Cannabis and Cannabinoids in Multiple Sclerosis: From Experimental Models to Clinical Practice-A Review

BACKGROUND

As far as 80% of people diagnosed with multiple sclerosis (MS) experience disabling symptoms in the course of the disease, such as spasticity and neuropathic pain. As first-line symptomatic therapy is associated with important adverse reactions, cannabinoids have become increasingly popular among patients with MS. This review intends to provide an overview of the evidence of the role of cannabinoids in treating symptoms related to MS and to encourage further research on this matter.

AREAS OF UNCERTAINTY

To date, the evidence supporting the role of cannabis and its derivatives in alleviating the MS-related symptoms comes only from studies on experimental models of demyelination. To the best of our knowledge, relatively few clinical trials inquired about the therapeutic effects of cannabinoids on patients with MS, with variable results.

DATA SOURCES

We conducted a literature search through PubMed and Google Scholar from the beginning until 2022. We included articles in English describing the latest findings regarding the endocannabinoid system, the pharmacology of cannabinoids, and their therapeutic purpose in MS.

RESULTS

Evidence from preclinical studies showed that cannabinoids can limit the demyelination process, promote remyelination, and have anti-inflammatory properties by reducing immune cell infiltration of the central nervous system in mice with experimental autoimmune encephalomyelitis. Moreover, it has been established that experimental autoimmune encephalomyelitis mice treated with cannabinoids experienced a significant reduction of symptoms and slowing of the disease progression. Given the complexity of human immune and nervous systems, cannabinoids did not have the anticipated effects on human subjects. However, data obtained from clinical trials showed some beneficial results of cannabinoids as a single or as add-on therapy in reducing the spasticity and pain related to MS.

CONCLUSION

Considering their various mechanisms of action and good tolerability, cannabinoids remain an interesting therapy for spasticity and chronic pain related to MS.

P11.31.B Pseudotumor Cerebri - a rare paraneoplastic manifestation

Background

Pseudotumor Cerebri (PC) is defined by an elevated intracranial pressure of unidentified cause, associated with normal cerebrospinal fluid (CSF) composition and no cause for hypertension on the neuroimaging evaluations. The symptoms described in association are headache, papilledema, changes in vision, and sometimes tinnitus. Its pathophysiology is far from being elucidated and the mechanisms proposed are multiple. There are some cases described in the literature in which PC is the first manifestation of a systemic neoplasm, most probably due to an abnormal response of the immune system to cancerous growth. We aim to emphasize a possible connection between adenocarcinoma of the lung and PC as the first paraneoplastic manifestation.

Material and Methods

We present the case of a 59-year-old patient, female, non-obese, who presented to the hospital for severe headache, blurred vision, tinnitus, and paresthesia on both her upper limbs. On the first evaluation, the usual blood tests showed an increased creatinine level, and the subsequent abdominal echography and CT scan revealed bilateral ureter hydronephrosis, without an obvious obstacle, for which nephrostomies were implanted. On the ophthalmological evaluation bilateral papillary edema was described, although the cerebral CT with angiography and MRI showed no pathological modifications. A lumbar puncture with manometry was performed, that showed a CSF pressure of approximately 500 mmH2O.

Results

Following the clinical, imagistic, and biological manifestations, the diagnosis of PC was established. The decision to start the corticotherapy was made, followed by the addition of acetazolamide. Although the treatment tented was not efficient, the neurosurgery team decided that she is not a suitable candidate for a CSF shunting procedure and the ophthalmologist advised against an optic nerve sheath fenestration. The evolution was unfavorable, with the persistence of the symptoms. She underwent extensive investigations, the second cerebral MRI showing a slight dilation of the ventricles. On the thoracic-abdominal-pelvic CT, a pulmonary nodule with a malignant aspect was described, the histopathological results pleading for adenocarcinoma. The decision to excise the lesion was made, but after the surgery, the patient developed a cardiorespiratory arrest, without response to resuscitation.

Conclusion

Although there is scarce evidence of PC as a paraneoplastic syndrome, the evolution and investigations results support the possibility of a causal relationship. This is, to our knowledge, the second case of adenocarcinoma of the lung that primarily presents with PC. Further studies must be conducted to understand the underlying pathophysiology of this condition and to develop new treatment possibilities.

Effect of Disease-Modifying Therapy on Disability in Relapsing-Remitting Multiple Sclerosis Over 15 Years

OBJECTIVE

To test the hypothesis that immunotherapy prevents long-term disability in relapsing-remitting multiple sclerosis (MS), we modeled disability outcomes in 14,717 patients.

