal phase III trials. Further research should advance the understanding of long-term disease control after active treatment periods and the mitigation of adverse events.

Prevalence of disability improvement in relapsing-remitting multiple sclerosis patients treated with cladribine tablets

BACKGROUND

To show the application of the prevalence estimator of Expanded Disability Status Scale (EDSS) improvement over time in patients treated with cladribine tablets in the phase III CLARITY/CLARITY extension trials.

METHODS

We evaluated relapsing-remitting MS patients who entered the CLARITY Extension study. Patients originally randomized in CLARITY to cladribine tablets 3.5 mg/kg, and placebo in CLARITY Extension (Early Cladribine [EC]) were compared to patients originally randomized to placebo and then assigned to cladribine tablets 3.5 mg/kg (Delayed Cladribine [DC]). EC was compared to DC group on the prevalence of EDSS improvement over time and on the cumulative incidence of EDSS improvement. Prevalence of improvement was assessed by a new approach based on the difference of Kaplan-Meier (KM) estimators, while the incidence of improvement was assessed by standard KM curves.

RESULTS

A total of 98 patients in the EC group and 244 patients in the DC group were compared. Patients in the EC group showed a significantly higher (p=0.011) prevalence of improvement at year 2: EC 21.3% [95%CI 13.6-29.3], DC 8.9% [95%CI 5.5-12.8]; and at year 5: EC 15.7% [95%CI 8.2-23.7], DC 8.3% [95%CI 4.5-12.4]). The cumulative incidence of improvement was also significantly different (HR= 1.82 (95%CI:1.13-2.94), p=0.013).

CONCLUSIONS

The assessment of prevalence of EDSS improvement is an alternative outcome to assess if a treatment induces and maintain an improvement over the long term. This estimator resulted more powerful than the cumulative incidence of improvement to detect a treatment effect of cladribine vs placebo over 5 years.

Immune Reconstitution Following Autologous Hematopoietic Stem Cell Transplantation for Multiple Sclerosis: A Review on Behalf of the EBMT Autoimmune Diseases Working Party

Multiple sclerosis (MS) is a central nervous system (CNS) disorder, which is mediated by an abnormal immune response coordinated by T and B cells resulting in areas of inflammation, demyelination, and axonal loss. Disease-modifying treatments (DMTs) are available to dampen the inflammatory aggression but are ineffective in many patients. Autologous hematopoietic stem cell transplantation (HSCT) has been used as treatment in patients with a highly active disease, achieving a long-term clinical remission in most. The rationale of the intervention is to eradicate inflammatory autoreactive cells with lympho-ablative regimens and restore immune tolerance. Immunological studies have demonstrated that autologous HSCT induces a renewal of TCR repertoires, resurgence of immune regulatory cells, and depletion of proinflammatory T cell subsets, suggesting a "resetting" of immunological memory. Although our understanding of the clinical and immunological effects of autologous HSCT has progressed, further work is required to characterize the mechanisms that underlie treatment efficacy. Considering that memory B cells are disease-promoting and stem-like T cells are multipotent progenitors involved in self-regeneration of central and effector memory cells, investigating the reconstitution of B cell compartment and stem and effector subsets of immunological memory following autologous HSCT could elucidate those mechanisms. Since all subjects need to be optimally protected from vaccine-preventable diseases (including COVID-19), there is a need to ensure that vaccination in subjects undergoing HSCT is effective and safe. Additionally, the study of vaccination in HSCT-treated subjects as a means of evaluating immune responses could further distinguish broad immunosuppression from immune resetting.

Integrated Lymphopenia Analysis in Younger and Older Patients With Multiple Sclerosis Treated With Cladribine Tablets

