By Dhirendra Tripathi
Investing.com – Biomarin stock (NASDAQ:BMRN) fell 8% Tuesday as the U.S. Food and Drug Administration placed a clinical hold on of its gene therapy study.
The study evaluated a gene therapy in adults with phenylketonuria, a genetic disorder caused due to a deficiency of the enzyme PAH.
The enzyme is required for the metabolism of Phe, an essential amino acid found in most protein-containing foods. If the active enzyme is not present in sufficient quantities, Phe accumulates to abnormally high levels in the blood and becomes toxic to the brain, resulting in a variety of complications including severe intellectual disability and seizures.
The FDA's clinical hold was based on interim safety findings from a pre-clinical study. The company is also pausing further enrollment of participants outside the U.S.
"More than 3,000 patients have been treated with gene therapy, and there are no reports of cancers emerging as a consequence,” the company said in a note, after cases of malignancy were found in a study on mice.
The company has only dosed humans in the Phearless phase 1/2 clinical study with lower doses, it said. Due in part to the risk previously identified by historical rodent studies, it said the liver health of Phearless study participants is regularly monitored.