A recent meta-analyses of clinical studies and case reports that examined the safety of idursulfase therapy, which is an enzyme therapy, has shown that this form of treatment is safe for those with mucopolysaccharidosis type II (MPS II), also known as Hunter syndrome. This analysis aimed to evaluate a variety of other studies in order to ensure that they all had similar results and no bias. Researchers on this project urge that this type of study is conducted more often in order to ensure that all treatments for all diseases are the best for patients.
About Mucopolysaccharidosis Type II (MPS II)
Mucopolysaccharidosis type II (MPS II), which is also known as Hunter syndrome, is a rare, progressive disease that usually affects male children. The mutated gene for this syndrome is carried on the X chromosome, which must be passed down by both parents, which is why it is extremely rare in females. It affects approximately one in every 100,000 to 170,000 male births.
Cases of Hunter syndrome vary in severity. Those with a more severe form decline very quickly, while people with milder forms can have longer lives. Symptoms do depend on severity, but physical symptoms tend to present themselves when children are between the ages of two to four. Symptoms include a broad nose, full lips, an enlarged tongue, rounded cheeks, a deep and hoarse voice due to enlarged vocal cords, and narrow nasal passages. People with this disorder can also experience an enlarged spleen and liver, macrocephaly, hydrocephalus, and inguinal hernia. As MPS II progresses, respiratory distress is common and requires medical intervention.
Treatment for MPS II includes enzyme replacement therapy, which was approved by the FDA in 2006, and symptomatic, supportive treatment. Occupational, physical, and developmental therapy are all common treatments, along with surgery for hernias and joint contractures. Problems with breathing and swallowing can be helped by removing the tonsils and adenoids. A tracheostomy relieves the airway of pressure to aid with breathing as well. Hearing devices can be used to help with hearing loss. Ventricular shunts can relieve hydrocephalus. Finally, doctors recommend genetic counseling for families that have a child with Hunter syndrome.
About the Study
This study was published in the Orphanet Journal of Rare Diseases, and was conducted in order to evaluate multiple studies that examined the safety and efficacy of idursulfase treatment. As it is often difficult to conduct randomized clinical trials of rare diseases due to their low prevalence, the differences in how they manifest in people, and long latency periods, these diseases are often studied through case reports, rare disease registries, and observational studies.
In this study, researchers wanted to ensure that none of the studies or case reports had any bias or incorrect information or results. They did so through a systematic review of case reports of patients treated with enzyme replacement therapy. Looking at the percent of cases that showed improvement in efficacy and no harm to the patients was the endpoint. They found that all of the reports that they examined showed “moderate strength of evidence.” These researchers believe that more analyses of this kind could improve conclusions in personalized care and rare diseases.
Find the study here.