Long-term safety data from the cladribine tablets clinical development program in multiple sclerosis.

BACKGROUND: Long-term safety data are of particular interest for any newly approved treatment in multiple sclerosis such as cladribine tablets 10 mg (MAVENCLAD®; 3.5 mg/kg cumulative dose over 2 years, referred to as cladribine tablets 3.5 mg/kg), which is approved in Europe and the USA. Here we provide the final report on the integrated analysis of the safety profile of cladribine tablets 3.5 mg/kg from the clinical development program, including final data from the PREMIERE registry. METHODS: Safety data for cladribine tablets 3.5 mg/kg from three previously reported Phase III studies (CLARITY, CLARITY Extension and ORACLE-MS), as well as the prospective, observational PREMIERE registry (which ran from November 2009 to October 2018; consisting of patients who had participated in at least one of the Phase III trials) were combined to provide the Monotherapy Oral cohort. Serious adverse events (SAEs) and predefined SAEs of special interest were recorded. Observation-adjusted incidence rates per 100 patient-years (Adj-AE per 100 PY) were used to assess adverse events (AEs). Standardized incidence ratios for malignancies were calculated in relation to a matched GLOBOCAN reference population, and risk differences (cladribine tablets versus placebo) were estimated. RESULTS: The Monotherapy Oral cohort comprised 923 patients who received cladribine tablets 3.5 mg/kg and 641 patients who received placebo. Overall, the reported number of SAEs was higher in the cladribine tablets 3.5 mg/kg group (133/923 [14.4%] patients with at least 1 SAE), versus the placebo group (68/641 [10.6%] patients with at least 1 SAE). Four patients in the cladribine tablets 3.5 mg/kg group had lymphopenia classified as a serious event (resulting in an Adj-AE of 0.10 per 100 PY) and 2 patients had serious herpes zoster (resulting in an Adj-AE of 0.05 per 100 PY). There were no cases in the corresponding placebo groups. There was no difference between the cladribine tablets 3.5 mg/kg group and placebo in the overall incidence of infections. However herpetic infection AEs occurred more frequently in the cladribine tablets 3.5 mg/kg group (driven primarily by herpes zoster, followed by oral herpes and herpes simplex). Overall, there was a numerical imbalance in malignancy incidence between cladribine tablets 3.5 mg/kg and placebo, with an Adj-AE of 0.26 and 0.12 per 100 PY, respectively; however the difference was not statistically significant. The rate of malignancies observed with cladribine tablets 3.5 mg/kg in the final integrated safety analysis was not different from the expected rate in the matched GLOBOCAN reference population (standardized incidence ratio, 0.88; 95% CI, 0.44-1.69). CONCLUSION: Additional patient-years of observation do not significantly alter the conclusions of earlier interim analyses, and no new major safety findings were identified in this consolidated analysis of safety data of cladribine tablets 3.5 mg/kg monotherapy in patients with relapsing-remitting multiple sclerosis.

Therapy Optimization in Multiple Sclerosis: a cohort study of therapy adherence and risk of relapse.

OBJECTIVES: The objective of the Therapy Optimization in MS (TOP MS) Study was to prospectively assess the relationship between MS disease-modifying therapy (DMT) adherence and MS relapse risk over 2 years. METHODS: Potential participants were recruited for TOP MS by specialty pharmacies who dispensed glatiramer acetate and beta interferons for MS nationwide. Signed IRB-approved informed consents were returned to the pharmacies. TOP MS used electronic data capture with monthly patient entries. Adherence, measured by medication possession ratio (MPR), was derived from pharmacy shipment records. Logistic regression examined the association between protocol-defined relapses and DMT MPR (<0.5; >0.5-<0.9; >0.9). RESULTS: TOP MS enrolled 3151 persons with MS, and 2410 completed the full 2 years. Across all therapies, the mean MPR for the 2-year completer cohort of 2049 who maintained the same DMT was 0.9+0.2 (range: 0.1-1.0), with 63.8% reaching a 2-year MPR >0.9. Evaluated by categories of MPR, the proportion of participants remaining relapse-free for 24 months increased with increasing MPR, and the proportion with >1 relapses declined with increasing levels of MPR (p<0.0008). Regression analysis revealed the odds of relapse for a patient in the MPR >0.9 MPR group was 64% that of a patient in the MPR <0.5 category (p=0.02). Use of >1 DMT prior to the current one was an independent predictor of relapse. CONCLUSIONS: The study provides class III evidence that improvement in adherence to DMT for MS is associated with improved clinical outcomes as measured by relapse reduction.

