DUBLIN – Obseva SA's stock plunged 65% Thursday on news that it was terminating development of its in vitro fertilization (IVF) drug, nolasiban, after it missed the primary endpoint of a confirmatory phase III trial. The result blindsided both Obseva and investors, as the outcome was at odds with that of a previous phase III study, Implant 2, which had demonstrated a statistically significant and clinically relevant improvement in the rate of successful pregnancy at 12 weeks.