An inter-laboratory comparison of PNH clone detection by high-sensitivity flow cytometry in a Russian cohort

[Efficacy of iptacopan monotherapy for suboptimal response to eculizumab in patients with paroxysmal nocturnal hemoglobinuria]

AIM

To evaluate the hematological response within 4 weeks of iptacopan monotherapy in patients with paroxysmal nocturnal hemoglobinuria and suboptimal response to long-term eculizumab therapy.

MATERIALS AND METHODS

The analysis included 8 patients, median age 32 years, with persistent anemia on long-term therapy with eculizumab. The hematological response was assessed when switching to oral monotherapy with iptacopan 200 mg twice daily for 4 weeks.

RESULTS

After 4 weeks of iptacopan therapy, an increase in hemoglobin levels by more than 20 g/l was achieved in 7/8 (88%), and a complete response in 6/8 (75%) patients. The median increase in hemoglobin levels was 32.5 g/l from the initial 85.5 g/l (74-100) to 121.5 g/l (80-141); p=0.00013. Independence from red blood cell transfusions was achieved in 100% of cases. Achieving a hematological response to iptacopan therapy was accompanied by a decrease in the level of absolute reticulocyte count, bilirubin and lactate dehydrogenase, as well as a negative result of the anti-C3d direct antiglobulin test.

CONCLUSION

The oral complement factor B inhibitor iptacopan is an effective treatment option for paroxysmal nocturnal hemoglobinuria in patients with a suboptimal response to complement inhibitor C5 due to more effective control of extravascular C3-mediated hemolysis.

Clinical guidelines for the management of patients with paroxysmal nocturnal hemoglobinuria

Introduction. Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired clonal disease of the blood system characterized by intravascular hemolysis, bone marrow dysfunction and an increased risk of thrombotic and organ complications.

Aim — to provide relevant clinical recommendations for the provision of medical care to adults and children with PNH.

Basic information. Experts from the National Hematological Society association which is focused on the promotion of hematology, transfusiology and bone marrow transplantation along with experts from the public organization, National Society of Pediatric Hematologists and Oncologists, have developed current clinical recommendations for providing medical care to adults and children with PNH. The recommendations address in detail the issues of etiology, pathogenesis, epidemiology, and clinical manifestations of the disease. Special attention is paid to the diagnosis, differential diagnosis, and treatment of PNH based on the principles of evidence.

The efficacy and safety of eculizumab biosimilar in patients with paroxysmal nocturnal hemoglobinuria. Results of a phase III randomized open-label comparative clinical trial

Aim. To establish the equivalent efficacy and comparable safety profile of biosimilar Acveris and referent eculizumab product Soliris used for the treatment of paroxysmal nocturnal hemoglobinuria (PNH). Materials and methods. Were included in the phase III multicenter 28 PNH patients, open-label clinical trial. Participants were randomized (1:1) into 2 treatment groups: investigational product (Acveris, n=14) and referent product (Soliris, n=14). Patients received eculizumab as the intravenous infusion 600 mg once a week during the first 4 weeks, 900 mg at week 5 and then 900 mg every 14 days (2 days) up to week 27 of the study. The efficacy, pharmacokinetics, pharmacodynamics, safety and immunogenicity of the compared products were analyzed after the end of 27 weeks of the study. The primary efficacy endpoint was the area under the curve LDH concentrationtime (AUCLDH) throughout the study period weeks 527. Results. The difference between the mean AUCLDH values between the Acveris and Soliris groups was 5380.0 [-38 773.87; 49 533.87] U/ldays. The 95% CI limits for the difference in mean AUCLDH values between the groups fit the preset 95% CI [-146 500.9146 500.9] U/ldays and establish the equivalent efficacy of the biosimilar and referent product according to the primary efficacy endpoint. The safety profile of both Acveris and Soliris was expected and comparable according to the proportion of patients with adverse events. The formation of binding antibodies to eculizumab was not detected in both the groups. Conclusion. The study established the equivalent efficacy of biosimilar product Acveris and referent eculizumab product with the evidence of effective suppression of intravascular hemolysis in PNH patients along with a comparable favorable safety profile.

Randomized multicenter noninferiority phase III clinical trial of the first biosimilar of eculizumab

Currently, eculizumab is the main effective treatment for paroxysmal nocturnal hemoglobinuria (PNH). The aim of this randomized multicenter noninferiority study was to evaluate the efficacy and safety of the Biosimilar (Elizaria) in comparison with the Originator (Soliris) in patients with PNH. Biosimilar and Originator were administered at a dose of 600 mg weekly for 4 weeks at the initial stage in naive patients, as well as for maintenance therapy at a dose of 900 mg every 2 weeks in all patients. The primary endpoint was a comparative assessment of hemolytic activity based on the area under the lactate dehydrogenase (LDH) concentration–time curve during the maintenance therapy. Thirty-two (32) patients were randomized for therapy with Biosimilar (n = 16) or Originator (n = 16). The mean values of LDH concentration–time curve were similar in both treatment groups without statistically significant differences (p > 0.05). Evaluation of secondary endpoints has shown no statistically significant differences between the groups. Safety values were comparable in both treatment groups. The data obtained confirm that the Biosimilar is not inferior to the Originator in terms of the main efficacy parameter, and is also comparable with it in terms of safety and additional efficacy parameters. Clinicaltrials.gov identifier: NCT04463056

