A randomized Phase 1b trial evaluating the pharmacodynamics of ilofotase alfa in adults with hypophosphatasia

Lothar Seefried; Juliane Bernholz; Maarten Kraan; Yvonne Nitschke; Frank Rutsch; Markus Mallek; Sina Kleinert; Franca Genest

doi:10.1093/jbmr/zjaf185

. 2025 Dec 11;41(3):231–241. doi: 10.1093/jbmr/zjaf185

A randomized Phase 1b trial evaluating the pharmacodynamics of ilofotase alfa in adults with hypophosphatasia

Lothar Seefried ^1,^✉, Juliane Bernholz ², Maarten Kraan ³, Yvonne Nitschke ^4,⁵, Frank Rutsch ^6,⁷, Markus Mallek ⁸, Sina Kleinert ⁹, Franca Genest ¹⁰

¹ Osteology/Clinical Trial Unit, University of Wuerzburg, 97074 Wuerzburg, Germany

² AM-Pharma, Stadsplateau 6, 3521 AZ Utrecht, The Netherlands

³ AM-Pharma, Stadsplateau 6, 3521 AZ Utrecht, The Netherlands

⁴ Department of General Pediatrics, Muenster University Children's Hospital, Albert-Schweitzer-Campus 1, 48149 Münster, Germany

⁵ INTEC Network of Ectopic Calcification, Center for Medical Genetics Ghent, Corneel Heymanslaan 10, 9000 Ghent, Belgium

⁶ Department of General Pediatrics, Muenster University Children's Hospital, Albert-Schweitzer-Campus 1, 48149 Münster, Germany

⁷ INTEC Network of Ectopic Calcification, Center for Medical Genetics Ghent, Corneel Heymanslaan 10, 9000 Ghent, Belgium

⁸ MVZ Dr Eberhard & Partner Dortmund GbR (UEBAG), PO box 10 10 40, 44010 Dortmund, Germany

⁹ MVZ Dr Eberhard & Partner Dortmund GbR (UEBAG), PO box 10 10 40, 44010 Dortmund, Germany

¹⁰ Osteology/Clinical Trial Unit, University of Wuerzburg, 97074 Wuerzburg, Germany

^✉

Corresponding author: Lothar Seefried, Osteology/Clinical Trial Unit, University of Wuerzburg, Brettreichstraße 11, 97074 Wuerzburg, Germany (lothar.seefried@uni-wuerzburg.de).

Roles

Lothar Seefried: Conceptualization, Formal analysis, Investigation, Methodology, Project administration, Writing - original draft, Writing - review & editing

Juliane Bernholz: Formal analysis, Funding acquisition, Project administration, Writing - original draft, Writing - review & editing

Maarten Kraan: Conceptualization, Formal analysis, Funding acquisition, Methodology, Project administration, Writing - original draft, Writing - review & editing

Yvonne Nitschke: Formal analysis, Writing - original draft, Writing - review & editing

Frank Rutsch: Formal analysis, Writing - original draft, Writing - review & editing

Markus Mallek: Data curation, Formal analysis, Writing - original draft, Writing - review & editing

Sina Kleinert: Data curation, Investigation, Writing - original draft, Writing - review & editing

Franca Genest: Formal analysis, Investigation, Project administration, Writing - original draft, Writing - review & editing

PMCID: PMC13017612 PMID: 41378916

Abstract

Hypophosphatasia is a rare genetic disease caused by deficient alkaline phosphatase (AP) activity. In adults, this causes functional limitations, substantial disability with pain and reduced quality of life. This Phase 1b, single-center, open-label trial investigated ilofotase alfa, a fully human recombinant protein intended as enzyme replacement therapy, in adults with hypophosphatasia. Changes in plasma levels of AP substrates inorganic pyrophosphate and pyridoxal-5′-phosphate were evaluated. Participants were randomized 1:1 to receive at 0.8 or 3.2 mg/kg ilofotase alfa intravenously over 1 h. Twelve participants were enrolled and completed the trial. At baseline, all participants had reduced AP activity and elevated pyridoxal-5′-phosphate. The greatest reduction in inorganic pyrophosphate and pyridoxal-5′-phosphate occurred 2 h after start of dosing in both treatment groups. Across the 10-d follow-up period, inorganic pyrophosphate values returned to baseline levels more rapidly in the 0.8 mg/kg group compared with the 3.2 mg/kg group. Mean circulating AP activity peaked 24 h after dosing and subsequently declined but remained above the lower limit of normal throughout the study. A dose-proportional increase in ilofotase alfa was observed, reaching peak concentration 1-h post-infusion. Eight treatment-emergent adverse events occurred, all classified as mild. These data demonstrate that single-dose ilofotase alfa enhances AP activity and results in dose-dependent reductions in primary disease-specific biomarkers without undesired effects on mineral homeostasis.

