MS Drug Poses Hard Choices for Women Wanting Children

From Drugs.com - February 8, 2018

MS Drug Tysabri (Natalizumab) Poses Hard Choices for Women Wanting Children

THURSDAY, Feb. 8, 2018 -- A powerful multiple sclerosis drug presents women with a tough dilemma if they would like to have children, a pair of new studies suggests.

Those who take Tysabri (natalizumab) to manage their MS are more likely to suffer a relapse during pregnancy if they stop taking the drug before they conceive, the first study found.

But if a woman remains on Tysabri while trying to get pregnant, her unborn child could face serious health risks, the second study showed.

Fetal exposure to Tysabri up to 12 weeks of gestation was associated with an increased risk of miscarriage, the Italian researchers discovered. Babies exposed to the drug in the womb also tended to have shorter length and lower weight at birth.

The researchers said their findings provide a path forward for couples who'd like to start a family.

"Our findings suggest that if women who take natalizumab for MS want to become pregnant, it may be best to continue treatment up until a pregnancy test is positive and then at that point discontinue use," lead researcher Dr. Emilio Portaccio said in a statement.

"While there is still a risk of increased disease activity, this course of action may lower that risk," said Portaccio, a neurologist with the Don Carlo Gnocchi Foundation in Florence.

Other MS experts are less certain, arguing that these studies simply provide more data for couples to consider when planning a family.

"I do not think decisions should be made based on any one study," said Kathy Costello, associate vice president of health care access for the National MS Society.

Multiple sclerosis is an autoimmune disease in which the body mistakenly attacks nerve cells. Tysabri helps control the disease by blocking immune cells from leaving the bloodstream and traveling into the central nervous system, where they can attack nerve cells and disrupt communication between brain and body, Costello said.

It's a drug typically prescribed for MS patients who have not responded to other treatments or ca not tolerate them, the researchers said.

During pregnancy, women usually see an easing of their MS symptoms, possibly because the immune system naturally backs off to protect the health of the fetus, Costello explained. However, risk of relapse returns following delivery and can be even sharper, particularly if the patient has stopped taking Tysabri.

On the other hand, regulatory agencies have recommended that women discontinue Tysabri for at least three months before conception, given studies that have linked the drug to increased risk of miscarriage, the authors added. The drug has also been linked to an increased risk for a rare, and sometimes fatal, brain infection.

To test the safety of Tysabri during pregnancy for both mother and child, Portaccio and his colleagues tracked 92 pregnancies in 83 women taking the drug. There ended up being 74 live births among the pregnancies.

The women were divided into two groups, depending on when they took their last dose of Tysabri.


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