Homology cleared to resume gene therapy trial for rare metabolic disease after FDA lifts hold
A few months after getting the stop sign from the FDA, Homology Medicines is now able to restart its Phase II trial of a gene therapy for the rare metabolic disease phenylketonuria, or PKU.
The FDA had shown concerns that Homology’s gene therapy, known as HMI-102, might lead to liver damage issues. In announcing the hold had been lifted, Homology said there were no hospitalizations required pertaining to the elevated liver function tests seen in the trial of adults.
Homology said it plans to share protocol changes with clinical trial sites to ensure the study can continue without another hitch. The changes include administering T cell inhibitor tacrolimus, which is typically used to help prevent organ rejection after transplant, and a shorter course of steroids, the biotech said.
The Massachusetts biotech is taking the “same approach” in an ongoing gene editing trial for the same disease and in another gene therapy study for Hunter syndrome.
“Similar regimens have been shown to dampen the immune response to AAVs in the clinical setting,” the company said in a statement.
Albert SeymourHomology plans to give an update on the program, known as pheNIX, this fall, CSO and president Albert Seymour said in a statement. Those updates, by year’s end, “should help better define the therapeutic potential of the pipeline,” Cowen analysts noted.
Investors didn’t react so well to the news, sending Homology’s stock $FIXX down almost 9% after the opening bell Monday.
Liver toxicity has been one of the more-documented risks attributed to gene therapies delivered with an adeno-associated virus. This happens particularly when AAV gene therapies are delivered at high doses. Homology’s high dose, at 100 trillion viruses per kilogram, is about the same as Novartis’ spinal muscular atrophy gene therapy Zolgensma.
Homology’s PKU gene therapy hold was lifted before BioMarin’s, which the company said in February was possibly “several quarters” away.
People with PKU are born without a certain enzyme required to break up the amino acid phenylalanine, which can cause neurologic and other symptoms if it builds up in the bloodstream.