MSBase: an international, online registry and platform for collaborative outcomes research in multiple sclerosis.

Observational cohort studies are a powerful tool to assess the long-term outcome in chronic diseases. This study design has been utilized in local and regional outcome studies in multiple sclerosis (MS) and has yielded invaluable epidemiological information. The World Wide Web now provides an excellent opportunity for an international, collaborative cohort study of MS outcomes. A web platform--MSBase--has been designed to collect prospective data on patients with MS. It is purely observational, enabling participating neurologists to contribute data on diagnosis, treatment and progress, to review anonymous aggregate data and to benchmark their patient population against other patient subsets or the entire dataset. MSBase facilitates collaborative research by allowing the online creation of investigator-initiated regional, national and international substudies. The registry aims to answer epidemiological questions that can only be addressed by prospective assessments of large patient cohorts. The registry is funded through the independent MSBase Foundation, and governed by an International Scientific Advisory Board. The MSBase Foundation commenced operations in July 2004 and since then, 22 neurologists from 11 countries have joined MSBase and are contributing 2400 patients to the total data pool.

Longitudinal MRI study: the effects of azathioprine in MS patients refractory to interferon beta-1b.

An open-label study was performed to assess the effectiveness of oral azathioprine (AZA) on augmenting the response to interferon beta-1b (IFNbeta-1b) in patients with treatment-refractory relapsing-remitting MS. Six IFNbeta-1b-treated MS patients with continued disease activity were studied on IFNbeta-1b and AZA therapy for a median period of 15 months. A 69% reduction in the number of contrast-enhancing lesions was observed during the combination therapy (p = 0.002).

A pilot study of recombinant insulin-like growth factor-1 in seven multiple sderosis patients.

The purpose of this open-label, crossover study was to determine the safety and efficacy of recombinant insulin-like growth factor-1 (rhIGF-1) using magnetic resonance imaging (MRI) and clinical measures of disease activity in seven multiple sderosis (MS) patients. Monthly clinical and MPI examinations were performed during a 24-week baseline and a 24-week treatment period with rhIGF-1. The primary outcome measure was contrast enhancing lesion (CEL) frequency on treatment compared to baseline. Secondary outcome measures included dinical and MRI measures of disease activity including: white matter lesion load (WMLL), magnetization transfer ratio (MTR), T1-Hypointensity volume, cervical spine cross-sectional area and proton magnetic resonance spectroscopic (MRS) imaging for determining regional metabolite ratios. rhIGF-1 (Cephalon) was administered at a dose of 50 mg subcutaneously twice a day for 6 months. rhIGF-1 was safe and well tolerated with no severe adverse reactions. There was no significant difference between baseline and treatment periods for any MRI or clinical measures of disease activity. Although rhIGF-1 did not alter the course of disease in this small cohort of MS patients, the drug was well tolerated. Further studies using rhIGF-1 alone or in combination with other therapies may be of value because of the proposed mechanism of action of this growth factor on the oligodendrocyte and remyelination.

Inactivation of peroxynitrite in multiple sclerosis patients after oral administration of inosine may suggest possible approaches to therapy of the disease.

