Arena rises after hours on Phase II PAH data

Arena Pharmaceuticals Inc. (NASDAQ:ARNA) jumped $7.60 (41%) to $25.99 in after-hours trading Monday after it said ralinepag (APD811) significantly improved absolute change from baseline in pulmonary vascular resistance (PVR) in a Phase II trial to treat pulmonary arterial hypertension (PAH), meeting the study's primary endpoint.

In the 61-patient trial, the oral agonist of prostacyclin (IP) receptor (PGI2; PTGIR) improved median PVR from baseline by 163.9 dyn.s.cm^-5 vs. a worsening of 0.7 dyn.s.cm^-5 for placebo (p=0.02). On a percentage basis, ralinepag improved PVR by 29.8% from baseline vs. placebo (p=0.03)...