The Assistance Publique – Hôpitaux de Paris, in collaboration with the Leeds Cancer Centre at St. James’s University Hospital, completed a study that aimed to evaluate hematological response in patients with paroxysmal nocturnal hemoglobinuria (PNH) and anemia in the 6-month period after initiation of anti-C5 antibody treatment.

The retrospective, observational study enrolled 92 adult participants aged 18 years and older with confirmed clinical diagnosis of PNH and anemia (baseline hemoglobin, <10 g/dL) who were incident users of anti-C5 antibody treatment (ie, eculizumab and ravulizumab).

The primary outcome of the study is increase from baseline in hemoglobin (time frame, between days 100 and 200), considering increases of 2 g/dL or greater in the absence of transfusions occurring after day 14 postindex date.

In addition, the study included 2 secondary outcome measures: hemoglobin response (time frame, between days 100 and 200) and transfusion avoidance (time frame, between days 15 and 200).

Read more about PNH therapies

For hemoglobin response, the investigators consider achieving hemoglobin of 12 g/dL or greater in the absence of blood transfusions occurring after the day 14 postindex date.

Transfusion avoidance—a dichotomous endpoint—was defined by the proportion of participants without transfusions during the initial 6-month treatment period starting from 2 weeks after the index date.

The study used real-world data obtained from multiple data sets, and the results will be used as an external control for the APPOINT-PNH (NCT04820530) trial with iptacopan in anti-C5 naive patients.

Exclusion criteria applied to pregnant women, subjects with hereditary complement deficiency, subjects with reticulocyte count inferior to 60×10^9/L, and those who underwent bone marrow transplantation within 1 year prior to initiating anti-C5 treatment.

The study was initiated on January 18, 2023, and was completed March 1, 2023.


Hematological response in patients with paroxysmal nocturnal hemoglobinuria treated with anti-C5 antibody: an external control arm study for iptacopan use in anti-C5 naïve patients (APPEX). May 6, 2023. Accessed May 9, 2023.