During the 2016 American Society of Hematology (ASH) meeting in San Diego, California data from Alexion’s Phase 1/2 Trial of ALXN1210 for the treatment of paroxysmal nocturnal hemoglobinuria (PNH) was presented and the early results seem encouraging.
Patients with PNH have clinical evidence of abnormally high concentration of serum lactate dehydrogenase (LDH). Abnormalities in LDH levels can lead to blood flow deficiency (ischemia)
heart attack/stroke, low blood pressure or muscle injuries.
About the study
The Phase 1/2 trial was a multicenter, open-label 24-week study of intrapatient dose-escalation evaluating Alexion’s ALXN1210 in patients 18 years or older diagnosed with PNH who had mean LDH levels ≥3 times the upper limit of normal and were unaffected by complement inhibitor therapy.
Two cohorts of patients received different dosing levels in the study. Cohort 1 (n=6) received either 400- or 600-mg IV induction doses followed by a 900-mg maintenance dose q4w; Cohort 2 (n=7) received 600- and 900-mg induction doses, followed by an 1800-mg maintenance dose q4w for up to 24 weeks.
All patients in the study saw a decrease in LDH on day 8 (the first evaluable time point) and improvements were sustained throughout all dosing intervals. Mean percentage of LDH reductions from baseline in cohort 1 was 85.9% at day 169 and 85.2% in cohort 2 at day 141 (the last available time points).
Hemoglobin levels were improved or stable in both cohorts 1 and 2. Among 5 patients in the study with red blood cell transfusions in the 12 months prior to treatment, (2 in cohort 1, 3 in cohort 2), only 50% of the patients in the first cohort, became free of transfusions, while all of the patients in cohort 2 were transfusion free.
ALXN1210 is a is a longer-acting anti-C5 antibody that inhibits terminal complement. ALXN1210 is also in a Phase 3 clinical trial
for the treatment of aHUS.
About paroxysmal nocturnal hemoglobinuria
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disorder in which red blood cells break apart prematurely. It is an acquired hematopoietic stem cell disorder.
Some hematopoietic stem cells in individuals with PNH are defective and consequently produce defective blood cells. These defective red blood cells of PNH are extremely susceptible to premature destruction by a particular part of a person’s own immune system called the complement system.