APLS 2017 Annual Report

15 A total of 24 subjects received single doses of APL-2 at doses up to 1440 mg and 16 subjects received multiple doses of APL-2 for 28 consecutive days at doses up to 270 mg/day. A total of eleven subjects received either single or multiple administrations of a placebo in these trials. We observed the following in the trials: • APL-2 was well tolerated in both trials with no serious adverse events reported; • the PK of APL-2 in humans was in line with our expectations derived from preclinical data, with little inter-subject variability observed; • in the multiple ascending dose trial, the plasma concentration of APL-2 increased over time, reaching maximum concentration after the last day of administration on day 28; and • in both trials, we observed a dose-dependent increase in C3 that is indicative of APL-2 binding to C3. In these trials, we assessed inhibition of hemolysis of red blood cells by using ex vivo serum-induced hemolysis. In the multiple ascending dose trial, at a dose level of 180 mg/day of APL-2, reduction of ex vivo serum-induced hemolysis was observed as early as seven days after initiation of treatment, continued for the duration of treatment, and reached a maximum of more than 80% in two of the four subjects who received 180/mg day of APL-2 and of more than 60% in the other two subjects. At the dose level of 270 mg/day of APL-2, reduction of ex vivo serum-induced hemolysis was observed as early as seven days after initiation of treatment, continued for the duration of treatment, and reached a maximum reduction of more than 90% in three of the four subjects who received 270 mg/day of APL-2. The fourth subject on active treatment had a more moderate reduction compared to placebo. Preclinical Studies We have conducted numerous preclinical studies of APL-2 in animals and in laboratory samples to assess the safety of APL-2, including repeat-dose subcutaneous and intravenous toxicity studies of APL-2 in rats, rabbits and monkeys for durations of up to nine months. In these studies, there were no significant macroscopically observable or clinical pathology drug-related changes in any species at any of the doses tested. Similarly, there was no evidence of a potential for adverse effects on myocardial conduction, cardiovascular and respiratory systems in either species and no genotoxicity potential was observed. In addition, no signs of infection were observed in any of the studies that we conducted. The main toxicity observed at the highest doses tested was microscopic kidney damage, likely resulting from accumulation of APL-2 in the kidney, which is one of the organs we believe to be responsible for its clearance from the body. While there is no animal model of PNH, APL-2 inhibited both hemolysis of red blood cells by the membrane attack complex and C3 fragment deposition on the surface of these cells in preclinical studies that we conducted ex vivo on blood samples from patients with PNH. Autoimmune Hemolytic Anemia (Systemic APL-2) Autoimmune hemolytic anemia, or AIHA, comprises a group of rare, autoimmune diseases characterized by autoantibody- initiated premature destruction of red blood cells and classified by the type of immunoglobulin involved in causing the disease and its thermal optimum for binding red blood cells. Complement plays a major role in red blood cell destruction in AIHA through extravascular hemolysis, which corresponds to the removal and destruction of opsonized red blood cells from the blood vessels by the spleen or liver, and intravascular hemolysis, which corresponds to the destruction of the red blood cells following the formation of the membrane attack complex in the membrane of the red blood cells in the blood vessels. We are developing APL-2 as a therapy for two subtypes of AIHA: cold agglutinin disease, or CAD, and warm antibody AIHA, or wAIHA. There is no FDA-approved drug therapy specifically for either subtype of AIHA. The primary and secondary therapies, which include corticosteroids, splenectomy, alkylating agents and immunosuppressive drugs, are associated with low response rates, relapses and clinically significant adverse effects. We believe that C3 inhibition has the potential to prevent C3-related opsonization and extravascular hemolysis in AIHA patients, and that inhibiting the complement system by targeting C3 may have the same impact, if not greater, as other complement pathway drugs in these diseases. We plan to initiate a Phase 2 open-label, prospective, 12-month trial in patients with a primary diagnosis of wAIHA or CAD in the first half of 2018 to assess safety, tolerability and preliminary evidence of activity of C3 complement inhibition with APL-2 in these patients. We plan to enroll 12 patients, six patients with wAIHA in cohort 1 and six patients with CAD in cohort 2. Patients in each cohort will receive either 270 mg/day or 360 mg/day of APL-2 treatment for up to 12 months. Dose escalation from 270 mg/day to 360 mg/day or de-escalation from 360 mg/day to 270 mg/day may occur after thorough evaluation of available safety and