Clinical trial registration number: ClinicalTrials.gov number: NCT05890794.

Keywords: hypophosphatasia, ilofotase alfa, alkaline phosphatase, bone, inorganic pyrophosphate, pyridoxal-5′-phosphate

Introduction

Hypophosphatasia is a rare inherited metabolic disorder due to variants in the ALPL gene, coding for the tissue-nonspecific isoform of alkaline phosphatase (TNAP), which leads to deficient alkaline phosphatase (AP) activity.^1–3 Alkaline phosphatase is crucial for bone mineralization and vitamin B₆ metabolism.³ It is also involved in nucleotide metabolism by hydrolysis of adenosine phosphates to yield adenosine in various tissues, including kidney, bone, liver, nasal cavity epithelium, and bronchi, as well as the nervous system,⁴ where AP may be involved in neuronal development as well as synaptic transmission, neurotransmitter conversion, and purinergic signaling.⁵

The widespread systemic activity of AP in multiple tissues and processes in combination with the large number (>480) of known ALPL gene variants and variable expressivity, results in a complex clinical disease profile for hypophosphatasia.^6–9 While manifestations of the disease in the perinatal setting can be severe and life-threatening, the vast majority of patients experience less critical but burdensome signs and symptoms. Hypophosphatasia at a young age is characterized by defective bone and teeth mineralization and can also affect growth. Later in life, less specific signs and symptoms involving other organs become increasingly prevalent.^10–12 Patients can develop wide-ranging complications, including generalized musculoskeletal pain, fatigue, exhaustion, and protracted recovery periods, and diverse symptoms in the central and peripheral nervous systems, including headache, sleep disturbance, depression, neuropathic pain, and anxiety.¹⁰^,¹³^,¹⁴

Hypophosphatasia causes considerable disability and compromises quality of life, even in patients without overt skeletal manifestations.¹¹^,¹²^,¹⁵^,¹⁶ To date, the lack of effective disease-modifying treatments has meant the management of patients with skeletal manifestations is merely focused on symptom relief with non-steroidal anti-inflammatories drugs, and supportive measures, such as physiotherapy, which cannot fully compensate for the reduced quality of life and mobility issues.⁸^,¹⁷^,¹⁸ Hence, there is a clear unmet treatment need.

The diagnosis of hypophosphatasia in adults according to recently published recommendations,¹⁹^,²⁰ is based on the finding of reduced circulating AP levels in combination with key diagnostic criteria including elevated substrate levels, genetic confirmation of an ALPL variant, and further clinical signs and symptoms, such as pseudofractures, chondrocalcinosis, and nephrocalcinosis.^21–25 Specifically, AP deficiency leads to elevated levels of its direct substrates inorganic pyrophosphate (PPi) and pyridoxal-5′-phosphate (PLP), as well as increases in phosphoethanolamine (PEA), which not only function as biomarkers for diagnosis and assessment of treatment interventions in clinical trials but also play a pivotal role in the pathophysiology of various clinical manifestions.²⁶

Inorganic pyrophosphate is a potent inhibitor of proper hydroxyapatite crystal formation thereby compromising physiological mineralization of bone and teeth. In children with hypophosphatasia, elevated PPi serum levels can lead to developmental alterations of the growth plates with subsequent bone deformities and growth retardation, while adults may experience pseudofractures.³ Hydrolyzation of PLP by AP is considered critical for vitamin B6 to cross the blood–brain barrier as pyridoxal (PL). Consequently, low levels of AP in hypophosphatasia are considered to cause an imbalance in the PL/PLP ratio, with low levels of dephosphorylated PL and reduced bioavailability of vitamin B6 in the central nervous system, eventually causing vitamin B6-dependent seizures in infants with hypophosphatasia.²⁷ This mechanism is also assumed to play a role in further clinical manifestations owing to altered neurotransmitter conversion and synthesis. The pathophysiological role of other putative substrates and metabolites like PEA and adenosine triphosphate (ATP), as well as lipopolysaccharide (LPS), requires further investigation.³^,²⁸^,²⁹

