Hematopoietic stem cell transplantation in Niemann-Pick disease type B monitored by chitotriosidase activity

Hematopoietic Stem Cell Transplantation for Storage Disorders: Present Status

Storage disorders are a group of inborn errors of metabolism caused by the defective activity of lysosomal enzymes or transporters. All of these disorders have multisystem involvement with variable degrees of neurological features. Neurological manifestations are one of the most difficult aspects of treatment concerning these diseases. The available treatment modalities for some of these disorders include enzyme replacement therapy, substrate reduction therapy, hematopoietic stem cell transplantation (HSCT) and the upcoming gene therapies. As a one-time intervention, the economic feasibility of HSCT makes it an attractive option for treating these disorders, especially in lower and middle-income countries. Further, improvements in peri-transplantation medical care, better conditioning regimens and better supportive care have improved the outcomes of patients undergoing HSCT. In this review, we discuss the current evidence for HSCT in various storage disorders and its suitability as a mode of therapy for the developing world.

Overview of clinical, molecular, and therapeutic features of Niemann-Pick disease (types A, B, and C): Focus on therapeutic approaches

Niemann-Pick disease (NPD) is another type of metabolic disorder that is classified as lysosomal storage diseases (LSDs). The main cause of the disease is mutation in the SMPD1 (type A and B) or NPC1 or NPC2 (type C) genes, which lead to the accumulation of lipid substrates in the lysosomes of the liver, brain, spleen, lung, and bone marrow cells. This is followed by multiple cell damage, dysfunction of lysosomes, and finally dysfunction of body organs. So far, about 346, 575, and 30 mutations have been reported in SMPD1, NPC1, and NPC2 genes, respectively. Depending on the type of mutation and the clinical symptoms of the disease, the treatment will be different. The general aim of the current study is to review the clinical and molecular characteristics of patients with NPD and study various treatment methods for this disease with a focus on gene therapy approaches.

Ovarian tissue cryopreservation in the pediatric with rare diseases- experience from China's first and the largest ovarian tissue cryobank

Background

There is limited information about the efficacy of ovarian tissue cryopreservation (OTC) in children. In the present study, we report eight patients with rare diseases who underwent OTC in China's first and largest ovarian tissue cryobank.

Procedure

Data from girls with rare diseases who underwent OTC between September 2020 and November 2022 were retrospectively analyzed. We also compared the number of cryopreserved cortex pieces, follicle number, and AMH in those with rare diseases and age-matched children with non-rare diseases who also underwent OTC in our cryobank.

Results

The median age of the children was 5.88 ± 3.52 (range 2-13) years old. Unilateral oophorectomy was undertaken via laparoscopy in all of the children. The diseases in the 8 patients were: 4 mucopolysaccharidoses (MPS I two cases, IVA two cases), 1 Diamond-Blackfan anemia (DBA), 1 Fanconi anemia (FA), 1 hyperimmunoglobulin E syndrome (HIES), 1 Niemann-Pick disease. The number of cryopreserved cortex pieces was 17.13 ± 6.36, and the follicle count per 2 mm biopsy was 447.38 ± 524.35. No significant difference in age, the count of cryopreserved cortex pieces, follicle number per 2 mm biopsy, and AMH level was seen between the 20 children with non-rare diseases and those with rare diseases.

Conclusions

The reports help practitioners counsel girls with rare diseases about fertility preservation. The demand for OTC in pediatrics will likely grow as a standard of care.

Enzyme replacement therapy for children with acid sphingomyelinase deficiency in the real world: A single center experience in Taiwan

Background

Acid sphingomyelinase deficiency (ASMD) is a lysosomal storage disease with multi-systemic involvement, with no disease-modifying treatment available. Olipudase alfa is an investigational enzyme product developed to replace the deficient acid sphingomyelinase in ASMD patients. Several clinical trials have reported promising safety and efficacy results in adult and pediatric patients. However, no data have been reported outside of the clinical trial setting yet. This study aimed to evaluate major outcomes in pediatric chronic ASMD patients receiving olipudase alfa in the real-world setting.

Materials and methods

Two children with type A/B (chronic neuropathic) ASMD have received olipudase alfa treatment since May 2021. Clinical parameters, including height, weight, complete blood count, liver function tests, lipid profiles, biomarkers, abdominal ultrasonography with shear wave elastography, chest computed tomography, nerve conduction studies, neurodevelopmental evaluations, and six-minute walk tests, were checked at baseline and every three to six months in the first year of enzyme replacement therapy (ERT) to assess its efficacy and safety.

Results

The two patients in our study started olipudase alfa treatment at the age of 5 years and 8 months and 2 years and 6 months. During the first year of treatment, both patients saw a reduction in their hepatic and splenic volumes as well as liver stiffness. Height z-score, weight z-score, lipid profiles, biomarker levels, interstitial lung disease scores, and bone mineral densities also improved over time. The six-minute walk test showed a gradual increase in walking distance in both patients. There were no obvious improvements or deterioration in neurocognitive function and peripheral nerve conduction velocities after treatment. No severe infusion-associated reactions were noted during the first year of treatment. One patient had two episodes of transient but significantly elevated liver enzymes during the dose-escalation phase. The patient was asymptomatic, and the impaired liver function resolved spontaneously within two weeks.

Conclusion

Our results provide real-world experience that olipudase alfa is safe and effective in improving major systemic clinical outcomes for pediatric chronic ASMD patients. Monitoring of liver stiffness by shear wave elastography is a noninvasive procedure that can monitor treatment efficacy during ERT.

Scope and Burden of Non-Standard of Care Hematopoietic Stem Cell Transplantation in Pediatric Leukodystrophy Patients

Inherited leukodystrophies are a group of diseases affecting central nervous system myelin that lead to death or significant health problems. Although for most leukodystrophies there are no curative treatments, for a handful of diseases hematopoietic stem cell transplantation (HSCT; bone marrow transplant) can stop disease progression, and if initiated in a timely fashion, prevent many or all neurologic and other systems involvement. However, HSCT is a complex procedure with significant morbidity and mortality risks. The study goal was to determine whether HSCT was being more widely used outside of those leukodystrophies for which HSCT is typically employed. The authors conducted a 2-year retrospective review of HSCT performed across the United States in 51 children's hospitals that are part of the Pediatric Health Information System. The authors screened for 10th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10) codes for leukodystrophies in which HSCT is "nonstandard," including sphingolipidoses, Fabry disease, Gaucher disease, and Niemann-Pick disease, and excluded patients who had ICD-10 codes for leukodystrophies that are HSCT candidates, specifically X-linked adrenoleukodystrophy, metachromatic leukodystrophy, Krabbe disease, and Hurler disease. The authors identified 91 patients (from a total cohort of 937) with one of the nonstandard leukodystrophies who had HSCT. HSCT was performed at 20 of the hospitals, with the majority performed at only 6 hospitals. Average costs ($786 846) per patient were more than 6 times higher than patients who did not have HSCT. The data show that an unexpectedly large number of leukodystrophy patients are receiving transplants for conditions in which HSCT is not typically used, and which are associated with high medical costs.