Effect of cladribine tablets on lymphocyte reduction and repopulation dynamics in patients with relapsing multiple sclerosis

BACKGROUND

Immune reconstitution therapies (IRT) for patients with multiple sclerosis are used for short, intermittent treatment periods to induce immune resetting and allow subsequent treatment-free periods. Cladribine tablets are postulated to be an IRT that causes selective and transient reductions in CD19⁺ B cells and T cells, followed by reconstitution of adaptive immune function.

OBJECTIVE

To characterize long-term lymphocyte count changes in pooled data from the 2-year CLARITY and subsequent 2-year CLARITY Extension studies, and the PREMIERE registry (Long-term CLARITY cohort).

METHODS

Data from patients randomized to placebo (n = 435) or cladribine tablets 10 mg (MAVENCLAD^®; 3.5 mg/kg cumulative dose over 2 years, referred to as cladribine tablets 3.5 mg/kg; n = 685) in CLARITY or CLARITY Extension, including time spent in the PREMIERE registry were pooled to provide long-term follow-up data. The study investigated absolute lymphocyte counts (ALC) up to 312 weeks and B and T cell subsets up to 240 weeks after the first dose, in patients receiving placebo or cladribine tablets 3.5 mg/kg administered as two short (4 or 5 days) weekly treatments at the start of months 1 and 2 in each treatment year, followed by no further active treatment.

RESULTS

Treatment with cladribine tablets 3.5 mg/kg resulted in selective reductions in B and T lymphocytes. Lymphocyte recovery began soon after treatment in each of years 1 and 2. Median ALC recovered to the normal range and CD19⁺ B cells recovered to threshold values by week 84, approximately 30 weeks after the last dose of cladribine tablets in year 2. Median CD4⁺ T cell counts recovered to threshold values by week 96 (approximately 43 weeks after the last dose of cladribine tablets in year 2). Median CD8⁺ cell counts never dropped below the threshold value.

CONCLUSION

These results show the dynamics of lymphocyte count changes following treatment with cladribine tablets 3.5 mg/kg. The immune cell repopulation results provide further evidence that cladribine tablets may represent a form of IRT.

Safety of cladribine tablets in the treatment of patients with multiple sclerosis: An integrated analysis

BACKGROUND

Treating patients with relapsing multiple sclerosis (MS) with cladribine tablets (two times 4 or 5 days of treatment each year for 2 years) results in long-lasting efficacy, with continued stability in many patients for 4 or more years. Safety and tolerability outcomes from individual clinical studies with cladribine tablets have been reported previously.

OBJECTIVE

Report safety data from an integrated analysis of clinical trials and follow-up in patients with MS to further characterize the safety profile of cladribine tablets.

METHODS

Data for patients treated with cladribine tablets 10 mg (MAVENCLAD^®; 3.5 mg/kg cumulative dose over 2 years, referred to as cladribine tablets 3.5 mg/kg) as monotherapy (n = 923) or placebo (n = 641) in Phase III clinical trials (CLARITY, CLARITY Extension and ORACLE-MS) and followed up in the PREMIERE registry were aggregated (Monotherapy Oral cohort). To better characterize rare events, additional data from earlier studies which involved the use of parenteral cladribine in patients with MS, and the ONWARD study, in which patients were given cladribine tablets in addition to interferon (IFN)-β or placebo plus IFN-β were included in an All Exposed cohort (cladribine, n = 1926; placebo, n = 802). Adjusted adverse events incidences per 100 patient-years (Adj-AE per 100 PY) were calculated for the integrated analyses.

RESULTS

The incidence rate of treatment-emergent adverse events (TEAEs) in the Monotherapy Oral cohort was 103.29 vs. 94.26 Adj-AEs per 100 PY for placebo. TEAEs that occurred more frequently with cladribine tablets were mainly driven by the TEAEs of lymphopenia (Adj-AE per 100 PY 7.94 vs. 1.06 for placebo) and lymphocyte count decreased (Adj-AE per 100 PY 0.78 vs. 0.10 for placebo) as anticipated due to the mode of action of cladribine. An increase in TEAE incidence rate was also observed in the cladribine tablets 3.5 mg/kg group vs. placebo for herpes zoster (Adj-AE per 100 PY 0.83 vs. 0.20, respectively). There were no cases of systemic, serious disseminated herpes zoster attributed to treatment with cladribine tablets. In general there was no increase in the risk of infections including opportunistic infections with cladribine tablets versus placebo, except for herpes zoster. Periods of severe lymphopenia (< 0.5 × 10⁹ cells/L) were associated with an increased frequency of infections, but the nature of these was not different to that observed in the overall patient group treated with cladribine tablets 3.5 mg/kg. Within the constraints of a limited sample size, malignancy rates in the overall clinical program for cladribine in MS did not show evidence of an increase compared to placebo-treated patients and there was no increase in the incidence of malignancies over time in cladribine-treated patients.

CONCLUSION

The AE profile for cladribine tablets 3.5 mg/kg as a monotherapy has been well-characterized in a pooled population of patients from early to more advanced relapsing MS. There was no increased risk for infections in general except for a higher incidence of herpes zoster. Lymphopenia was amongst the most frequently observed TEAEs that occurred at a higher incidence with cladribine relative to placebo. There was also no increase in malignancy rates for cladribine relative to placebo.

