Improving outcome measures in late onset Pompe disease: Modified Rasch-Built Pompe-Specific Activity scale.

BACKGROUND AND PURPOSE: The Rasch-Built Pompe-Specific Activity (R-PAct) scale is a patient-reported outcome measure specifically designed to quantify the effects of Pompe disease on daily life activities, developed for use in Dutch- and English-speaking countries. This study aimed to validate the R-PAct for use in other countries. METHODS: Four other language versions (German, French, Italian, and Spanish) of the R-PAct were created and distributed among Pompe patients (≥16 years old) in Germany, France, Spain, Italy, and Switzerland and pooled with data of newly diagnosed patients from Australia, Belgium, Canada, the Netherlands, New Zealand, the USA, and the UK and the original validation cohort (n = 186). The psychometric properties of the scale were assessed by exploratory factor analysis and Rasch analysis. RESULTS: Data for 520 patients were eligible for analysis. Exploratory factor analysis suggested that the items separated into two domains: Activities of Daily Living and Mobility. Both domains independently displayed adequate Rasch model measurement properties, following the removal of one item ("Are you able to practice a sport?") from the Mobility domain, and can be added together to form a "higher order" factor as well. Differential item functioning (DIF)-by-language assessment indicated DIF for several items; however, the impact of accounting for DIF was negligible. We recalibrated the nomogram (raw score interval-level transformation) for the updated 17-item R-PAct scale. The minimal detectable change value was 13.85 for the overall R-PAct. CONCLUSIONS: After removing one item, the modified-R-PAct scale is a valid disease-specific patient-reported outcome measure for patients with Pompe disease across multiple countries.

Smartphone-Based Assessment of Mobility and Manual Dexterity in Adult People with Spinal Muscular Atrophy.

Background: More responsive, reliable, and clinically valid endpoints of disability are essential to reduce size, duration, and burden of clinical trials in adult persons with spinal muscular atrophy (aPwSMA). Objective: The aim is to investigate the feasibility of smartphone-based assessments in aPwSMA and provide evidence on the reliability and construct validity of sensor-derived measures (SDMs) of mobility and manual dexterity collected remotely in aPwSMA. Methods: Data were collected from 59 aPwSMA (23 walkers, 20 sitters and 16 non-sitters) and 30 age-matched healthy controls (HC). SDMs were extracted from five smartphone-based tests capturing mobility and manual dexterity, which were administered in-clinic and remotely in daily life for four weeks. Reliability (Intraclass Correlation Coefficients, ICC) and construct validity (ability to discriminate between HC and aPwSMA and correlations with Revised Upper Limb Module, RULM and Hammersmith Functional Scale - Expanded HFMSE) were quantified for all SDMs. Results: The smartphone-based assessments proved feasible, with 92.1% average adherence in aPwSMA. The SDMs allowed to reliably assess both mobility and dexterity (ICC > 0.75 for 14/22 SDMs). Twenty-one out of 22 SDMs significantly discriminated between HC and aPwSMA. The highest correlations with the RULM were observed for SDMs from the manual dexterity tests in both non-sitters (Typing, ρ= 0.78) and sitters (Pinching, ρ= 0.75). In walkers, the highest correlation was between mobility tests and HFMSE (5 U-Turns, ρ= 0.79). Conclusions: This exploratory study provides preliminary evidence for the usability of smartphone-based assessments of mobility and manual dexterity in aPwSMA when deployed remotely in participants' daily life. Reliability and construct validity of SDMs remotely collected in real-life was demonstrated, which is a pre-requisite for their use in longitudinal trials. Additionally, three novel smartphone-based performance outcome assessments were successfully established for aPwSMA. Upon further validation of responsiveness to interventions, this technology holds potential to increase the efficiency of clinical trials in aPwSMA.

Nociceptive Pain in Patients with Neuromuscular Disorders - A Cross-Sectional Clinical Study.

