DiaMedica Therapeutics Inc has announced positive interim results from Part 1a of its Phase 2 study investigating DM199 for the treatment of preeclampsia. The study met pre-specified safety and efficacy endpoints, showing highly statistically significant reductions in both systolic and diastolic blood pressure in the combined cohorts 6 to 9 dose range.

DM199, rinvecalinase alfa, is a recombinant form of the KLK1 protein designed to influence blood pressure regulation and vascular health. Preeclampsia remains a serious pregnancy complication with no approved pharmacological treatments in the US or Europe, creating a significant unmet medical need globally.

The Phase 2 trial is an investigator-sponsored, open-label, single-centre, single-arm safety and pharmacodynamic proof-of-concept study conducted at Tygerberg Hospital, Cape Town, South Africa. It is led by Catherine Cluver, professor of maternal/fetal medicine at Stellenbosch University, in collaboration with DiaMedica. The trial plans to enroll up to 90 women with preeclampsia and 30 women with fetal growth restriction.

In the interim analysis, cohort 9 (highest dose) showed the most substantial blood pressure reductions five minutes post-infusion, with mean systolic blood pressure falling by 35 mmHg and diastolic by 15 mmHg. The pooled cohorts 6–9 also demonstrated significant blood pressure reductions sustained up to 24 hours post-infusion.

DM199 was well tolerated with no serious treatment emergent adverse events reported. Mild side effects included nausea, headache, and flushing. Importantly, DM199 did not cross the placental barrier, a major safety consideration in developing preeclampsia treatments.

The study also found a statistically significant reduction in the uterine artery pulsatility index, suggesting improved uterine artery blood flow and placental perfusion, which may support fetal growth and disease modification.

Rick Pauls, president and CEO of DiaMedica, said: “These interim results exceeded our expectations demonstrating DM199’s potential to be a first-in-class, disease modifying therapy for preeclampsia, coupled with a promising fetal exposure profile.”

Professor Catherine Cluver added: “Mothers suffering with preeclampsia have no approved treatment options to address the root cause of the disease, ultimately putting their life and the health of the fetus at risk. DM199’s ability to safely reduce blood pressure represents an exciting development in the search for an effective treatment.”

The trial will continue with enrollment in the dose expansion cohort and a fetal growth restriction cohort based on observed reductions in pulsatility index.