Twenty Years of Subcutaneous Interferon-Beta-1a for Multiple Sclerosis: Contemporary Perspectives.

Multiple sclerosis (MS) is a chronic, progressive, inflammatory disorder of the central nervous system. Relapsing-remitting MS (RRMS), the most common form of the disease, is characterized by transient neurological dysfunction with concurrent accumulation of disability. Over the past three decades, disease-modifying therapies (DMTs) capable of reducing the frequency of relapses and slowing disability worsening have been studied and approved for use in patients with RRMS. The first DMTs were interferon-betas (IFN-ßs), which were approved in the 1990s. Among them was IFN-ß-1a for subcutaneous (sc) injection (Rebif®), which was approved for the treatment of MS in Europe and Canada in 1998 and in the USA in 2002. Twenty years of clinical data and experience have supported the efficacy and safety of IFN-ß-1a sc in the treatment of RRMS, including pivotal trials, real-world data, and extension studies lasting up to 15 years past initial treatment. Today, IFN-ß-1a sc remains an important therapeutic option in clinical use, especially around pregnancy planning and lactation, and may also be considered for aging patients, in which MS activity declines and long-term immunosuppression associated with some alternative therapies is a concern. In addition, IFN-ß-1a sc is used as a comparator in many clinical studies and provides a framework for research into the mechanisms by which MS begins and progresses.

Relapses in people with multiple sclerosis treated with cladribine tablets followed for up to 5 years: a plain language summary.

WHAT IS THIS SUMMARY ABOUT?: This is a summary of an article originally published in the Multiple Sclerosis Journal. The article presents the results from the CLARITY and CLARITY Extension studies, which looked at how well cladribine tablets work in treating people with multiple sclerosis (shortened to MS). Cladribine tablets are a medication approved for treating relapsing forms of MS. This study looked at how treatment with cladribine tablets affects the frequency and severity of relapses in people with MS. A relapse is when new symptoms develop or old symptoms return or get worse after a period of stability or improvement. WHAT HAPPENED IN THE STUDIES?: In the CLARITY study, 870 people received either cladribine tablets (3.5 mg/kg, the approved dose) or placebo (a dummy pill). After the CLARITY study ended, some participants who received cladribine tablets chose to take part in a second study called the CLARITY Extension study. Of these participants, 98 were given placebo for 2 more years following an interval period of up to 10 months between participating in each study. WHAT WERE THE RESULTS?: People with MS who were treated with cladribine tablets for 2 years in the CLARITY study had lower risks of any relapse compared with those given placebo. Participants taking placebo (after cladribine tablets) in the CLARITY Extension study experienced these same benefits, which continued for up to 3 more years after having received cladribine tablets in the CLARITY study. WHAT DO THE RESULTS MEAN?: Researchers concluded the recommended 2-year dosing of cladribine tablets may reduce the number and severity of relapses in people with MS for up to 5 years. Clinical Trial Registration: NCT00213135 (ClinicalTrials.gov) Clinical Trial Registration: NCT00641537 (ClinicalTrials.gov).

The effect of cladribine tablets in people with more active multiple sclerosis: a plain language summary.

WHAT IS THIS SUMMARY ABOUT?: This article summarizes the findings from a previously published article in Current Medical Research and Opinion. Cladribine tablets are an oral treatment for relapsing multiple sclerosis (shortened to MS), that are given for 4 periods of 4 to 5 days over 2 years (for a total of 20 days). In this analysis, researchers looked at the effects of taking either cladribine tablets or placebo (dummy pills) in a group of people with MS who had more active MS inflammation and had participated in a clinical study (called the CLARITY study). Some of these participants had taken prior medicines for MS. WHAT WERE THE RESULTS?: Researchers found that in people with more active MS, treatment with cladribine tablets led to a lower risk of relapse and there were more people who had no relapses. People also had a lower chance of their MS worsening and had fewer new lesions in the brain. These benefits were seen regardless of whether the participants had prior treatment. WHAT DO THE RESULTS MEAN?: Researchers concluded that in these people with more active MS, treatment with cladribine tablets led to better outcomes over 2 years compared with treatment with placebo tablets, regardless of whether the participants had taken any prior MS treatments. Clinical Trial Registration: NCT00213135 (ClinicalTrials.gov).