Background: Muscle pain is a common symptom in patients with neuromuscular disorders (NMD) and accounts for severely reduced quality of life. OBJECTIVE: This clinical study aimed to observe possible differences in pain prevalence among distinct NMDs and to determine whether the patients' nociceptive pain is influenced by gender, muscle strength and psychological factors and to examine potential pain-associated alterations in muscle properties. Methods: The cross-sectional study on nociceptive pain in various NMDs involved patient-reported outcomes, muscle strength evaluations (dynamometry and quick motor function test (QMFT)), nociceptive pain evaluations (muscular pressure pain threshold (PPT)), and non-invasive measurement of muscle stiffness, frequency, decrement, relaxation, and creep (myotonometry). Results: Involving 81 NMD patients and a control group, the study found high variability in pain prevalence among the subgroups. Patients with DM2 and FSHD had significantly higher levels of pain prevalence compared to other examined NMD subgroups and the control group. Female gender, high fatigue levels (representing factors such as depression, anxiety, stress, and impairment of quality of life), and low QMFT scores (representing reduced muscle strength) showed an association with increased sensitivity to pressure pain in the arm and leg region. As assessed by myotonometry, less pain is experienced in neck muscles with a high muscle tone, high stiffness, and a short relaxation time highlighting the importance of intrinsic muscular tone for their pressure pain sensitivity. Conclusion: Individualized therapeutic concepts including psychological and physical approaches in the pain management of patients with NMDs, especially in women, should be considered. Further research in this field is necessary to gain a more detailed insight into the perception of muscle pain.

Start, switch and stop (triple-S) criteria for enzyme replacement therapy of late-onset Pompe disease: European Pompe Consortium recommendation update 2024.

BACKGROUND AND PURPOSE: Two novel enzyme replacement therapies (ERTs), studied in phase 3 trials in late-onset Pompe patients, reached marketing authorization by the European Medicines Agency in 2022 and 2023. The European Pompe Consortium (EPOC) updates and extends the scope of the 2017 recommendations for starting, switching and stopping ERT. METHODS: The European Pompe Consortium consists of 25 neuromuscular and metabolic experts from eight European countries. This update was performed after an in-person meeting, three rounds of discussion and voting to provide a consensus recommendation. RESULTS: The patient should be symptomatic, that is, should have skeletal muscle weakness or respiratory muscle involvement. Muscle magnetic resonance imaging findings showing substantial fat replacement can support the decision to start in a patient-by-patient scenario. Limited evidence supports switching ERT if there is no indication that skeletal muscle and/or respiratory function have stabilized or improved during standard ERT of 12 months or after severe infusion-associated reactions. Switching of ERT should be discussed on a patient-by-patient shared-decision basis. If there are severe, unmanageable infusion-associated reactions and no stabilization in skeletal muscle function during the first 2 years after starting or switching treatment, stopping ERT should be considered. After stopping ERT for inefficacy, restarting ERT can be considered. Six-monthly European Pompe Consortium muscle function assessments are recommended. CONCLUSIONS: The triple-S criteria on ERT start, switch and stop include muscle magnetic resonance imaging as a supportive finding and the potential option of home infusion therapy. Six-monthly long-term monitoring of muscle function is highly recommended to cover insights into the patient's trajectory under ERT.

Suitability of the Respicheck questionnaire and Epworth sleepiness scale for therapy monitoring in myotonic dystrophy type 1.