Ilofotase alfa is a full-length human recombinant protein intended as an enzyme replacement therapy for patients with hypophosphatasia. It is a soluble recombinant chimeric enzyme, designed based on human intestinal AP, with substitution of the crown domain (amino acid residues 360-430) by the human placental AP sequence to enhance stability and biological activity.²⁸ Ilofotase alfa shows increased heat stability, substrate specificity, and enzyme activity toward PLP and LPS compared with human intestinal AP.²⁸ Activity of the compound toward various AP substrates and its efficacy in animal models of hypophosphatasia has also been evaluated.³⁰ In humans, ilofotase alfa has been shown to be well tolerated, stable, and highly active in clinical trials of acute kidney injury (AKI), and in healthy participants, but it has not thus far been investigated in patients with hypophosphatasia.³¹^,³²

This Phase 1b trial was a single-center, open-label, randomized, parallel-group clinical trial acting as a pilot for a potential Phase 2/3 trial. Here, we report on the effectiveness of 2 different doses of ilofotase alfa (0.8 and 3.2 mg/kg) in terms of reducing circulating levels of PPi and PLP, increasing PL/PLP ratio, as well as its safety and tolerability in adult patients with hypophosphatasia.

Materials and methods

Trial design

This was a single-center, open-label, randomized, parallel group clinical trial in adults with hypophosphatasia. Biological sex was not considered a relevant factor in this study and no selection criteria were applied for this. The distribution of participant sex (8 female and 4 male) in this trial was reflective of the natural epidemiology of hypophosphatasia. Participants were randomized 1:1 to receive a single dose of 0.8 or 3.2 mg/kg ilofotase alfa, administered as a single 50 mL dose over a 1-h intravenous infusion. The trial included a 2-d run-in, where baseline samples were taken before ilofotase alfa was given on day 1, followed by 9 d of observation (days 2-10), and then a remote follow-up assessment on day 15.

All procedures were performed at the Clinical Osteology and Clinical Trial Unit of the University of Würzburg, Germany. Participants stayed at the unit from baseline to day 10. The trial was conducted in accordance with the principles of the Declaration of Helsinki and all applicable laws and was approved by the applicable ethics committee. All participants gave written informed consent before any study-related procedures.

Trial participants

Eligible participants were aged 18-85 yr with diagnosed hypophosphatasia based on having genetically confirmed ALPL variants, a medical history with at least 2 independent measures of AP below the lower limit of normal (LLN), and at least 1 measurement of PP_i or PLP above the upper limit of normal (ULN). Participants were excluded, if they had used bisphosphonates in the last 2 yr, or any other compound affecting bone metabolism, including asfotase alfa, within the last 3 mo, or nonsteroidal anti-inflammatories within the last 2 wk, or corticosteroids within 4 wk.

Trial objectives and assessments

The primary objective of this exploratory trial was to evaluate the change in plasma PP_i and PLP levels after 0.8 or 3.2 mg/kg ilofotase alfa. The exploratory objectives were to assess its safety, pharmacokinetic, and pharmacodynamic profiles.

In addition to PP_i and PLP, further hypophosphatasia-associated biomarkers were assessed as part of the pharmacodynamic profile, and included PL, PEA, ATP, AP activity, bone turnover markers (procollagen type 1 N propeptide [PINP], C-terminal telopeptide [CTX-1], and PTH in serum), and other exploratory biomarkers (25OHD and C-terminal fibroblast growth factor 23 [iFGF-23]).

Demographics, medical history, and prior and concomitant medications were collected at screening. Safety assessments included continuous active surveillance for adverse events, laboratory assessments, vital signs, physical examinations, and baseline 12-lead electrocardiograms.

Sample collection and laboratory assays

Sample collection

Blood and urine samples for biomarker analysis were collected from fasting participants on days −2 and −1, pre-dose on day 1, then daily on days 2-10. As participants were permitted to have breakfast after dosing to avoid potential side effects and bias due to prolonged fasting and dehydration, additional samples for PP_i, PLP, and PL analysis at 2, 4, and 8 h after infusion were collected in non-fasting participants.

Inorganic pyrophosphate, PLP, PL, AP activity, iFGF-23, PTH, CTX-1, PINP, and 25OHD were measured in plasma. Adenosine and PEA were measured in urine.

Ilofotase alfa serum concentrations were measured on day 1 predose and at the end of infusion, then 2, 4, and 8 h after dosing started, then daily from days 2-10. Blood samples were collected predose on days 1 and 10 for analyzing antidrug antibodies to ilofotase alfa (Figure S1).