Analysis of frequency and severity of relapses in multiple sclerosis patients treated with cladribine tablets or placebo: The CLARITY and CLARITY Extension studies.

BACKGROUND: In the CLARITY (CLAdRIbine Tablets treating multiple sclerosis orallY) study of patients with relapsing-remitting multiple sclerosis, treatment with cladribine tablets 3.5 mg/kg (CladT) significantly reduced the annualised relapse rate (ARR) versus placebo; this effect was sustained in CLARITY Extension, without further treatment. OBJECTIVE: To assess the frequency and severity of relapses in patients treated with CladT versus placebo in CLARITY over 2 years and evaluate the durability of effect in patients who received no further treatment for 2 years in CLARITY Extension. METHODS: In this post hoc analysis, ARRs were calculated for qualifying and all relapses, and qualifying and all severe relapses (i.e. requiring steroid treatment or leading to hospitalisation) in patients treated with CladT (n = 433) and placebo (n = 437) in CLARITY, and those from the CladT group who received placebo in CLARITY Extension (n = 98). RESULTS: At Month 6, Year 1 and Year 2, patients receiving CladT had a significantly lower risk of qualifying or all relapses (all p < 0.0001), and qualifying or all severe relapses (all p < 0.005), compared with placebo. This effect was sustained in CLARITY Extension without further treatment. CONCLUSION: The results show durable efficacy of cladribine tablets 3.5 mg/kg for reducing frequency and severity of relapses in patients with relapsing-remitting multiple sclerosis.CLARITY: NCT00213135; CLARITY Extension: NCT00641537.

Cladribine as a Potential Object of Nucleoside Transporter-Based Drug Interactions.

Cladribine is a nucleoside analog that is phosphorylated in its target cells (B and T-lymphocytes) to its active triphosphate form (2-chlorodeoxyadenosine triphosphate). Cladribine tablets 10 mg (Mavenclad®), administered for up to 10 days per year in 2 consecutive years (3.5-mg/kg cumulative dose over 2 years), are used to treat patients with relapsing multiple sclerosis. Cladribine has been shown to be a substrate of various nucleoside transporters (NTs). Intestinal absorption and distribution of cladribine throughout the body appear to be essentially mediated by equilibrative NTs (ENTs) and concentrative NTs (CNTs), specifically by ENT1, ENT2, ENT4, CNT2 (low affinity), and CNT3. Other efficient transporters of cladribine are the ABC efflux transporters, specifically breast cancer resistance protein, which likely modulates the oral absorption and renal excretion of cladribine. A key transporter for the intracellular uptake of cladribine into B and T-lymphocytes is ENT1 with ancillary contributions of ENT2 and CNT2. Transporter-based drug interactions affecting absorption and target cellular uptake of a prodrug such as cladribine are likely to reduce systemic bioavailability and target cell exposure, thereby possibly hampering clinical efficacy. In order to manage optimized therapy, i.e., to ensure uncompromised target cell uptake to preserve the full therapeutic potential of cladribine, it is important that clinicians are aware of the existence of NT-inhibiting medicinal products, various lifestyle drugs, and food components. This article reviews the existing knowledge on inhibitors of NT, which may alter cladribine absorption, distribution, and uptake into target cells, thereby summarizing the existing knowledge on optimized methods of administration and concomitant drugs that should be avoided during cladribine treatment.

Review of Transporter Substrate, Inhibitor, and Inducer Characteristics of Cladribine.