Myotonic dystrophy type 1 (DM1) is an autosomal dominant trinucleotide disorder that often leads to respiratory dysfunction resulting in hypoventilation symptoms, reduced quality of life and causing premature death if untreated. To early identify symptoms of hypoventilation, the Respicheck questionnaire was developed as a screening tool. Symptomatic therapies like inspiratory muscle training (IMT) are recommended to strengthen respiratory muscles and reduce or even prevent hypoventilation symptoms. Our study aimed to evaluate the Respicheck questionnaire's suitablility to monitor the efficacy of IMT. Patients with genetically confirmed DM1 were randomly assigned to either IMT - endurance or strength training, or control group. At baseline, end of study and four interim visits, pulmonary function tests, Respicheck questionnaire and Epworth sleepiness scale were assessed. While patients in training groups achieved a substantial improvement after nine months of regular IMT in pulmonary function tests, the Respicheck score did not improve likewise. Similarly, the ESS score did not change significantly in both training and control groups. Consequently, we conclude that either improvement of respiratory function is not necessarily associated with clinical improvement, or respiratory muscle weakness was not the only reason for hypoventilation syndrome, or both questionnaires are not sensitive enough to detect slight clinical changes.

Prediction of respiratory impairment in myotonic dystrophies using the 'Respiratory involvement symptom checklist' (Respicheck).

Chronic hypoventilation due to involvement of respiratory muscles is a frequent symptom in autosomal dominant inherited myotonic dystrophies, especially in type 1 (DM1), leading to a severely reduced quality of life, an early need for ventilatory support, or premature death. Thus, early knowledge of respiratory muscle weakness is essential to initiate further diagnostic and therapeutic measures. To get early, simple, and reliable information about respiratory impairment in DM patients, we performed a prospective controlled cohort study with DM1 and DM2 patients analysing the suitability of 'Respiratory involvement symptom checklist (Respicheck) as a clinically meaningful screening questionnaire for ventilatory impairment in patients with DM1 or DM2. Clinical assessments included a one-time pulmonary function test (spirometry and manometry) and the completion of the Respicheck. 172 participants were enrolled in this study (74 DM1, 72 DM2, 26 healthy controls). With a cut-off RespicheckCAT score of 4, the Respicheck can distinguish between patients with and without respiratory impairment with higher sensitivity and positive predictive value for DM1 than DM2 patients (DM1: sensitivity 77-87; positive predictive value 50-94%; DM2: sensitivity 67-80%; positive predictive value 14-38). In summary, our results confirm a clinically meaningful use of the Respicheck to detect respiratory impairments predominantly in DM1 patients.

Evaluation of myotonometry for myotonia, muscle stiffness and elasticity in neuromuscular disorders.

Neuromuscular disorders show extremely varied expressions of different symptoms and the involvement of muscles. Non-invasively, myotonia and muscle stiffness are challenging to measure objectively. Our study aims to test myotonia, elasticity, and stiffness in various neuromuscular diseases and to provide reference values for different neuromuscular disease groups using a novel handheld non-invasive myometer device MyotonPRO®. We conducted a monocentric blinded cross-sectional study in patients with a set of distinct neuromuscular diseases (NCT04411732, date of registration June 2, 2020). Fifty-two patients in five groups and 21 healthy subjects were enrolled. We evaluated motor function (6-min walk test, handheld dynamometry, Medical Research Council (MRC) Scale) and used ultrasound imaging to assess muscle tissue (Heckmatt scale). We measured muscle stiffness, frequency, decrement, creep, or relaxation using myotonometry with the device MyotonPRO®. Statistically, all values were calculated using the t test and Mann-Whitney U test. No differences were found in comparing the results of myotonometry between healthy and diseased probands. Furthermore, we did not find significant results in all five disease groups regarding myotonometry correlating with muscle strength or ultrasound imaging results. In summary, the myometer MyotonPRO® could not identify significant differences between healthy individuals and neuromuscular patients in our patient collective. Additionally, this device could not distinguish between the five different groups of disorders displaying increased stiffness or decreased muscle tone due to muscle atrophy. In contrast, classic standard muscle tests could clearly decipher healthy controls and neuromuscular patients.

Nociceptive pain in adult patients with 5q-spinal muscular atrophy type 3: a cross-sectional clinical study.

