New Drug Shows Promise for Preeclampsia Treatment in Early Trial

A trial at Tygerberg Hospital in Cape Town, South Africa, is testing a drug originally developed for stroke that shows promise in treating preeclampsia, a potentially fatal complication of pregnancy. The drug, called DM199, stabilized dangerously high blood pressure in pregnant women after researchers identified the effective dose.

It was the fall of 2024 when Abigail Hendricks learned she was pregnant with her fifth child. Hendricks, who was 33 at the time and living in Cape Town, already had high blood pressure. Soon, the headaches began. From time to time, her vision would blur. Then protein started showing up in her urine. A month before she was due to give birth, she was losing blood pressure control. A normal reading is 120 over 80, but hers climbed to 163 over 101.

Hendricks had developed preeclampsia, a potentially fatal complication of pregnancy involving damage to the blood vessels and high amounts of fluid loss. It can lead to dangerous swelling of the lungs, brain, and heart and massive hemorrhaging. The medical team believed Hendricks' life was in danger — and so was her baby's.

Cathy Cluver, a professor of obstetrics and gynecology at nearby Stellenbosch University, has been searching for a treatment for preeclampsia for a decade. Tygerberg Hospital does about eight to 9,000 deliveries a year of only high-risk women, including those with preeclampsia who do their best to delay delivery. It's important for a baby to stay inside the womb as long as possible but this can jeopardize the health of the mother.

Preeclampsia occurs when the placenta sends out a kind of molecular distress call that it's not getting enough oxygen. "It's saying, 'I need more blood supply, so I'll push the blood pressure up,'" says Cluver, who had preeclampsia herself when she was pregnant with her first child. Conventional medications to treat high blood pressure are risky because even though they might lower the mother's blood pressure, they may also reduce blood flow to the baby — right when the placenta is demanding more oxygen.

"It really is one of the most serious complications of pregnancy," says Cluver, making it one of the leading causes of maternal mortality worldwide — with at least 42,000 maternal deaths each year.

About two years ago, Cluver received an email from DiaMedica Therapeutics, a U.S.-based pharmaceutical company. They were testing a drug for certain types of stroke called DM199 that functioned in a way they thought might also work for preeclampsia. Cluver was skeptical at first, but on closer inspection, she and her colleagues thought maybe it was worth trying out. "It could potentially work because it's ticking all the boxes of what we would want," she says.

So they began a trial at the hospital for mothers with dangerously high blood pressure and who were scheduled to deliver their babies early. "I was so nervous that first day," says Cluver. "We started the infusion and you never quite know what's going to happen."

The team enrolled small groups of women with each group receiving a slightly higher amount of the drug. Fifteen patients in, there was no sign that it was having any effect. "I thought, 'this drug is not real,'" says Jacqui Thake, a research nurse at Stellenbosch University who is overseeing the trial. "There was really no difference in the blood pressure — maybe slightly here and there but nothing major."

When the 16th patient received the next highest dose, however, "we literally just opened up this IV infusion and then her blood pressure stabilized," recalls Cluver. "We suddenly saw these sky-high blood pressures coming down and we were like, 'We don't believe this. This is impossible!'"