Endocrinology
Hypophosphatasia (HPP): Strensiq, for prescribers
Strensiq on what its first fill waits on, what the label requires you to monitor and what an insurer asks to see, with FDA decisions, label changes and open trials for hypophosphatasia (HPP).
When to suspect hypophosphatasia (HPP) and what to test →The hypophosphatasia (HPP) prescribing guide
One page per drug with the dispensing gate, prior authorization documentation, dosing, monitoring and interactions, each line sourced.
The drugs side by side
Each cell is a summary of that drug's prescribing guide, which carries the full detail and a source on every line. Insurer thresholds are one public policy shown as an example; plans differ.
| Strensiqasfotase alfa | |
|---|---|
| Label dated | December 12, 2025 |
| Starting dose | 6mg/kg/week: 2mg/kg 3 times a week or 1mg/kg 6 times a week; may increase for lack of efficacy (no improvement in respiratory status, growth or radiographs) to 3mg/kg 3 times a week, 9mg/kg/week. |
| Dispensing gate | No REMS; boxed warning for anaphylaxis, so initiate under healthcare provider supervision; confirm perinatal/infantile- or juvenile-onset HPP, record current weight, obtain baseline eye exam and renal ultrasound, and fax the Rx form to PANTHERx Rare, the exclusive preferred specialty pharmacy |
| Required monitoring | Eye exam and renal ultrasound at baseline and periodically; weight for dose recalculation; growth, respiratory status and radiographs for response; anti-drug antibody testing via Alexion if HPP worsens after an initial response; serum ALP is uninterpretable on treatment |
| Example PA threshold | Cigna example, effective September 15, 2026: ALPL variants, low baseline ALP or elevated PLP, PPi or urinary PEA; current or past HPP manifestations or a parent or sibling with HPP; onset before 18; geneticist, endocrinologist, metabolic or HPP specialist |
| Support line | Alexion OneSource, 1-888-765-4747, Monday to Friday 8:30am to 8pm ET, enrollment fax 1-800-420-5150; PANTHERx Rare 1-844-787-6747, fax 1-844-787-2527; CoPay Program as little as $0 for commercial plans with a variable annual maximum; no published bridge or free-drug program |
- Label dated
- December 12, 2025
- Starting dose
- 6mg/kg/week: 2mg/kg 3 times a week or 1mg/kg 6 times a week; may increase for lack of efficacy (no improvement in respiratory status, growth or radiographs) to 3mg/kg 3 times a week, 9mg/kg/week.
- Dispensing gate
- No REMS; boxed warning for anaphylaxis, so initiate under healthcare provider supervision; confirm perinatal/infantile- or juvenile-onset HPP, record current weight, obtain baseline eye exam and renal ultrasound, and fax the Rx form to PANTHERx Rare, the exclusive preferred specialty pharmacy
- Required monitoring
- Eye exam and renal ultrasound at baseline and periodically; weight for dose recalculation; growth, respiratory status and radiographs for response; anti-drug antibody testing via Alexion if HPP worsens after an initial response; serum ALP is uninterpretable on treatment
- Example PA threshold
- Cigna example, effective September 15, 2026: ALPL variants, low baseline ALP or elevated PLP, PPi or urinary PEA; current or past HPP manifestations or a parent or sibling with HPP; onset before 18; geneticist, endocrinologist, metabolic or HPP specialist
- Support line
- Alexion OneSource, 1-888-765-4747, Monday to Friday 8:30am to 8pm ET, enrollment fax 1-800-420-5150; PANTHERx Rare 1-844-787-6747, fax 1-844-787-2527; CoPay Program as little as $0 for commercial plans with a variable annual maximum; no published bridge or free-drug program
FDA decisions for hypophosphatasia (HPP)
From the Trial Friend FDA decision calendar, which records each date from the sponsor's or the FDA's own announcement.
No pending or recent decisions on the calendar.
Recent label changes
What changed in each label revision, from the FDA's approval letters and the labels' own revision lists.
- December 2025Strensiq. The current version of the label on DailyMed is dated December 12, 2025. Its highlights still read revised July 2024, and its Patient Information is also dated July 2024. FDA label
- July 2024Strensiq. The label added a boxed warning for severe allergic reactions, including anaphylaxis. It also added the advice to start Strensiq under a healthcare provider's supervision and updated the allergy warning. FDA label
- June 2020Strensiq. The FDA approved an efficacy supplement to the Strensiq application on June 12, 2020. The current Instructions for Use carry an approval date of June 2020. Drugs@FDA record
- October 2015Strensiq. The FDA first approved Strensiq on October 23, 2015, for perinatal/infantile- and juvenile-onset HPP. Drugs@FDA record
Open trials
Questions prescribers ask about Hypophosphatasia (HPP)
Does Strensiq require a REMS?
No. Strensiq has no REMS. Its prescribing guide lists what does gate the first fill and its source.
What monitoring does Strensiq require?
Eye exam and renal ultrasound at baseline and periodically; weight for dose recalculation; growth, respiratory status and radiographs for response; anti-drug antibody testing via Alexion if HPP worsens after an initial response; serum ALP is uninterpretable on treatment.
What do insurers require before covering Strensiq?
This is one public insurer policy, an example rather than every plan. Cigna example, effective September 15, 2026: ALPL variants, low baseline ALP or elevated PLP, PPi or urinary PEA; current or past HPP manifestations or a parent or sibling with HPP; onset before 18; geneticist, endocrinologist, metabolic or HPP specialist.
Which support program starts Strensiq patients on therapy?
Alexion OneSource, 1-888-765-4747, Monday to Friday 8:30am to 8pm ET, enrollment fax 1-800-420-5150; PANTHERx Rare 1-844-787-6747, fax 1-844-787-2527; CoPay Program as little as $0 for commercial plans with a variable annual maximum; no published bridge or free-drug program.
A reference for licensed professionals, checked on November 10, 2026. Labels and plan policies change; the label on DailyMed and the plan's current policy govern. Not medical advice. For patients: the Hypophosphatasia (HPP) page and the first 90 days pages for Strensiq.