Cladribine is a nucleoside analog that is phosphorylated in its target cells (B- and T-lymphocytes) to its active adenosine triphosphate form (2-chlorodeoxyadenosine triphosphate). Cladribine tablets 10 mg (Mavenclad®) administered for up to 10 days per year in 2 consecutive years (3.5-mg/kg cumulative dose over 2 years) are used to treat patients with relapsing multiple sclerosis. The ATP-binding cassette, solute carrier, and nucleoside transporter substrate, inhibitor, and inducer characteristics of cladribine are reviewed in this article. Available evidence suggests that the distribution of cladribine across biological membranes is facilitated by a number of uptake and efflux transporters. Among the key ATP-binding cassette efflux transporters, only breast cancer resistance protein has been shown to be an efficient transporter of cladribine, while P-glycoprotein does not transport cladribine well. Intestinal absorption, distribution throughout the body, and intracellular uptake of cladribine appear to be exclusively mediated by equilibrative and concentrative nucleoside transporters, specifically by ENT1, ENT2, ENT4, CNT2 (low affinity), and CNT3. Renal excretion of cladribine appears to be most likely driven by breast cancer resistance protein, ENT1, and P-glycoprotein. The latter may play a role despite its poor cladribine transport efficiency in view of the renal abundance of P-glycoprotein. There is no evidence that solute carrier uptake transporters such as organic anion transporting polypeptides, organic anion transporters, and organic cation transporters are involved in the transport of cladribine. Available in vitro studies examining the inhibitor characteristics of cladribine for a total of 13 major ATP-binding cassette, solute carrier, and CNT transporters indicate that in vivo inhibition of any of these transporters by cladribine is unlikely.

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.

Early 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 tablets 10 mg (3.5 or 5.25 mg/kg cumulative dosage over two years) significantly reduced lesions associated with multiple sclerosis versus placebo in participants following a first clinical demyelinating event (FCDE). OBJECTIVE: To determine the timing of effects of cladribine tablets on lesion activity assessed by magnetic resonance imaging (MRI). METHODS: This post hoc analysis assessed the effect of cladribine tablets versus placebo in ORACLE-MS on secondary MRI endpoints including T1 gadolinium-enhancing (Gd+), new or enlarging T2 lesions, and combined unique active lesions assessed on MRI scans performed at screening and every 3 months thereafter. RESULTS: Compared to placebo, cladribine tablets 3.5 mg/kg treatment appeared to lead to a trend of reductions in the mean number of T1 Gd+ lesions by Week 13 (first post-baseline scan: 0.37 vs. 1.00), new or enlarging T2 (0.20 vs. 1.01) and combined unique active (0.29 vs. 1.91) lesions by Week 24. Low lesion counts were maintained with cladribine tablets throughout 96 weeks. Similar results were observed with the 5.25 mg/kg dosage. CONCLUSION: In participants with an FCDE, cladribine tablets appeared to reduce lesion numbers within 13 weeks (time of first evaluation).

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.

Efficacy of cladribine tablets in high disease activity patients with relapsing multiple sclerosis: post hoc analysis of subgroups with and without prior disease-modifying drug treatment.

