Real-world evidence study finds no new-onset diabetes or drug-related hyperglycemia in Pompe disease patients treated with avalglucosidase alfa.

Avalglucosidase alfa therapy for Pompe disease is diluted in dextrose 5% solution in water (D5W) for infusion, which raises questions about the potential for hyperglycemia or worsening diabetes. Using United States insurance claims data, we assessed the impact of biweekly infusions on hyperglycemia, new-onset diabetes mellitus, insulin resistance, and prediabetes in patients with Pompe disease. After starting avalglucosidase alfa treatment, 1 of 26 patients had one claim for hyperglycemia, which was attributed to acute pancreatitis.

Combined sequence and copy number analysis improves diagnosis of limb girdle and other myopathies.

OBJECTIVE: Clinical and genetic heterogeneities make diagnosis of limb-girdle muscular dystrophy (LGMD) and other overlapping disorders of muscle weakness complicated and expensive. We aimed to develop a comprehensive next generation sequence-based multi-gene panel ("The Lantern Focused Neuromuscular Panel") to detect both sequence variants and copy number variants in one assay. METHODS: Patients with clinical diagnosis of LGMD or other overlapping muscular dystrophies in the United States were tested by PerkinElmer Genomics in 2018-2021 via "The Lantern Project," a sponsored diagnostic testing program. Sixty-six genes related to LGMD subtypes- and other myopathies were investigated. Main outcomes were diagnostic yield, gene-variant spectrum, and LGMD subtypes' prevalence. RESULTS: Molecular diagnosis was established in 19.6% (1266) of 6473 cases. Major genes contributing to LGMD were identified including CAPN3 (5.4%, 68), DYSF (4.0%, 51), GAA (3.7%, 47), ANO5 (3.6%, 45), and FKRP (2.7%, 34). Genes of other overlapping MD subtypes identified included PABPN1 (10.5%, 133), VCP (2.2%, 28), MYOT (1.2% 15), LDB3 (1.0%, 13), COL6A1 (1.5%, 19), FLNC (1.1%, 14), and DNAJB6 (0.8%, 10). Different sizes of copy number variants including single exon, multi-exon, and whole genes were identified in 7.5% (95) cases in genes including DMD, EMD, CAPN3, ANO5, SGCG, COL6A2, DOK7, and LAMA2. INTERPRETATION: "The Lantern Focused Neuromuscular Panel" enables identification of LGMD subtypes and other myopathies with overlapping clinical features. Prevalence of some MD subtypes was higher than previously reported. Widespread deployment of this comprehensive NGS panel has the potential to ensure early, accurate diagnosis as well as re-define MD epidemiology.

Pompe disease ascertained through The Lantern Project, 2018-2021: Next-generation sequencing and enzymatic testing to overcome obstacles to diagnosis.

The Lantern Project is an ongoing complimentary diagnostic program for patients in the United States sponsored by Sanofi and implemented by PerkinElmer Genomics. It combines specific enzymatic, biomarker, and genetic testing to facilitate rapid, accurate laboratory diagnosis of Pompe disease and several other lysosomal storage diseases, and a multigene next-generation sequencing panel including Pompe disease, LGMD, and other neuromuscular disorders. This article reports data for Pompe disease collected from October 2018 through December 2021, including acid α-glucosidase (GAA) enzyme assay and GAA sequencing (standard or expedited for positive newborn screening [NBS] to rule out infantile-onset Pompe disease [IOPD]) and the Focused Neuromuscular Panel, which includes GAA. One hundred forty patients (12 received only GAA enzyme testing, 128 had GAA sequencing alone or in addition to enzyme assay) have been confirmed with Pompe disease in this project. Eight of the 140 had a variant of unknown significance, but GAA activity ≤2.10 µmol/L/h, thus were confirmed with Pompe disease. Three diagnosed patients 0-2 years old had cross-reactive immunologic material (CRIM)-negative GAA variants and thus IOPD. One additional infant with presumptive IOPD had a homozygous frameshift c.1846del, likely CRIM-negative; symptoms were not provided. Among the 128 patients with molecular results, the c.-32-13T>G splice variant was homozygous in 11, compound-heterozygous in 98, and absent in 19. Proximal muscle weakness (58 patients) was the most common sign reported at testing; elevated creatine kinase (29 patients) was the most common laboratory result. The most common symptom categories were muscular (73 patients), musculoskeletal (13 patients), and respiratory (23 patients). Clinical information was not available for 42 samples, and 17 infants had only "abnormal NBS" or "low GAA" reported. Cardiac symptoms in 7 included potentially age-related conditions in five c.-32-13T>G-compound-heterozygous adults (myocardial infarction, heart murmur/palpitations, congestive heart failure: 1 each; 2 with atrial fibrillation) and hypertrophic cardiomyopathy in 2 children (1 and 2 years old) with presumptive IOPD. One novel GAA variant was observed in a patient with enzyme activity 0.31 µmol/L/h: c.1853_1854ins49, a frameshift pathogenic variant. The Lantern Project demonstrates the combinatorial utility of enzyme assay, targeted single-gene testing, and a focused neuromuscular next-generation sequencing panel in diagnosing Pompe disease.

