Deyanira Corzo

A Randomized Study of Alglucosidase Alfa in Late-Onset Pompe's Disease

BACKGROUND Pompes disease is a metabolic myopathy caused by a deficiency of acid alpha glucosidase (GAA), an enzyme that degrades lysosomal glycogen. Late-onset Pompes disease is characterized by progressive muscle weakness and loss of respiratory function, leading to early death. We conducted a randomized, placebo-controlled trial of alglucosidase alfa, a recombinant human GAA, for the treatment of late-onset Pompes disease. METHODS Ninety patients who were 8 years of age or older, ambulatory, and free of invasive ventilation were randomly assigned to receive biweekly intravenous alglucosidase alfa (20 mg per kilogram of body weight) or placebo for 78 weeks at eight centers in the United States and Europe. The two primary end points were distance walked during a 6-minute walk test and percentage of predicted forced vital capacity (FVC). RESULTS At 78 weeks, the estimated mean changes from baseline in the primary end points favored alglucosidase alfa (an increase of 28.1+/-13.1 m on the 6-minute walk test and an absolute increase of 3.4+/-1.2 percentage points in FVC; P=0.03 and P=0.006, respectively). Similar proportions of patients in the two groups had adverse events, serious adverse events, and infusion-associated reactions; events that occurred only in patients who received the active study drug included anaphylactic reactions and infusion-associated reactions of urticaria, flushing, hyperhidrosis, chest discomfort, vomiting, and increased blood pressure (each of which occurred in 5 to 8% of the patients). CONCLUSIONS In this study population, treatment with alglucosidase alfa was associated with improved walking distance and stabilization of pulmonary function over an 18-month period. (ClinicalTrials.gov number, NCT00158600.)

Clinical features of late-onset Pompe disease: a prospective cohort study.

The objective of this 12‐month study was to describe the clinical features of late‐onset Pompe disease and identify appropriate outcome measures for use in clinical trials. Assessments included quantitative muscle testing (QMT), functional activities (FAA), 6‐min walk test (6MWT), and pulmonary function testing (PFT). Percent predicted values indicated quantifiable upper and lower extremity weakness, impaired walking ability, and respiratory muscle weakness. Significant declines in arm and leg strength and pulmonary function were observed during the study period. The outcome measures were demonstrated to be safe and reliable. Symptom duration was identified as the best predictor of the extent of skeletal and respiratory muscle weakness. Muscle Nerve 38: 1236–1245, 2008

Nephrotic Syndrome Complicating α-Glucosidase Replacement Therapy for Pompe Disease

We report a patient with Pompe disease who developed reversible nephrotic syndrome during prolonged, high-dose, experimental, enzyme replacement therapy with recombinant human acid α-glucosidase (rhGAA). Because of the development of antibodies to rhGAA and concomitant clinical decline, escalating doses of rhGAA were administered as part of an experimental immune tolerance regimen. Histologic evaluation of kidney tissue revealed glomerular deposition of immune complexes containing rhGAA itself, in a pattern of membranous nephropathy. To our knowledge, this is the first reported case of nephrotic syndrome occurring during enzyme replacement therapy. The nephrotic syndrome gradually resolved after the rhGAA dose was decreased, indicating that decreasing the antigenic load can ameliorate glomerular immune complex deposition associated with enzyme replacement in a highly sensitized patient.

Cardiac arrhythmias following anesthesia induction in infantile‐onset Pompe disease: a case series

Background:  Patients with infantile‐onset Pompe disease suffer from marked hypertrophic cardiomyopathy and an increased risk of arrhythmia. A noncompliant left ventricle predisposes these infants to diastolic heart failure with elevated left ventricular enddiastolic pressure (LVEDP); these patients also commonly develop systolic heart failure. Given this baseline cardiac physiology, coronary perfusion pressure becomes highly sensitive to abrupt changes in diastolic blood pressure (DBP).

Effect of enzyme therapy in juvenile patients with Pompe disease: A three-year open-label study

Pompe disease is a rare neuromuscular disorder caused by deficiency of acid α-glucosidase. Treatment with recombinant human α-glucosidase recently received marketing approval based on prolonged survival of affected infants. The current open-label study was performed to evaluate the response in older children (age 5.9-15.2 years). The five patients that we studied had limb-girdle muscle weakness and three of them also had decreased pulmonary function in upright and supine position. They received 20-mg/kg recombinant human α-glucosidase every two weeks over a 3-year period. No infusion-associated reactions were observed. Pulmonary function remained stable (n = 4) or improved slightly (n = 1). Muscle strength increased. Only one patient approached the normal range. Patients obtained higher scores on the Quick Motor Function Test. None of the patients deteriorated. Follow-up data of two unmatched historical cohorts of adults and children with Pompe disease were used for comparison. They showed an average decline in pulmonary function of 1.6% and 5% per year. Data on muscle strength and function of untreated children were not available. Further studies are required.

Long-term monitoring of patients with infantile-onset Pompe disease on enzyme replacement therapy using a urinary glucose tetrasaccharide biomarker.