Peroxynitrite has been implicated in the pathogenesis of multiple sclerosis (MS) and its animal model experimental allergic encephalomyelitis (EAE). Previously, we have shown that administration of uric acid (UA), a peroxynitrite scavenger, is therapeutic in EAE We have also shown that MS patients have lower levels of serum uric acid than healthy individuals or those with other neurological diseases. The aim of this investigation was therefore to raise serum UA levels in MS patients. Oral administration of UA failed to increase low serum UA levels, evidently due to its degradation by gastrointestinal bacteria. However, serum UA could be raised and maintained at elevated levels for a year and more without reported side-effects by oral administration of its precursor inosine. Three of 11 patients given inosine showed some evidence of clinical improvement and there was no sign of disease progression in the remaining patients. Gadolinium-enhanced lesions, observed in two patients before receiving inosine, could not be detected after either 10 or IS months inosine treatment These data provide evidence that serum UA levels can be readily manipulated and that the benefit of higher levels to individuals with MS should be studied further in greater number of patients.

Interferon beta-1b and intravenous methylprednisolone promote lesion recovery in multiple sclerosis.

OBJECTIVE: To determine whether lesion evolution in relapsing-remitting multiple sclerosis (RRMS) patients is altered by treatment with interferonbeta1b (IFNbeta-1b) or by intravenous methylprednisolone (IVMP) as measured by magnetization transfer imaging. METHODS: Magnetization transfer ratios (MTR) of 225 contrast enhancing lesions (CEL), in four RRMS patients were serially determined for 12 months before and 12-18 months after contrast enhancement in a baseline vs treatment trial with IFNbeta-1b. During the baseline period, 185 new CEL were identified: 76 were treated with IVMP (1 g/day x 5 days) and designated steroid CEL (S-CEL); the remaining 109 were considered baseline lesions (BCEL). During IFNbeta-1b treatment, 40 CEL (IFN-CEL) were identified. After image co-registration, regions of interest (ROIs) defining new CEL were transferred to the MTR image set to determine the mean lesion MTR on each monthly exam. The lesion MTR was compared to MTR of normal appearing white matter (NAWM) on the same exam. RESULTS: As early as 12 months prior to enhancement, the MTR of CEL was reduced compared to NAWM (mean 9.43 +/- 3.2%; P<0.001). The further reduction in MTR (28% +/- 4.0) at the time of contrast enhancement was not significantly different for BCEL, S-CEL or IFN-CEL Following enhancement, lesion recovery for IFN-CEL (P=0.02) and S-CEL (P=0.002) was significantly higher than BCEL CONCLUSION: IFNbeta-1b and IVMP reduce tissue damage and promote lesion recovery in RRMS patients. The additional benefit of IVMP compared to IFNbeta-1b may be related to its inhibitory effect on demyelination.

Enhancing magnetic resonance imaging lesions and cerebral atrophy in patients with relapsing multiple sclerosis.

OBJECTIVE: To examine the relation between the frequency of enhancing magnetic resonance imaging lesions and their characteristics of enhancement and atrophy in patients with early relapsing multiple sclerosis. DESIGN: Analysis of number of enhancing lesions, ventricular volumes and diameters, and lesion characteristics on monthly magnetic resonance imaging scans during natural history follow-up. SETTING: A clinical research institution. PATIENTS: Sixteen patients with confirmed early relapsing multiple sclerosis. MAIN OUTCOME MEASURE: Cerebral atrophy as measured by ventricular enlargement. RESULTS: Numbers of enhancing lesions correlated well with an increase of ventricular size. This correlation was strongest for patients with a high proportion of concentric ring-enhancing lesions with central contrast pallor. CONCLUSIONS: Inflammatory events, especially those within lesions with associated blood-brain barrier breakdown, affect the ensuing loss of brain parenchyma. Patients with a high proportion of lesions with central contrast pallor, which is likely associated with more extensive tissue damage, have a higher rate of atrophic changes.

Increased activated human T cell lymphotropic virus type I (HTLV-I) Tax11-19-specific memory and effector CD8+ cells in patients with HTLV-I-associated myelopathy/tropical spastic paraparesis: correlation with HTLV-I provirus load.