Systematic literature review and network meta-analysis of cladribine tablets versus alternative disease-modifying treatments for relapsing-remitting multiple sclerosis

OBJECTIVE

To assess the comparative efficacy and safety of cladribine tablets versus alternative disease modifying treatments (DMTs) in patients with active relapsing-remitting multiple sclerosis (RRMS), and in a subgroup with high disease activity (HRA + DAT), using systematic literature review (SLR) and network meta-analysis (NMA).

METHODS

MEDLINE, Embase, MEDLINE In-Process and CENTRAL databases were systematically searched to identify English-language publications of relevant studies of approved DMTs for RRMS. Searches were conducted from database inception to January 2017. Conference websites and trial registries were also searched. NMA considered the effects of DMTs on annualized relapse rate (ARR), confirmed disease progression (CDP), no evidence of disease activity (NEDA) and safety.

RESULTS

Of 10,825 articles retrieved and screened, 44 studies assessing 12 DMTs contributed to the NMA. In patients with active RRMS, cladribine tablets were associated with a significant 58% reduction in ARR versus placebo (p < .05); cladribine tablets were similar or significantly better than other DMT regimens and ranked fourth among DMTs, behind alemtuzumab, natalizumab and ocrelizumab. For CDP for 6 months and NEDA, improvements with cladribine tablets were significantly greater than those of placebo (p < .05), with no comparator DMT demonstrating significantly better results. Similar findings were reported in the HRA + DAT population. Overall adverse event risk for cladribine tablets did not differ significantly from that of placebo and most alternative DMTs.

CONCLUSION

In this first NMA to consider cladribine tablets, ocrelizumab and daclizumab for treatment of RRMS, cladribine tablets are a comparatively effective and safe alternative to other DMTs in both active RRMS and HRA + DAT populations.

Real-world effectiveness of cladribine for Australian patients with multiple sclerosis: An MSBase registry substudy

BACKGROUND/OBJECTIVE

Observational clinical data from cladribine-treated patients with relapsing forms of multiple sclerosis (MS) were recorded in the Australian MS registry powered by the MSBase registry platform (5-year follow-up) and analysed to complement information from the pivotal cladribine clinical trials in MS.

METHODS

A cohort of 90 cladribine-treated patients with follow-up data reported by treating physicians and recorded in the Australian MSBase registry (database lock February 2016) were examined. Clinical data included Expanded Disability Status Scale (EDSS) scores, relapses and other disease-modifying drugs (DMDs) administered before and after cladribine treatment.

RESULTS

Mean age on starting cladribine was 47 years; mean age at MS onset was 34 years, and median baseline EDSS score was 5.25. Disability trajectories in patients with sufficient follow-up suggested an overall increasing trend prior to cladribine treatment which was reduced during the 2-year post-treatment. Approximately 80% of patients were EDSS progression-free, 65% remained relapse-free after 2 years and median time to next DMD was 1.7 years.

CONCLUSION

These observational data suggest a disease-modifying effect in this cohort of relapsing MS patients characterised by older and more disabled patients. Since these data represent a single-arm cohort, clinical trials and larger comparative post-marketing studies are needed to validate and extend these findings.

Long-Term Disease Stability Assessed by the Expanded Disability Status Scale in Patients Treated with Cladribine Tablets 3.5 mg/kg for Relapsing Multiple Sclerosis: An Exploratory Post Hoc Analysis of the CLARITY and CLARITY Extension Studies

INTRODUCTION

In the Cladribine Tablets Treating Multiple Sclerosis Orally (CLARITY) study, cladribine tablets significantly reduced relapse rates and improved findings on magnetic resonance imaging versus placebo in patients with relapsing multiple sclerosis. In the CLARITY Extension study, treatment with cladribine tablets for 2 years followed by placebo for 2 years produced similar clinical benefits to 4 years of cladribine tablets. The objective of this exploratory post hoc analysis was to evaluate long-term disease stability (assessed by the Expanded Disability Status Scale [EDSS] score) after treatment with cladribine tablets.

METHODS

Patients enrolled into CLARITY Extension who were previously randomized to cladribine tablets 3.5 mg/kg in the CLARITY study were included in this post hoc analysis. Two treatment groups were investigated-patients randomized to cladribine tablets 3.5 mg/kg in CLARITY and thereafter randomized to placebo in CLARITY Extension (the CP3.5 group) or to cladribine tablets 3.5 mg/kg in CLARITY Extension (the CC7 group). In each treatment group, EDSS scores at 6-month intervals, EDSS score improvement/worsening each year, and time to 3- and 6-month confirmed EDSS progression were assessed from CLARITY baseline over 5 years of follow-up (including a variable bridging interval between studies). All analyses are descriptive, and no statistical comparisons were performed for between-treatment group differences.

RESULTS

The median (95% confidence interval [CI]) EDSS score for patients in the CP3.5 group at 5 years was 2.5 (2.0-3.5) compared with 3.0 (2.5-3.5) at baseline. In the CC7 group, median EDSS score (95% CI) at 5 years was 2.0 (2.0-3.0) compared with 2.5 (2.5-3.0) at baseline. During year 5 for the CP3.5 group, and based on changes in minimum score each year, EDSS score stability was observed in 53.9% of patients, improvement in 21.3%, and worsening in 24.7%. In the CC7 group, EDSS score remained stable in 66.1%, improved in 18.1%, and worsened in 15.8% of patients. Over 70% of patients in both treatment groups did not show 3- or 6-month confirmed EDSS progression at 5 years from CLARITY baseline.

CONCLUSIONS

These findings confirm long-term beneficial effects on disability afforded by either the recommended dose of cladribine tablets over 4 years (cumulative dose, 3.5 mg/kg) or a higher cumulative dose.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00213135 (CLARITY); NCT00641537 (CLARITY Extension).