Cladribine tablets (CladT) preferentially reduce B and T lymphocyte levels. As aging is associated with a decline in immune function, the effect of CladT on lymphocyte levels may differ by age. This post hoc analysis combined data from the Phase 3 CLARITY, CLARITY Extension, and ORACLE-MS studies to examine the effect of age (≤50 or >50 years) on lymphopenia following CladT 3.5 mg/kg (CladT3.5; cumulative dose over 2 years) treatment over 96 weeks. Both CladT3.5 and placebo were given over Weeks 1 and 5 (Year 1 treatment) and Weeks 48 and 52 (Year 2 treatment) from the start of the studies. Absolute lymphocyte count (ALC) and levels of lymphocyte subsets were examined in 1564 patients (Age ≤50 [placebo: N=566; CladT3.5: N=813]; Age >50 [placebo: N=75; CladT3.5: N=110]). In both age groups, following CladT3.5 treatment, nadir for ALC occurred at Week 9 (8 weeks following start of Year 1 treatment) and Week 55 (7 weeks following start of Year 2 treatment) of the 96-week period; for CD19+ B lymphocytes, nadir occurred at Week 9 (Year 1) and Week 52 (Year 2). For CD4+ T lymphocytes, nadir occurred at Week 16 (Year 1) in both age groups, and at Weeks 60 and 72 (Year 2) in the Age ≤50 and >50 groups, respectively. Nadir for CD8+ T lymphocytes occurred at Week 16 (Year 1) and Week 72 (Year 2) in the Age ≤50 group and levels remained in the normal range; nadir occurred at Week 9 (Year 1) and Week 96 (Year 2) in the Age >50 group. Lymphocyte recovery began soon after nadir following CladT3.5 treatment and median levels reached normal range by end of the treatment year in both age groups. By Week 96, ~25% of patients treated with CladT3.5 reported ≥1 episode of Grade ≥3 lymphopenia (Gr≥3L). The rate of certain infections was numerically higher in older versus younger patients who experienced Gr≥3L. In conclusion, CladT3.5 had a similar effect on ALC and lymphocyte subsets in both younger and older patient groups.

Neurological update: treatment escalation in multiple sclerosis patients refractory to fingolimod-potentials and risks of subsequent highly active agents

A critical issue in the management of relapsing MS (RMS) is the discontinuation of disease-modifying treatments (DMT) due to lack of efficacy, intolerability or impending risks. With new therapeutic agents introduced into the treatment of RMS, immediate- and long-term consequences of sequential drug use, as well as the effect of the sequence in which the drugs are given, are unclear but may affect efficacy, adverse events, and long-term immunocompetence. In the absence of clinical studies specifically addressing these concerns, observations from clinical practice are of particular value in guiding current management algorithms. Prompted by a study published by Ferraro et al. in this journal, we set out to provide an overview of the published real-world evidence on the effectiveness and safety of switching from fingolimod to another DMT in patients with active RMS. Seventeen publications reporting relevant information were identified. The literature suggests that immune cell depletion induced by alemtuzumab or ocrelizumab is associated with an increased risk of relapse and worsening disability in patients switching from fingolimod compared to patients switching from other therapeutic agents. However, the evidence reported for natalizumab and cladribine is inconclusive. While shortening of the washout period may limit early disease reactivation after fingolimod discontinuation, there is no strong evidence that the duration of the washout period or the absolute lymphocyte count at baseline are predictors of attenuated long-term efficacy. Further real-world studies are required to better understand outcomes among patients who are under-represented in controlled trials.

Potential therapeutic strategies in chronic inflammatory demyelinating polyradiculoneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune neuropathy involving peripheral nerve and nerve roots. The pathological hallmark of CIDP is macrophage-induced demyelination. Antibodies against nerve fibers, complement decomposition, abnormalities in plasma and cerebrospinal fluid cytokine profile, and changes of peripheral blood cell proportion were also reported in CIDP patients. These findings in immunopathology provide support for the introduction of potential therapeutic options for the treatment of CIDP. In this review, we systematically listed the potential therapeutic strategies targeting different components of the immune system by comparing the treatment of other autoimmune inflammatory diseases of the nervous system. Several ongoing clinical trials will assess the efficacy and safety of potential CIDP treatments.

Bruton's Tyrosine Kinase Inhibitors in Multiple Sclerosis: Pioneering the Path Towards Treatment of Progression?

