Positive results from PRIMROSE 1 and PRIMROSE 2 studies of Yselty to treat heavy menstrual bleeding due to uterine fibroids.- ObsEva SA + Kissei

ObsEva SA announced top-line results from the PRIMROSE 1 and 2 studies of Yselty (linzagolix) to assess the efficacy and safety in women with heavy menstrual bleeding due to uterine fibroids .

PRIMROSE 1 met the primary endpoint at week 24, and showed that women receiving linzagolix experienced a statistically significant and clinically meaningful reduction in menstrual blood loss (?80 mL and a greater than 50% reduction from baseline) compared to placebo. Women receiving 200 mg with ABT achieved a 75.5% (P<0.001) responder rate and those receiving 100 mg without ABT achieved a 56.4% (P=0.003) responder rate. The pooled week 24 data from these two Phase III studies support a best-in-class profile, with a responder rate of 84.7% in women receiving linzagolix 200 mg with ABT, and 56.6% in women receiving linzagolix 100 mg without ABT.

In addition, new data from PRIMROSE 2 demonstrate that continued treatment with linzagolix for 52 weeks provides sustained efficacy and is well tolerated. Responder rates of 91.6% and 53.2% were observed in women receiving 200 mg with ABT and 100 mg without ABT, respectively, both of which are similar to the responder rates observed at week 24 of the study.

Across both studies, women receiving linzagolix experienced statistically significant improvements across a number of clinically relevant secondary endpoints, including reduction in pain, improvement in anemia and quality of life. In PRIMROSE 1, the incidence of adverse events was similar between placebo and active treatment. The most frequently observed adverse events, with an incidence greater than 5%, were headache and hot flushes. In addition, a minimal mean percentage change in lumbar spine bone mineral density (BMD) from baseline was observed in both treatment arms at week 24. In PRIMROSE 2, the most frequently observed adverse events, with an incidence >5%, were headache, hot flushes and anemia. In addition, a small incremental change in BMD was observed at week 52 compared to week 24.

ObsEva is now preparing its regulatory submissions to the European Medicines Agency (EMA) and the FDA which it anticipates submitting in 4Q 2020 and 1H 2021, respectively. Data from across the clinical trial program will be submitted for presentation at upcoming scientific conferences.