BACKGROUND: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by mutations in the SMN gene, leading to progressive muscular weakness, atrophy and so far neglected musculoskeletal pain. This study is the first to characterize nociceptive pain in patients living with SMA type 3 by assessing whether muscle pain is associated with alterations in muscle strength, function, stiffness, frequency, decrement, relaxation, or creep. METHODS: We performed a cross-sectional pilot study on 20 SMA3 patients. We evaluated motor function and muscle strength (dynamometry, quick motor function test and 6-min-walk test), nociceptive pain (pressure algometer evaluating muscular pressure pain threshold (PPT)) and non-invasive measurement of muscle stiffness, frequency, decrement, relaxation, or creep (myotonometry with the MyotonPro®). For statistical analysis, we used t tests, Mann-Whitney U tests and linear regression. RESULTS: Significantly more women than men reported musculoskeletal pain (p = 0.003). A lower score in dynamometry was associated with lower scores in PPT in all extremities reflecting a higher sensitivity of these muscles to pressure. We did not find significant correlations between the PPT values and the MyotonPro values in the corresponding muscles. Assessments of PPT before and after the 6-min walk test did not show clinical meaningful changes. Besides nociceptive pain, fatigue was prevalent in 50% and pain in 55% of the patients. CONCLUSIONS: Muscle pain in SMA3 is associated with muscular weakness in the arms and legs, but not with changes in muscular stiffness, frequency, decrement, relaxation, or creep. This shows that muscle pain in SMA3 is mainly caused by changes in the dysbalanced musculoskeletal system due to muscle weakness.

Hypoventilation syndrome in neuromuscular disorders.

PURPOSE OF REVIEW: Hypoventilation syndrome in neuromuscular disorders (NMDs) is primarily due to respiratory muscle weakness and results in increased morbidity and mortality. This article highlights current aspects of neuromuscular hypoventilation syndrome, including pathophysiology, clinical symptoms, assessment, respiratory involvement in various NMD, and causal and symptomatic treatments with an emphasis on recent research and advances. RECENT FINDINGS AND SUMMARY: New therapeutic agents have been developed within the last years, proving a positive effect on respiratory system. Symptomatic therapies, including mechanical ventilation and cough assistance approaches, are important in NMD and respiratory muscle training may have benefit in strengthening respiratory muscles and should be offered patients with respiratory muscle weakness the same way as physiotherapy. Correct respiratory assessments and their correct interpretation are hallmarks for early diagnosis of hypoventilation syndrome and treatment.

Associations Between Variant Repeat Interruptions and Clinical Outcomes in Myotonic Dystrophy Type 1.

OBJECTIVE: To assess the association between variant repeat (VR) interruptions in patients with myotonic dystrophy type 1 (DM1) and clinical symptoms and outcome measures after cognitive behavioral therapy (CBT) intervention. METHODS: Adult patients with DM1 were recruited within the OPTIMISTIC trial (NCT02118779). Disease-related history, current clinical symptoms and comorbidities, functional assessments, and disease- and health-related questionnaires were obtained at baseline and after 5 and 10 months. After genetic analysis, we assessed the association between the presence of VR interruptions and clinical symptoms' long-term outcomes and compared the effects of CBT in patients with and without VR interruptions. Core trial outcome measures analyzed were: 6-minute walking test, DM1-Activ-C, Checklist Individual Strength Fatigue Score, Myotonic Dystrophy Health Index, McGill-Pain questionnaire, and Beck Depression inventory-fast screen. Blood samples for DNA testing were obtained at the baseline visit for determining CTG length and detection of VR interruptions. RESULTS: VR interruptions were detectable in 21/250 patients (8.4%)-12 were assigned to the standard-of-care group (control group) and 9 to the CBT group. Patients with VR interruptions were significantly older when the first medical problem occurred and had a significantly shorter disease duration at baseline. We found a tendency toward a milder disease severity in patients with VR interruptions, especially in ventilation status, mobility, and cardiac symptoms. Changes in clinical outcome measures after CBT were not associated with the presence of VR interruptions. CONCLUSIONS: The presence of VR interruptions is associated with a later onset of the disease and a milder phenotype. However, based on the OPTIMISTIC trial data, the presence of VR interruptions was not associated with significant changes on outcome measures after CBT intervention. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov NCT02118779.