In multiple sclerosis (MS) persisting disability can derive from acute relapses or, alternatively, from slow and steady deterioration, termed chronic progression. Emerging data suggest that the latter process occurs largely independent from relapse activity or development of new central nervous system (CNS) inflammatory lesions. Pathophysiologically, acute relapses develop as a consequence of de novo CNS infiltration of immune cells, while MS progression appears to be driven by a CNS-trapped inflammatory circuit between CNS-established hematopoietic cells as well as CNS-resident cells, such as microglia, astrocytes, and oligodendrocytes. Within the last decades, powerful therapies have been developed to control relapse activity in MS. All of these agents were primarily designed to systemically target the peripheral immune system and/or to prevent CNS infiltration of immune cells. Based on the above described dichotomy of MS pathophysiology, it is understandable that these agents only exert minor effects on progression and that novel targets within the CNS have to be utilized to control MS progression independent of relapse activity. In this regard, one promising strategy may be the inhibition of the enzyme Bruton's tyrosine kinase (BTK), which is centrally involved in the activation of B cells as well as myeloid cells, such as macrophages and microglia. In this review, we discuss where and to what extent BTK is involved in the immunological and molecular cascades driving MS progression. We furthermore summarize all mechanistic, preclinical, and clinical data on the various BTK inhibitors (evobrutinib, tolebrutinib, fenebrutinib, remibrutinib, orelabrutinib, BIIB091) that are currently in development for treatment of MS, with a particular focus on the potential ability of either drug to control MS progression.

High-Efficacy Therapies for Treatment-Naïve Individuals with Relapsing-Remitting Multiple Sclerosis

There are > 18 distinct disease-modifying therapy (DMT) options covering 10 mechanisms of action currently approved by the US Food and Drug Administration for the treatment of relapsing-remitting multiple sclerosis (RRMS). Given the multitude of available treatment options, and recent international consensus guidelines offering differing recommendations, there is broad heterogeneity in how the DMTs are used in clinical practice. Choosing a DMT for newly diagnosed patients with MS is currently a topic of significant debate in MS care. Historically, an escalation approach to DMT was used for newly diagnosed patients with RRMS. However, the evidence for clinical benefits of early treatment with high-efficacy therapies (HETs) in this population is emerging. In this review, we provide an overview of the DMT options and MS treatment strategies, and discuss the clinical benefits of HETs (including ofatumumab, ocrelizumab, natalizumab, alemtuzumab, and cladribine) in the early stages of MS, along with safety concerns associated with these DMTs. By minimizing the accumulation of neurological damage early in the disease course, early treatment with HETs may enhance long-term clinical outcomes over the lifetime of the patient.

Anti-HBs titers are not decreased after treatment with oral Cladribine in patients with Multiple Sclerosis vaccinated against Hepatitis B virus

BACKGROUND

Oral cladribine is a novel treatment for Multiple Sclerosis (MS). It is a purine nucleoside antimetabolite analogue that is incorporated into the DNA, resulting in single-strand breaks in DNA and apoptosis of replicating lymphocytes. Specifically, Cladribine induces limited depletion of CD4 and CD8 T cell subsets and more marked depletion of memory B cell subsets. Therefore, natural and acquired humoral responses against pathogens may be potentially reduced. The aim of this study was to assess longitudinal variation of antiHBs titers in patients with MS treated with Cladribine.

METHODS

Patients with MS treated with 1 cycle of Cladribine (3,5 mg/kg) and previously vaccinated against Hepatitis B virus (HBV) were enrolled. Anti-HBs titers were compared before and after 12 months from Cladribine treatment. Total lymphocyte count was also analysed.

RESULTS

Among the 13 RMS patients (10 F, 3 M, mean age 33,8, SD 5,9) enrolled, all had anti-HBs titers >10 mg/dl at baseline. Anti-HBs titer dropped below the reference value at 12 months after Cladribine only in 1 case. Pre-post Cladribine mean anti-HBs values were not significantly different considering the whole cohort (Wilcoxon-Mann-Whitney Test p = 0,762). Four patients had grade 1 and 1 patient grade 2 lymphocytopenia at 12 months.

CONCLUSIONS

Cladribine does not seem to reduce humoral immune responses in subjects previously vaccinated against HBV, even in case of lymphocytopenia. These results, if confirmed in larger populations, appear reassuring also for other vaccinations (i.e. COVID19). The low impact of Cladribine on plasma cells may explain such findings.