The efficacy of cladribine tablets in CIS patients retrospectively assigned the diagnosis of MS using modern criteria: Results from the ORACLE-MS study

Background

Multiple sclerosis (MS) diagnostic criteria have changed since the ORACLE-MS study was conducted; 223 of 616 patients (36.2%) would have met the diagnosis of MS vs clinically isolated syndrome (CIS) using the newer criteria.

Objective

The objective of this paper is to assess the effect of cladribine tablets in patients with a first clinical demyelinating attack fulfilling newer criteria (McDonald 2010) for MS vs CIS.

Methods

A post hoc analysis for subgroups of patients retrospectively classified as fulfilling or not fulfilling newer criteria at the first clinical demyelinating attack was conducted.

Results

Cladribine tablets 3.5 mg/kg (n = 68) reduced the risk of next attack or three-month confirmed Expanded Disability Status Scale (EDSS) worsening by 74% vs placebo (n = 72); p = 0.0009 in patients meeting newer criteria for MS at baseline. Cladribine tablets 5.25 mg/kg (n = 83) reduced the risk of next attack or three-month confirmed EDSS worsening by 37%, but nominal significance was not reached (p = 0.14). In patients who were still CIS after applying newer criteria, cladribine tablets 3.5 mg/kg (n = 138) reduced the risk of conversion to clinically definite multiple sclerosis (CDMS) by 63% vs placebo (n = 134); p = 0.0003. Cladribine tablets 5.25 mg/kg (n = 121) reduced the risk of conversion by 75% vs placebo (n = 134); p < 0.0001.

Conclusions

Regardless of the criteria used to define CIS or MS, 3.5 mg/kg cladribine tablets are effective in patients with a first clinical demyelinating attack.

ClinicalTrials.gov registration: The ORACLE-MS study (NCT00725985).

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, alemtuzumab, and natalizumab in the treatment of relapsing-remitting multiple sclerosis with high disease activity in England

AIMS

Cladribine tablets were the first oral short-course treatment approved for highly active relapsing multiple sclerosis (MS). The Association of British Neurologists guidelines currently recommend two infusion therapies, alemtuzumab and natalizumab, to treat high disease activity relapsing remitting MS (HDA-RRMS). This analysis assessed the cost-effectiveness of cladribine tablets in HDA-RRMS compared with alemtuzumab and natalizumab, from the perspective of the National Health Service (NHS) in England.

MATERIALS AND METHODS

A cohort-based Markov model with 11 health states (10 Expanded Disability Status Scale [EDSS] plus death) was developed. Transition matrices from the British Columbia registry were used to model the natural history of EDSS. The treatment effect on EDSS was modelled using hazard ratios for 6-month confirmed disability progression from an indirect treatment comparison (ITC). Relapses and drug-related adverse events were modeled via annualized relapse rates and event probabilities, with associated costs and quality-adjusted life year (QALY) losses. Utilities were derived from trials and the literature, and costs from NHS and literature sources. Uncertainty was assessed via probabilistic and deterministic sensitivity analyses.

RESULTS

Cladribine tablets were dominant (i.e., less costly and more effective) vs alemtuzumab and natalizumab in pairwise comparisons, and the dominant strategy in fully incremental analyses. Incremental cost was driven largely by drug acquisition and administration costs, and incremental QALY gain largely by differences in delayed EDSS progression. Cladribine tablets had a 93% probability of being cost-effective at a threshold of GBP 30,000 per QALY gained, and remained dominant across the scenario analyses tested. The greatest influence on results was the treatment effect on disability progression derived from the ITC.

LIMITATIONS

Uncertainty over the efficacy of DMT beyond trial durations. In line with other comparative effectiveness analyses, the network meta-analysis informing this cost-effectiveness analysis was associated with a degree of uncertainty. No treatment switching analyses were undertaken.

CONCLUSIONS

Cladribine tablets are a cost-effective alternative to alemtuzumab and natalizumab in the treatment of HDA-RRMS from the perspective of the NHS in England.

Long-term follow-up of patients with relapsing multiple sclerosis from the CLARITY/CLARITY Extension cohort of CLASSIC-MS: An ambispective study

BACKGROUND

CLASSIC-MS evaluated the long-term efficacy of cladribine tablets in patients with relapsing multiple sclerosis.

OBJECTIVE

Report long-term mobility and disability beyond treatment courses received in CLARITY/CLARITY Extension.

METHODS

This analysis represents CLASSIC-MS patients who participated in CLARITY with/without participation in CLARITY Extension, and received ⩾1 course of cladribine tablets or placebo (N = 435). Primary objective includes evaluation of long-term mobility (no wheelchair use in the 3 months prior to first visit in CLASSIC-MS and not bedridden at any time since last parent study dose (LPSD), i.e. Expanded Disability Status Scale (EDSS) score <7). Secondary objective includes long-term disability status (no use of an ambulatory device (EDSS < 6) at any time since LPSD).

RESULTS

At CLASSIC-MS baseline, mean ± standard deviation EDSS score was 3.9 ± 2.1 and the median time since LPSD was 10.9 (range = 9.3-14.9) years. Cladribine tablets-exposed population: 90.6% (N = 394), including 160 patients who received a cumulative dose of 3.5 mg/kg over 2 years. Patients not using a wheelchair and not bedridden: exposed, 90.0%; unexposed, 77.8%. Patients with no use of an ambulatory device: exposed, 81.2%; unexposed, 75.6%.