[Home infusion therapy for Pompe disease: Recommendations for German-speaking countries]. / Heiminfusionstherapie bei Morbus Pompe: Konsensusempfehlungen für den deutschsprachigen Raum.

BACKGROUND: Pompe disease is a lysosomal multisystem disorder with predominant proximal myopathy. Treatment with enzyme replacement therapy (ERT) is available requiring life-long biweekly infusions of recombinant α-glucosidase. To minimize the burden of ERT patients ask for home infusion therapy. AIMS AND METHODS: Pompe disease experts from Germany, Austria, and Switzerland discussed in two consensus meetings in 2019 and 2020 requirements for home infusion therapy, adequate execution of treatment, and the legal situation for delegating physicians. RESULTS AND DISCUSSION: Home infusion therapy is principally feasible for patients with Pompe disease if certain preconditions are fulfilled, but the decision to implement has to be made on an individual basis. The treating physician delegates the execution of ERT ad personam to nursing staff but retains full legal responsibility. Home infusion therapy has to be carried out by specially trained and qualified staff. Infusion-related risks comprise mainly allergic reactions, and adequate medical treatment must be warranted. In German-speaking countries, clear rules for conducting home infusion therapy are needed to reduce psychosocial stress for patients with Pompe disease, and providing legal certainty for delegating physicians.

STIG study: real-world data of long-term outcomes of adults with Pompe disease under enzyme replacement therapy with alglucosidase alfa.

BACKGROUND: Pompe disease is one of the few neuromuscular diseases with an approved drug therapy, which has been available since 2006. Our study aimed to determine the real-world long-term efficacy and safety of alglucosidase alfa. METHODS: This multicenter retrospective study (NCT02824068) collected data from adult Pompe disease patients receiving ERT for at least 3 years. Demographics and baseline characteristics, muscle strength, lung function (FVC), walking capability (6MWT), and safety were assessed once a year. Evaluation was done on the group and individual levels, using quantitative linear models (t test) and general univariate linear models (ANOVA). FINDINGS: Sixty-eight adult Pompe disease patients from four countries (Spain, Taiwan, Italy, Germany (STIG)) participated. The mean follow-up was 7.03 years ± 2.98. At group level in all outcome measures, an initial improvement followed by a secondary decline was observed. After 10 years, the 6MWT%pred showed the most sustained positive effect (p = 0.304). The MRC%max remained stable with a mild decline (p = 0.131), however, FVC%pred deteriorated significantly (p < 0.001) by 14.93% over 10 years of ERT. The progression rate of FVC%pred under ERT could be explained in most of the patients (83.5%) by the disease severity at baseline. Furthermore, our study shows a decline in the FVC combined with an increase in non-invasive and invasive ventilation requirements in adult Pompe disease patients over time. CONCLUSIONS: The STIG real-world study confirms an initial efficacy of ERT in the first years with a secondary sustained decline in multiple outcome measures. Further efforts are required to establish a more valid long-term monitoring and improved therapies.

[Home infusion therapy for Pompe disease: Recommendations for German-speaking countries]. / Heiminfusionstherapie bei Morbus Pompe: Konsensusempfehlungen für den deutschsprachigen Raum.

BACKGROUND: Pompe disease is a lysosomal multisystem disorder with predominant proximal myopathy. Treatment with enzyme replacement therapy (ERT) is available requiring life-long biweekly infusions of recombinant α-glucosidase. To minimize the burden of ERT patients ask for home infusion therapy. AIMS AND METHODS: Pompe disease experts from Germany, Austria, and Switzerland discussed in two consensus meetings in 2019 and 2020 requirements for home infusion therapy, adequate execution of treatment, and the legal situation for delegating physicians. RESULTS AND DISCUSSION: Home infusion therapy is principally feasible for patients with Pompe disease if certain preconditions are fulfilled, but the decision to implement has to be made on an individual basis. The treating physician delegates the execution of ERT ad personam to nursing staff but retains full legal responsibility. Home infusion therapy has to be carried out by specially trained and qualified staff. Infusion-related risks comprise mainly allergic reactions, and adequate medical treatment must be warranted. In German-speaking countries, clear rules for conducting home infusion therapy are needed to reduce psychosocial stress for patients with Pompe disease, and providing legal certainty for delegating physicians.