Treatment With Cladribine Selects IFNγ+IL17+ T Cells in RRMS Patients - An In Vitro Study

Background

Multiple sclerosis (MS) is an incurable autoimmune disease mediated by a heterogeneous T cell population (CD3+CD161+CXCR3−CCR6+IFNγ−IL17+, CD3+CXCR3+CCR6+IFNγ+IL17+, and CD3+CXCR3+IFNγ+IL17− phenotypes) that infiltrates the central nervous system, eliciting local inflammation, demyelination and neurodegeneration. Cladribine is a lymphocyte-depleting deoxyadenosine analogue recently introduced for MS therapy as a Disease Modifying Drug (DMD). Our aim was to establish a method for the early identification and prediction of cladribine responsiveness among MS patients.

Methods

An experimental model was designed to study the cytotoxic and immunomodulatory effect of cladribine. T cell subsets of naïve relapsing-remitting MS (RRMS) patients were analyzed ex vivo and in vitro comparatively to healthy controls (HC). Surviving cells were stimulated with rh-interleukin-2 for up to 14days. Cell proliferation and immunophenotype changes were analyzed after maximal (phorbol myristate acetate/ionomycin/monensin) and physiological T-cell receptor (CD3/CD28) activation, using multiparametric flow cytometry and xMAP technology.

Results

Ex vivo CD161+Th17 cells were increased in RRMS patients. Ex vivo to in vitro phenotype shifts included: decreased CD3+CCR6+ and CD3+CD161+ in all subjects and increased CD3+CXCR3+ in RRMS patients only; Th17.1 showed increased proliferation vs Th17 in all subjects; CD3+IL17+ and CD3+IFNγ+IL17+ continued to proliferate till day 14, CD3+IFNγ+ only till day 7. Regarding cladribine exposure: RRMS CD3+ cells were more resistant compared to HC; treated CD3+ cells proliferated continuously for up to 14 days, while untreated cells only up to 7 days; both HC/RRMS CD3+CXCR3+ populations increased from baseline till day 14; in RRMS patients vs HC, IL17 secretion from cladribine-treated cells increased significantly, in line with the observed proliferation of CD3+IL17+ and CD3+IFNγ+IL17+ cells; in both HC/RRMS, cladribine led to a significant increase in CD3+IFNγ+ cells at day 7 only, having no further effect at day14. IFNγ and IL17 secreted in culture media decreased significantly from ex vivo to in vitro.

Conclusions

CD3+ subtypes showed different responsiveness due to selectivity of cladribine action, in most patients leading to in vitro survival/proliferation of lymphocyte subsets known as pathogenic in MS. This in vitro experimental model is a promising tool for the prediction of individual responsiveness of MS patients to cladribine and other DMDs.

Immunomodulatory Effects Associated with Cladribine Treatment

Cladribine is a synthetic deoxyadenosine analogue with demonstrated efficacy in patients with relapsing-remitting multiple sclerosis (MS). The main mechanism of action described for cladribine is the induction of a cytotoxic effect on lymphocytes, leading to a long-term depletion of peripheral T and B cells. Besides lymphocyte toxicity, the mode of action may include immunomodulatory mechanisms affecting other cells of the immune system. In order to induce its beneficial effects, cladribine is phosphorylated inside the cell by deoxycytidine kinase (DCK) to its active form. However, the mechanism of action of cladribine may also include immunomodulatory pathways independent of DCK activation. This in vitro study was designed to explore the impact of cladribine on peripheral blood mononuclear cells (PBMC) subsets, and to assess whether the immunomodulatory mechanisms induced by cladribine depend on the activation of the molecule. To this end, we obtained PBMCs from healthy donors and MS patients and performed proliferation, apoptosis and activation assays with clinically relevant concentrations of cladribine in DCK-dependent and -independent conditions. We also evaluated the effect of cladribine on myeloid lineage-derived cells, monocytes and dendritic cells (DCs). Cladribine decreased proliferation and increased apoptosis of lymphocyte subsets after prodrug activation via DCK. In contrast, cladribine induced a decrease in immune cell activation through both DCK-dependent and -independent pathways (not requiring prodrug activation). Regarding monocytes and DCs, cladribine induced cytotoxicity and impaired the activation of classical monocytes, but had no effect on DC maturation. Taken together, these data indicate that cladribine, in addition to its cytotoxic function, can mediate immunomodulation in different immune cell populations, by regulating their proliferation, maturation and activation.

