Improving the efficiency of clinical trials in multiple sclerosis

BACKGROUND

Phase 3 clinical trials for disease-modifying therapies in relapsing-remitting multiple sclerosis (RRMS) have utilized a limited number of conventional designs with a high degree of success. However, these designs limit the types of questions that can be addressed, and the time and cost required. Moreover, trials involving people with progressive multiple sclerosis (MS) have been less successful.

OBJECTIVE

The objective of this paper is to discuss complex innovative trial designs, intermediate and composite outcomes and to improve the efficiency of trial design in MS and broaden questions that can be addressed, particularly as applied to progressive MS.

METHODS

We held an international workshop with experts in clinical trial design.

RESULTS

Recommendations include increasing the use of complex innovative designs, developing biomarkers to enrich progressive MS trial populations, prioritize intermediate outcomes for further development that target therapeutic mechanisms of action other than peripherally mediated inflammation, investigate acceptability to people with MS of data linkage for studying long-term outcomes of clinical trials, use Bayesian designs to potentially reduce sample sizes required for pediatric trials, and provide sustained funding for platform trials and registries that can support pragmatic trials.

CONCLUSION

Novel trial designs and further development of intermediate outcomes may improve clinical trial efficiency in MS and address novel therapeutic questions.

The Effect of Respiratory Viral Infections on Breakthrough Hemolysis in Patients with Paroxysmal Nocturnal Hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by hemolysis and thrombosis and is associated with significant morbidity and mortality. Although complement inhibitors have significantly changed the outcomes in PNH patients, breakthrough hemolysis (BTH) may still occur as a response to stress factors such as pregnancy, surgery, and infections. Despite the well-described association between bacterial infections and hemolysis in PNH patients, little is known about the effect of respiratory viruses on triggering hemolytic episodes. This is the first study, to our knowledge, addressing this question. We retrospectively analyzed 34 patients with PNH disease between 2016 and 2018, who were on eculizumab treatment and who presented with respiratory symptoms and were subsequently tested for 10 respiratory viruses (influenza A, influenza B, parainfluenza, respiratory syncytial virus, adenovirus, rhinovirus, and human metapneumovirus). NTS+ patients had higher inflammatory markers, with the majority requiring antibiotics. Acute hemolysis, along with a significant drop in hemoglobin, was noted in the NTS+ group, with three of them requiring a top-up transfusion and two requiring an extra dose of eculizumab. Furthermore, the time from the last eculizumab dose was longer in the NTS+ patients who had BTH, than those who did not. Our data indicate that respiratory virus infections pose a significant risk for BTH in PNH patients on complement inhibitor treatment, underlining the need for regular screening and close monitoring of patients with respiratory symptoms. Furthermore, it implies a higher risk for patients who are not established on complement inhibitors, suggesting the necessity for greater vigilance in these patients.

030 Post COVID-19 syndrome dysautonomia: a tertiary referral centre experience

(33%)

Autonomic testing showed normal blood pressure responses to pressor stimuli, a mean respiratory sinus arrhythmia of 18.89b/m, and Valsalva ratio of 2.09. Postural tachycardia syndrome (PoTS) was diagnosed in 12 patients, autonomically mediated syncope (AMS) in 11, neurogenic orthostatic hypotension (NOH) in two, and initial orthostatic hypotension (IOH) in seven.

Normal supine and upright plasma noradrenaline levels were measured in 34 patients (mean 283.38 pg/ml supine; 472.43pg/ml tilted).

Autonomic testing was reassuring (PoTS and syncope) in the majority with abnormal testing (n=32, or 52%). Further phenotyping of PoTS to exclude neuropathic pathology may be needed. IOH and OH are important considerations.

Thrombus Distribution in Vaccine-induced Immune Thrombotic Thrombocytopenia after ChAdOx1 nCoV-19 Vaccination

This case series reports 40 patients (median age, 41 years [interquartile range (IQR) 32- 52, 22 men) with confirmed vaccine-induced immune thrombotic thrombocytopaenia after administration of their first ChAdOx1 nCov-19 (AstraZeneca) vaccine: 80% (n=32) developed symptoms within the first 14 days and 20% (n=8) within 14-28 days. The location and extent of thrombi were evaluated using CT, MRI and ultrasound. Of the 40, 73% (n=29) presented with neurological symptoms and had confirmed cerebral venous sinus thrombosis, 30% (n=12) had extension of their primary thrombus, and 20% (n=8) died. 83% of those who underwent additional imaging (25 of 30) had occult thrombosis.

