The Food and Drug Adminis-tration (FDA) has approved Invivoscribe’s LeukoStrat companion diagnostic test and Novartis Pharmaceutical’s Rydapt (mido-staurin) for the treatment of acute myeloid leukemia (AML). The LeukoStrat CDx FLT3 Mutation assay will be the first companion diagnostic approved for AML treatment. This signal ratio assay detects mutations in the FMS-like tyrosine kinase 3 (FLT3) gene such as internal tandem duplication (ITD) and tyrosine kinase domain mutations. It also detects larger ITD mutations that many current next-generation sequencing (NGS)-based assays miss. Because these mutations are associated with an aggressive phenotype and high prevalence of relapse in patients with AML, assessing the mutation status of FLT3 is considered critical for prognosis and the determination of appropriate treatment options.

If the LeukoStrat test detects an FLT3 mutation in blood or bone marrow samples, then the patient might be eligible for treatment with Rydapt, which functions as a kinase inhibitor that blocks enzymes that promote cell growth. Treatment with Rydapt and chemotherapy has been shown to extend lifespans and delay the onset of complications in patients with AML when compared to treatment with chemotherapy alone.

Currently only Invivoscribe’s subsidiary can perform the LeukoStrat test. Invivoscribe will continue its agreement with Thermo Fisher Scientific to seek an expanded FDA approval that will allow the sale of assay kits to other laboratories.