BACKGROUND: Relapsing-remitting multiple sclerosis (RRMS) patients with high disease activity (HDA) experience more severe disease than those without HDA. This analysis describes the efficacy of cladribine tablets 3.5 mg/kg in HDA patient subgroups that were either treated with disease-modifying drugs (DMDs) prior to study entry or were treatment naïve. METHODS: Post hoc analysis of the 96 week Cladribine Tablets Treating Multiple Sclerosis Orally (CLARITY) study compared cladribine tablets 3.5 mg/kg to placebo in subgroups of patients meeting the high relapse activity plus disease activity on treatment definition of HDA. Patients were categorized into either prior DMD treatment or DMD treatment-naïve subgroups. Endpoints included annualized relapse rate (ARR), time to first relapse, time to disability progression and magnetic resonance imaging (MRI) outcomes. No inferential statistical analyses were conducted between subgroups. RESULTS: The DMD-naïve cohort (n = 187) was larger than the prior-DMD cohort (n = 102). In both the DMD-naïve and prior-DMD cohorts, cladribine tablets were associated with a reduction in ARR (rate ratio [RR]: 0.26; 95% confidence interval [CI]: 0.16-0.42; p < .0001 and RR: 0.55; 95% CI: 0.32-0.95; p = .0324, respectively). In both subgroups, cladribine tablets increased the time to relapse versus placebo (hazard ratio [HR]: 0.36; 95% CI: 0.21-0.62; p = .0002 for DMD-naïve cohort and HR: 0.50; 95% CI: 0.24-1.02; p = .0557 for prior-DMD cohort). Significant differences were observed for all assessed disability and MRI outcomes independently of previous treatment. CONCLUSION: Post hoc evidence suggests consistent treatment benefits of cladribine tablets 3.5 mg/kg during the 96 week CLARITY study among HDA-RRMS patients who were either previously treated with DMDs or were treatment naïve.

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.

The Development of Cladribine Tablets for the Treatment of Multiple Sclerosis: A Comprehensive Review.

Cladribine is a purine nucleoside analog initially developed in the 1970s as a treatment for various blood cancers. Due to the molecule's ability to preferentially reduce T and B lymphocytes, it has been developed into an oral formulation for the treatment of multiple sclerosis (MS). The unique proposed mechanism of action of cladribine allows for the therapy to be delivered orally over two treatment-week cycles per year, one cycle at the beginning of the first month and one cycle at the beginning of the second month of years 1 and 2, with the potential for no further cladribine treatment required in years 3 and 4. This review summarizes the clinical development program for cladribine tablets in patients with MS, including the efficacy endpoints and results from the 2-year phase III CLARITY study in patients with relapsing-remitting MS (RRMS), the 2-year CLARITY EXTENSION study, and the phase III ORACLE-MS study in patients with a first clinical demyelinating event at risk for developing MS. Efficacy results from the phase II ONWARD study, in which cladribine tablets were administered as an add-on to interferon-ß therapy in patients with RRMS, are also summarized. A review of all safety data, including lymphopenia, infections, and malignancies, is provided based on data from all trials in patients with MS, including the initial parenteral formulation studies. Based on these data, cladribine tablets administered at 3.5 mg/kg over 2 years have been approved across the globe for various forms of relapsing MS. The development of cladribine tablets for the treatment of multiple sclerosis: a comprehensive review (MP4 279143 kb).

Pregnancy Outcomes During the Clinical Development Program of Cladribine in Multiple Sclerosis: An Integrated Analysis of Safety.

