O. Pearson
Swansea Bay University Health Board NeurologyAuthor Of 2 Presentations
LB01.02 - Phase 2 clinical trial evidence that a retinoid-X receptor agonist promotes remyelination in people with relapsing-remitting multiple sclerosis
Abstract
Background
Retinoid acid X receptor [RXR] gamma agonists promote oligodendrocyte progenitor cell differentiation and remyelination following experimental demyelination.
Objectives
To assess the safety and efficacy of bexarotene, a non-specific RXR agonist licensed for cutaneous T-cell lymphoma, as a remyelinating therapy in people with relapsing remitting multiple sclerosis.
Methods
In a double-blind, placebo-controlled, phase 2a trial (Cambridge Centre for Myelin Repair: CCMR-One), participants aged 18-50 years with relapsing remitting multiple sclerosis, stable on dimethyl fumarate for at least 6 months, were randomised to bexarotene 300mg/m2 or placebo for 6 months. The primary efficacy outcome was change in mean lesional magnetisation transfer ratio (MTR) for lesions whose baseline MTR was below the median lesional MTR for that patient. The secondary efficacy outcome was change in full-field visual evoked potential (VEP) latency in eyes with electrophysiological evidence of optic neuropathy (baseline latency >118ms). We analysed by intention to treat.
Results
52 patients were randomised 1:1 to receive six months of bexarotene or placebo. Two placebo patients withdrew before receiving study drug and one bexarotene patient withdrew consent during the trial. All bexarotene patients experienced adverse effects, notably central hypothyroidism (26 [100%]) and hypertriglyceridaemia (24 [92%, mean maximum of 6.79 mmol/L ,SD 4.4]; as well as rash (13 [50%]) and neutropenia (10 [38%]). Two discontinued placebo because of adverse events and five discontinued bexarotene because of rash [2], neutropenia, triglyceridaemia and mood disturbance. The primary efficacy outcome was negative (mean submedian lesion MTR change was 0.25pu in the bexarotene group versus 0.09pu in the placebo group, p=0.54), but in an exploratory, lesion-level analysis, though treatment difference in submedian lesions was too small to achieve significance, it was statistically significantly greater than in supermedian lesions (p=0·007). This suggests that bexarotene has a biological effect on MTR and that this effect is dependent on baseline lesional MTR. This interpretation is supported by the finding that bexarotene treatment reduced full field visual evoked potential latency compared to placebo in the 52 eyes with delayed VEPS at baseline, by 4·66 ms/eye (95% CI -8·38 -0·93; p=0·014) and in all eyes, by a per-protocol analysis, by 4.02ms/eye (P=0.015).
Conclusions
Despite a negative primary efficacy outcome, evidence from both magnetisation transfer ratio imaging and visual evoked potentials suggest that a retinoic X receptor agonist, bexarotene, promotes remyelination in people with multiple sclerosis. We have also a heterogeneous response of MS lesions to a drug promoting remyelination. Although bexarotene’s safety profile precludes its widespread use, these data support efforts to develop a selective RXR-gamma agonist.
SS02.01 - COVID-19 in people with MS: A large community-based study of the UK MS Register
Abstract
Background
The Coronavirus Disease 2019 (COVID-19) pandemic has introduced uncertainties into the multiple sclerosis (MS) community and the focus so far has been the severity of infection among people with MS (pwMS) who have COVID-19. This approach has left questions about the risk of contracting disease in pwMS unanswered which has implications as society gradually returns to normal.
Objectives
To evaluate the trend of COVID-19 incidence in pwMS, their behaviour in response to the outbreak, and the effect of their demographic and clinical characteristics on the likelihood of contracting COVID-19.
Methods
The United Kingdom MS Register (UKMSR) has been collecting demographic and MS related data since 2011 from pwMS all over the UK. On 17 March 2020, existing participants of the UKMSR were asked to join the COVID-19 study. The study was also advertised through social media. In this on-going study, pwMS answer a COVID-19 related survey at participation and a different follow-up survey every two weeks depending on whether they report COVID-19.
Results
We estimate the nationwide overall incidence of COVID-19 in pwMS as 10% (n=522) among 5237 participants until 24 June 2020. The weekly incidence peaked during the 2nd week after lockdown started on 23 March 2020 (13.2%) and remained high until it dropped to 3.5% in the 10th week. The mean (standard deviation) age of the study population was 52.4 (11.9), 76.1% (n=3985) were female, and 95.7% (n=5012) were of white ethnicity. PwMS with a higher web-based Expanded Disability Status Scale (EDSS) score are more likely to self-isolate (odds ratio [OR] 1.389, 95%CI [confidence interval] 1.333−1.447). PwMS who are taking disease modifying therapies (DMTs) and those with progressive MS tend to self-isolate more (OR 1.259, 95%CI 1.059−1.497 and OR 1.245, 95% CI 1.013−1.531, respectively). Older age, progressive MS, and white ethnicity were associated with a lower likelihood of having COVID-19 (OR 0.969, 95%CI 0.957−0.982 and OR 0.595, 95% 0.422−0.838 and OR 0.495, 95%CI 0.347−0.705, respectively). Gender, EDSS, MS Impact Scale version 29 scores and DMTs did not alter the likelihood of contracting COVID-19.
Conclusions
To our knowledge, this is the largest community-based study of COVID-19 in pwMS worldwide. The trend of COVID-19 in pwMS is comparable to that of the UK general population. During a period with strict physical distancing measures, pwMS are not at an increased risk of contracting COVID-19.