The impact of interrupting enzyme replacement therapy in late-onset Pompe disease.

BACKGROUND: Late-onset Pompe disease (LOPD) is a rare autosomal recessive disorder caused by mutations in the GAA gene, leading to progressive weakness of locomotor and respiratory muscles. Enzyme replacement therapy (ERT), administered every second week, has been proven to slow down disease progression and stabilize pulmonary function. Due to the COVID-19 pandemic in Germany, ERT was interrupted at our centre for 29 days. As reports on ERT discontinuation in LOPD are rare, our study aimed to analyse the impact of ERT interruption on the change in clinical outcome. METHODS: We performed a prospective cohort study in 12 LOPD patients. Clinical assessments were performed after ERT interruption and after the next three consecutive infusions. We assessed motor function by muscle strength testing, a 6-minute-walk-test, pulmonary function tests, and adverse events. For statistical analysis, an estimated baseline was calculated based on the individual yearly decline. RESULTS: The mean time of ERT interruption was 49.42 days (SD ± 12.54). During ERT interruption, seven patients reported 14 adverse events and two of them were severe. Frequent symptoms were reduced muscle endurance/increased muscle fatigability and shortness of breath/worsening of breathing impairment. After ERT interruption, significant deterioration was found for MIP%pred (p = 0.026) and MRC%pred, as well as a trend to clinical deterioration in FVC%pred and the 6MWT%pred. CONCLUSION: Interruption of ERT was associated with a deterioration in the core clinical outcome measures. Therefore, an interruption of ERT should be kept as short as possible.

Utility and Results from a Patient-Reported Online Survey in Myotonic Dystrophies Types 1 and 2.

INTRODUCTION: Myotonic dystrophies (DMs) are the most frequent autosomal dominant neuromuscular disorders in adults. Our objective was to evaluate the utility of an online survey in a rare disease as well as to assess and compare the onset and the progression of clinical symptoms in patients with myotonic dystrophy types 1 (DM1) and 2 (DM2). METHODS: We conducted a patient's reported online survey assessing demographics, disease-related symptoms (age of onset, first symptom, time of diagnosis, current symptoms, inheritance, and family history) combined with capturing current symptoms by validated questionnaires. The questionnaire consisted of open, closed, single- and multiple-choice questions. Multiple answers were possible in some cases. Patients with genetically confirmed DM1 or DM2 who were registered in the German DM registry or the Deutsche Gesellschaft für Muskelkranke e.V. - Diagnostic Group for DMs were invited to participate in this online survey. We calculated descriptive and exploratory analysis, where applicable. RESULTS: Out of 677 data sets from respondents, 394 were suitable for final analysis, containing completed questionnaires from 207 DM1 (56% female) and 187 DM2 patients (71% female). The median age of onset was 28 years for DM1 and 35 years for DM2. Muscular symptoms were most frequently reported as the first symptom. The onset of myotonia was earlier than the onset of muscle weakness in both DM1 and DM2. Forty-four percent of patients with DM1 and one-third of patients with DM2 indicated muscle weakness as the first symptom. Patients with DM1 were significantly younger when experiencing muscle weakness as first symptom. Fatigue was only mentioned by a small fraction of patients as a first symptom but increased significantly in the course of the disease. There was no statistically significant difference in the incidence of cataracts, cardiac symptoms, and gastrointestinal symptoms between DM1 and DM2. Falls were reported almost equally in both groups, and most of the patients reported 2-3 falls within the past year. DISCUSSION: Overall, as our results are consistent with the results of clinical studies and online registries, it can be assumed that this type of systematic gathering of data from patients with rare diseases is useful and provides realistic and appropriate results. Due to the nature of online surveys and the absence of an assessor, some uncertainty remains. Furthermore, survey frauds cannot be completely excluded. An additional clinical assessment could confirm the given information and will improve the utility and validity of reported symptoms participants provide in online surveys. Therefore, we recommend a combination of data collecting by online surveys and clinical assessments.