INTRODUCTION: Although use of contraception was pre-specified during cladribine clinical trials for multiple sclerosis, some pregnancies did occur. OBJECTIVE: This analysis reports on pregnancy outcomes in the cladribine clinical development program. METHODS: Pregnancy outcomes in female patients (direct pregnancies) and those arising from partner pregnancies (i.e., female partners of male study participants with multiple sclerosis) were evaluated from an integrated safety analysis of ten studies of cladribine in multiple sclerosis (nine clinical trials and a long-term safety registry), with patients treated with cladribine tablets, parenteral cladribine, or placebo (all-exposed cohort; 1976 patients received cladribine and 802 received placebo). Pregnancies that occurred during the 'at-risk' period for cladribine (during treatment or within 6 months thereafter) are reported as a separate group. RESULTS: In the all-exposed cohort, 70 direct pregnancies occurred among 62 female patients (cladribine, n = 49; placebo, n = 21). Pregnancy outcomes were: live births (cladribine, n = 19 [38.8%]; placebo, n = 9 [42.9%]), elective terminations (cladribine, n = 14 [28.6%]; placebo, n = 4 [19.0%]), spontaneous abortions (cladribine, n = 11 [22.4%]; placebo, n = 5 [23.8%]), and therapeutic terminations (cladribine, n = 5 [10.2%]; placebo, n = 2 [9.5%]); in the remaining placebo recipient, the pregnancy outcome was unknown. There were two reports of congenital malformations (cladribine, n = 1; placebo, n = 1), both of which occurred with pregnancies arising > 2 years after exposure to the last dose of study medication. Sixteen direct pregnancies occurred during the 'at-risk' period for cladribine; outcomes for these were: live births, n = 3 (18.8%); elective terminations, n = 10 (62.5%); spontaneous abortions, n = 2 (12.5%); and therapeutic terminations, n = 1 (6.2%). Corresponding findings for direct pregnancies among placebo recipients were (n = 11): live births, n = 5 (45.5%); elective terminations, n = 2 (18.2%); spontaneous abortions, n = 3 (27.3%); and unknown, n = 1 (9.1%). No cases of congenital malformation were reported for pregnancies during the 'at-risk' period. There were an additional nine partner pregnancies in female partners of cladribine-treated male patients, all of which resulted in live births; of these, two pregnancies occurred within the 'at-risk' period for cladribine. CONCLUSIONS: While limited by the small number of pregnancies and related data from the cladribine clinical development program, highlighting the need for further study, the observations made in the present analysis were generally consistent with epidemiological data on pregnancy outcomes for the general population or women with multiple sclerosis. There were no congenital malformations in pregnancies that occurred during cladribine treatment or within 6 months after the last dose. As the data available for cladribine-exposed pregnancies in patients with multiple sclerosis are limited, a non-interventional post-authorization safety study has been initiated to obtain more information on this subject. CLINICAL TRIAL REGISTRATION: CLARITY: NCT00213135; CLARITY Extension: NCT00641537; ORACLE MS: NCT00725985; ONWARD: NCT00436826; PREMIERE: NCT01013350.

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)-ß or placebo plus IFN-ß 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.

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.

Benefit-risk Assessment of Cladribine Using Multi-criteria Decision Analysis (MCDA) for Patients With Relapsing-remitting Multiple Sclerosis.

PURPOSE: We applied Multi-Criteria Decision Analysis (MCDA) methods in a structured benefit-risk assessment of cladribine and newer approved disease-modifying drugs (DMDs) for patients with relapsing-remitting multiple sclerosis (RRMS). METHODS: Decision conferencing with clinical neurologists as decision makers was used to create an MCDA model that incorporated available evidence on DMDs for RRMS and clinical judgments about the relevance of the evidence. Benefit-risk assessments were conducted for DMDs in both patients with RRMS and patients with RRMS with high disease activity (HDA; defined as ≥2 relapses in the previous year). Treatment options included cladribine and recently approved DMDs available in European Union countries at the time of assessment (December 2015): alemtuzumab, dimethyl fumarate, fingolimod, natalizumab, and teriflunomide. To account for the relative importance of DMD effects, scores for the MCDA model were weighted to ensure that the most clinically important attributes carried more weight in the final benefit-risk calculation. The neurologists weighted different efficacy and safety profile attributes without any reference to individual DMDs to disassociate the assessment of weights with any specific DMD. The neurologists did not do direct comparisons between DMDs. FINDINGS: The highest overall weighted preference value for the RRMS model was for dimethyl fumarate (63) followed closely by cladribine (62). For patients with RRMS and HDA, cladribine had the highest overall weighted preference value (76), followed by alemtuzumab (62) and natalizumab (61). The benefit-risk balance of cladribine in patients with RRMS and specifically patients with RRMS who exhibited HDA characterized by high relapse activity (≥2 relapses in the previous year) was more favorable than the other DMDs included in the model. IMPLICATIONS: The balance of high efficacy and the safety profile makes cladribine an important treatment option to consider, both in patients with RRMS and patients with HDA. Regular, single-country meetings could be organized to explore how differences in cultural values (scores and weights) and updated input data might affect the usefulness of MCDA in different, real-world, dynamic clinical settings.