Drug safety evaluation of alemtuzumab for multiple sclerosis

Long-term drug treatment in multiple sclerosis: safety success and concerns

INTRODUCTION

The portfolio of multiple sclerosis (MS) disease modifying treatments (DMTs) has significantly expanded over the past two decades. Given the lifelong use of MS pharmacotherapy, understanding their long-term safety profiles is essential in determining suitable and personalized treatment.

AREAS COVERED

In this narrative review, we summarize the short-, mid-, and long-term safety profile of currently available MS DMTs categories. In addition to the initial trial findings, safety outcomes derived from long-term extension studies (≥5-20 years) and safety-based prescription programs have been reviewed. In order to better understand the risk-benefit ratio for each particular DMT group, a short description of the DMT-based efficacy outcomes has been included.

EXPERT OPINION

Long-term extension trials, large observational studies and real-world databases allow detection of rare and potentially serious adverse events. Two-year-long trials are unable to fully capture the positive and negative effects of immune system modulation and reconstitution. DMT-based monitoring programs can provide greater insights regarding safe use of MS medications in different patient populations and clinical settings. During the process of shared DMT decision, both MS care providers and their patients should be aware of an ever-expanding number of drug-based adverse events and their influence on the risk-benefit analysis.

Effects of cladribine tablets on lymphocyte subsets in patients with multiple sclerosis: an extended analysis of surface markers

Background

Cladribine tablets 3.5 mg/kg cumulative over 2 years (CT3.5) had significant clinical/imaging effects in patients with clinically isolated syndrome (CIS; ORACLE-MS) or relapsing-remitting MS (RRMS; CLARITY and CLARITY Extension). This analysis compared the effect of cladribine tablets on the dynamics of immune cell reduction and reconstitution in ORACLE-MS, CLARITY, and CLARITY Extension during the first year of treatment (i.e. the first course of CT1.75) in patients randomized to CT3.5.

Methods

Lymphocyte subtypes were analyzed using multiparameter flow cytometry. Changes in cell counts and relative proportions of lymphocytes were evaluated at weeks 5, 13, 24, and 48.

Results

Across studies, consistent and comparable selective kinetics of immune cell populations occurred following the first treatment year with CT. A rapid reduction in CD16⁺/CD56⁺ cells (week 5 nadir), a more marked reduction in CD19⁺ B cells (week 13 nadir), and a less-pronounced effect on CD4⁺ (week 13 nadir) and CD8⁺ T cells (week 24 nadir) was shown. There was little effect on neutrophils or monocytes. Lymphocyte recovery began after treatment with CT3.5. Regarding relative proportions of naïve and memory T-cell subtypes in ORACLE-MS, the proportion of naïve-like naturally occurring T-regulatory cells (nTregs) decreased, and the proportion of memory-like nTregs increased, relative to total CD4⁺ T cells.

Conclusions

CT3.5 has comparable effects on the immune systems of patients with CIS or RRMS. The pronounced reduction and recovery dynamics of CD19⁺ B cells and relative changes in the proportion of some immune cell subtypes may underlie the clinical effects of CT3.5.

Cost-effectiveness of alemtuzumab and natalizumab for relapsing-remitting multiple sclerosis treatment in Iran: decision analysis based on an indirect comparison

BACKGROUND

Alemtuzumab and natalizumab are approved as second-line therapies for relapsing-remitting multiple sclerosis (RRMS) patients in Iran who have shown an inadequate response to other disease-modifying therapy (DMT). In the absence of head-to-head trials, evaluations based on decision analytic modeling may be a suitable alternative to compare alemtuzumab and natalizumab in RRMS.

PURPOSE

To evaluate the cost-effectiveness of alemtuzumab compared with natalizumab in RRMS in Iran, based on an indirect comparison of clinical trial data.

METHODS

A cost-utility analysis was conducted using a cohort-based Markov model to analyze cost-utility in a cohort of 1,000 RRMS patients treated with alemtuzumab or natalizumab who had failed at least one previous DMT. Costs were measured in 2018 US Dollars, and were estimated from both the societal and National Healthcare Service (NHS) perspective over a 20-year time horizon in Iran. One-way deterministic sensitivity analyses were carried out to investigate the impact of individual variables on model results.

RESULTS

Alemtuzumab dominated natalizumab in both NHS and societal perspective analyses. From the NHS perspective, the total discounted costs per patient were estimated at $147,417 and $150,579 for alemtuzumab and natalizumab, respectively, over 20 years. The discounted quality-adjusted life years were estimated to be 7.07 and 6.05, respectively. Results were similar for the societal perspective analysis. Results were most sensitive to acquisition costs and the time horizon, while no sensitivity was observed for Expanded Disability Status Scale (EDSS) health-states utility, relapse relative risk, adverse event or EDSS-related costs, and laboratory/monitoring costs.

CONCLUSION

Alemtuzumab was dominant in the treatment of RRMS compared with natalizumab due to lower total cost, greater efficacy and slowing of disease progression, and lower rate of relapses over a 20-year time horizon in Iran. Comparative head-to-head trials and long-term follow-up are needed to confirm these results.

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.

How do we manage and treat a patient with multiple sclerosis at risk of tuberculosis?

Tuberculosis continues to be a serious health problem worldwide. The disease continues to be underdiagnosed and not properly treated. In conditions that affect the immune system, such as multiple sclerosis (MS), latent tuberculosis may thrive and reactivate during the use of immunomodulatory and immunosuppressive drugs. Among the best treatment options for patients with latent or active tuberculosis who have MS are IFN-β, glatiramer acetate and mitoxantrone. Drugs leading to a reduced number and/or function of lymphocytes should be avoided or used with caution. Tuberculosis must always be investigated in patients with MS and treated with rigor.