[Results of phase Ib open multicenter clinical trial of the safety, pharmacokinetics and pharmacodynamics of first biosimilar of eculizumab in untreated patients with paroxysmal nocturnal hemoglobinuria during induction of therapy]

Currently, the main pathogenetic method for the treatment of paroxysmal nocturnal hemoglobinuria (PNH) is the treatment with recombinant monoclonal antibodies that block the C5 component of the complement system. Eculizumab is the first biotechnological drug, which is a monoclonal antibody, with proven clinical efficacy and safety for the treatment of patients with PNH, which is used in world clinical practice. In Russia, in the framework of the state program Development of the pharmaceutical and medical industry for 20132020 was developed Elizaria (JSC GENERIUM) the first biosimilar of the original drug eculizumab.

AIM

To evaluate the pharmacokinetic and pharmacodynamic parameters, as well as safety and immunogenicity parameters of the drug Elizara in the induction phase of therapy in previously untreated patients with PNH.

MATERIALS AND METHODS

The study included 11 patients with PNH aged 26 to 75 years who had not previously received eculizumab. Each of the study participants was injected with the studied drug Elizaria at a dose of 600 mg intravenously once a week for 4 weeks.

RESULTS

During the clinical study, it was noted that the concentration of the studied drug significantly increased by the time the infusion was completed and then gradually decreased to a minimum at the end of the dosing interval. The average concentration of eculizumab 5 minutes before the administration of the study drug at all visits exceeded 35 g/ml, the minimum concentration sufficient to completely inhibit intravascular hemolysis in patients with PNH. The pharmacodynamic efficacy of the drug Elizaria was confirmed by a decrease in the concentration of the membrane-attack complex (MAC) after the first infusion of the drug was maintained at stable levels until visit 5. A persistent decrease in the level of MAC and a four-fold decrease in the average values of lactate dehydrogenase to visit 5 from 1286.4 to 280.9 U/l demonstrated a marked decrease in activity and stabilization of the hemolytic process against the background of the induction of therapy with Elizaria at a dose of 600 mg once a week and confirmed the effecacy of the study drug. Among the 9 adverse events, only 5 had a relationship with the studied drug, including one serious adverse event in the form of an allergic reaction, which, according to the researcher, had a possible cause-effect relationship with the infusion of the studied drug. In 2 patients, low-titer binding anti-drug antibodies were detected without neutralizing activity during treatment with the studied drug, which may indicate its low immunogenicity.

CONCLUSION

The study evaluated the pharmacokinetic and pharmacodynamic properties of the drug Elizaria in the regimen of induction therapy in previously untreated patients with PNH, confirming its efficacy. The study demonstrated the safety and low immunogenicity of the study drug.

Comparison of High Sensitivity and Conventional Flow Cytometry for Diagnosing Overt Paroxysmal Nocturnal Hemoglobinuria and Detecting Minor Paroxysmal Nocturnal Hemoglobinuria Clones

Background

High sensitivity flow cytometry (HS-FCM) was recently developed for diagnosing paroxysmal nocturnal hemoglobinuria (PNH). We compared its performance with conventional flow cytometry (C-FCM) for diagnosing overt PNH and detecting minor (0.1–1%) PNH clones in aplastic anemia (AA)/low-grade myelodysplastic syndrome (MDS) patients.

Methods

C-FCM and HS-FCM were performed simultaneously on 41 samples from healthy controls and 23 peripheral blood samples from 15 AA/low-grade MDS and eight PNH patients, using a Navios flow cytometer (Beckman Coulter, Miami, FL, USA). Results were compared.

Results

No healthy control samples had PNH clone size >0.01%. For granulocytes, C-FCM detected a smaller PNH clone size than HS-FCM (mean difference: 0.7–1.7%). In AA/low-grade MDS patients, three samples showed >1% PNH clones with C-FCM but not with HS-FCM. Seven samples showed minor PNH clones by C-FCM, but HS-FCM showed negative results for all these samples. In PNH patients, C-FCM detected a smaller PNH clone size than HS-FCM (mean difference: 1.9–5.0%). For red blood cells, C-FCM detected a greater PNH clone size than HS-FCM (mean difference: 1.5%). In AA/low-grade MDS patients, C-FCM showed >1% PNH clones in six samples, but HS-FCM showed >1% PNH clones in none of the samples. C-FCM detected minor PNH clones in nine samples, but six of them were negative by HS-FCM. In PNH patients, C-FCM detected a greater PNH clone size than HS-FCM (mean difference: 2.5%).

Conclusions

HS-FCM can sensitively detect minor PNH clones and reduce false-positive C-FCM minor PNH clone cases in AA/low-grade MDS patients.