Achillion Pharmaceuticals, Inc. announced that the final data set for ACH-4471 (newly designated “danicopan”) proof of concept Phase 2 trial in untreated patients with paroxysmal nocturnal hemoglobinuria (PNH) was accepted for oral presentation at the 24thCongress of the European Hematology Association (EHA). Additionally, the Company has received acceptance for the use of the name danicopan for its oral, small molecule factor D inhibitor, ACH-4471, from the United States Adopted Names (USAN) Council and the World Health Organization’s International Nonproprietary Names (INN) Expert Committee. The Company’s first-generation oral complement factor D inhibitor, danicopan, was evaluated for safety and efficacy in untreated patients with PNH. This is a Phase 2, open-label, multiple dose trial in adult patients with anemia, defined as a hemoglobin <12 g/dL, and LDH =1.5X upper limit of normal (ULN) at enrollment. This clinical trial enrolled ten patients and was comprised of two Parts where patients were administered danicopan orally, three times a day at a dose determined by clinical response. In Part 1 of the study, patients received study medication for 28 days. The primary objective was the reduction in LDH from baseline at Day 28. In Part 2, based on a review of safety and efficacy data through Day 20 along with prespecified LDH reduction criteria, patients, who in the opinion of the Principal Investigator received benefit from danicopan, were offered continued dosing for up to 8 additional weeks. These patients were enrolled into a long-term extension study which began at the conclusion of Part 2. PNH is thought to be caused by a mutation resulting in the absence of receptors normally present on red blood cells (RBCs) that interact with the complement system. The complement system typically functions normally in these patients but due to the lack of key receptors, known as CD55 and CD59, on the surface of the PNH RBCs, the complement system treats these cells as foreign and destroys them via hemolysis in the circulatory system (intravascular) and in the liver or spleen (extravascular). The complement alternative pathway (AP) is a critical factor in the development of extravascular hemolysis. Complement factor D is a critical protein within the amplification loop of the AP and it is believed that inhibiting it could control the AP response. Furthermore, this mechanism of action represents a potentially distinct and unique therapeutic approach for controlling intravascular and extravascular hemolysis associated with PNH.