CONCLUSION

With a median 10.9 years' follow-up after CLARITY/CLARITY Extension, findings suggest the sustained long-term mobility and disability benefits of cladribine tablets.

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.

COVID-19 in patients with multiple sclerosis treated with cladribine tablets: An update

Background

We previously summarized outcomes for 46 cladribine tablets (CladT)-treated patients with multiple sclerosis (MS) and confirmed or suspected COVID-19, as reported to the Merck KGaA Global Patient Safety Database. This report updates on these findings, to 15 January 2021, for a total of 272 reported cases of COVID-19 among CladT recipients.

Methods

Case definitions: confirmed (COVID-19 diagnostic test was positive); suspected (no confirmatory test performed/reported). Cases fulfilling the criteria of hospitalized, medically significant, or fatal were designated as serious and outcomes were classified per usual pharmacovigilance practice.

Results

The evaluable cohort comprised 261 patients (confirmed COVID-19, n=160; suspected, n=101); an additional 11 patients had symptoms compatible with COVID-19 but were not evaluated further given their negative diagnostic tests. Median time to onset of COVID-19 from the most recent preceding CladT treatment course was 162 days (n=139). Outcomes were: recovered/recovering, n=133 (51%); not recovered/not resolved, n=19 (7%); died, n=1 (0.4%); and not reported/missing/pending, n=108 (41%). Of the total cohort, 40 (15%) experienced serious COVID-19.

Conclusion

Our results suggest that CladT-treated patients with MS are generally not at greater risk of serious disease and/or a severe outcome with COVID-19 compared with the general population and other patients with MS who acquired COVID-19.

Effectiveness and safety profile of cladribine in an Italian real-life cohort of relapsing-remitting multiple sclerosis patients: a monocentric longitudinal observational study

INTRODUCTION

Cladribine is approved for the treatment of active relapsing MS (RRMS), but its positioning in MS therapeutic scenario still needs to be fully elucidated.

METHODS

This is a monocentric, observational, real-world study on RRMS patients treated with cladribine. Relapses, magnetic resonance imaging (MRI) activity, disability worsening, and loss of no-evidence-of-disease-activity-3 (NEDA-3) status were assessed as outcomes. White blood cell, lymphocyte counts and side effects were also evaluated. Patients were analyzed overall and in subgroups according to the last treatment before cladribine. The relationship between baseline characteristics and outcomes was tested to identify predictors of response.

RESULTS

Among the 114 patients included, 74.9% were NEDA-3 at 24 months. We observed a reduction of relapses and MRI activity, along with a stabilization of disability. A higher number of gadolinium-enhancing lesions at baseline was the only risk factor for loss of NEDA-3 during follow-up. Cladribine was more efficacious in switchers from first-line therapies or naïves. Grade I lymphopenia was more frequent at month 3 and 15. No grade IV lymphopenia cases were observed. Independent predictors of grade III lymphopenia were a lower baseline lymphocyte count and a higher number of previous treatments. Sixty-two patients presented at least one side effect and globally 111 adverse events were recorded, none of them was serious.

CONCLUSIONS

Our study confirms previous data on cladribine effectiveness and safety. Cladribine is more effective when placed early in the treatment algorithm. Real-world data on larger populations with longer follow-up are needed to confirm our findings.

Humoral immune response and lymphocyte levels after complete vaccination against COVID-19 in a cohort of multiple sclerosis patients treated with cladribine tablets

BACKGROUND

Patients with multiple sclerosis (MS) receiving immunomodulatory drugs were excluded from clinical trials on COVID-19 vaccines. Therefore, data regarding the efficacy of COVID-19 vaccines to induce humoral immunity in MS patients treated with B- and T-cell depleting agents is urgently warranted. Cladribine tablets are a high-efficacy disease-modifying treatment that exerts its therapeutic effect via sustained but transient lymphocyte depletion.

AIM

We report humoral responses in a German cohort of MS patients treated with cladribine tablets.

METHODS

This retrospective analysis included patients ≥18 years who were treated with cladribine tablets for relapsing MS in the first or second year and were fully vaccinated against COVID-19. Two weeks after the second vaccination at the earliest, blood samples were obtained for the assessment of anti-SARS-CoV-2 IgG antibodies, lymphocyte counts, B-cells, CD4+ T-cells, and CD8+ T-cells. Anti-SARS-CoV-2 IgG antibodies were quantified with the LIAISON® SARS-CoV-2 TrimericS IgG assay. Positivity was defined at a cutoff value of 33.8 BAU/mL.

RESULTS

In total, 38 patients (73.7% female, aged 23-66 years) were included in the analysis. Ten patients (26.3%) were treatment-naïve before initiating treatment with cladribine tablets. Most patients (84.2%) received mRNA vaccines. The time between the last dose of cladribine tablets and vaccination ranged between 2 and 96 weeks. Six patients (15.8%) were vaccinated within 4 weeks of their last cladribine dose. All patients achieved positive anti-SARS-CoV-2 IgG antibody levels. Humoral immune response was independent of age, time of vaccination in relation to the last cladribine dose, lymphocyte counts as well as B- and T-cell counts.

CONCLUSIONS

Treatment with cladribine tablets did not impair humoral response to COVID-19 vaccination. Time since last cladribine dose, age, prior therapy, lymphocyte count as well as B- and T-cell counts had no effect on seropositivity of anti-SARS-CoV-2 IgG antibodies.

Durability of no evidence of disease activity-3 (NEDA-3) in patients receiving cladribine tablets: The CLARITY extension study

Background:

No evidence of disease activity (NEDA-3) is a patient-centric outcome increasingly used as the goal of multiple sclerosis treatment.

