Safety, Efficacy, Pharmacokinetic, and Pharmacodynamic Study of ALXN1820 in Adult Participants With Sickle Cell Disease

A Phase 2a, Randomized, Open-Label Study to Evaluate Multiple Dosing Regimens of Subcutaneous ALXN1820 in Adult Participants With Sickle Cell Disease

Status

Terminated

Phases

Phase 2

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT05565092

Acronym

PHOENIX

Enrollment

Registered

2022-10-04

Start date

2023-02-22

Completion date

2024-01-09

Last updated

2025-01-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Sickle Cell Disease (SCD)

Keywords

Sickle Cell Disease, ALXN1820, SCD

Brief summary

The primary objective of this study is to assess the safety and tolerability of ALXN1820 SC (subcutaneous) in participants with SCD (Sickle Cell Disease).

Interventions

DRUGALXN1820

ALXN1820 will be administered subcutaneously.

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

TREATMENT

Masking

NONE

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

* Confirmed diagnosis of SCD (HbSS, or HbSβ0-thalassemia). * Body weight ≥ 40 kg (inclusive) at Screening. * Must follow protocol-specified contraception guidance while on treatment and for up to 6 months after last dose. * Hemoglobin between 5.5 and 10 g/dL at Screening * Have had 1 to 10 VOCs in the past 12 months. * Patients receiving hydroxyurea must have been on a stable dose for ≥ 3 months prior to providing informed consent, with no anticipated need for dose adjustment during the study. * Patients will be vaccinated with MCV4 and serogroup B meningococcal vaccinations at least 14 days before dosing, if not already vaccinated within 3 years before the first dose. * Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae vaccination are up to date according to current national/local vaccination guidelines for patients with SCD.

Exclusion criteria

* Planned initiation, termination, or dose alteration of hydroxyurea during the study. * Receiving Voxelotor (OXBRYTA) or crizanlizumab (ADAKVEO) within 60 days of providing informed consent. * Receiving treatment with recombinant human erythropoetins (eg, epoetin alfa). * Treated with complement inhibitors within 6 months prior to the first dose. * Patients who are on chronic transfusion or receive a transfusion within 60 days of first dose. * Any significant disease or disorder which, in the opinion of the Investigator, may put the participant at risk. * Hepatitis B (positive hepatitis surface antigen \[HBsAg\] or positive core antibody (anti-HBc) with negative surface antibody \[anti-HBs\]) or hepatitis C viral infection (hepatitis C virus \[HCV\] antibody positive, except for patients with documented successful treatment and documented sustained virologic response) at Screening. * Active systemic bacterial, viral, or fungal infection within 14 days prior to dosing. * Participation (ie, last protocol-required study visit) in a clinical study within 90 days or 5 half-lives of the investigational agent, whichever is longer, before initiation of dosing on Day 1. * Participation in more than 1 clinical study of a monoclonal antibody (mAb), or participation in a clinical study of a mAb within the 6 months or 5 half-lives of the mAb, whichever is longer, prior to Screening, during which the participant was exposed to the active study drug. * Severe renal impairment (estimated glomerular filtration rate \[eGFR\] \< 30 mL/min/1.73 m2 ) or on chronic dialysis. * History of allergy or hypersensitivity to excipients of ALXN1820 (eg, polysorbate 80). * History of complement deficiency. * History of N meningitidis, S pneumoniae, or H influenzae infection. * History of malignancy with the exception of a nonmelanoma skin cancer or carcinoma in situ of the cervix that has been treated with no evidence of recurrence within 5 years. * Participants who are pregnant or breastfeeding.

Design outcomes

Primary

Measure	Time frame
Number of Participants With Treatment-Emergent Adverse Events and Serious Adverse Events	Baseline through Day 211 (Cohorts 1 and 2) and through Day 169 (Optional Cohort 3)

Secondary

Measure	Time frame
Pharmacokinetics: Serum ALXN1820 Concentration	Baseline through Day 211 (Cohorts 1 and 2) and through Day 169 (Optional Cohort 3)
Change From Baseline in Serum Concentration of Total and Free Properdin Through Day 211 (Cohorts 1 and 2) and Day 169 (Optional Cohort 3)	Baseline through Day 211 (Cohorts 1 and 2) and Day 169 (Optional Cohort 3)
Change From Baseline Complement Alternative Pathway Activity Through Day 211 (Cohorts 1 and 2) and Day 169 (Optional Cohort 3)	Baseline through Day 211 (Cohorts 1 and 2) and Day 169 (Optional Cohort 3)
Change From Baseline in Complement Biomarkers Through Week 12 (Cohorts 1 and 2)	Baseline, Week 12
Change From Baseline in Hemolysis Markers at Week 12 (Cohorts 1 and 2)	Baseline, Week 12
Change From Baseline in Hemopexin at Week 12 (Cohorts 1 and 2)	Baseline, Week 12
Number of Participants With Antidrug Antibodies to ALXN1820	Baseline through Day 211 (Cohorts 1 and 2) and through Day 169 (Optional Cohort 3)
Change From Baseline in Hemoglobin Level at Week 12 (Cohorts 1 and 2)	Baseline, Week 12

Countries

United States

Participant flow

Recruitment details

Per Sponsor decision, the study was terminated. Only 2 participants were enrolled. Due to concerns regarding participant confidentiality, no data are reported.

Participants by arm

Arm	Count
ALXN1820 300 mg QW Participants received 300 mg QW.	0
ALXN1820 600 mg Q4W Participants received 600 mg Q4W.	0
ALXN1820 300 mg Q2W (Optional Cohort) Participants received 300 mg Q2W.	0
Total	0

Adverse events

Event type	EG000 affected / at risk	EG001 affected / at risk	EG002 affected / at risk
deaths Total, all-cause mortality	0 / 0	0 / 0	0 / 0
other Total, other adverse events	0 / 0	0 / 0	0 / 0
serious Total, serious adverse events	0 / 0	0 / 0	0 / 0