Chart validation of an algorithm for identifying hereditary progressive muscular dystrophy in healthcare claims.

BACKGROUND: Muscular dystrophies (MDs) are a group of inherited conditions characterized by progressive muscle degeneration and weakness. The rarity and heterogeneity of the population with MD have hindered therapeutic developments as well as epidemiological and health outcomes research. The objective of the study was to develop and validate a case-finding algorithm utilizing administrative claims data to identify and characterize patients with MD. METHODS: This retrospective cohort study used medical chart validation to evaluate an ICD-9/10 coding algorithm in a large commercial claims database. Patients were identified who had ≥2 office visits with a diagnosis of hereditary progressive MDs from January 1, 2013 through December 31, 2016, were male, and younger than 18 years at the time of first MD diagnosis. Cases who met the algorithm were then validated against medical charts. Diagnoses of MD and specific type (Duchenne, Becker, or other MD) were confirmed by medical chart review by trained reviewers. Positive predictive value (PPV) and 95% confidence intervals (CI) were calculated using a 2 × 2 contingence table. Patient demographic, clinical, and health utilization characteristics were summarized using basic descriptive statistics. RESULTS: Charts were obtained and reviewed for 109 patients who met the algorithm. The PPV of the case-identifying algorithm for MD was 95% (95% CI 88-98%). Of the 103 confirmed MD cases, 87 patients (85%, 95% CI 76-91%) had Duchenne or Becker MD; 76 patients (74%, 95% CI 64-82%) had Duchenne MD, and 11 patients (11%, 95% CI 5-18%) had Becker MD. A total of 74 (67.9%) patients had ≥1 pediatric complex chronic condition (other than neurologic/neuromuscular disease); 54 (49.5%) had cardiovascular conditions; 14 (12.8%) had respiratory conditions; 50 (45.9%) had bone-related issues; 11 (10.1%) had impaired growth; and 6 (5.5%) had puberty delay. CONCLUSIONS: The results of this study demonstrate that the case-finding algorithm accurately identified patients with MD, primarily Duchenne MD, within a large administrative database. The algorithm, which was constructed using a few items easily accessible from claims, can be used to facilitate epidemiological and health outcomes research in the Duchenne patient population.

Variability and trends in corticosteroid use by male United States participants with Duchenne muscular dystrophy in the Duchenne Registry.

BACKGROUND: Treatment options for Duchenne muscular dystrophy remain limited, although consensus treatment guidelines recommend corticosteroid use. METHODS: This retrospective analysis assessed corticosteroid use in ambulatory and nonambulatory US males with Duchenne, age 35 and under, or Becker muscular dystrophy, who enrolled in The Duchenne Registry from 2007 to 2016 (formerly DuchenneConnect). RESULTS: The mean (SD) age of corticosteroid use initiation was 5.9 (2.5) years, and deflazacort use (54%) was slightly more common than prednisone/prednisolone (46%). Among all responses from those with Duchenne, 63% were currently on corticosteroids, 12% were no longer on corticosteroids, and 25% had never been on corticosteroids. Among those who were nonambulatory, 49% were currently on corticosteroids, 28% had discontinued corticosteroids, and 23% had never used corticosteroids. Primary reasons for never initiating therapy were that corticosteroids were not prescribed or recommended and concerns about side effects. Corticosteroid use was maximal at age 8 (84% on corticosteroids) and gradually declined from age 10 to 19. The primary reasons for corticosteroid discontinuation were problems with side effects (65%) or not enough benefit (28%). Average doses of corticosteroids were below recommended doses. In the 159 responses with Becker muscular dystrophy, 20% were currently using corticosteroids. CONCLUSIONS: Recognizing the self-selected nature of participation, it appears that a considerable proportion of US participants registered with The Duchenne Registry were either not on corticosteroids or not on recommended doses despite consensus recommendations. Side effects were a consideration in initiating and discontinuing treatment. These data reinforce the need for additional treatment options for those affected by Duchenne.

DMD genotype correlations from the Duchenne Registry: Endogenous exon skipping is a factor in prolonged ambulation for individuals with a defined mutation subtype.

