The GSP Neonatal Creatine Kinase-MM kit works by measuring concentration of a type of protein called CK-MM, which is part of a group of proteins called creatine kinase
The US Food and Drug Administration authorised marketing of the first test to aid in newborn screening for Duchenne Muscular Dystrophy (DMD), a rare genetic disorder that causes progressive muscle deterioration and weakness.
“Diagnostics that can safely and effectively screen newborns can help health care professionals identify and discuss potential treatment options with parents and caregivers before symptoms or effects on a baby’s health may be noticeable,” said Tim Stenzel, Director of the Office of In Vitro Diagnostics and Radiological Health, FDA Center for Devices and Radiological Health. “This authorisation reflects our commitment to fostering innovation in devices to help inform and provide options to patients and their caregivers. Early screening can help identify individuals who need additional follow up or treatment.”
The GSP Neonatal Creatine Kinase-MM kit authorised is intended to aid in screening newborns for DMD. Newborn screening is a series of tests to help health care professionals identify serious diseases and conditions shortly after birth. As part of this screening, a newborn screening card is used to collect a small amount of blood from a prick of an infant’s heel, sometimes called a heel stick. The collected, dried blood samples are used to test for a variety of diseases and conditions.
Authorisation of the GSP Neonatal Creatine Kinase-MM kit enables laboratories to add this test to their newborn screening panel if they choose to do so, but this authorisation does not signal a recommendation for DMD to be added to the RUSP as a condition for which newborn screening is recommended. The GSP Neonatal Creatine Kinase-MM kit is not intended for DMD diagnosis or for screening of other forms of muscular dystrophies.
The GSP Neonatal Creatine Kinase-MM kit works by measuring the concentration of a type of protein called CK-MM, which is part of a group of proteins called creatine kinase. Creatine kinase is found in muscle tissue and CK-MM enters the blood stream in increased amounts when there is muscle damage. This test measures the levels of CK-MM from the dried blood samples collected from the prick of a newborn’s heel 24-48 hours after birth. Elevated levels of CK-MM detected by the kit may indicate presence of DMD. Results showing elevated CK-MM must be confirmed using other testing methods, such as muscle biopsies, genetic and other laboratory tests.
DMD, while rare, is the most common type of muscular dystrophy. It is caused by an absence of dystrophin, a protein that helps keep muscle cells intact. The first symptoms are usually seen between three and five years of age and worsen over time. The disease often occurs in people without a known family history of the condition and primarily affects boys, but in rare cases it can affect girls. DMD occurs in about one in 3,600 male live-born infants worldwide.
The FDA reviewed the GSP Neonatal Creatine Kinase-MM kit through the de novo premarket review pathway, a regulatory pathway for low-to-moderate risk devices of a new type. During this process, the FDA evaluated data from a clinical study of 3,041 newborns whose dried blood samples were tested for protein levels that are associated with DMD. In the study, the kit was able to accurately identify the four screened newborns that had DMD-causing genetic mutations. The device manufacturer also tested 30 samples from newborns with clinically confirmed cases of DMD, all of which were correctly identified by the test.
Along with this authorisation, the FDA is establishing criteria, called special controls, that must be met for tests of this type, including certain design verification, design validation and labelling requirements. When met, these special controls, along with general controls, provide a reasonable assurance of safety and effectiveness for tests of this type. This action also creates a new regulatory classification, which means that subsequent devices of the same type, with the same intended use, may go through the FDA’s 510(k) pathway, whereby devices can obtain clearance by demonstrating substantial equivalence to a predicate device.
Risks associated with use of the kit include false negative test results. As part of the clinical study, the device manufacturer performed genetic testing, an accepted method of diagnosing DMD, on 173 patient samples including a subset of patients identified as negative by the GSP Neonatal Creatine Kinase-MM kit. Genetic testing on the negative samples did not identify any DMD-causing genetic variants, confirming the negative screening results by the GSP Neonatal Creatine Kinase-MM kit.
The FDA granted marketing authorisation of the GSP Neonatal Creatine Kinase-MM kit to PerkinElmer.