Blood samples for plasma analysis of PPi and ATP were collected in lithium-heparin-coated tubes and centrifuged at 2000 × g for 10 min at 4 °C within 15 min after collection, to separate plasma from cells. Supernatant plasma was immediately filtered using 50 kDa ultrafiltration units (Vivaspin Turbo 4 mL 50 kDa filter tubes, Sartorius) in a 40-min centrifugation step at 2200 × g to remove ilofotase alfa and remnant thrombocytes. Serum samples for analysis of PLP and PL were protected from light immediately. Blood samples for assessing the pharmacokinetics of ilofotase alfa and antidrug antibodies, as well as additional biomarkers in serum, were collected in vacutainer tubes with clot activator gel and incubated for 30 min before centrifuging at 2000 × g for 10 min at 4 °C within 15 min after incubation. All samples were stored at −80 °C until shipment or analysis.

For the analytes PPi, PLP, PL, and ATP, each sample was analyzed twice; the first analysis was performed in 3 runs, with 4 samples (participants) per run, and the second analysis included all samples in a single run. Results from both analyses were comparable; the results of the second analysis were used for data evaluation.

Trial medication

Trial medication was provided by AM-Pharma as a concentrate for infusion (aqueous buffer, pH 7.0). Before administration, this was diluted with sterile sodium chloride 0.9% for injection, to a final volume of 50 mL.

P‌Pi assay

Inorganic pyrophosphate was quantified using ATP sulfurylase to convert PPi into ATP in the presence of excess adenosine 5′-phosphosulfate, at the research laboratory of the Department of General Pediatrics at the Munster University Hospital, Munster, Germany. A standard curve (range 10-0.156 μM, 2-fold dilution steps) was prepared for each run by diluting powder PPi (#71501, Sigma-Aldrich, Taufkirchen, Germany) in distilled water, using water alone as a negative control. For PPi conversion, 35 μL of reaction mixture (25 mM Tris pH 8, 1 mM magnesium chloride, 20 mM magnesium sulfate, 50 μM adenosine 5′-phosphosulfate [Sigma-Aldrich, Taufkirchen, Germany], and 0.1 μL ATP sulfurylase, diluted 1:10 [#7175-AS, R&D systems]) was added to each well of a 96-well reaction plate. Per well, 5 μL of standard curve or plasma sample was added in duplicate and mixed well. Samples were incubated at 37 °C for 30 min followed by 90 °C for 10 min and left at 4 °C until the next step. Following PPi conversion, the sample was mixed 1:1 with BacTiter-Glo reagent (Promega Corporation) and incubated for 5 min at room temperature in white 96-well plates (final volume 40 μL per well). Luminescence was analyzed on a TriStar2 Multimode Reader LB942 plate reader (Berthold Technologies).

PL/PLP assay

Plasma PLP and PL concentration measurements were conducted by MVZ Dr Eberhard & Partner using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Deuterated PL (Sigma-Aldrich) and deuterated PLP (TRC) were used as internal standards, stored frozen as 10 mM stock solutions in methanol (Biosolve). Test samples were prepared by mixing 50 μL plasma sample with 50 μL LC-MS grade water (Biosolve) and 150 μL internal standard solution (500 nM deuterated PL and PLP in 0.6-N-trichloroacetic acid [Sigma-Aldrich]) for protein precipitation. After centrifugation for 5 min at 14 000 U/min, the supernatant was transferred into sample cups and analyzed by LC-MS/MS (4 μL sample injection volume). For quantification, calibration samples were prepared and analyzed simultaneously with the test samples by serial dilution (x-fold dilution steps) of vitamin B6 plasma control (Chromsystems) with water, leading to a final PL and PLP concentration range of 480-0 and 335-0 nM, respectively.

The LC-MS/MS analysis was done on an Acquity I-Class UPLC system from Waters, equipped with a binary solvent manager, an autosampler with flow-through needle and column manager, connected to a mass spectrometer Waters TQs-micro with electrospray ionization (ESI). Waters MassLynx (v4.2 SCN 1001) was used for system control, data acquisition, and data processing. Chromatographic separation was performed using an HSS-T3 column (Waters, 1.8 μm; 2.1 × 100 mm). Mobile phase A (MP A) contained 0.37% acetic acid (Fisher Scientific) and 0.01% heptafluorobutyric acid (Sigma-Aldrich) in water; mobile phase B (MP B) contained 0.1% formic acid (Sigma-Aldrich) in acetonitrile (Biosolve, LC/MS grade). Total run time was 4.5 min with a flow rate set to 0.5 mL/min, using the following gradient: (1) initial conditions: 97.5% MP A; (2) 0.80 min: 97.5% MP A; (3) 2.60 min: 96.0% MP A; (4) 3.41 min: 10.0% MP A; (5) 4.00 min: 10.0% MP A; (6) 4.01 min: 97.5% MP A; (7) 4.50 min: 97.5% MP A.