Purpose: To investigate the correlation of the urinary glucose tetrasaccharide, Glcα1-6Glcα1-4Glcα1-4Glc, (Glc4) with skeletal muscle glycogen content and the long-term clinical response to enzyme replacement therapy with recombinant human acid alpha glucosidase in infantile Pompe disease.Methods: Eighteen patients, ≤6 months old, were enrolled in a clinical trial of enzyme replacement therapy for up to 142 weeks. Urinary Glc4, skeletal muscle glycogen, and other clinical and laboratory assessments were made at baseline and at regular intervals. Urinary Glc4 was determined using an isotope-dilution tandem mass spectrometric assay. The clinical response to treatment was defined according to the motor function response. Trends in urinary Glc4 were correlated with the clinical response and compared with serum enzyme markers of skeletal muscle damage, creatine kinase, aspartate aminotransferase, and alanine aminotransferase.Results: Urinary Glc4, in contrast to the serum markers, correlated closely with skeletal muscle glycogen content and with the clinical response. Patients with the best response to treatment maintained the lowest levels of Glc4 throughout the trial.Conclusion: The results from this study support the use of urinary Glc4 for monitoring patients with infantile-onset Pompe disease on therapy.

Identification of critical regions for clinical features of distal 10q deletion syndrome.

Array comparative genomic hybridization studies were performed to further characterize cytogenetic abnormalities found originally by karyotype and fluorescence in situ hybridization in five clinical cases of distal 10q deletions, including several with complex cytogenetic rearrangements and one with a partial male‐to‐female sex‐reversal phenotype. These results have enabled us to narrow the previously proposed critical regions for the craniofacial, urogenital, and neuropsychiatric disease‐related manifestations associated with distal 10q deletion syndrome. Furthermore, we propose that haploinsufficiency of the DOCK1 gene may play a crucial role in the pathogenesis of the 10q deletion syndrome. We hypothesize that alteration of DOCK1 and/or other genes involved in regulation and signaling of multiple pathways can explain the wide range of phenotypic variability between patients with similar or identical cytogenetic abnormalities.

A computer adaptive testing approach for assessing physical functioning in children and adolescents

The purpose of this article is to demonstrate: (1) the accuracy and (2) the reduction in amount of time and effort in assessing physical functioning (self‐care and mobility domains) of children and adolescents using computer‐adaptive testing (CAT). A CAT algorithm selects questions directly tailored to the childs ability level, based on previous responses. Using a CAT algorithm, a simulation study was used to determine the number of items necessary to approximate the score of a full‐length assessment. We built simulated CAT (5‐, 10‐, 15‐, and 20‐item versions) for self‐care and mobility domains and tested their accuracy in a normative sample (n=373; 190 males, 183 females; mean age 6y 11mo [SD 4y 2m], range 4mo to 14y 11mo) and a sample of children and adolescents with Pompe disease (n=26; 21 males, 5 females; mean age 6y 1mo [SD 3y 10mo], range 5mo to 14y 10mo). Results indicated that comparable score estimates (based on computer simulations) to the full‐length tests can be achieved in a 20‐item CAT version for all age ranges and for normative and clinical samples. No more than 13 to 16% of the items in the full‐length tests were needed for any one administration. These results support further consideration of using CAT programs for accurate and efficient clinical assessments of physical functioning.

The Cost-Effectiveness of Initial Treatment of Multiple Myeloma in the U.S. With Bortezomib Plus Melphalan and Prednisone Versus Thalidomide Plus Melphalan and Prednisone or Lenalidomide Plus Melphalan and Prednisone With Continuous Lenalidomide Maintenance Treatment

The outlook for transplant-ineligible multiple myeloma patients has improved enormously over recent years with the incorporation of new agents into standard regimens. Novel regimens combine melphalan and prednisone (MP) with bortezomib (VMP), with thalidomide (MPT), and with lenalidomide with (MPR-R) and without (MPR) lenalidomide maintenance. The efficacy, safety, and cost-effectiveness of these regimens have not yet been compared; therefore, we conducted a pharmacoeconomic analysis using data from randomized controlled trials versus MP. Using a Markov model developed from a U.S. payers perspective, we compared VMP with MPT and MPR-R over a lifetime horizon. MPT and MPR-R were chosen because, like VMP, they are superior to MP in response and outcomes. Data from the Velcade as Initial Standard Therapy in Multiple Myeloma (VISTA; VMP), Intergroupe Francophone du Myelome (IFM) 99-06 (MPT), and MM-015 (MPR-R) trials were used. The IFM 99-06 study was selected because of the superior activity in this study compared with other MPT studies. Using patient-level (VMP) and published (MPT, MPR-R) data, we estimated the health-state transition and adverse event probabilities for each regimen, related costs, and state-specific utility estimates. Costs (in 2010 U.S. dollars) and health outcomes were discounted at 3%. Discounted lifetime direct medical costs were lowest with VMP at

Fractures in children with Pompe disease: a potential long-term complication

119,102. MPT cost