METHODS

We studied patients from MSBase followed for ≥1 year, with ≥3 visits, ≥1 visit per year, and exposed to MS therapy, and a subset of patients with ≥15-year follow-up. Marginal structural models were used to compare the cumulative hazards of 12-month confirmed increase and decrease in disability, Expanded Disability Status Scale (EDSS) step 6, and the incidence of relapses between treated and untreated periods. Marginal structural models were continuously readjusted for patient age, sex, pregnancy, date, disease course, time from first symptom, prior relapse history, disability, and MRI activity.

RESULTS

A total of 14,717 patients were studied. During the treated periods, patients were less likely to experience relapses (hazard ratio 0.60, 95% confidence interval [CI] 0.43-0.82, p = 0.0016), worsening of disability (0.56, 0.38-0.82, p = 0.0026), and progress to EDSS step 6 (0.33, 0.19-0.59, p = 0.00019). Among 1,085 patients with ≥15-year follow-up, the treated patients were less likely to experience relapses (0.59, 0.50-0.70, p = 10^-9) and worsening of disability (0.81, 0.67-0.99, p = 0.043).

CONCLUSION

Continued treatment with MS immunotherapies reduces disability accrual by 19%-44% (95% CI 1%-62%), the risk of need of a walking aid by 67% (95% CI 41%-81%), and the frequency of relapses by 40-41% (95% CI 18%-57%) over 15 years. This study provides evidence that disease-modifying therapies are effective in improving disability outcomes in relapsing-remitting MS over the long term.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that, for patients with relapsing-remitting MS, long-term exposure to immunotherapy prevents neurologic disability.

Delay from treatment start to full effect of immunotherapies for multiple sclerosis

In multiple sclerosis, treatment start or switch is prompted by evidence of disease activity. Whilst immunomodulatory therapies reduce disease activity, the time required to attain maximal effect is unclear. In this study we aimed to develop a method that allows identification of the time to manifest fully and clinically the effect of multiple sclerosis treatments (‘therapeutic lag’) on clinical disease activity represented by relapses and progression-of-disability events. Data from two multiple sclerosis registries, MSBase (multinational) and OFSEP (French), were used. Patients diagnosed with multiple sclerosis, minimum 1-year exposure to treatment, minimum 3-year pretreatment follow-up and yearly review were included in the analysis. For analysis of disability progression, all events in the subsequent 5-year period were included. Density curves, representing incidence of relapses and 6-month confirmed progression events, were separately constructed for each sufficiently represented therapy. Monte Carlo simulations were performed to identify the first local minimum of the first derivative after treatment start; this point represented the point of stabilization of treatment effect, after the maximum treatment effect was observed. The method was developed in a discovery cohort (MSBase), and externally validated in a separate, non-overlapping cohort (OFSEP). A merged MSBase-OFSEP cohort was used for all subsequent analyses. Annualized relapse rates were compared in the time before treatment start and after the stabilization of treatment effect following commencement of each therapy. We identified 11 180 eligible treatment epochs for analysis of relapses and 4088 treatment epochs for disability progression. External validation was performed in four therapies, with no significant difference in the bootstrapped mean differences in therapeutic lag duration between registries. The duration of therapeutic lag for relapses was calculated for 10 therapies and ranged between 12 and 30 weeks. The duration of therapeutic lag for disability progression was calculated for seven therapies and ranged between 30 and 70 weeks. Significant differences in the pre- versus post-treatment annualized relapse rate were present for all therapies apart from intramuscular interferon beta-1a. In conclusion we have developed, and externally validated, a method to objectively quantify the duration of therapeutic lag on relapses and disability progression in different therapies in patients more than 3 years from multiple sclerosis onset. Objectively defined periods of expected therapeutic lag allows insights into the evaluation of treatment response in randomized clinical trials and may guide clinical decision-making in patients who experience early on-treatment disease activity. This method will subsequently be applied in studies that evaluate the effect of patient and disease characteristics on therapeutic lag.

Redefining the Multiple Sclerosis Severity Score (MSSS): The effect of sex and onset phenotype

BACKGROUND

The Multiple Sclerosis Severity Score (MSSS) is a widely used measure of the disability progression rate. However, the global MSSS may not be the best basis for comparison between all patient groups.

OBJECTIVE

We evaluated sex-specific and onset phenotype-specific MSSS matrices to determine if they were more effective than the global MSSS as a basis for comparison within these subsets.

METHODS

Using a large international dataset of multiple sclerosis (MS) patient records and the original MSSS algorithm, we constructed global, sex-specific and onset phenotype-specific MSSS matrices. We compared matrices using permutation analysis.

