ALXN1850 for Hypophosphatasia

No longer recruiting at 5 trial locations

Overseen By Alexion Pharmaceuticals, Inc.

Age: 18 - 65

Sex: Any

Trial Phase: Phase 1

Sponsor: Alexion

Must not be taking: Asfotase alfa

Disqualifiers: Hyperparathyroidism, Hypoparathyroidism, Fracture, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

Duration: 12 weeks

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests a new treatment called ALXN1850 (also known as Efzimfotase alfa) for individuals with hypophosphatasia (HPP), a rare bone disease. Researchers aim to assess the safety and tolerability of the treatment when administered by IV (intravenous) or injection under the skin. They will use different doses to determine the optimal method of administration. Individuals diagnosed with HPP who do not require enzyme replacement therapy after the trial might be suitable candidates. As a Phase 1 trial, this research focuses on understanding how the treatment works in people, offering participants the opportunity to be among the first to receive it.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. However, if you are using asfotase alfa, you must have stopped it at least 6 months before joining the trial.

Is there any evidence suggesting that ALXN1850 is likely to be safe for humans?

Research shows that ALXN1850, also known as efzimfotase alfa, is under investigation as a treatment for hypophosphatasia (HPP). In early studies, researchers are assessing how well people tolerate this treatment by administering it in varying doses to monitor for side effects.

Early results suggest that most participants tolerate the treatment well, experiencing no serious side effects. However, as with any new treatment, some side effects may occur, such as mild reactions at the injection site or other minor issues. Since this study is in its early phase, the primary goal is to ensure the treatment's safety. This phase is crucial for determining if any adjustments are necessary before expanding the trial to more participants.

ALXN1850 is also being compared to a similar treatment studied for over five years. This earlier treatment showed positive results, offering hope that ALXN1850 might also prove safe and effective. More detailed information will become available as the study progresses. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising?

Unlike the standard of care for hypophosphatasia (HPP), which often involves enzyme replacement therapies like asfotase alfa, ALXN1850 offers a new approach with its novel delivery method. ALXN1850 is administered via intravenous (IV) infusion or subcutaneous (SC) injection across multiple dosages, providing flexibility in how patients receive their treatment. Researchers are particularly excited about the potential for improved efficacy and patient experience, as this method could enhance how the body absorbs and utilizes the treatment.

What evidence suggests that ALXN1850 might be an effective treatment for HPP?

Research has shown that ALXN1850, also known as efzimfotase alfa, is a promising treatment for hypophosphatasia (HPP). Previous studies demonstrated its effectiveness in lowering certain disease indicators in patients. ALXN1850 represents a newer type of enzyme replacement therapy designed to improve the body's mineral management, potentially addressing the main issue of HPP, which is poor bone development. Early trials found it to be generally safe and effective in the body. While more research is needed, these initial findings suggest that ALXN1850 could effectively treat HPP. ^{1 3 6 7 8}

Are You a Good Fit for This Trial?

Inclusion Criteria

Confirmed clinical diagnosis of HPP

Not anticipated to require further treatment with enzyme replacement therapy to treat participant's HPP after study completion

Willing and able to follow protocol-specified contraception requirements

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive ALXN1850 via IV infusion and/or SC in a dose-escalating manner

12 weeks

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• ALXN1850

How Is the Trial Designed?

Group I: ALXN1850 Experimental Treatment 1 Intervention

Three experimental cohorts will be administered 3 dosages (low, medium, high) of ALXN1850, respectively, via IV infusion and/or SC over multiple administration intervals.

Who Is Running the Clinical Trial?

Alexion

Lead Sponsor

Trials

247

Recruited

38,600+

Marc Dunoyer

Alexion

Chief Executive Officer since 2021

PhD in Molecular Biology, University of Brussels

Christophe Hotermans

Alexion

Chief Medical Officer since 2021

MD, University of Leuven

Alexion Pharmaceuticals, Inc.

Lead Sponsor

Trials

267

Recruited

141,000+

Dr. Alberto R. Martinez

Alexion Pharmaceuticals, Inc.

Chief Medical Officer since 2010

MD from University of Sao Paulo

Marc Dunoyer

Alexion Pharmaceuticals, Inc.

Chief Executive Officer since 2021

PhD in Molecular Biology

Alexion Pharmaceuticals

Lead Sponsor

Trials

231

Recruited

36,700+

Marc Dunoyer

Alexion Pharmaceuticals

Chief Executive Officer since 2021

B.A. in Psychology from the University of New Hampshire

Christophe Hotermans

Alexion Pharmaceuticals

Chief Medical Officer since 2023

MD

Citations

1. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/39135540/

phase 1, dose-escalation study in adults with ... Our results showed that efzimfotase alfa has acceptable safety and pharmacokinetics and is effective for reducing biomarkers (measurable ...

2. clinicaltrials.gov clinicaltrials.gov/study/NCT06079359

NCT06079359 | Phase 3 Study of ALXN1850 in Treatment- ... The primary purpose of this study is to evaluate the efficacy of ALXN1850 versus placebo on radiographic outcomes in pediatric participants with HPP who have ...

3. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC11425692/

Safety, pharmacokinetics, and pharmacodynamics of ... Efzimfotase alfa (ALXN1850) is a second-generation TNSALP enzyme replacement therapy in development for HPP. This first-in-human open-label, dose-escalating ...

4. clinicaltrials.gov clinicaltrials.gov/study/NCT06079281

Phase 3 Study of ALXN1850 Versus Placebo in Adolescent ... The primary objective of this study is to assess the efficacy of ALXN1850 versus placebo on functional outcomes in adolescent and adult participants with HPP ...

5. io.nihr.ac.uk io.nihr.ac.uk/wp-content/uploads/2025/07/36874-Efzimfotase-Alfa-for-Hypophosphatasia-V1.0-JUL2025-NON-CONF.pdf

Health Technology Briefing July 2025 ClinicalTrials.gov. Phase 3 Study of ALXN1850 in Pediatric Participants With HPP Previously. Treated With Asfotase Alfa (CHESTNUT). Trial ID: NCT06079372. 2023.

6. clinicaltrials.gov clinicaltrials.gov/study/NCT04980248

Study of ALXN1850 in Participants With Hypophosphatasia ... This is an open-label, dose-escalating study to assess safety, tolerability, pharmacokinetic (PK), pharmacodynamic (PD), and immunogenicity of ALXN1850

7. withpower.com withpower.com/trial/phase-3-hypophosphatasia-11-2023-fdc52

ALXN1850 for Hypophosphatasia (HICKORY Trial) The safety data for ALXN1850, also known as asfotase alfa, includes findings from several studies. A five-year study (NCT01163149) evaluated the efficacy and ...

8. medchemexpress.com medchemexpress.com/efzimfotase-alfa.html?srsltid=AfmBOoqddk74-5ajVLtKmIeuMXdjTl6hgxvHM-NhqvpuHjJqt4ykcMoh

Efzimfotase alfa (ALXN-1850) SAFETY DATA SHEET (SDS). Request for HNMR Report. We have received your request and will respond to you as soon as possible. [e-mail]; 609-228 ...