Multiple reaction monitoring was performed using the following transitions in ESI-positive mode (parent ion m/z > quantitative daughter ion m/z; qualitative daughter ion m/z): 168 > 150 for PL, retention time 2.4 min; 171 > 153 for deuterated PL, retention time 2.4 min; 248 > 150; 122 for PLP, retention time 1.15 min; 251 > 153 for deuterated PLP, retention time 1.15 min.

Frozen 10 mM stock solutions of PL and PLP (Sigma-Aldrich) in 0.1 M hydrochloric acid were used to prepare 20 nM (low), 75 nM (mid), and 200 nM (high) pooled control samples in water for daily quality control. Analytical measurement range of the assay was 0-500 nmol/L for both PL and PLP, limit of quantitation of the assay was 2.56 nmol/L for PL and 2.25 nmol/L for PLP and estimated limit of detection of 0.70 nmol/L for PL and 0.59 nmol/L for PLP. The within-run and between-run precision was <4.6% for PL and <5.9% for PLP.

PEA assay

Urine PEA concentration measurements were conducted by MVZ Dr Eberhard & Partner using LC-MS/MS. Deuterated PEA (TRC) was used as internal standards, stored frozen as 10 mM stock solutions in water (Biosolve). Test samples were prepared by mixing 20 μL urine sample with 200 μL internal standard solution (3.00 μM deuterated PEA in methanol [Biosolve]). After centrifugation for 5 min at 14 000 U/min 10 μL of the supernatant was transferred into sample cups, derivatized at ambient temperature using AccQ-Tag Ultra Derivatization Kit (Waters GmbH) and analyzed by LC-MS/MS (1 μL sample injection volume). For quantification, calibration samples were prepared and analyzed simultaneously with the test samples by serial dilution (x-fold dilution steps) of Multilevel Calibrator Set Amino Acid Analysis (Chromsystems) with water, leading to a final PEA concentration range of 500-0 μM.

The LC-MS/MS analysis was performed on an Acquity I-Class UPLC system from Waters, equipped with a binary solvent manager, an autosampler with flow-through needle and column manager, connected to a mass spectrometer Waters TQs-micro with ESI. Waters MassLynx (v4.2 SCN 1001) was used for system control, data acquisition, and data processing. Chromatographic separation was performed using an Cortecs UPLC C18 (Waters, 1.8 μm; 2.1 × 150 mm). MP A contained 0.1% formic acid (Sigma-Aldrich) in water; MP B contained 0.1% formic acid (Sigma-Aldrich) in acetonitrile (Biosolve, LC/MS grade). Total run time was 5.0 min with a flow rate set to 0.45 mL/min, using the following gradient: (1) initial conditions: 100% MP A; (2) 1.00 min: 100% MP A; (3) 3.00 min: 92.0% MP A; (4) 3.2 min: 5% MP A; (5) 4.0 min: 5% A; (6) 4.5 min: 100% MP A; and (7) 5.0 min: 100% MP A.

Multiple reaction monitoring was performed using the following transitions in ESI-positive mode (parent ion m/z > quantitative daughter ion m/z): 312 > 171 for PEA, retention time 2.95 min; 316 > 171 for deuterated PEA, retention time 2.95 min.

MassCheck Amino Acid Analysis Controls (Chromsystems, Gräfelfing, Germany) were used for daily quality control. Analytical measurement range of the assay was 0-1000 μmol/L, limit of quantitation of the assay was 0.44 μmol/L, and an estimated limit of detection of 0.13 nmol/L. The within-run and between-run precision was <8.7% for PEA.

Ilofotase alfa and antidrug antibodies

Ilofotase alfa serum concentrations and antidrug antibodies were determined at ICON Bioanalytical Laboratories using a validated electrochemiluminescence immunoassay and an electrochemiluminescent (ECL) ligand-binding assay, respectively.

