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Fetal Therapy for Gaucher Disease

A fetal therapy for Gaucher disease clinical trial offers new hope for expecting couples

Gaucher disease causes glucocerebroside to build up in cells, which leads to organ damage. Gaucher disease types 2 and 3 affect the brain, liver, and spleen. Because of the brain involvement, types 2 and 3 are also known as neuronopathic Gaucher disease.

Currently, there are no treatments for the neurological symptoms of Gaucher disease types 2 and 3. But for the first time, there’s hope on the horizon.

Fetal Therapy: A New Hope

In utero enzyme therapy (fetal therapy) delivers medication before birth. It may give babies with Gaucher disease types 2 or 3 a chance at a healthier life.

University of California, San Francisco (UCSF) pediatric surgeon and researcher Dr. Tippi MacKenzie is the lead investigator in a fetal therapy clinical trial. “We’re investigating an approach for treating eight different genetic conditions where people are missing a very critical enzyme required for healthy cell function,” says Dr. MacKenzie. “Gaucher disease types 2 and 3 are two of the conditions included in this clinical trial.”

What is Fetal Therapy?

Fetal therapy involves giving medication to a fetus within the pregnant person’s uterus. Fetal therapy is not a new technique, but the UCSF trial is the first time anyone has used it to deliver enzymes.

“Much of the cell and organ damage in Gaucher disease starts in the fetal stage, so clearly, it’s not good enough to wait until after birth to start treatment,” says Dr. MacKenzie. “The hope is that giving medication as early as possible will improve the child’s chance at a healthier life.”

Why give enzyme therapy before birth?

After birth, babies with Gaucher disease receive treatment to replace the enzymes their bodies can’t make. “But after a baby is born, the blood-brain barrier is closed, so if you give enzyme replacement therapy (ERT) then, it doesn’t reach the brain,” Dr. MacKenzie says. “At that point, ERT can’t prevent neurological symptoms and brain damage.”

She and her team hope that giving ERT before the blood-brain barrier closes will prevent brain damage from occurring.

How is fetal therapy given?

For this procedure, a technician applies medication to numb the skin of the pregnant person’s abdomen. Then, a specialist uses ultrasound to guide a small needle through the abdomen and into the umbilical vein to inject the enzymes. The umbilical vein is in the umbilical cord, which connects the fetus to the placenta.

When is fetal therapy given?

Giving infusions through the umbilical vein is relatively safe starting at 18 to 20 weeks of pregnancy. According to Dr. MacKenzie, her team designed the trial so infusions can start right after a fetal Gaucher disease diagnosis.

“If parents choose to enroll, they come to UCSF and go through a screening process,” she says. “If they’re a good candidate, we start doing the infusions as early as possible after 18 weeks. The infusions happen every two to four weeks until birth.”

What are the Risks of Fetal Therapy?

For each infusion, there is less than 1% risk of:

  • Bleeding
  • Pre-term labor
  • Fetal death

Every medical procedure has some risk. But fetal enzyme therapy is very safe in experienced hands. “The fetal therapy technique we’re using in this clinical trial is already in use for other conditions such as fetal anemia,” says Dr. MacKenzie. These infusions have been performed safely at UCSF.

Is Fetal Therapy for Gaucher Disease Available?

The U.S. Food and Drug Administration (FDA) has not approved fetal therapy as a treatment for Gaucher disease. But parents can access it through the UCSF clinical trial.

Fetal Therapy Clinical Trial for Gaucher Disease Types 2 and 3

So far, there are no Gaucher disease participants in the clinical trial, but Dr. MacKenzie hopes to get at least one. “These are rare diseases, so it’s rare that parents would even know their child has them.”

She wants to make sure Gaucher carriers know about the UCSF clinical trial. “Before this trial, many parents may not have wanted to do fetal testing for Gaucher disease because there was nothing they could do about it,” she says. “Now, they have this option for fetal therapy. So I think it’s worth doing the prenatal screening to find out.”

The National Institutes of Health is sponsoring the clinical trial, and anyone who is eligible can apply.

“All medical costs for the procedure are covered, and so are travel costs,” says Dr. MacKenzie. “We’re treating all trial participants here at UCSF, so we know we can offer the best care and have the most experienced team involved.”

Treatment after fetal therapy

After birth, most children who received fetal enzyme therapy will still need ERT for the rest of their lives. ERT will treat the non-neurological symptoms of Gaucher disease.

“We want to make sure parents understand that fetal therapy won’t prevent their child from needing continued treatment,” Dr. MacKenzie says. “Gaucher disease is a chronic condition, but with fetal therapy, we hope it will be a much more manageable chronic condition.”

Is Fetal Therapy a Cure for Gaucher Disease Types 2 and 3?

According to Dr. MacKenzie, fetal enzyme replacement therapy is not a cure for Gaucher disease but a first step in a lifelong treatment journey. For some people, a bone marrow transplant or gene therapy may be a more permanent treatment, and they may no longer need ERT.

But if organ damage is already present, a bone marrow transplant or gene therapy can’t reverse the damage. This is why fetal therapy could be so crucial in the success of other treatments.

Possible future cures

“Medicine continues to evolve,” Dr. MacKenzie says. “For example, there are now gene therapy clinical trials for Gaucher disease and similar conditions.”

Currently, babies cannot receive gene therapy before birth. “But if fetal therapy can prevent organ damage, the patient will be a much better candidate for something like gene therapy later,” she says. “And this combination may offer a definitive cure.”

How the National Gaucher Foundation Can Help

If you or a loved one lives with Gaucher disease, the National Gaucher Foundation is here for your family. We offer resources to optimize your health with Gaucher disease and connect you with the support you need.



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