Cerebral venous sinus thrombosis and thrombocytopenia after COVID-19 vaccination - A report of two UK cases

Recent reports have highlighted rare, and sometimes fatal, cases of cerebral venous sinus thrombosis (CVST) and thrombocytopenia following the Vaxzevria vaccine. An underlying immunological mechanism similar to that of spontaneous heparin-induced thrombocytopenia (HIT) is suspected, with the identification of antibodies to platelet factor-4 (PF4), but without previous heparin exposure. This unusual mechanism has significant implications for the management approach used, which differs from usual treatment of CVST. We describe the cases of two young males, who developed severe thrombocytopenia and fatal CVST following the first dose of Vaxzevria. Both presented with a headache, with subsequent rapid neurological deterioration. One patient underwent PF4 antibody testing, which was positive. A rapid vaccination programme is essential in helping to control the COVID-19 pandemic. Hence, it is vital that such COVID-19 vaccine-associated events, which at this stage appear to be very rare, are viewed through this lens. However, some cases have proved fatal. It is critical that clinicians are alerted to the emergence of such events to facilitate appropriate management. Patients presenting with CVST features and thrombocytopenia post-vaccination should undergo PF4 antibody testing and be managed in a similar fashion to HIT, in particular avoiding heparin and platelet transfusions.

COVID-19 leukoencephalopathy with subacute magnetic resonance imaging findings of vasculitis and demyelination

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) commonly results in a respiratory illness in symptomatic patients; however, those critically ill can develop a leukoencephalopathy. We describe two patients who had novel subacute MRI findings in the context of coronavirus disease 2019 (COVID-19) leukoencephalopathy, which we hypothesize could implicate a potent small-vessel vasculitis, ischemic demyelination and the presence of prolonged ischemia. Recent evidence of the direct neuroinvasiness of SARS-CoV-2 leading to ischemia and vascular damage supports this hypothesis.

Development of forced normalisation psychosis with ethosuximide

A 50-year-old man with known multidrug resistant coexistent focal and generalised epilepsy was commenced on ethosuximide, with normalisation of his electroencephalogram and cessation of absence seizures. Within 3 weeks, he developed a rapidly worsening paranoid psychosis with visual and olfactory hallucinations. A month after the cessation of ethosuximide and concurrent treatment with olanzapine, his psychosis resolved and permitted reinitiation of ethosuximide at a lower dose without recurrence of psychotic symptoms.

Continuous Positive Airway Pressure: Is it a route for infection in those with Obstructive Sleep Apnoea?

INTRODUCTION

Continuous positive airway pressure (CPAP) is the standard treatment for obstructive sleep apnoea (OSA), with limited data about the prevalence of respiratory infections and microbial colonization in these patients.

OBJECTIVES

The aim of this study was to determine if CPAP use is associated with respiratory infections and to identify the organisms that colonize or infect these patients.

METHOD

A retrospective, case-controlled study in patients diagnosed with OSA was carried out. 137 patients were recruited and interviewed using a questionnaire. A nasal swab was taken from each patient. Patients using CPAP machines had swabs taken from masks and humidifiers.

RESULTS

66 (48.2%) patients received CPAP treatment with 60.6% of them having a heated humidifier. 78.8% were male, with the majority using a full face mask (63.6%). No significant difference was seen in the prevalence of rhinosinusitis, lower respiratory tract infections and hospital admissions for pneumonia between CPAP and non-CPAP treated patients. The presence of a humidifier did not influence the prevalence of infections. Commensal flora was predominantly cultured from nasal swabs from both patient groups. Coagulase Negative Staphylococci and Diphtheroids were the main organisms cultured from masks and humidifiers respectively.

CONCLUSIONS

This study shows that the use of CPAP, choice of mask and humidifier have no significant impact on the prevalence of infections and micro-organisms isolated. This is very reassuring to the physician prescribing CPAP therapy and users.