New drugs go through a long and arduous process before they can grace a doctor’s office. One of the last steps is making sure it is safe, where it faces a barrage of standards it must meet.
In a recent study, a team from St. George’s University in London looked into the cardiac safety of the fertility drug nolasiban. Nolasiban is a fertility drug that acts as an antagonist to oxytocin receptors. The result is intended to reduce uterine contractions and increase endometrial blood flow, which many studies think can increase fertility.
While a good candidate, some studies suggest oxytocin receptor antagonists (like nolasiban) might have cardiovascular risks. Oxytocin alone can increase what is called the QTc-interval, a measurement on an electrocardiogram doctors use to diagnose heart issues and increase the risk of arrhythmia. As nolasiban inhibits oxytocin activation, the team thought that it might reduce the QTc-interval. They note that, so far, there isn’t any evidence showing the nolasiban increases cardiovascular risk, but better safe than sorry.
The team enrolled 45 women to test in a phase 1, double-blind, single-center and randomized. Essentially, this means the study should result in reliable data but suffer from a small group size. Nolasiban was administered at two doses, alongside a placebo. They looked at both direct cardiac effects and possible indirect effects via changes in sex hormones.
The results showed no significant nolasiban-dependent changes in QTc-interval or other cardiac safety parameters, including other electrocardiogram measurements and heart rate. The team did see some QTc changes, though, but found that sex hormone changes were causing them. These were peripheral findings, however, with other studies providing conflicting evidence.
The study concludes, “The findings of this study confirm that nolasiban is not associated with any QTcF prolongation of regulatory concern in healthy women at doses up to 1800 mg. Further, we observed a relationship between the duration of heart rate and progesterone levels, and the JTcp subinterval and oestrogen levels.”