Antisense oligonucleotide (AON)-mediated exon skipping is an emerging therapeutic for individuals with Duchenne muscular dystrophy (DMD). Skipping of exons adjacent to common exon deletions in DMD using AONs can produce in-frame transcripts and functional protein. Targeted skipping of DMD exons 8, 44, 45, 50, 51, 52, 53, and 55 is predicted to benefit 47% of affected individuals. We observed a correlation between mutation subgroups and age at loss of ambulation in the Duchenne Registry, a large database of phenotypic and genetic data for DMD (N = 765). Males amenable to exon 44 (N = 74) and exon 8 skipping (N = 18) showed prolonged ambulation compared to other exon skip groups and nonsense mutations (P = 0.035 and P < 0.01, respectively). In particular, exon 45 deletions were associated with prolonged age at loss of ambulation relative to the rest of the exon 44 skip amenable cohort and other DMD mutations. Exon 3-7 deletions also showed prolonged ambulation relative to all other exon 8 skippable mutations. Cultured myotubes from DMD patients with deletions of exons 3-7 or exon 45 showed higher endogenous skipping than other mutations, providing a potential biological rationale for our observations. These results highlight the utility of aggregating phenotypic and genotypic data for rare pediatric diseases to reveal progression differences, identify potentially confounding factors, and probe molecular mechanisms that may affect disease severity.

An Evidence-Based, Community-Engaged Approach to Develop an Interactive Deliberation Tool for Pediatric Neuromuscular Trials.

Duchenne/Becker muscular dystrophy (DBMD) and spinal muscular atrophy (SMA) are rare neuromuscular disorders that present challenges to therapeutic and clinical trial decision making. We developed an interactive, evidence-based online tool designed to encourage thoughtful deliberation of the pros and cons of trial participation and to inform meaningful discussions with healthcare providers. Prior research demonstrates the importance of tool availability at the time each family is considering trial participation, which may be prior to the informed consent process. The tool is intended to be easily modified to other pediatric disease communities. Tool development was informed by prior qualitative research, literature reviews, and stakeholder input. Specific items were derived based on an online exploratory questionnaire of parents whose children participated in a trial for DBMD or SMA to understand motivations for participation. Parent participants in the exploratory survey reported strong impact of altruistic and individual benefit motivations and placed much greater emphasis on anticipated trial benefits than on harms when making participation decisions. We used this data to develop the evidence-based deliberation tool using a community-engaged approach. We initially targeted the tool for DBMD while using SMA survey data to evaluate ease of transition to that population. We conducted two iterative sets of activities to inform development and refinement of the tool: (1) community engagement of key stakeholders and (2) user experience testing. These activities suggest that the tool may increase deliberation and the weighing of benefits and harms. Ongoing evaluation will determine the acceptability and efficacy of this online intervention.

Practical Considerations for Using Online Methods to Engage Patients in Guideline Development.

Clinical practice guidelines (CPGs) have been widely used in healthcare policy, practice, and for suggesting future research. As patients increasingly become involved in CPG development to produce patient-centered recommendations, more research is needed on methods to engage patients, particularly methods allowing for scalable engagement of large, diverse, and geographically distributed groups of patients. In this article, we discuss practical considerations for using online methods to engage patients in CPG development. To inform this discussion, we conducted a rapid, systematic review of literature on patient involvement in CPG development and used qualitative evidence synthesis techniques to make inferences about potential advantages and challenges of using online methods to engage patients in this context. We identified 79 articles containing information about involving patients in CPG development. Potential advantages include the ability of online methods to facilitate greater openness and honesty by patients, as well as to reflect the diversity of patient views, which in turn further improve the utility of CPGs. Potential challenges of using online methods may include the extra skill, time, and certain types of resources that may be needed for patient engagement, as well as the difficulty engaging specific patient populations. However, these challenges are mitigated by growing calls for patient engagement as normative for CPG development in addition to patients' increasing familiarity with online technologies. These practical considerations should be examined empirically as guideline development groups further explore the appropriateness of using online methods to engage patients across different stages of CPG development.

Delayed onset of ambulation in boys with Duchenne muscular dystrophy: Potential use as an endpoint in clinical trials.

Individuals with Duchenne muscular dystrophy (DMD) often exhibit delayed motor and cognitive development, including delayed onset of ambulation. Data on age when loss of independent ambulation occurs are well established for DMD; however, age at onset of walking has not been well described. We hypothesize that an effective medication given in early infancy would advance the age when walking is achieved so that it is closer to age-matched norms, and that this discrete event could serve as the primary outcome measure in a clinical trial. This study examined three data sets, Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet); Dutch Natural History Survey (DNHS); and Parent Project Muscular Dystrophy (PPMD). The distribution of onset of ambulation in DMD (mean ± SD) and median age, in months, at the onset of ambulation was 17.3 (±5.5) and 16.0 in MD STARnet, 21.8 (±7.1) and 20.0 in DNHS, and 16.1 (±4.4) and 15 in PPMD. Age of ambulation in these data sets were all significantly later (P <0.001) than the corresponding age for typically developing boys, 12.1 (±1.8). A hypothetical clinical trial study design and power analyses are presented based on these data.

