Why Ra Pharmaceuticals, Inc. Got Hammered Today

Ra Pharmaceuticals (NASDAQ: RARX) characterized its interim phase 2 data testing RA101495 SC in patients with paroxysmal nocturnal hemoglobinuria (PNH) as "positive," but the market sees it differently with shares of the biotech down 37% at 3:27 p.m. EST Monday.

The ongoing trial enrolled three types of patients: ones who have never been treated, those who were being switched from Alexion Pharmaceuticals' (NASDAQ: ALXN) Soliris but were otherwise fine, and those who weren't being adequately treated by Soliris.

RA101495 SC seems to work fairly well in treatment-naive patients with the level of lactate dehydrogenase (LDH), a marker for PNH, going down rapidly. Half of the patients who were transfusion-dependent before the trial have been transfusion-free since starting RA101495 SC.

Source: Fool.com