18 and older, any sex, with Paroxysmal Nocturnal Hemoglobinuria (PNH). Patients with the condition only — healthy volunteers not accepted.
Results — posted to ClinicalTrials.gov
Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.
Percentage of Participants Who Achieved Adequate Control of Intravascular HemolysisPrimary· Week 4 through Week 26
Participants were considered to have had adequate control of intravascular hemolysis if all of their lactose dehydrogenase (LDH) readings from Week 4 through Week 26 inclusive had values less than or equal to ≤ 1.5 × upper limit of normal (ULN). Participants must have greater than or equal to (≥) 50 percent (%) of scheduled LDH measures in those weeks, must not have had more than (\>) 2 consecutive visits without LDH measures, must not have experienced breakthrough hemolysis, and must not have discontinued study treatment early. Participants were considered not to have had adequate control of
Group
Value
95% CI
REGN3918
75.0
57.7 – 92.3
Percentage of Participants Who Achieved Transfusion AvoidancePrimary· Up to 26 Weeks
Transfusion avoidance was defined as not having received red blood cell (RBC) transfusion during the first 26 weeks. A transfusion was counted only if it was per-protocol, that is, it followed the predefined transfusion algorithm: RBC transfusion due to a post-baseline hemoglobin level \< 9 grams per deciliter (g/dL) (with anemia symptoms) or a post-baseline hemoglobin level \< 7 g/dL (without anemia symptoms).
Group
Value
95% CI
REGN3918
87.5
74.3 – 100.0
Percentage of Participants Who Had Breakthrough Hemolysis (BTH)Secondary· Baseline up to 26 Weeks
Breakthrough hemolysis was defined as the measurement of LDH ≥ 2 ULN concomitant with associated signs or symptoms at any time subsequent to an initial achievement of disease control (i.e., LDH ≤ 1.5 ULN).
Group
Value
95% CI
REGN3918
0
0 – 0
Percentage of Participants Who Achieved Normalization of Intravascular HemolysisSecondary· Week 4 through Week 26
A participant was considered to have achieved normalization of intravascular hemolysis if their LDH readings between Week 4 through Week 26 inclusive had values ≤ 1.0 ULN. A participant must have ≥ 50% of scheduled LDH measures in those weeks, must not have had \> 2 consecutive visits without LDH measures, must not have experienced breakthrough hemolysis, and must not have discontinued study treatment early. A participant was considered not to have achieved normalization of intravascular hemolysis if they failed any of these criteria.
Group
Value
95% CI
REGN3918
16.7
1.8 – 31.6
Time to First Lactate Dehydrogenase (LDH) ≤1.5 x ULNSecondary· Up to Week 26
A time-to-first-event analysis was used to estimate the proportion of participants achieving transfusion avoidance at Week 26.
Group
Value
95% CI
REGN3918
13.625
± 3.6927
Percentage of Days With LDH ≤ 1.5 ULN From Week 4 Through Week 26Secondary· Week 4 through Week 26
Percentage of days was calculated as number of days with LDH ≤ 1.5 x ULN divided by the participant's total treatment duration (total number of days on treatment from Week 4 through Week 26). LDH ≤ 1.5 x ULN was used as an indicator of adequate control of intravascular hemolysis.
Group
Value
95% CI
REGN3918
93.4
± 18.76
Change From Baseline in LDH Levels at Week 26Secondary· Baseline, Week 26
Change from baseline in LDH levels at Week 26 was reported.
Group
Value
95% CI
REGN3918
-5.070
± 0.1467
Percent Change From Baseline in LDH Levels at Week 26Secondary· Baseline, Week 26
Percent change from baseline in LDH levels at Week 26 was reported.
Group
Value
95% CI
REGN3918
-81.72
± 1.847
Rate of Transfusion With Red Blood Cells (RBCs)Secondary· Baseline up to Week 26
The rate of transfusion with RBCs for a participant was the total number of transfusions divided by total person-years of time on treatment.
Group
Value
95% CI
REGN3918
1.039
0.187 – 5.772
Number of Units of Transfusion With RBCsSecondary· Baseline up to Week 26
Transfusions with RBCs proceeded according to the following predefined criteria that triggered a transfusion; however, the actual number of units to be transfused is at the discretion of the investigator: • Transfuse with RBC(s) if the post-baseline hemoglobin level is \<9 g/dL with symptoms resulting from anemia or • Transfuse with RBC(s) if the post-baseline hemoglobin level is \<7 g/dL.
Group
Value
95% CI
REGN3918
3.625
± 4.274
Change From Baseline in RBC Hemoglobin Levels at Week 26Secondary· Baseline, Week 26
Hemoglobin levels in participants with PNH was measured. Change from baseline in RBC hemoglobin at Week 26 was reported.
Group
Value
95% CI
REGN3918
15.0
± 3.24
Change From Baseline in Free Hemoglobin Levels at Week 26Secondary· Baseline, Week 26
Change from baseline in free hemoglobin levels at Week 26 was assessed.
Group
Value
95% CI
REGN3918
-9.19
± 16.264
Adverse events — posted to ClinicalTrials.gov
Time frame: From first dose to Week 26.
Reporting threshold: 5%.
Adverse-event reports describe events observed during the trial — not all are caused by the drug.
The primary objective of the study is to demonstrate a reduction in intravascular hemolysis by REGN3918 over 26 weeks of treatment in patients with active PNH who are treatment-naive to complement inhibitor therapy or have not recently received complement inhibitor therapy.
The secondary objectives of the study are:
* To evaluate the safety and tolerability of REGN3918.
* To evaluate the effect of REGN3918 on parameters of intravascular hemolysis
* To assess the concentrations of total REGN3918 in serum.
* To evaluate the incidence of treatment-emergent anti-drug antibodies to REGN3918 over time
* To evaluate the effect of REGN3918 on patient-reported outcomes (PROs) measuring fatigue and health-related quality of life
Publications & conference data
8 peer-reviewed publications reference this trial (live from Europe PMC):
NCT04162470 — REGN3918 in Patients With Paroxysmal Nocturnal Hemoglobinuria (PNH) to Evaluate Its Long Term Safety, Efficacy and Toler
· Phase 3
· terminated
NCT03115996 — Study of the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of REGN3918 in Healthy Volunteers
· Phase 1
· completed
Other recruiting trials for Paroxysmal Nocturnal Hemoglobinuria (PNH)
Currently open trials in the same condition.
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Publications: Europe PMC API search by NCT ID, retrieved 10 June 2026
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by Regeneron Pharmaceuticals
Last refreshed: 26 June 2023
Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT03946748.