Effect of the Oral GnRH Antagonist Linzagolix on Uterine Fibroid-Related Severe Anemia [A105

Abstract

INTRODUCTION: Iron-deficiency anemia is common in women with uterine fibroid (UF)-related heavy menstrual bleeding. Severe anemia is defined as hemoglobin (Hb) levels <10g/dL. The effect of linzagolix, an oral GnRH antagonist, on UF-related severe anemia was assessed in two Phase 3 trials. METHODS: PRIMROSE 1 and 2 are randomized, double-blind, placebo-controlled Phase 3 trials investigating the efficacy and safety of linzagolix 100 mg and 200 mg once daily, with or without hormonal add-back therapy (ABT) in the treatment of UF. Subjects were considered responders if an increase of ≥2g/dL from baseline was achieved. Patients with severe anemia were given iron supplements until they reached the Hb levels >12g/dL. RESULTS: In PRIMROSE 1, of 165 subjects with severe anemia, 57.9%, 61.5%, 82.1% and 65.2% of patients were responders at 24 weeks, in the respective treatment groups (100 mg, 100 mg+ABT, 200 mg and 200 mg+ABT), compared to 50% in the placebo group. In PRIMROSE 2, of 93 patients with severe anemia, 62.5%, 75%, 60% and 73.7%, respectively, were responders, compared to 46.2% for placebo. Given the small sample sizes, statistical significance was not reached. Improvements were maintained at week 52: in PRIMROSE 1, 69.2%, 62.5%, 81.3% and 75% of patients were responders in the respective treatment groups, compared to 40% in placebo, in PRIMROSE 2, 66.7%, 100%, 80%, 87% were responders, respectively. CONCLUSION: High and low doses of linzagolix improved Hb levels in patients with UF suffering from severe anemia.