Expert opinion on COVID-19 vaccination and the use of cladribine tablets in clinical practice

BACKGROUND

Gaps in current evidence and guidance leave clinicians with unanswered questions on the use of cladribine tablets for the treatment of multiple sclerosis (MS) in the era of the COVID-19 pandemic, in particular relating to COVID-19 vaccination.

OBJECTIVE

We describe a consensus-based program led by international MS experts with the aim of supplementing current guidelines and treatment labels by providing timely recommendations relating to COVID-19 vaccination and the use of cladribine tablets in clinical practice.

METHODS

A steering committee (SC) of 10 international MS experts identified 7 clinical questions to answer concerning the use of cladribine tablets and COVID-19 vaccination, which addressed issues relating to patient selection, timing and efficacy, and safety. Clinical recommendations to address each question were drafted using available evidence combined with expert opinion from the SC. An extended faculty of 28 MS experts, representing 19 countries, in addition to the 10 SC members, voted on the recommendations. Consensus on recommendations was achieved when ⩾75% of respondents expressed an agreement score of 7-9, on a 9-point scale.

RESULTS

Consensus was achieved on all 13 recommendations. Clinical recommendations are provided on whether all patients with MS receiving cladribine tablets should be vaccinated against COVID-19, and whether they should be prioritized; the timing of vaccination around dosing of cladribine tablets (i.e. before and after a treatment course); and the safety of COVID-19 vaccination for these patients.

CONCLUSION

These expert recommendations provide timely guidance on COVID-19 vaccination in patients receiving cladribine tablets, which is relevant to everyday clinical practice.

A Model-Based Economic Evaluation of Cladribine Versus Alemtuzumab, Ocrelizumab and Natalizumab for the Treatment of Relapsing-Remitting Multiple Sclerosis with High Disease Activity in Chile

PURPOSE

The aim of this study was to evaluate the cost effectiveness of cladribine compared with alemtuzumab, natalizumab, and ocrelizumab for the treatment of highly active multiple sclerosis (HAD-MS) from the perspective of the Chilean health care public sector.

MATERIALS AND METHODS

A Markov model was used to compare costs and quality-adjusted life-years (QALYs) over a 45-year time horizon using a 3% discount rate for costs and outcomes. Natural history of the disease was modeled in terms of progression of disability according to the Expanded Disability Status Scale (EDSS). A network meta-analysis was used as a source of comparative effectiveness for disability progression and annual relapse rates. Differences in costs and outcomes were modeled for only 10 years due to high temporal uncertainty. Ocrelizumab was assumed to have the same efficacy as cladribine due to lack of data. Direct costs were taken from national tariffs and expressed in 2019 US dollars. Utilities for EDSS health states were obtained from the literature. Second-order uncertainty was characterized through deterministic and probabilistic sensitivity analysis.

FINDINGS

Compared with natalizumab (the current strategy covered in Chile), cladribine is associated with incremental costs and QALYs of US$70,989 and 1.875, respectively (incremental cost-effectiveness ratio [ICER] $37,861). Ocrelizumab was extendedly dominated by cladribine and natalizumab, and alemtuzumab was dominated by cladribine. A scenario analysis of a 10% discount did not modify the results substantially, but showed a decrease in the ICER of cladribine versus natalizumab (ICER $29,833/QALY).

IMPLICATIONS

Cladribine is a new oral alternative to treat patients with HAD-MS that is expected to produce higher QALYs than all evaluated alternatives. In the context of a conservative analysis, cladribine cannot be considered cost effective for the Chilean health care public sector using a 1 GDP per capita threshold. However, under reasonable discount scenarios, cladribine becomes an attractive alternative for the health system.

