A University of British Columbia medical trial that gave an erectile dysfunction medication to pregnant women experiencing complications has been halted after 11 Dutch babies died of a lung condition in a similar study.
The trial was looking for treatment for early intrauterine growth restriction (IUGR), a rare condition where babies don't fully develop within the womb. In some cases, it's because the placenta doesn't supply enough nutrition, and so the baby slows down its growth to match the nutrient supply, UBC's head of Maternal-Fetal Medicine Dr. Kenneth Lim explained at the program's start.
Women with IUGR are often forced to choose between leaving the baby in the womb, which can often lead to stillbirth, or intervening to deliver the baby early, which increases chances of the baby's death or disability.
Because sildenafil — the generic erectile dysfunction drug often known by the brand name Viagra — improves blood flow, doctors theorized that it could help women with IUGR by increasing placental nutrition. (Pfizer, the company that distributes Viagra, issued a release stating that their drugs were not involved in the study.)
"If using sildenafil means that the baby can stay in the womb for longer, it can greatly increase survival and improve outcomes," Lim said at the beginning of the study, known as the STRIDER trial.
Pregnant women were recruited all over Canada, with specific focus on Vancouver, Toronto, and Montreal. The trial was approved by Health Canada and received funding from the Canadian Institutes for Health Research.
But both the STRIDER trial and a similar study at Amsterdam University Medical Centre have now been halted after several infant deaths.
The Dutch study, which launched in 2015, found sildenafil to have adverse effects, according to a press briefing released Monday.
Ninety-three pregnant participants with IUGR were given sildenafil, while 90 were given a placebo. Babies died in both groups: 19 in the sildenafil group, and nine in the placebo group. But the primary difference was the presence of a lung disease in the sildenafil group.
Of the babies born to women who took sildenafil, 11 died due to a lung disease that caused high blood pressure. Three of the babies in the placebo group had the same lung disease, but none of them died from it.
Lim, the program head at UBC, found out about the Dutch developments late last week and immediately notified the university, he said in a statement e-mailed to HuffPost Canada.
"We are not aware of any increase in adverse health outcomes among Canadian participants," Lim said.
"But we cannot take any chances with the health of mothers and their infants, so we moved quickly to suspend any further activity until we, our research colleagues around the world, and our respective monitoring boards and research ethics boards can make sense of the findings and this latest, tragic development."
Only one Canadian woman is currently pregnant and taking either the drug or placebo, and she was contacted right away, Lim said. The school also plans to contact the 20 other Canadian woman who were previously part of the trial.
"The loss of a child under any circumstance is a tragedy for the parents and their loved ones, and we were very saddened and concerned upon learning of this news late last week," he added.
Both UBC and Amsterdam University Medical Centre said they will analyze the information they have already collected, including monitoring the health of the children born to trial participants, Lim said in his statement. In addition to UBC and Amsterdam University Medical Centre, nine other hospitals participated in IUGR studies, including facilities in the U.K., Australia and New Zealand, he added.
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