To discern the T cell subtype associated with T cell differentiation, the expression of CD45RA and CD27 was measured from total CD8(high) cells and from human T cell lymphotropic virus type I (HTLV-I) Tax11-19 peptide-specific CD8(+) cells in peripheral blood lymphocytes of patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Phenotypically defined memory and/or effector cells (CD45RA(-)CD27(+), CD45RA(+)CD27(-), and CD45RA(-)CD27(-)) were increased in HAM/TSP CD8(+) cells, compared with those of HTLV-I-seronegative healthy control subjects. The percentage of human leukocyte antigen (HLA)-DR-positive cells was also increased in CD8(+) cells of HAM/TSP, compared with those in HLA-DR(+)CD8(+) cells of healthy control subjects. HTLV-I provirus load correlated with the frequency of Tax11-19-specific CD8(+) cells. The high frequency of memory and/or effector type HTLV-I Tax11-19-specific CD8(+) cells suggests that continuous restimulation driven by HTLV-I antigens in vivo may be associated with the pathogenesis of HAM/TSP.

VLA-4/CD49d downregulated on primed T lymphocytes during interferon-beta therapy in multiple sclerosis.

Effects on adhesion molecules of immune cells might contribute to the mode of action of interferon-beta (IFN-beta) in multiple sclerosis (MS). We have serially monitored the cell surface expression of integrins CD49d (VLA-4) and CD11a (LFA-1) on fresh T lymphocyte subpopulations from 5 MS patients monthly for 2 months prior to treatment and for 3 months on treatment with IFN-beta1b. In parallel, we assessed inflammatory disease activity by monthly contrast-enhanced magnetic resonance imaging (MRI). IFN-beta treatment specifically downregulated CD49d expression on CD8+ and CD4+/CD45RO+ 'memory' T lymphocytes and differentially modulated the proportion of CD4+, CD8+ and CD27+ T cells. These effects may play an important role in the reduction of central nervous system cell trafficking and inflammation in MS.

Increased lymphoproliferative response to human herpesvirus type 6A variant in multiple sclerosis patients.

Several reports have suggested an association of human herpesvirus 6 (HHV-6) and multiple sclerosis (MS) based on immunohistochemical demonstration of HHV-6 antigens in inflammatory lesions, detection of increased HHV-6 specific serum antibody titers, and amplification of HHV-6 DNA from sera and cerebrospinal fluid of MS patients but not in controls. Characterization of the cellular immune response of MS patients to HHV-6 may further clarify the role of HHV-6 in MS and provide insight into the pathogenesis of this immune-mediated disease. We have compared lymphoproliferative responses to HHV-6A (U1102)-, HHV-6B (Z29)-, and HHV-7 (H7SB)-infected cell lysates in healthy controls and patients with MS. Most healthy controls (71%) proliferated to HHV-6B lysate, and fewer (33%) responded to the HHV-6A lysate. In contrast, 67% of MS patients had a lymphoproliferative response to HHV-6A, which is a significant increase in comparison with healthy controls. A similar frequency of lymphoproliferative response (78%) to HHV-6B was demonstrated in MS patients. Lymphoproliferation to HHV-7 lysate was demonstrated in 23% of healthy controls and 28% of MS patients. These results indicate that the lymphoproliferative response to the HHV-6A variant, which was recently reported to have greater neurotropism, is increased in MS patients.

Involvement of IL-15 in the pathogenesis of human T lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis: implications for therapy with a monoclonal antibody directed to the IL-2/15R beta receptor.

Human T lymphotropic virus type I (HTLV-I) is the causative agent of an inflammatory neurological disease termed HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). An ongoing lymphocyte activation exists in patients with HAM/TSP, which was demonstrated by the spontaneous proliferation of their PBMC ex vivo. It was shown that spontaneous proliferation present in HAM/TSP is due, in part, to an IL-2/IL-2R autocrine loop. However, addition of Abs against IL-2 or IL-2R alpha only partially inhibited the spontaneous proliferation. Since IL-15 is a cytokine with similar functional characteristics to those of IL-2, we reasoned that IL-15 might be an additional growth factor that contributes to the spontaneous proliferation observed in HAM/TSP. In this study, we demonstrated that IL-15 mRNA expression was elevated in PBMC obtained from HAM/TSP patients when compared with those of the normal donors. Furthermore, we showed that the addition of blocking Abs against IL-15 or its receptor inhibited the spontaneous proliferation of HAM/TSP PBMC. Addition of Abs directed toward both IL-15 and IL-2, or their receptors, inhibited the proliferation almost completely. These data suggest the existence of two autocrine loops involving IL-15/IL-15R and IL-2/IL-2R, both contributing to the spontaneous proliferation of HAM/TSP PBMC.