Objective:

Determine treatment durability of cladribine tablets beyond 2 years considering the variable bridging interval of 0.1–116.0 weeks between CLARITY and CLARITY Extension.

Methods:

Between CLARITY and CLARITY Extension, patients transitioned from cladribine tablets 3.5 mg/kg to placebo (CP3.5 group, n = 98) or continued further treatment with cladribine tablets 3.5 mg/kg (CC7.0 group, n = 186). Treatment assignment was randomized and blinded in both CLARITY and CLARITY Extension.

Results:

The 2-year NEDA-3 in CLARITY Extension (encompassing both years of CLARITY Extension) was 29.6% in the CP3.5 group and 32.8% in the CC7.0 group. There was no evidence that treatment effect differed with varying bridging intervals. For patients in the CP3.5 group with a bridging interval of ⩽48 weeks, 1 year NEDA-3 (the first year of CLARITY Extension) was 44.4% (28/63) compared with 31.4% (11/35) in patients with a bridging interval of >48 weeks.

Conclusion:

Treatment with cladribine tablets in CLARITY, followed by either placebo or cladribine tablets in CLARITY Extension, produced sustained benefits for NEDA-3 and its constituent elements for a follow up period up to 6 years from CLARITY baseline.

Treatment satisfaction, safety, and tolerability of cladribine tablets in patients with highly active relapsing multiple sclerosis: CLARIFY-MS study 6-month interim analysis

Background Multiple sclerosis (MS) is a chronic disabling disease that is associated with negative effects on health-related quality of life (HRQoL) due to reduced physical and psychosocial functioning. Cladribine tablets 10 mg (3.5 mg/kg cumulative dose over 2 years) have been approved for the treatment of adult patients with highly active relapsing multiple sclerosis (RMS). The ongoing CLARIFY-MS study (NCT03369665; EudraCT number: 2017-002632-17) aims to assess the effect of cladribine tablets 3.5 mg/kg on HRQoL of patients with highly active RMS. Objective To report on the design of the CLARIFY-MS study, baseline patient characteristics, and results of a pre-planned interim analysis focusing on treatment satisfaction, safety, and tolerability that includes all data reported till 6 months after start of treatment. Methods The CLARIFY-MS study is a 2-year, open-label, single-arm, prospective, multicenter, phase IV study. Eligible patients with highly active RMS were assigned to receive cladribine tablets 3.5 mg/kg over 2 years. Treatment satisfaction was assessed using the Treatment Satisfaction Questionnaire for Medication (TSQM, v1.4; scale range from 0 to 100, higher values indicating higher satisfaction). Safety assessments, including occurrence of treatment-emergent adverse events (TEAEs; any adverse event reported after drug administration), serious adverse events (SAEs), and lymphocyte counts, were summarized descriptively. Results A total of 482 patients from 85 sites in Europe were treated with cladribine tablets. Mean patient age was 37.4 years, 338 (70.1%) were women, median EDSS was 2.5, and 345 (71.6%) were prior users of disease-modifying therapy (DMT). During the first 6 months after the start of treatment, and before reaching the full dose of cladribine tablets, mean TSQM global satisfaction score for the overall population was 70.4 (standard deviation, ± 18.48). The side effects score was 91.9 (± 17.68), convenience scored 86.6 (± 13.57), and effectiveness was 65.8 (± 21.14). A total of 275 patients (57.1%) reported at least one TEAE and 9 patients (1.9%) had a SAE. The majority of observed lymphopenia cases were of grade 1 or 2; 33 (6.8%) of the total study cohort had grade 3 lymphopenia, and no grade 4 lymphopenia was reported. Conclusion Patients reported high treatment satisfaction (TSQM) with cladribine tablets in this pre-planned interim analysis at 6 months. Few serious, and no unexpected, adverse events were reported, and there were no instances of grade 4 lymphopenia over the first 6 months. These preliminary data indicate good tolerability and convenience of administration of cladribine tablets in patients with highly active RMS.

Cladribine tablets versus other disease-modifying oral drugs in achieving no evidence of disease activity (NEDA) in multiple sclerosis-A systematic review and network meta-analysis

INTRODUCTION

Assuming full control of the relapsing-remitting multiple sclerosis (RRMS) is the main target for practitioners. Disease control could be defined as no clinical relapse, absence of 3-month confirmed disability progression expressed on the Expanded Disability Status Scale (EDSS), as well as no disease activity on magnetic resonance imaging (MRI). NEDA-3 (no evidence of disease activity) is a composite endpoint used primarily in clinical trials, comprising these 3 measurements of disease activity. The aim of this study is to compare cladribine tablets (CT) with oral disease-modifying drugs (DMDs) - fingolimod (FTY), dimethyl fumarate (DMF), and teriflunomide (TERI) - with regard to NEDA-3 and its clinical (relapse and disability progression) and MRI (no new T1 Gd+ lesions or no new T2 lesions or no enlargement of existing lesions) components occurrence during a 24-month follow-up.

METHODS

In June 2018, a systematic review of MEDLINE, Embase and Cochrane database was performed. Due to the lack of head-to-head trials directly comparing cladribine tablets to oral drugs of interest, an indirect network meta-analysis (NMA) was applied, with placebo as a common comparator. NMA was performed with Bayesian approach and Markov chain Monte Carlo (MCMC) method for estimating posterior distributions. Additional data used in the analysis were taken from conference abstracts or post hoc analyses of pooled data from the clinical studies.