RESULTS

Our final dataset included 30,203 MS cases, with 28.9% males and 6.5% progressive-onset cases. Our global MSSS matrix did not differ from previously published data (p > 0.05). The progressive-onset-specific matrix differed significantly from the relapsing-onset-specific matrix (p < 0.001), with lower MSSS attributed to cases with the same Expanded Disability Status Score (EDSS) and disease duration. When evaluated with a simulation, using an onset-specific MSSS improved statistical power in mixed cohorts. There were no significant differences by sex.

CONCLUSION

The differences in the disability accrual rate between progressive- and relapsing-onset MS have a significant effect on MSSS. An onset-specific MSSS should be used when comparing the rate of disability progression among progressive-onset cases and for mixed cohorts.

Data quality evaluation for observational multiple sclerosis registries

Objective:

Objective and reproducible evaluation of data quality is of paramount importance for studies of ‘real-world’ observational data. Here, we summarise a standardised data quality, density and generalisability process implemented by MSBase, a global multiple sclerosis (MS) cohort study.

Methods:

Error rate, data density score and generalisability score were developed using all 35,869 patients enrolled in MSBase as of November 2015. The data density score was calculated across six domains (follow-up, demography, visits, MS relapses, paraclinical data and therapy) and emphasised data completeness. The error rate evaluated syntactic accuracy and consistency of data. The generalisability score evaluated believability of the demographic and treatment information. Correlations among the three scores and the number of patients per centre were evaluated.

Results:

Errors were identified at the median rate of 3 per 100 patient-years. The generalisability score indicated the samples’ representativeness of the known MS epidemiology. Moderate correlation between the density and generalisability scores (ρ = 0.58) and a weak correlation between the error rate and the other two scores (ρ = −0.32 to −0.33) were observed. The generalisability score was strongly correlated with centre size (ρ = 0.79).

Conclusion:

The implemented scores enable objective evaluation of the quality of observational MS data, with an impact on the design of future analyses.

CAN WE REALLY PREVENT ALZHEIMER’S DISEASE?

Alzheimer’s disease, a neurodegenerative disorder that affects mainly the elderly people, was declared a public health priority by the World Health Organization. Because the main clinical manifestations are cognitive, behavioral and psychological symptoms, patients diagnosed with this disease have a significantly lower quality of life. This type of dementia has an inexorably progressive evolution so, families and health care staff, must make great efforts to provide a decent standard of living for these patients. Because it has a huge economic burden and there is no treatment to stop or cure the disease, it is important to emphasises modifiable risk factors and to apply prevention strategies, proved by scientific evidence.

Comparative effectiveness of glatiramer acetate and interferon beta formulations in relapsing–remitting multiple sclerosis

Background:

The results of head-to-head comparisons of injectable immunomodulators (interferon β, glatiramer acetate) have been inconclusive and a comprehensive analysis of their effectiveness is needed.

Objective:

We aimed to compare, in a real-world setting, relapse and disability outcomes among patients with multiple sclerosis (MS) treated with injectable immunomodulators.

Methods:

Pairwise analysis of the international MSBase registry data was conducted using propensity-score matching. The four injectable immunomodulators were compared in six head-to-head analyses of relapse and disability outcomes using paired mixed models or frailty proportional hazards models adjusted for magnetic resonance imaging variables. Sensitivity and power analyses were conducted.

Results:

Of the 3326 included patients, 345–1199 patients per therapy were matched (median pairwise-censored follow-up was 3.7 years). Propensity matching eliminated >95% of the identified indication bias. Slightly lower relapse incidence was found among patients treated with glatiramer acetate or subcutaneous interferon β-1a relative to intramuscular interferon β-1a and interferon β-1b ( p≤0.001). No differences in 12-month confirmed progression of disability were observed.

Conclusion:

Small but statistically significant differences in relapse outcomes exist among the injectable immunomodulators. MSBase is sufficiently powered to identify these differences and reflects practice in tertiary MS centres. While the present study controlled indication, selection and attrition bias, centre-dependent variance in data quality was likely.

Chronic progressive external ophtalmoplegia (CPEO) - case presentation

We present the case of a patient aged 38 years with Chronic Progressive External Ophthalmoplegia (CPEO), a slowly progressive myopathy primarily involving and often limited to the extraocular muscles. Medical history, clinical examination and laboratory studies are revealed. The implicated gene mutations and differential diagnosis are approached.

Risk of relapse phenotype recurrence in multiple sclerosis

OBJECTIVES

The aim was to analyse risk of relapse phenotype recurrence in multiple sclerosis and to characterise the effect of demographic and clinical features on this phenotype.