Position of Cladribine Tablets in the Management of Relapsing-Remitting Multiple Sclerosis: An Expert Narrative Review From the United Arab Emirates

The use of immune reconstitution therapies (IRT) in patients with relapsing-remitting multiple sclerosis (RRMS) is associated with a prolonged period of freedom from relapses in the absence of continuously applied therapy. Cladribine tablets is a disease-modifying treatment (DMT) indicated for highly active relapsing multiple sclerosis (MS) as defined by clinical or imaging features. Treatment with cladribine tablets is effective and well tolerated in patients with active MS disease and have a low burden of monitoring during and following treatment. In this article, an expert group of specialist neurologists involved in the care of patients with MS in the United Arab Emirates provides their consensus recommendations for the practical use of cladribine tablets according to the presenting phenotype of patients with RRMS. The IRT approach may be especially useful for patients with highly active MS insufficiently responsive to treatment with a first-line DMT, those who are likely to adhere poorly to a continuous therapeutic regimen, treatment-naïve patients with high disease activity at first presentation, or patients planning a family who are prepared to wait until at least 6 months after the end of treatment. Information available to date does not suggest an adverse interaction between cladribine tablets and COVID-19 infection. Data are unavailable at this time regarding the efficacy of COVID-19 vaccination in patients treated with cladribine tablets. Robust immunological responses to COVID-19 infection or to other vaccines have been observed in patients receiving this treatment, and treatment with cladribine tablets per se should not represent a barrier to this vaccination.

Secondary Immunodeficiency and Risk of Infection Following Immune Therapies in Neurology

Secondary immunodeficiencies (SIDs) are acquired conditions that may occur as sequelae of immune therapy. In recent years a number of disease-modifying therapies (DMTs) has been approved for multiple sclerosis and related disorders such as neuromyelitis optica spectrum disorders, some of which are frequently also used in- or off-label to treat conditions such as chronic inflammatory demyelinating polyneuropathy (CIDP), myasthenia gravis, myositis, and encephalitis. In this review, we focus on currently available immune therapeutics in neurology to explore their specific modes of action that might contribute to SID, with particular emphasis on their potential to induce secondary antibody deficiency. Considering evidence from clinical trials as well as long-term observational studies related to the patients' immune status and risks of severe infections, we delineate long-term anti-CD20 therapy, with the greatest data availability for rituximab, as a major risk factor for the development of SID, particularly through secondary antibody deficiency. Alemtuzumab and cladribine have relevant effects on circulating B-cell counts; however, evidence for SID mediated by antibody deficiency appears limited and urgently warrants further systematic evaluation. To date, there has been no evidence suggesting that treatment with fingolimod, dimethyl fumarate, or natalizumab leads to antibody deficiency. Risk factors predisposing to development of SID include duration of therapy, increasing age, and pre-existing low immunoglobulin (Ig) levels. Prevention strategies of SID comprise awareness of risk factors, individualized treatment protocols, and vaccination concepts. Immune supplementation employing Ig replacement therapy might reduce morbidity and mortality associated with SIDs in neurological conditions. In light of the broad range of existing and emerging therapies, the potential for SID warrants urgent consideration among neurologists and other healthcare professionals.

Pre-Existing Humoral Immunological Memory Is Retained in Patients with Multiple Sclerosis Receiving Cladribine Therapy

Cladribine (CLAD) is a lymphodepleting agent approved for active relapsing multiple sclerosis (MS). The impact of CLAD on the adaptive humoral immune system has not sufficiently been studied. This study aimed to assess the influence of CLAD treatment on specific antibody titers to common pathogens. We included 18 MS patients treated with CLAD. Serum IgG antibody levels to measles, mumps, rubella, hepatitis B and varicella zoster virus (VZV), as well as diphtheria and tetanus toxins, were measured prior to the initiation of treatment and at 12 and 24 months after first CLAD administration. Moreover, specimens were longitudinally analyzed regarding absolute blood concentrations of IgG and main lymphocyte subsets. No reduction in antibody levels against measles, mumps, rubella, VZV, hepatitis B, diphtheria toxin and tetanus toxin associated with CLAD treatment was observed. Loss of seroprotection occurred in <1%. We found no significant impact of CLAD on absolute serum IgG levels. Absolute lymphocyte counts were significantly reduced at the end of each treatment year (p < 0.00001 and p < 0.000001). This study suggests that CLAD does not interfere with the pre-existing humoral immunologic memory in terms of pathogen-specific antibody titers.