RESULTS

Six randomised clinical trials (RCTs) presenting NEDA, with active treatment compared to placebo, were included in the NMA: CLARITY (CT), FREEDOMS and FREEDOMS II (FTY), CONFIRM and DEFINE (DMF) and TEMSO (TERI). The rate of NEDA-3 was significantly higher in cladribine tablets vs DMF: OR (odds ratio)=1.76 (95% CrI [credible intervals]: 1.02-3.03) and TERI: OR=2.78 (95% CrI: 1.60-4.83), but not vs FTY. For the MRI NEDA results were as follows - cladribine tablets vs DMF: OR=1.87 (95% CrI: 1.18-2.97); cladribine tablets vs TERI: OR=6.59 (95% CrI: 4.32-10.09); cladribine tablets vs FTY: OR=1.58 (95% CrI: 1.10-2.29). The comparison of clinical NEDA did not reach significance vs either DMF or TERI and evaluation vs FTY was not possible because of lack of data.

CONCLUSIONS

Cladribine in the form of tablets was significantly more effective in achieving NEDA-3 than DMF and TERI, but there was no significant difference vs FTY. Cladribine tablets was more effective than all oral comparators considering the MRI NEDA. For clinical NEDA, the superiority vs DMF and vs TERI was not confirmed, and vs FTY evaluation was not possible.

Effect of cladribine on COVID-19 serology responses following two doses of the BNT162b2 mRNA vaccine in patients with multiple sclerosis

BACKGROUND

multiple sclerosis (MS) patients are treated with immunomodulatory treatments that can influence their ability to develop a protective antibody response to the SARS-CoV-2 vaccine. Vaccine efficacy is important for treatment decision and for patients' reassurance. The main objective is to assess antibody response to SARS-CoV-2 vaccine in MS patients treated with cladribine.

METHODS

Serology response was tested in 97 participants, 67 MS patients and 30 healthy controls (HCs), using two independent methods, 2-3 weeks following the second dose of the BNT162b2 vaccine.

RESULTS

HCs (n = 30) and MS patients treated with cladribine (n = 32) had 100% positive serology response against the SARS-CoV-2 spike protein following the second vaccine dose (mean S1/S2-IgG and RBD-IgG:284.5 ± 104.9, 13,041±9411 AU/mL and 226.3 ± 121.4, 10,554±11,405 AU/mL respectively). Comparable findings were observed for untreated MS patients, and interferon beta-1a-treated MS patients (mean S1/S2-IgG: 282.1 ± 100.1, 276.9 ± 94.31 AU/mL respectively). No correlation was found between lymphocyte counts, treatment duration, or time between cladribine dose and vaccination, and serology response or antibody titers.

CONCLUSION AND RELEVANCE

Cladribine treated MS patients are able to produce antibodies to the SARS-CoV-2 mRNA vaccine. In the era of the COVID-19 pandemic, it is reassuring and important for both patients and physicians and will allow to develop consensus guidelines.

Cladribine Tablets and Relapsing-Remitting Multiple Sclerosis: A Pragmatic, Narrative Review of What Physicians Need to Know

Immune reconstitution therapy (IRT) is an emerging management concept for multiple sclerosis, whereby a short course of treatment provides long-lasting suppression of disease activity. "Cladribine tablets 10 mg" refers to a total cumulative dose of cladribine given over 2 years (henceforth referred to as cladribine tablets 3.5 mg/kg); it is a relatively new treatment option that is hypothesised to act as an IRT acting preferentially on the adaptive immune system. A randomised, 2-year, placebo-controlled trial (CLARITY) showed that treatment with cladribine tablets reduced indices of disease activity (relapses, lesions on magnetic resonance images, disability progression) and that this effect outlasted the pharmacologic effect of the treatment on the immune system (mainly a reduction in circulating B and T cells, with little effect on components of the innate immune system such as monocytes). CLARITY Extension, a 2-year extension to this trial, demonstrated durable efficacy, also in patients who received the standard 2-year course of cladribine tablets 3.5 mg/kg and were re-randomised to placebo for a further 2 years. Relative risk reductions for relapse rate with cladribine tablets 3.5 mg/kg were similar for patients with or without prior high disease activity. Reductions in disability progression with cladribine tablets 3.5 mg/kg were higher in patients with prior high relapse rates with or without prior treatment non-response. In this review, we describe the therapeutic profile of cladribine tablets 3.5 mg/kg and provide practical information on initiating this treatment option in the most appropriate patients.

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.

Subgroup analysis of clinical and MRI outcomes in participants with a first clinical demyelinating event at risk of multiple sclerosis in the ORACLE-MS study

BACKGROUND

In the Phase 3, 96-week ORACLE-MS study, cladribine 10 mg tablets (3.5 mg/kg or 5.25 mg/kg cumulative dose over 2 years) significantly reduced the rate of conversion to clinically definite multiple sclerosis (CDMS) per the Poser criteria (henceforth referred to as CDMS), multiple sclerosis (MS) per the 2005 McDonald criteria, and the number of new or persisting T1 gadolinium-enhancing (Gd+), new or enlarging T2, and combined unique active (CUA) lesions versus placebo in participants with a first clinical demyelinating event (FCDE). Patient demographic and disease characteristics may be predictors of disease progression. The current study analyzed the effect of cladribine tablets in subgroups of participants in the ORACLE-MS study by baseline demographics and disease characteristics.