Serum ilofotase alfa concentrations were determined using a validated ECL ligand-binding procedure (Meso Scale Discovery). The lower limit of quantitation was 4.0 ng/mL and the upper limit of quantitation was 500 ng/mL, with overall mean accuracy and precision values of ±20.0% at each concentration of the quality-control samples (10.0, 66.0, and 400 ng/mL). Duplicates were not allowed to exceed the coefficient of variation of 20.0%.

Antidrug antibodies were determined by an ECL ligand-binding assay, for which a confirmatory cut-point of 11.9% was established during method validation. Any trial sample signal reduction equal to or higher than the specificity cut-point was confirmed positive, and any signal reduction lower than the specificity cut-point was scored negative. Duplicates were not allowed to exceed the coefficient of variation of 20.0%. Antidrug antibody positivity required confirmation in 2 assay steps to be considered positive. For post-baseline results, a participant was to be considered positive if negative at baseline and had at least one positive post-baseline result, or positive at baseline and had at least one positive post-baseline result with a titer higher.

Statistical analysis

As this was an exploratory trial, no formal statistics or sample size calculations were conducted. All participants who received ilofotase alfa were included in the safety analysis. The intent-to-treat population included all randomized participants and was used for the analysis of all biomarkers.

A central site-specific randomization list and respective random-code envelopes were created, allocating participants 1:1 to either the 0.8 or 3.2 mg dose. The site was instructed to use random-code envelopes in a predefined order. A 1:1 block randomization (block size 4) strategy was used, without further stratification.

For all biomarkers, maximum change from baseline (absolute and relative) was summarized descriptively using SAS (v9.4 or later; SAS Institute). Baseline was defined per participant as the median of all available baseline measurements (day −2, day −1, and day 1 [predose]). Change from baseline at timepoint x was calculated as the value at timepoint x minus the baseline value; and to calculate the relative change divided by the baseline value. For the PL/PLP ratio, fold-change from baseline was calculated as the ratio at timepoint x divided by the baseline ratio.

Pharmacokinetic parameters were determined for each participant by noncompartmental analysis using Phoenix WinNonlin (Version 8.3.4; Tripos LP), applying scheduled timepoints. Parameters were summarized by treatment and included the total area under the plasma concentration-time curve from zero to time infinity (AUC_inf) or to last measured time (AUC_0−t), peak plasma concentration (C_max), time to reach C_max (T_max), total body clearance (CL), volume of distribution (Vd), and terminal half-life (t_1/2).

Results

Demographics and baseline characteristics

Twelve adult participants with a confirmed diagnosis of hypophosphatasia were enrolled; all of whom completed the trial per protocol. Six participants were randomized 1:1 to receive either 0.8 or 3.2 mg/kg ilofotase alfa (Figure 1). The first participant received the first dose on May 17, 2023, and the last participant visit was on July 12, 2023.

Participant disposition. CONSORT diagram showing participant disposition throughout the trial.

Participant baseline characteristics are summarized in Table 1. The overall mean (SD) age was 50 (11) yr, and 8 participants were female. Treatment groups were largely balanced regarding baseline characteristics with the exception of participants in the 3.2 mg/kg group being predominantly females (n = 5) and having tentatively higher baseline AP activity and lower serum PLP and urine PEA levels compared with the 0.8 mg/kg group. Hypophosphatasia-related medical history is summarized in Table S1. Pain was the most common symptom, reported by 75% (9/12) of the participants, followed by skeletal manifestations by 50% (6/12), and fatigue by 42% (5/12).

Table 1.

Participant demographics and baseline characteristics.

