A Phase 3 interventional study of INZ-701 and Control Arm (Conventional Therapy) in Ectonucleotide Pyrophosphatase/Phosphodiesterase1 Deficiency, Autosomal Recessive Hypophosphatemic Rickets and Generalized Arterial Calcification of Infancy, sponsored by Inozyme Pharma. Terminated at 11 sites in 8 countries. Open to participants aged 1 Year to 12 Years. Per ClinicalTrials.gov, last updated 2026-10-01.
Sponsored by Inozyme Pharma (part of BioMarin Pharmaceutical) · Phase 3, Interventional, and Treatment
The study was terminated by the sponsor prior to planned completion based on a review of the data across indications and overall program considerations. Study termination was not related to participant safety.
The primary purpose of Study INZ701-106 (The ENERGY 3 Study) is to assess the efficacy and safety of INZ-701 in children with ENPP1 Deficiency.
INZ-701 is an ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) enzyme replacement therapy (ERT) in development for the treatment of ENPP1 Deficiency, an ultra-rare genetic disorder with an incidence of 1 in 64,000 pregnancies.
Study INZ701-106 (The ENERGY 3 Study) is a multi-center, randomized in a 2:1 ratio, controlled, open-label Phase 3 study to evaluate the efficacy and safety of INZ-701 in children with ENPP1 Deficiency.
The study will consist of a Screening Period of up to 52 days (including a washout period of up to 7 days for prohibited medications post-Randomization) and a Randomized Treatment Period (INZ-701 or control) of 52 weeks, followed by an Open-label Extension Period during which all study participants may receive INZ-701, and an End of Study (EOS) Safety visit 30 days after the last dose of INZ-701.
Inozyme Pharma is the lead sponsor of 12 studies on the registry; none are open to participants now.
Of its 6 completed or terminated interventional studies of FDA-regulated products, 2 (33%) have results posted.
First submitted before Inozyme Pharma became part of BioMarin Pharmaceutical.
Counted across the registry records on this site, refreshed daily.
The criteria were revised on the registry on Oct 1, 2026. See what changed
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Study participants must meet all of the following inclusion criteria:
Exclusion Criteria
Study participants meeting any of the following exclusion criteria will not be eligible to participate in the study:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Subjects randomized to the INZ-701 arm will be administered a 2.4 mg/kg once weekly dose by subcutaneous (SC) injection for the duration of the 52-week Randomized Treatment Period (RTP). RTP will be followed by a Low-dose Open-label Extension Period during which all study participants will receive INZ-701 at a dose of 2.4 mg/kg QW while the primary analysis is pending. If dose escalation criteria are met, all participants will transition to the Randomized Extension Period (REP) where participants who were originally randomized to INZ-701 during RTP will transition to a higher dose regimen of INZ-701 at 1.8 mg/kg twice weekly. Participants who were originally randomized to the active control arm during RTP will continue receiving INZ-701 at 2.4 mg/kg QW in the REP.
Drug: INZ-701
Subjects randomized to the control arm will continue taking their conventional therapy as clinically indicated by their treating physician for the duration of the 52-week Randomized Treatment Period.
Drug: Control Arm (Conventional Therapy)
Recombinant fusion protein that contains the extracellular domains of human ENPP1 coupled with an Fc fragment from an immunoglobulin gamma-1 (IgG1) antibody.
Also known as: (rhENPP1-Fc).
Conventional therapy is defined as oral phosphate supplements and calcitriol or other active forms of vitamin D3 (or analogs). No other agents for treatment of ENPP1 Deficiency are allowed in the control arm.
Change from Baseline in Plasma Inorganic Pyrophosphate (PPi) concentration through Week 52
For each subject, plasma PPi will be measured via a series of blood samples obtained throughout the study, comparing the subject's baseline value over time.
Time frame: 52 weeks (Baseline through Week 52)
Change from Baseline in skeletal abnormalities as measured by the Radiographic Global Impression of Change (RGI-C) global score through Week 52
The RGI-C is an overall radiographic score which can be used to monitor response to a therapeutic intervention comparing scores from 2 time points. A determination of healing on a scale of 0 to +3 with 0 being no change or healing and +3 being complete healing; worsening is also measured on a scale of 0 to -3 with 0 being no change and -3 being severe worsening.
Time frame: 52 weeks (Baseline through Week 52)
Change from Baseline in rickets as measured by Rickets Severity Score (RSS) total score through Week 52
The RSS assesses rickets severity by utilizing a scoring system that uses a scale from 0 to 4 for the wrists and 0 to 6 for the knees, to generate a total score of 0 to 10, where 0 is normal and 10 is the worst score possible ie, most severe skeletal abnormalities observed radiographically.
Time frame: Baseline, Week 26, Week 52
Change from Baseline in growth Z-score (height/body length and weight) through Week 52
A Z-score represents the degree to which that particular measurement for that individual differs from the reference value in the general population. (height/body length and weight) through Week 52
Time frame: Baseline, Day 29, Week 8, Week 13, Week 26, Week 39, Week 52
Area under the Plasma Concentration versus Time Curve (AUC) of INZ-701
For each subject, variation of concentration of INZ-701 in the plasma will be measured via a series of blood samples obtained throughout the study, comparing the subject's baseline value over time.
Time frame: 52 weeks (Randomized Treatment Period)
Maximum Plasma Concentration (Cmax) of INZ-701
For each subject, the maximum concentration of INZ-701 in the plasma will be measured via a series of blood samples obtained throughout the study, comparing the subject's baseline value over time.
Time frame: 52 weeks (Randomized Treatment Period)
Change from Baseline in ENPP1 activity (µM/min) through week 52
For each subject, the activity of INZ-701 (µM/min) in the serum will be assessed through hydrolysis of a substrate to the enzyme, via a series of blood samples obtained throughout the study, comparing the subject's baseline value over time.
Time frame: 52 weeks (Randomized Treatment Period)
Ran from Nov 2023 to primary completion in Jan 2026, 26 months.
Completion moved once since we started tracking on Sep 25, 2026: Feb 2026 → Aug 2026, on Oct 1, 2026.
Earlier changes are on the record history on ClinicalTrials.gov ↗
How these figures are worked out, and which studies are left out of them.
The study was terminated by the sponsor prior to planned completion based on a review of the data across indications and overall program considerations. Study termination was not related to participant safety.
The study was terminated by the sponsor prior to planned completion based on a review of the data across indications and overall program considerations. Study termination was not related to participant safety.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is terminated, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Efmirenpase alfa
Hypophosphatemic Rickets, Autosomal Recessive, 1