Effect of the Terminal Complement Inhibitor Eculizumab on Patient Reported Outcomes in Paroxysmal Nocturnal Hemoglobinuria (PNH): Phase III Triumph Study Results.

Abstract

Abstract Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hemolytic anemia in which complement-sensitive RBCs are destroyed leading to chronic intravascular hemolysis. PNH patients suffer from diverse and serious hemolysis-induced morbidities leading to a poor quality of life (QoL). Fatigue in PNH patients may be disabling and levels are similar to anemic cancer patients. Fatigue is multifactoral, related to both the underlying anemia and hemolysis. Patients suffer from reduced global health status, patient functioning, pain and dyspnea. Treatment with the terminal complement inhibitor eculizumab reduces intravascular hemolysis and improves anemia. The impact of eculizumab treatment on levels of fatigue and other patient reported outcomes was prospectively examined in a double-blind placebo controlled study (TRIUMPH) using two distinct instruments, the FACIT-Fatigue and the EORTC QLQ-C30. Improvements in QoL were quantified using standardized effect sizes (SES), a measure of the magnitude of the clinical benefit in various instruments. Eculizumab treatment, as compared to placebo, was associated with a very large and significant improvement in fatigue as measured by the FACIT-Fatigue scale (SES=1.13, P<0.001) as well as the EORTC QLQ-C30 fatigue subscale (SES=1.12, P<0.001). Similarly, the percentage of patients achieving a pre-specified minimally important difference (MID) was 53.7% versus 20.5% of eculizumab- and placebo-treated patients, respectively (P=0.003) using the FACIT-Fatigue; 67.7% versus 24.4%, respectively (P<0.001) with the EORTC QLQ-C30. Treatment independent univariate analyses showed that reduction in intravascular hemolysis (decreased LDH levels) and improvement in anemia (increased hemoglobin levels) were both significantly associated with an improvement in fatigue. Further, multivariate analyses indicated that reduction in hemolysis was more predictive than improvement in anemia of an improvement in fatigue. Eculizumab treatment was also associated with significant improvements with moderate to large SES in the following EORTC QLQ-C30 subscales: global health status (0.87, P<0.001); role functioning (0.93, P<0.001); social functioning (0.57, P=0.003); cognitive functioning (0.78, P=0.002); physical functioning (1.01, P<0.001); emotional functioning (0.51, P=0.008); pain (0.65, P=0.002); dyspnea (0.69, P<0.001); and appetite loss (0.50, P<0.001). These data demonstrate that resolution of intravascular hemolysis with eculizumab treatment results in large and clinically meaningful improvements in patient reported outcomes including fatigue, global health status, patient functioning, and disease-related symptoms in PNH.