NCT06015750

Mitigate Immune-Mediated Loss of Therapeutic Response to Asfotase Alfa (STRENSIQ®) for Hypophosphatasia

An Interventional, Prospective Open-Label Study of Immunosuppressive Therapies to Mitigate Immune-Mediated Loss of Therapeutic Response to Asfotase Alfa (STRENSIQ®) for Hypophosphatasia (RESTORE)

• Status: Withdrawn
• Phase: Phase 4
• Study type: Interventional
• Enrollment: 0 (actual)
• Sponsor: Alexion Pharmaceuticals, Inc. · Industry
• Sex: All
• Age: 2 Years – 18 Years
• Healthy volunteers: Not accepted

Summary

The primary objective of this study is to evaluate the effect of immunosuppressive therapy (IST) in participants treated with asfotase alfa who demonstrate immune-mediated loss of effectiveness (LoE).

Detailed description

The administration of biological drugs to patients, especially for chronic conditions, carries a risk of eliciting anti-drug antibodies. Neutralizing antibodies can neutralize the clinical benefit of the agent. In postmarketing safety surveillance, some patients treated with asfotase alfa demonstrated an initial response, but subsequently recurrence and progression of disease. Consequently, the FDA requested a study to assess a potential serious risk of immune-mediated loss of effectiveness.

Conditions

• Hypophosphatasia

Interventions

Type	Name	Description
DRUG	methotrexate	Methotrexate will be administered SC or orally weekly for 104 weeks.
DRUG	rituximab	Rituximab will be administered intravenously (IV) continuously weekly, for up to 74 weeks.
DRUG	bortezomib	Bortezomib will be administered via IV bolus or SC, as needed.
DRUG	IVIg	IVIg will be administered via IV monthly through initial 74 weeks.
DRUG	Folic Acid	Folic acid will be given orally as long as methotrexate is being dosed.

Timeline

• Start date: 2026-07-29
• Primary completion: 2030-03-13
• Completion: 2030-03-13
• First posted: 2023-08-29
• Last updated: 2025-12-18

Regulatory

• FDA-regulated drug study