Utility of maximum inspiratory and expiratory pressures as a screening method for respiratory insufficiency in slowly progressive neuromuscular disorders.

The aim of this study was to assess whether different cut-offs of maximum inspiratory and/or expiratory pressure (MIP/MEP) are valuable screening parameters to detect restrictive respiratory insufficiency. Spirometry, MIP, MEP and capillary blood gas analysis were obtained from patients with confirmed neuromuscular disorders. We calculated regression analysis, sensitivity, specificity and predictive values. We enrolled 29 patients with myotonic dystrophy type 1 (DM1), 19 with late-onset Pompe disease (LOPD), and 24 with spinal muscular atrophy type 3. Moderate to high reduction in manometry was exclusively found in LOPD and DM1 patients. Significant associations were found between manometry and spirometry. Highest adjusted r2 was found for MIP % predicted and forced vital capacity (FVC) % predicted. Manometry predicted abnormal FVC and forced expiratory volume 1 s (FEV1). MEP > 80 cmH2O predicted normal FVC and FEV1, regardless of cut-off values. MIP and MEP did not positively predict alterations in capillary blood gas analysis. Disease-specific cut-offs of manometry did not increase the prediction rate of patients with abnormal FVC and FEV1. Predicted values should be calculated for a more comprehensive interpretation of manometry results. MIP and MEP can serve as a screening parameter for patients with neuromuscular disorders, but parallel testing of both MIP and MEP needs to be performed to increase the positive prediction probability across disease groups.

A role for cannabinoids in the treatment of myotonia? Report of compassionate use in a small cohort of patients.

BACKGROUND: The symptomatic treatment of myotonia and myalgia in patients with dystrophic and non-dystrophic myotonias is often not satisfactory. Some patients anecdotally report symptoms' relief through consumption of cannabis. METHODS: A combination of cannabidiol and tetrahydrocannabinol (CBD/THC) was prescribed as compassionate use to six patients (four patients with myotonic dystrophy types 1 and 2, and 2 patients with CLCN1-myotonia) with therapy-resistant myotonia and myalgia. CBD/THC oil was administered on a low dose in the first 2 weeks and adjusted to a higher dose in the following 2 weeks. Myotonia behaviour scale (MBS), hand-opening time, visual analogue scales (VAS) for myalgia and myotonia, and fatigue and daytime sleepiness severity scale (FSS, ESS) were performed weekly to monitor treatment response. RESULTS: All patients reported an improvement of myotonia especially in weeks 3 and 4 of treatment: MBS improved of at least 2 points in all patients, the hand-opening time variously improved in 5 out of 6 patients. Chronic myalgia was reported by both DM2 patients at baseline, one of them experienced a significant improvement of myalgia under treatment. Some gastrointestinal complaints, as abdominal pain and diarrhoea, improved in 3 patients; however, 4 out of 6 patients reported new-onset constipation. No other relevant side effect was noticed. CONCLUSIONS: These first empirical results suggest a potentially beneficial role of CBD/THC in alleviating myotonia and should encourage further research in this field including a randomized-controlled trial on larger cohorts.

Safety and Treatment Effects of Nusinersen in Longstanding Adult 5q-SMA Type 3 - A Prospective Observational Study.