METHODS

This analysis retrospectively examined data collected from 616 participants enrolled in the ORACLE-MS study (placebo, n=206; cladribine tablets 3.5 mg/kg, n=206; cladribine tablets 5.25 mg/kg, n=204). Five subgroups were predetermined by baseline demographics, including sex, age (<30 or ≥30 years), classification of FCDE, and lesion characteristics, including absence or presence of T1 Gd+ lesions and number of T2 lesions (<9 or ≥9). Selected endpoints of the ORACLE-MS study were re-analyzed for these subgroups. The primary and main secondary endpoints were time to conversion to CDMS and MS (2005 McDonald criteria), respectively. Secondary magnetic resonance imaging (MRI) endpoints included cumulative T1 Gd+ and new or enlarging T2 lesions. Cox proportional hazards models were used to evaluate time to conversion to CDMS and MS (2005 McDonald criteria). This analysis focused primarily on the results for the cladribine tablets 3.5 mg/kg group because this dosage is approved for relapsing forms of MS.

RESULTS

In the overall intent-to-treat (ITT) population, cladribine tablets 3.5 mg/kg significantly reduced the risk of conversion to CDMS (hazard ratio [HR]=0.326; P<0.0001) and MS (2005 McDonald criteria; HR=0.485; P<0.0001) versus placebo. Similar effects of cladribine tablets on risk of conversion were observed in post hoc analyses of subgroups defined by various baseline characteristics. In both the ITT population and across subgroups, cladribine tablets 3.5 mg/kg reduced the numbers of cumulative T1 Gd+ (range of rate ratios: 0.106-0.399), new or enlarging T2 (range of rate ratios: 0.178-0.485), and CUA (range of rate ratios: 0.154-0.384) lesions versus placebo (all nominal P<0.03). Multivariate Cox proportional hazards models revealed that age (HR=0.577, nominal P<0.0001), FCDE classification (HR=0.738, nominal P=0.0043), presence of T1 Gd+ lesions (HR=0.554, nominal P<0.0001), and number of T2 lesions (HR=0.417, nominal P<0.0001) at baseline were factors associated with risk of conversion to MS (2005 McDonald criteria), whereas no baseline factors examined were associated with risk of conversion to CDMS.

CONCLUSION

In this post hoc analysis of the ORACLE-MS study, cladribine tablets reduced the risk of conversion to multiple sclerosis and lesion burden in participants with an FCDE in the overall ITT population and multiple subgroups defined by baseline demographics and lesion characteristics.

Multicentre Observational Study of Treatment Satisfaction with Cladribine Tablets in the Management of Relapsing Multiple Sclerosis in the Arabian Gulf: The CLUE Study

INTRODUCTION

Inconvenient administration and side effects of some disease-modifying therapies (DMTs) for relapsing multiple sclerosis (RMS) can deter adherence. We evaluated treatment satisfaction with cladribine tablets (CladT) for RMS in the Arabian Gulf.

METHODS

This was a non-interventional, multicentre, prospective observational study in non-pregnant/lactating adults (aged ≥ 18 years) with RMS eligible for 1st treatment with CladT (EU labelling). The primary outcome was overall treatment satisfaction at 6 months (Treatment Satisfaction Questionnaire for Medication [TSQM]-14, v. 1.4), Global Satisfaction subscale. Secondary endpoints were TSQM-14 scores for convenience, satisfaction with side effects and satisfaction with effectiveness. Patients provided written informed consent.

RESULTS

Of 63 patients screened, 58 received CladT and 55 completed the study. Mean age was 33 ± 9 years; mean weight 73 ± 17 kg; 31% male/69% female; mostly from the United Arab Emirates (52%) or Kuwait (30%). All had RMS (mean 0.9 ± 1.1 relapses in the past year), mean Expanded Disability Status Scale (EDSS) 1.4 ± 1.2; 36% were DMT-naïve. Mean [95% CI] score was high for overall treatment satisfaction (77.8 [73.0-82.6]), ease of use (87.4 [83.7-91.0]), tolerability (94.2 [91.0-97.3]) and effectiveness (76.2 [71.6-80.7]). Scores were similar irrespective of DMT history, age, gender, relapse history or EDSS. No relapses or serious treatment-emergent adverse events (TEAE) occurred. Two severe TEAE occurred (fatigue, headache) and 16% reported lymphopenia (two cases of grade 3 lymphopenia). Absolute lymphocyte counts at baseline and 6 months were 2.2 ± 0.8 × 109/L and 1.3 ± 0.3 × 109/L, respectively.

CONCLUSIONS

Treatment satisfaction, ease of use, tolerability and patient-perceived effectiveness for CladT were high, irrespective of baseline demographics, disease characteristics and prior treatment.

Real-world use of cladribine tablets (completion rates and treatment persistence) in patients with multiple sclerosis in England: The CLARENCE study

BACKGROUND

Treatment with cladribine tablets, a high-efficacy disease-modifying therapy (DMT), has been available in England since 2017 for patients with highly active relapsing multiple sclerosis (MS). Real-world data on treatment completion, persistence and switching in patients treated with cladribine tablets are beginning to emerge, but only small single and multicentre cohorts have reported so far. This longitudinal retrospective observational study (CLARENCE) evaluated a large cohort (>1900) of patients with highly active relapsing MS, receiving cladribine tablets across England, to determine rates of treatment completion, persistence and switching in the real world.

METHODS

Using data obtained from Blueteq® forms, a compulsory requirement for DMT reimbursement in England, we evaluated rates of treatment completion (defined as the proportion of patients who received the full 2-year course of cladribine tablets), treatment persistence (defined as the proportion of patients who did not switch and/or discontinue treatment before receiving the full 2-year course) and treatment switch (defined as the proportion of patients who switched treatment from cladribine tablets to another DMT at any point after their first course). The change in Expanded Disability Status Scale (EDSS) score between Years 1 and 2 of treatment was also determined. All data were analysed descriptively.