METHODS

Information about relapses was collected using MSBase, an international observational registry. Associations between relapse phenotypes and history of similar relapses or patient characteristics were tested with multivariable logistic regression models. Tendency of relapse phenotypes to recur sequentially was assessed with principal component analysis.

RESULTS

Among 14,969 eligible patients (89,949 patient-years), 49,279 phenotypically characterised relapses were recorded. Visual and brainstem relapses occurred more frequently in early disease and in younger patients. Sensory relapses were more frequent in early or non-progressive disease. Pyramidal, sphincter and cerebellar relapses were more common in older patients and in progressive disease. Women presented more often with sensory or visual symptoms. Men were more prone to pyramidal, brainstem and cerebellar relapses. Importantly, relapse phenotype was predicted by the phenotypes of previous relapses. (OR = 1.8-5, p = 10(-14)). Sensory, visual and brainstem relapses showed better recovery than other relapse phenotypes. Relapse severity increased and the ability to recover decreased with age or more advanced disease.

CONCLUSION

Relapse phenotype was associated with demographic and clinical characteristics, with phenotypic recurrence significantly more common than expected by chance.

Sex as a determinant of relapse incidence and progressive course of multiple sclerosis

The aim of this work was to evaluate sex differences in the incidence of multiple sclerosis relapses; assess the relationship between sex and primary progressive disease course; and compare effects of age and disease duration on relapse incidence. Annualized relapse rates were calculated using the MSBase registry. Patients with incomplete data or <1 year of follow-up were excluded. Patients with primary progressive multiple sclerosis were only included in the sex ratio analysis. Relapse incidences over 40 years of multiple sclerosis or 70 years of age were compared between females and males with Andersen-Gill and Tweedie models. Female-to-male ratios stratified by annual relapse count were evaluated across disease duration and patient age and compared between relapse-onset and primary progressive multiple sclerosis. The study cohort consisted of 11 570 eligible patients with relapse-onset and 881 patients with primary progressive multiple sclerosis. Among the relapse-onset patients (82 552 patient-years), 48,362 relapses were recorded. Relapse frequency was 17.7% higher in females compared with males. Within the initial 5 years, the female-to-male ratio increased from 2.3:1 to 3.3:1 in patients with 0 versus ≥4 relapses per year, respectively. The magnitude of this sex effect increased at longer disease duration and older age (P < 10(-12)). However, the female-to-male ratio in patients with relapse-onset multiple sclerosis and zero relapses in any given year was double that of the patients with primary progressive multiple sclerosis. Patient age was a more important determinant of decline in relapse incidence than disease duration (P < 10(-12)). Females are predisposed to higher relapse activity than males. However, this difference does not explain the markedly lower female-to-male sex ratio in primary progressive multiple sclerosis. Decline in relapse activity over time is more closely related to patient age than disease duration.

Country, sex, EDSS change and therapy choice independently predict treatment discontinuation in multiple sclerosis and clinically isolated syndrome

Objectives

We conducted a prospective study, MSBASIS, to assess factors leading to first treatment discontinuation in patients with a clinically isolated syndrome (CIS) and early relapsing-remitting multiple sclerosis (RRMS).

Methods

The MSBASIS Study, conducted by MSBase Study Group members, enrols patients seen from CIS onset, reporting baseline demographics, cerebral magnetic resonance imaging (MRI) features and Expanded Disability Status Scale (EDSS) scores. Follow-up visits report relapses, EDSS scores, and the start and end dates of MS-specific therapies. We performed a multivariable survival analysis to determine factors within this dataset that predict first treatment discontinuation.

Results

A total of 2314 CIS patients from 44 centres were followed for a median of 2.7 years, during which time 1247 commenced immunomodulatory drug (IMD) treatment. Ninety percent initiated IMD after a diagnosis of MS was confirmed, and 10% while still in CIS status. Over 40% of these patients stopped their first IMD during the observation period. Females were more likely to cease medication than males (HR 1.36, p = 0.003). Patients treated in Australia were twice as likely to cease their first IMD than patients treated in Spain (HR 1.98, p = 0.001). Increasing EDSS was associated with higher rate of IMD cessation (HR 1.21 per EDSS unit, p<0.001), and intramuscular interferon-β-1a (HR 1.38, p = 0.028) and subcutaneous interferon-β-1a (HR 1.45, p = 0.012) had higher rates of discontinuation than glatiramer acetate, although this varied widely in different countries. Onset cerebral MRI features, age, time to treatment initiation or relapse on treatment were not associated with IMD cessation.

Conclusion

In this multivariable survival analysis, female sex, country of residence, EDSS change and IMD choice independently predicted time to first IMD cessation.