OBJECTIVE: Spinal muscular atrophy (SMA) is a progressive autosomal recessive motor neuron disease caused by loss of the SMN1 gene. Based on randomized clinical trials in children with SMA type 1 and 2, Nusinersen has been approved as the first treatment for all types of SMA, including adults with SMA type 3. METHODS: We evaluated the safety and treatment effects of Nusinersen in longstanding adult 5q-SMA type 3. Patients were treated with intrathecal loading doses at day 1, 14, 28 and 63, followed by maintenance dose every four months up to 300 days. We monitored the patients within SMArtCARE, a prospective open-label outcome study for disease progression, side effects and treatment efficacy, encompassing clinical examination including MRC sum score, vital capacity in sitting position (VC, VC % pred.), ALS Functional Rating Scale (ALS-FRS), 6-Minute-Walk-Test (6MWT), Revised Upper Limb Module (RULM), and Hammersmith Functional Rating Scale (HFMSE). We also measured biomarkers in the spinal fluid (phosphorylated neurofilament heavy chain pNFH, neuron-specific enolase NSE, proteins, ß-Amyloid 1-40, ß-Amyloid 1-42, tau and phospho-tau) and creatine kinase (CK). Assessments were performed at baseline, day 63 (V4), day 180 (V5) and day 300 (V6). For statistical analysis, we compared baseline to V4, V5 and V6, using the paired sample t-test. When there were significant differences, we added cohen's d and effect size r for evaluation of clinical meaningfulness. RESULTS: 19 patients were included, 17 of them have completed the observation period of 10 months (day 300, V6). Patients were aged 18 to 59 years with disease duration ranging from 6 to 53 years. Except for the 6MWT, the RULM and the peak cough flow, there were no relevant significant changes in all functional outcome assessments at V4, V5 or V6, compared to baseline. For the 6MWT, there was a statistically significant improvement at visit 5 and at visit 6. RULM-score increased significantly at V6, and peak cough flow at visit 5. In biomarker studies, there was a significant decline in NSE and pTAU as well as a slight increase in proteins. In safety analysis, overall, Nusinersen applications were well tolerated. Eleven patients reported adverse events that were related to the study procedures, comprising back pain in seven patients and post-lumbar-puncture headache following intrathecal administration in four patients. Post-lumbar-puncture headache was reported in three females and one male, in total eleven times of 108 punctures (10%). No serious adverse events occurred. CONCLUSIONS: This prospective observational study indicates a mild treatment effect in adults with long-standing SMA3 after 10 months of treatment with Nusinersen, which had never occurred in the natural history of the disease. In our cohort, the most significant outcome measures were the 6MWT with statistically significant changes after day 180 and day 300, RULM after day 300 and peak cough flow after day 180.

Genetic determinants of disease severity in the myotonic dystrophy type 1 OPTIMISTIC cohort.

OBJECTIVE: To evaluate the role of genetic variation at the DMPK locus on symptomatic diversity in 250 adult, ambulant patients with myotonic dystrophy type 1 (DM1) recruited to the Observational Prolonged Trial in Myotonic Dystrophy Type 1 to Improve Quality of Life-Standards, a Target Identification Collaboration (OPTIMISTIC) clinical trial. METHODS: We used small pool PCR to correct age at sampling biases and estimate the progenitor allele CTG repeat length and somatic mutational dynamics, and AciI digests and repeat primed PCR to test for the presence of variant repeats. RESULTS: We confirmed disease severity is driven by progenitor allele length, is further modified by age, and, in some cases, sex, and that patients in whom the CTG repeat expands more rapidly in the soma develop symptoms earlier than predicted. We revealed a key role for variant repeats in reducing disease severity and quantified their role in delaying age at onset by approximately 13.2 years (95% confidence interval 5.7-20.7, 2-tailed t test t = -3.7, p = 0.0019). CONCLUSIONS: Careful characterization of the DMPK CTG repeat to define progenitor allele length and presence of variant repeats has increased utility in understanding clinical variability in a trial cohort and provides a genetic route for defining disease-specific outcome measures, and the basis of treatment response and stratification in DM1 trials.