HTLV-I/II seroindeterminate Western blot reactivity in a cohort of patients with neurological disease.

The human T-cell lymphotropic virus type I (HTLV-I) is associated with a chronic, progressive neurological disease known as HTLV-I-associated myelopathy/tropical spastic paraparesis. Screening for HTLV-I involves the detection of virus-specific serum antibodies by EIA and confirmation by Western blot. HTLV-I/II seroindeterminate Western blot patterns have been described worldwide. However, the significance of this blot pattern is unclear. We identified 8 patients with neurological disease and an HTLV-I/II seroindeterminate Western blot pattern, none of whom demonstrated increased spontaneous proliferation and HTLV-I-specific cytotoxic T lymphocyte activity. However, HTLV-I tax sequence was amplified from the peripheral blood lymphocytes of 4 of them. These data suggest that patients with chronic progressive neurological disease and HTLV-I/II Western blot seroindeterminate reactivity may harbor either defective HTLV-I, novel retrovirus with partial homology to HTLV-I, or HTLV-I in low copy number.

Reduction in HTLV-I proviral load and spontaneous lymphoproliferation in HTLV-I-associated myelopathy/tropical spastic paraparesis patients treated with humanized anti-Tac.

Human T-lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a neurological disease that results from an interaction of retroviral infection and immune activation. In this study, five doses (1 mg/kg) of humanized anti-Tac antibody were administered to 9 HAM/TSP patients at weeks 0, 2, 6, 10, and 14. Preliminary immunological studies on HAM/TSP patients treated with humanized anti-Tac indicate that there is a selective down-regulation of activated T cells and a decrease in the HTLV-I viral load in peripheral blood lymphocytes, most likely through the selective removal of HTLV-I-infected, activated CD4+ lymphocytes.

Direct visualization of antigen-specific T cells: HTLV-1 Tax11-19- specific CD8(+) T cells are activated in peripheral blood and accumulate in cerebrospinal fluid from HAM/TSP patients.

Human T lymphotropic virus type 1 (HTLV-1) -associated myelopathy/tropic spastic paraparesis is a demyelinating inflammatory neurologic disease associated with HTLV-1 infection. HTLV-1 Tax11-19-specific cytotoxic T cells have been isolated from HLA-A2-positive patients. We have used a peptide-loaded soluble HLA-A2-Ig complex to directly visualize HTLV-1 Tax11-19-specific T cells from peripheral blood and cerebrospinal fluid without in vitro stimulation. Five of six HTLV-1-associated myelopathy/tropic spastic paraparesis patients carried a significant number (up to 13.87%) of CD8(+) lymphocytes specific for the HTLV-1 Tax11-19 peptide in their peripheral blood, which were not found in healthy controls. Simultaneous comparison of peripheral blood and cerebrospinal fluid from one patient revealed 2.5-fold more Tax11-19-specific T cells in the cerebrospinal fluid (23.7% vs. 9.4% in peripheral blood lymphocyte). Tax11-19-specific T cells were seen consistently over a 9-yr time course in one patient as far as 19 yrs after the onset of clinical symptoms. Further analysis of HTLV-1 Tax11-19-specific CD8(+) T lymphocytes in HAM/TSP patients showed different expression patterns of activation markers, intracellular TNF-alpha and gamma-interferon depending on the severity of the disease. Thus, visualization of antigen-specific T cells demonstrates that HTLV-1 Tax11-19-specific CD8(+) T cells are activated, persist during the chronic phase of the disease, and accumulate in cerebrospinal fluid, showing their pivotal role in the pathogenesis of this neurologic disease.

Virus-triggered acquired immunodeficiency by cytotoxic T-cell-dependent destruction of antigen-presenting cells and lymph follicle structure.