	0.8 mg/kg ilofotase alfa (N = 6)	3.2 mg/kg ilofotase alfa (N = 6)	Overall (N = 12)
Sex, n (%)
Male	3 (50)	1 (16.7)	4 (33.3)
Female	3 (50)	5 (83.3)	8 (66.7)
Age, yr
Mean (SD)	51 (8)	48 (13)	50 (11)
Median (range)	50 (41-62)	51 (30-68)	51 (30-68)
Height, cm
Mean (SD)	165.2 (9.0)	167.0 (7.2)	166.1 (7.8)
Median (range)	161.0 (158-178)	165.5 (160-178)	162.0 (158-178)
Weight, kg
Mean (SD)	70.3 (17.2)	67.6 (16.9)	68.9 (16.3)
Median (range)	68.5 (52.0-95.7)	63.8 (53.0-97.0)	68.6 (52.0-97.0)
BMI, kg/m ²
Mean (SD)	25.7 (6.0)	24.2 (5.3)	24.93 (5.5)
Median (range)	24.5 (20.7-36.5)	22.3 (19.2-32.8)	22.4 (19.2-36.5)
Plasma PP _i (μM)
Mean (SD)	6.4 (2.2)	5.6 (1.7)	6.0 (2.0)
Median (range)	6.7 (3.6-10.0)	5.5 (2.9-8.2)	6.0 (2.9-10.0)
Serum PLP (nmol/L)
Mean (SD)	1033.3 (807.7)	678.0 (392.0)	855.7 (633.1)
Median (range)	1052.5 (145-1992)	519.0 (335-1390)	664.5 (145-1992)
Urine PEA (mmol/mol creatinine)
Mean (SD)	38.7 (26.0)	20.6 (17.3)	29.6 (23.1)
Median (range)	40.8 (5.5-69.5)	15.8 (0.6-49.3)	25.4 (0.6-69.5)
AP activity, U/L
Mean (SD)	15.3 (7.2)	19.2 (5.2)	17.3 (6.3)
Median (range)	13.8 (8-27)	19.5 (13-26)	16.5 (8-27)

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Summary of participant characteristics and hypophosphatasia-related biomarker values at baseline.

Abbreviations: AP, alkaline phosphatase; PEA, phosphoethanolamine; PL, pyridoxal; PLP, pyridoxal-5′-phosphate; PPi, inorganic pyrophosphate.

Eight participants (n = 4 in each group) had 2 ALPL variants documented, while 4 participants (n = 2 in each group) had 1 known ALPL variant. Details regarding participants’ genotypes are provided in the supplementary material (Table S2).

Change from baseline in hypophosphatasia-related biomarkers

At baseline, mean (SD) plasma PP_i concentrations were 6.4 (2.2) and 5.6 (1.7) μM/L in the 0.8 and 3.2 mg/kg groups, respectively, with 8 of the 12 participants (n = 4 per group) having values above the ULN (normal range: 2-5 μM/L).³³^,³⁴ Following a single dose of ilofotase alfa, the greatest reduction in PPi occurred 2 h after start of dosing, reaching a mean (SD) of 4.0 (1.2) μM in the 0.8 mg/kg group and 1.2 (0.8) μM in the 3.2 mg/kg group, equivalent to a mean percentage change from baseline of −37% and −77%, respectively. Inorganic pyrophosphate levels declined below the LLN in 67% (4/6) of participants in the 3.2 mg/kg group 2 h after start of dosing but generally returned to within the normal range by 8 h. Inorganic pyrophosphate remained within the normal range throughout the 10 d for all participants in the 0.8 mg/kg group. All participants returned to their baseline value or higher within 6 d of treatment. Return to baseline levels was observed after a mean (SD) of 38.7 (42.5) and 77.3 (59.6) h for the 0.8 and 3.2 mg/kg dose groups, respectively (Figure 2A and Table S3).

Change in hypophosphatasia-related biomarkers throughout the 10-d trial period. Concentration–time profiles for (A) serum PPi, (B) serum PLP, (C) serum PL, (D) change in PL/PLP ratio, (E) urine PEA, and (F) AP activity after a single intravenous dose of 0.8 mg/kg (n = 6) or 3.2 mg/kg (n = 6) ilofotase alfa in adults with hypophosphatasia. PLP is hydrolyzed by alkaline phosphate to PL. Markers alone represent individual participant data; markers with error bars and lines represent the mean ± SD. Shaded areas represent normal ranges for PPi (2-5 μM), PLP (21-138 nmol/L), PEA (<5 mmol/L), and AP activity (35-128 IU/L). Abbreviations: CREA, creatinine; PEA, phosphoethanolamine; PL; pyridoxal; PLP, pyridoxal-5′-phosphate; PPi, inorganic pyrophosphate.

Baseline PLP levels were above the ULN (normal range: 21-138 nmol/L) for all participants and consistently decreased following ilofotase alfa treatment. The greatest reduction was observed 2 h after dosing, reaching a mean (SD) of 702.9 (574.2) nmol/L in the 0.8 mg/kg group and 241.0 (168.4) nmol/L in the 3.2 mg/kg group (mean percentage change from baseline: −35% and −66%, respectively). After this initial reduction, PLP levels reached or exceeded the ULN for all participants in both groups 8 h after infusion. Over subsequent days, PLP levels further increased toward baseline levels; this return to baseline appeared slower in the 3.2 mg/kg group than the 0.8 mg/kg group. Mean levels at day 10 remained below baseline in 33% (2/6) and 67% (4/6) of participants in the 0.8 and 3.2 mg/kg groups, respectively. For all other participants, PLP levels returned to baseline after a mean (SD) 46.0 (65.8) and 120.0 (0.0) h for the 0.8 and 3.2 mg/kg groups, respectively (Figure 2B and Table S3).