RESULTS

Blueteq® forms were completed for 1934 MS patients treated with cladribine tablets; of these patients, 691 (36%) were treatment naïve. The median EDSS score (range) at treatment initiation with cladribine tablets was 2.5 (0, 8.5). At time of analysis (September 2021, last follow-up point), a total of 1020 (53%) patients had completed the full 2-year course of cladribine tablets. At the same time point, 1762 (91%) patients were considered as treatment persistent (i.e., the patient had completed either 1 course of tablets with <18 months of follow-up data or the full 2-year course of cladribine tablets). Overall, 78 (4%) patients switched to another DMT at any point after their first course, which included 33 (1.7%) patients who switched after completing the full 2-year course. In terms of their disability, 469 (84%) patients had stable EDSS scores between Years 1 and 2 of treatment.

CONCLUSION

In this large real-world study of patients receiving cladribine tablets across England, high rates of treatment persistence and low rates of switching were observed, with only 1.7% of patients receiving the full 2-year course and switching treatment. The majority (84%) of evaluable patients showed stable disability between Years 1 and 2 of treatment. These findings complement earlier data from clinical trials and real-world studies, confirming the effectiveness of cladribine tablets for patients with highly active relapsing MS.

Expert Narrative Review of the Safety of Cladribine Tablets for the Management of Relapsing Multiple Sclerosis

Cladribine tablets (CladT) is a highly active oral disease-modifying therapy (DMT) for the management of relapsing multiple sclerosis (RMS). CladT acts as an immune reconstitution therapy, in that two short courses of treatment 1 year apart have been shown to suppress disease activity for a prolonged period in most patients, without need for continued DMT. Each course of CladT induces a profound reduction in B lymphocytes that recovers over months, and serious lymphopenia (Grade 3-4) is uncommon. Smaller reductions in levels of T lymphocytes occur slightly later: on average, these remain within the normal range and repopulate progressively. A larger effect occurs on CD8 vs. CD4 cells. Reactivation of latent or opportunistic infections (e.g. varicella zoster, tuberculosis) is mostly associated with very low lymphocyte counts (< 200/mm3). Screening and managing pre-existing infections, vaccinating non-exposed patients and delaying the 2nd year of treatment with CladT to allow lymphocytes to recover to > 800/mm3 (if necessary) are important for avoiding infections and higher-grade lymphopenia. There was no demonstrable or apparent effect of CladT on the efficacy of vaccinations, including against Covid-19. Adverse events consistent with drug-induced liver injury (DILI) represent a rare but potentially serious complication of CladT therapy in spontaneous adverse event reporting; patients should be screened for liver dysfunction before starting treatment. Ongoing hepatic monitoring is not required, but CladT must be withdrawn if signs and symptoms of DILI develop. There was a numerical imbalance for malignancies when comparing cladribine to placebo in the clinical programme, particularly in short-term data, but recent evidence shows that the risk of malignancy with CladT is similar to the background rate in the general population and to that with other DMTs. Overall, CladT is well tolerated with a favorable safety profile appropriate for the management of RMS.

Comparative effectiveness of cladribine tablets versus fingolimod in the treatment of highly active multiple sclerosis: A real-world study

BACKGROUND

Cladribine tablets and fingolimod have similar marketing authorisations in Europe for the treatment of patients with highly active relapsing multiple sclerosis (HA-RMS). In the absence of direct head-to-head studies, real-world data are important to assess the comparative effectiveness of these oral disease-modifying therapies (DMTs). The primary objective of the present study was to compare relapse rates between patients who received either cladribine tablets or fingolimod.

METHODS

This multicentre retrospective study conducted in the United Kingdom and Germany assessed non-inferiority in relapse rates of cladribine tablets versus fingolimod in HA-RMS patients over a 12-month period. Eligible patients who initiated treatment with cladribine tablets or fingolimod at least 12 months prior to the screening date were sampled consecutively until the target sample size was reached. Patients were censored at discontinuation of study treatment, commencement of another DMT, death, loss to follow-up, or at 12 months post-baseline, whichever happened earliest. The primary analytic timeframe for physician-confirmed relapse outcomes was the study effectiveness period (nine months of follow-up after an initial 12 weeks of treatment). Propensity score analysis was applied based on the inverse probability of treatment weighting approach.

RESULTS

The primary analytic cohort consisted of 1,095 HA-RMS patients: 610 (55.7%) receiving cladribine tablets and 485 (44.3%) receiving fingolimod. Fewer patients discontinued cladribine tablets and/or switched to another DMT compared with fingolimod (0.2% versus 3.5%, respectively). The primary endpoint, adjusted annualised relapse rate (ARR), was 0.10 (95% confidence interval [CI]: 0.07-0.14) for cladribine tablets and 0.14 (95% CI: 0.10-0.20) for fingolimod. The adjusted ARR ratio of cladribine tablets versus fingolimod was 0.68 (95% CI: 0.42-1.11). Given the entire 95% CI was less than the non-inferiority margin of 1.2, cladribine tablets was non-inferior to fingolimod.

CONCLUSIONS

In this real-world retrospective cohort study, cladribine tablets demonstrated comparable effectiveness to fingolimod at one year following treatment initiation. The full treatment dosage of cladribine tablets is completed over two years and so these results may be conservative.

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.