Engaging Patients and Caregivers Managing Rare Diseases to Improve the Methods of Clinical Guideline Development: A Research Protocol.

BACKGROUND: Clinical guidelines provide systematically developed recommendations for deciding on appropriate health care options for specific conditions and clinical circumstances. Up until recently, patients and caregivers have rarely been included in the process of developing care guidelines. OBJECTIVE: This project will develop and test a new online method for including patients and their caregivers in this process using Duchenne muscular dystrophy (DMD) care guidelines as an example. The new method will mirror and complement the RAND/UCLA Appropriateness Method (RAM)-the gold standard approach for conducting clinical expert panels that uses a modified Delphi format. RAM is often used in clinical guideline development to determine care appropriateness and necessity in situations where existing clinical evidence is uncertain, weak, or unavailable. METHODS: To develop the new method for engaging patients and their caregivers in guideline development, we will first conduct interviews with experts on RAM, guideline development, patient engagement, and patient-centeredness and engage with Duchenne patients and caregivers to identify how RAM should be modified for the purposes of patient engagement and what rating criteria should patients and caregivers use to provide their input during the process of guideline development. Once the new method is piloted, we will test it by conducting two concurrently run patient/caregiver panels that will rate patient-centeredness of a subset of DMD care management recommendations already deemed clinically appropriate and necessary. The ExpertLens™ system-a previously evaluated online modified Delphi system that combines two rounds of rating with a round of feedback and moderated online discussions-will be used to conduct these panels. In addition to developing and testing the new engagement method, we will work with the members of our project's Advisory Board to generate a list of best practices for enhancing the level of patient and caregiver involvement in the guideline development process. We will solicit input on these best practice from Duchenne patients, caregivers, and clinicians by conducting a series of round-table discussions and making a presentation at an annual conference on Duchenne. RESULTS: The study protocol was reviewed by RAND's Human Subjects Protection Committee, which determined it to be exempt from review. Interviews with RAM experts have been completed. The projected study completion date is May 2020. CONCLUSIONS: We expect that the new method will make it easier to engage large numbers of patients and caregivers in the process of guideline development in a rigorous and culturally appropriate manner that is consistent with the way clinicians participate in guideline development. Moreover, this project will develop best practices that could help involve patients and caregivers in the clinical guideline development process in other clinical areas, thereby facilitating the work of guideline developers.

Knowledge of carrier status and barriers to testing among mothers of sons with Duchenne or Becker muscular dystrophy.

Our study objective was to survey female carriers for Duchenne and Becker muscular dystrophy to identify barriers to carrier testing and the impact of carrier risk knowledge on cardiac and reproductive health management. We surveyed women who have or had biological sons with Duchenne or Becker muscular dystrophy and were enrolled in the US DuchenneConnect patient registry, with questions assessing knowledge of carrier status and recurrence risk, knowledge of care standards for carriers, and barriers to testing. Of the 182 eligible respondents, 25% did not know their carrier status and 14% incorrectly classified themselves as not at risk. Cost of testing was the most commonly identified barrier to testing. Women reporting unknown carrier status were 13 times as likely to express uncertainty regarding their recurrence risk compared to women reporting positive carrier status. 37% of women at an increased risk for cardiomyopathy had never had an echocardiogram. Women who were certain of their positive carrier status were twice as likely to have had an echocardiogram in the last five years compared to women with unknown carrier status. Future research on reducing barriers to counseling and carrier testing, such as cost, may improve care standard adherence.

Small deletions of SATB2 cause some of the clinical features of the 2q33.1 microdeletion syndrome.

Recurrent deletions of 2q32q33 have recently been reported as a new microdeletion syndrome. Clinical features of this syndrome include severe mental retardation, growth retardation, dysmorphic features, thin and sparse hair, feeding difficulties and cleft or high palate. The commonly deleted region contains at least seven genes. Haploinsufficiency of one of these genes, SATB2, a DNA-binding protein that regulates gene expression, has been implicated as causative in the cleft or high palate of individuals with 2q32q33 microdeletion syndrome. In this study we describe three individuals with smaller microdeletions of this region, within 2q33.1. The deletions ranged in size from 173.1 kb to 185.2 kb and spanned part of SATB2. Review of clinical records showed similar clinical features among these individuals, including severe developmental delay and tooth abnormalities. Two of the individuals had behavioral problems. Only one of the subjects presented here had a cleft palate, suggesting reduced penetrance for this feature. Our results suggest that deletion of SATB2 is responsible for several of the clinical features associated with 2q32q33 microdeletion syndrome.