Cost-Effectiveness of Newborn Screening for Spinal Muscular Atrophy in England

Newborn Screening for Spinal Muscular Atrophy: A 2.5-Year Experience in Hyogo Prefecture, Japan

Newborn screening (NBS) for spinal muscular atrophy (SMA) is necessary, as favorable outcomes can be achieved by treatment with disease-modifying drugs in early infancy. Although SMA-NBS has been initiated in Japan, its clinical results have not been fully reported. We report the findings of the initial 2.5 years of a pilot SMA-NBS of approximately 16,000 infants conducted from February 2021 in Hyogo Prefecture, Japan. Clinical data of 17 infants who tested positive were retrospectively obtained from the NBS follow-up centers participating in this multicenter cohort observational study. Genetic testing revealed 14 false positives, and three infants were diagnosed with SMA. Case 1 had two copies of survival motor neuron (SMN) 2 and showed SMA-related symptoms at diagnosis. Case 2 was asymptomatic, with two copies of SMN2. Asymptomatic case 3 had four copies of SMN2 exon 7, including the SMN1/2 hybrid gene. Cases 1 and 2 were treated within 1 month and case 3 at 8 months. All the patients showed improved motor function scores and did not require respiratory support. The identification of infants with SMA via NBS and early treatment improved their motor and respiratory outcomes. Thus, implementation of SMA-NBS at a nationwide scale should be considered.

Newborn screening for spinal muscular atrophy - what have we learned?

INTRODUCTION

Over the last decade, the treatment of spinal muscular atrophy (SMA) has become a paradigm of the importance of early and accurate diagnosis and prompt treatment. Three different therapeutic approaches that aims to increase SMN protein are approved now by Food and Drug Administration (FDA) and European Medicines Agency (EMA) for treatment of SMA; their efficacies have been demonstrated in pivotal trials.

AREAS COVERED

The authors report on the two controlled studies and real-world evidence that have demonstrated that the treatment of patients pre-symptomatically ensures normal or only slightly sub-normal motor development in children who would otherwise develop a severe form of the disease. Furthermore, the authors highlight the several newborn screening (NBS) methods that are now available, all of which are based on real-time PCR, that reliably and robustly diagnose SMA except in subjects with disease caused by a point mutation.

EXPERT OPINION

Pre-symptomatic treatment of SMA has been clearly demonstrated to prevent the most severe forms of the disease. NBS constitutes more than a simple test and should be considered as a global process to accelerate treatment access and provide global management of patients and parents. Even though the cost of NBS is low and health economics studies have clearly demonstrated its value, the fear of identifying more patients than the system can treat is often reported in large middle-income countries.