What side effects are associated with this type of intervention?

Common treatments for Hypophosphatemic Rickets include phosphate supplements and active vitamin D analogs, which can cause side effects such as gastrointestinal discomfort, hypercalcemia, and nephrocalcinosis. Enzyme replacement therapies, like those being studied in the INZ-701 trial for ENPP1 deficiency, may also present risks of immune reactions, injection site reactions, and potential long-term effects on organ systems. Patients should be closely monitored to manage and mitigate these side effects.

What prior FDA approvals exist?

Hypophosphatemic Rickets, particularly X-linked Hypophosphatemia (XLH), has seen FDA approval for treatments such as burosumab (Crysvita), a monoclonal antibody that targets and inhibits fibroblast growth factor 23 (FGF23). This treatment helps to regulate phosphate and vitamin D levels in the body. While enzyme replacement therapy like INZ-701 for ENPP1 Deficiency is being studied, there are no current FDA-approved enzyme replacement therapies specifically for Hypophosphatemic Rickets.

What other types of research exist?

As of 2024, promising novel alternatives to INZ-701 for treating Hypophosphatemic Rickets in patients with ENPP1 Deficiency include gene therapy approaches targeting the ENPP1 gene, and other enzyme replacement therapies under investigation. Additionally, therapies modulating the FGF23 pathway, such as burosumab, may offer benefits, although they are not specific to ENPP1 Deficiency.

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INZ-701 for ENPP1 Deficiency

Phase 3

Recruiting

Research Sponsored by Inozyme Pharma

Eligibility Criteria Checklist

Specific guidelines that determine who can or cannot participate in a clinical trial

Must have

Males and females ≥1 year and <13 years of age at Study Day 1

Female participants of childbearing potential must have a negative serum pregnancy test at Screening and must not be breastfeeding

Must not have

If receiving any of the following prohibited medications as indicated in the protocol: systemic corticosteroids (>5 mg prednisone equivalent per day), anti-fibroblast growth factor 23 (FGF23), and oral and/or IV bisphosphonates

Previous treatment with INZ-701

Timeline

Screening 3 weeks

Treatment Varies

Follow Up baseline, day 29, week 8, week 13, week 26, week 39, week 52

Awards & highlights

No Placebo-Only Group

Pivotal Trial

Summary

This trial is testing INZ-701, a treatment that replaces a missing enzyme, in children with a rare genetic disorder called ENPP1 Deficiency. The goal is to see if it is safe and effective. The treatment helps by providing the enzyme their bodies lack.

Who is the study for?

This trial is for children with ENPP1 Deficiency, showing specific bone abnormalities and growth plate activity. They must be between 1-12 years old, not pregnant or breastfeeding, willing to use contraception if applicable, and have certain vitamin D levels. Those who've had recent surgery or used certain medications like systemic corticosteroids are excluded.

What is being tested?

The ENERGY 3 Study tests the safety and effectiveness of INZ-701 compared to conventional therapy in treating skeletal issues caused by ENPP1 Deficiency in children. Participants will either receive INZ-701 or stick with standard treatments to see which works better.

What are the potential side effects?

While the side effects of INZ-701 are not detailed here, they may include reactions similar to other drugs targeting bone metabolism such as gastrointestinal symptoms, skin reactions, or changes in blood chemistry.

Eligibility Criteria

Inclusion Criteria

You may be eligible if you check “Yes” for the criteria below

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I am between 1 and 12 years old.

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I am not pregnant or breastfeeding.

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I have a genetic diagnosis of ENPP1 Deficiency confirmed by a certified lab.

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My scans show significant bone abnormalities.

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My knee growth plates are still open.

Exclusion Criteria

You may be eligible for the trial if you check “No” for criteria below:

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I am not taking high doses of steroids, anti-FGF23 drugs, or bisphosphonates.

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I have been treated with INZ-701 before.

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I can stop taking vitamin D3 or phosphate supplements before the study starts.

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I am not planning any orthopedic surgery that could affect study results within the next year.

Timeline

Screening ~ 3 weeks3 visits

Treatment ~ Varies

Follow Up ~ baseline, day 29, week 8, week 13, week 26, week 39, week 52

Screening ~ 3 weeks

Treatment ~ Varies

Follow Up ~baseline, day 29, week 8, week 13, week 26, week 39, week 52

This trial's timeline: 3 weeks for screening, Varies for treatment, and baseline, day 29, week 8, week 13, week 26, week 39, week 52 for reporting.

Treatment Details

Study Objectives

Study objectives can provide a clearer picture of what you can expect from a treatment.

Primary study objectives

Change from Baseline in Plasma Inorganic Pyrophosphate (PPi) concentration through Week 52

Secondary study objectives

Area under the Plasma Concentration versus Time Curve (AUC) of INZ-701

Change from Baseline in ENPP1 activity (µM/min) through week 52

Change from Baseline in growth Z-score (height/body length and weight) through Week 52

+3 more

Awards & Highlights

No Placebo-Only Group

All patients enrolled in this study will receive some form of active treatment.

Pivotal Trial

The final step before approval, pivotal trials feature drugs that have already shown basic safety & efficacy.

Trial Design

2Treatment groups

Experimental Treatment

Active Control

Group I: INZ-701Experimental Treatment1 Intervention

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 and the Open-label Extension Period.

Group II: Control Arm (Conventional Therapy)Active Control1 Intervention

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.

0 / 9Eligibility criteria met

Research Highlights

Information in this section is not a recommendation. We encourage patients to speak with their healthcare team when evaluating any treatment decision.

Mechanism Of Action

Side Effect Profile

Prior Approvals

Other Research

Hypophosphatemic Rickets is commonly treated with phosphate supplements and active forms of vitamin D (such as calcitriol), which help to increase phosphate levels in the blood and promote proper bone mineralization. Another emerging treatment is enzyme replacement therapy, like INZ-701 for ENPP1 deficiency, which aims to address the underlying genetic cause by replacing deficient or defective enzymes. This approach can potentially normalize phosphate metabolism and improve bone health more effectively. These treatments are crucial for patients as they directly target the biochemical pathways disrupted in Hypophosphatemic Rickets, thereby improving symptoms and preventing complications associated with the disease.

Oral Iron Replacement Normalizes Fibroblast Growth Factor 23 in Iron-Deficient Patients With Autosomal Dominant Hypophosphatemic Rickets.Recombinant growth hormone therapy for X-linked hypophosphatemia in children.