Early and sustained heavy menstrual bleeding reduction with linzagolix in fibroids

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Created On: 06/08/2025

Heavy menstrual bleeding, Uterine fibroids

This study sought to evaluate the timing of therapeutic effects of linzagolix in achieving a prominent reduction in uterine fibroids-related heavy menstrual bleeding.

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Key take away

Linzagolix rapidly and sustainably reduces heavy menstrual bleeding in women with uterine fibroids, with effects seen as early as 3 days.

Background

This study sought to evaluate the timing of therapeutic effects of linzagolix in achieving a prominent reduction in uterine fibroids-related heavy menstrual bleeding.

Method

This analysis utilized pooled data from the PRIMROSE 1 and PRIMROSE 2 studies—two placebo-controlled trials conducted in Europe and the United States. A total of 1,012 women (aged 18 years and above), all with ultrasound-detected uterine fibroids and excessive menstrual bleeding, were enrolled in the PRIMROSE studies. Treatment with linzagolix at 100 mg or 200 mg doses, given with or without ABT, was compared against placebo.

Participants were randomly assigned to one of five groups: linzagolix 100 mg or 200 mg, each with or without hormonal add-back therapy (ABT; 0.5 mg norethisterone acetate and 1 mg estradiol), or placebo. The primary endpoint was the time to initial achievement and sustained maintenance (up to 24 weeks) of clinically meaningful reductions in heavy menstrual bleeding. Kaplan-Meier analysis, adjusted for race and trial (PRIMROSE 1 vs. 2), was used to compare the cumulative incidence of early and sustained heavy menstrual bleeding reduction through week 24 between linzagolix and placebo groups.

Result

Linzagolix (oral gonadotropin-releasing hormone [GnRH] receptor antagonist) led to a markedly faster reduction in heavy menstrual bleeding symptoms when compared to placebo. Most linzagolix regimens (except 100 mg without ABT) attained median time to response in less than 4 weeks, with the 200 mg dose (with or without ABT) illustrating the most rapid effect—within just 3 days. By week 4, between 23.2% and 68.1% of volunteers receiving linzagolix experienced and maintained clinically significant reductions in heavy menstrual bleeding through week 24, when compared to only 7.8% in the placebo group.

Conclusion

Linzagolix provided a rapid and sustained reduction in heavy menstrual bleeding among women with uterine fibroids, presenting a promising non-surgical option for managing fibroid-related bleeding.