Virus-induced acquired immune suppression in mice infected with lymphocytic choriomeningitis virus is shown here to be caused by the CD8+-T-cell-dependent elimination of macrophages/antigen-presenting cells. Surprisingly, this is associated with severe destruction of the follicular organization of lymphoid organs, indicating a crucial role for dendritic cells and marginal zone macrophages in maintaining follicular structure. Once established, this immunopathology cannot be readily reversed by the elimination of CD8+ effector cells. Such a T-cell-mediated pathogenesis may play a pivotal role in acquired virus-induced immunosuppression and may represent one strategy by which virus escapes immune surveillance and establishes persistent infections in initially immunocompetent hosts.

Evidence for a role of IFN gamma in control of Listeria monocytogenes in T cell deficient mice.

The role of interferon (IFN) gamma in controlling chronic infections of Listeria monocytogenes (Listeria) was studied in athymic C57BL/6 nu/nu mice, and by treating thymectomized C57BL/6 +/+ mice with monoclonal rat CD4 and CD8-specific monoclonal antibodies (Mab). Mice treated with a combination of the two T cell subset antibodies were similar to athymic, nude mice in being able to control Listeria infection, keeping the titers below 3-5 log10 bacteria per organ, but they could not eliminate them completely. Treatment with antibodies to IFN gamma of nude or CD4+ + CD8+ - T cell-depleted mice suffering from chronic Listeria infection caused a marked increase of Listeria titers in liver and spleen. This result implies a role of IFN gamma in maintaining anti-Listeria resistance in mice lacking mature T cells.

Absence of effects of thymopentin on murine host resistance to Listeria monocytogenes.

The effects of various doses of Thymopentin, the synthetic 5 aminoacid fragment of thymopoietin injected on d -4 and d -1 on murine host resistance to Listeria monocytogenes were tested. The experiments did not reveal any regular dose-effect relationship; i.e. no or only marginal (more often small negative rather than positive) effects were observed on clearance and on resistance neither during the T cell independent first hour or the first 2 days of infection in euthymic or thymus deficient nude mice, nor during the T cell dependent phase after 2 days of infection in euthymic mice. Also survival of mice was not increased in a regular dose-effect relationship with dose ranges of Thymopentin from 0.3 ng-30 mg per 30 g mouse; furthermore, injections of 3 micrograms per 30 g mouse for varying time intervals from -3 days before up to 6 days after infection had no protective effect. Thus Thymopentin apparently does not induce measurable macrophage activation directly or cannot increase macrophage activation mediated by T cells in euthymic mice nor does it induce adequate T cell responses in nude mice to promote improved resistance to Listeria.

Mechanisms of macrophage-mediated tumor cell killing: a comparative analysis of the roles of reactive nitrogen intermediates and tumor necrosis factor.

The roles of tumor necrosis factor (TNF alpha) and reactive nitrogen intermediates (RNI) as effectors of macrophage-mediated tumor cell killing were investigated in a variety of tumor cell lines. Three TNF alpha-sensitive tumor targets were also susceptible to resting bone-marrow-derived mononuclear phagocytes (BMMP). This macrophage lytic activity was markedly diminished or even abolished by anti-TNF alpha, indicating that TNF alpha is the major effector of macrophage-mediated killing of these targets. The other 21 tumor cell lines examined were resistant to TNF alpha but, in their large majority, were more or less susceptible to killing by interferon gamma (IFN gamma)- and Corynebacterium parvum (CP)-activated BMMP. Among the various analogues of L-arginine used to assess the role of L-arginine-derived RNI as mediators of macrophage tumoricidal activity, NG-monomethyl-L-arginine (NMMA) was most efficient in suppressing RNI secretion by activated macrophages. In some macrophage tumor-cell combinations, NMMA inhibited both the generation of RNI and the expression of tumoricidal activity in a dose-dependent manner, suggesting a central role for RNI as effectors. In other combinations, NMMA in concentrations that abolished secretion of RNI either affected tumor-cell killing only after its induction by IFN gamma, or not at all. The findings not only support the thesis that macrophages posses various means of coping with tumor cells but also suggest that the mechanism becoming operative is determined predominantly by the pathway of macrophage activation and the properties of the tumor-cell type.