Mean baseline plasma PL levels were largely similar across both groups, except for 1 participant in the 3.2 mg/kg group whose baseline PL levels were notably higher than for other participants (45.5 nmol/L vs a range of 11.2-15.3 nmol/L for others in this group). Overall, PL levels increased after dosing, peaking 4 h after start of dosing for the 0.8 mg/kg group and 8 h for the 3.2 mg/kg group, reaching a mean (SD) of 67.1 (30.8) and 49.4 (16.3) nmol/L in the 0.8 and 3.2 mg/kg groups, respectively (Figure 2C).

The mean (SD) PL/PLP ratio at baseline was 0.03 (0.03) and 0.03 (0.01) in the 0.8 and 3.2 mg/kg groups, respectively. The greatest change in ratio was observed 4 h after dosing for the 0.8 mg/kg group and 2 h after dosing in the 3.2 mg/kg group, with mean (SD) change from baseline of 0.13 (0.09) and 0.18 (0.06), respectively (Figure 2D and Table S3). In 50% (3/6) and 83% (5/6) of participants in 0.8 and 3.2 mg/kg groups, the ratio remained above baseline throughout the trial. For the remaining participants, this returned to baseline after a mean (SD) of 168 (63.5) and 192 (non-calculable) h for 0.8 and 3.2 mg/kg groups, respectively.

Mean urine PEA normalized to creatinine remained largely unchanged across the 10-d period for the 0.8 mg/kg group. In the 3.2 mg/kg group, the greatest reduction was seen 48 h after dosing, reaching a mean (SD) of 10.1 (9.5) mmol/mol (mean percentage change of −52 [20]%) and remained below baseline levels throughout the 10-d period (Figure 2E and Table S3). In 50% (3/6) and 67% (4/6) of participants, PEA levels remained below baseline throughout the trial; this returned to baseline after a mean (SD) of 152.0 (90.9) and 132.0 (17.0) h for the 0.8 and 3.2 mg/kg doses, respectively (Figure 2E).

All 12 participants had circulating AP activity below 30 U/L before administration of ilofotase alfa. Mean circulating AP activity peaked 48 h after dosing and gradually declined thereafter. During the 10-d post-dose observation period, AP activity remained above baseline levels and the LLN for all participants (Figure 2F). No meaningful changes were observed in the other exploratory biomarker concentrations over time (Figure S2).

Safety and tolerability

Four participants experienced 8 treatment-emergent adverse events (TEAE); one TEAE of pain in extremity was reported by a participant in the 0.8 mg/kg ilofotase alfa group, and seven TEAEs were reported by three participants in the 3.2 mg/kg ilofotase alfa group (Table 2). The AEs reported for the 3.2 mg/kg group included dysgeusia (n = 2), headache (n = 1), restless arm syndrome (n = 1), restless legs syndrome (n = 1), upper abdominal pain (n = 1), and nausea (n = 1). All adverse events were mild in intensity; 4 events were considered by the investigator to be possibly related to study drug administration. No serious adverse events or otherwise clinically important events were reported or led to withdrawal from the study treatment, and no deaths occurred. No meaningful changes were observed in clinical chemistry, hematology, or urinalysis.

Table 2.

Overall summary of adverse events following a single intravenous dose of ilofotase alfa in adults with hypophosphatasia.

	Participants, n (%)	Events, n	Participants, n (%)	Events, n	Participants, n (%)	Events, n
	0.8 mg/kg ilofatase alfa N = 6		3.2 mg/kg ilofatase alfa N = 6		Overall N = 12
Treatment-emergent AEs (TEAEs)	1 (16.7)	1	3 (50)	7	4 (33.3)	8
Mild	1 (16.7)	1	3 (50)	7	4 (33.3)	8
Moderate	0 (0.0)	0	0 (0.0)	0	0 (0.0)	0
Severe	0 (0.0)	0	0 (0.0)	0	0 (0.0)	0
TEAE by preferred term
Dysgeusia	0 (0.0)	0	2 (33.3)	2	2 (16.7)	2
Headache	0 (0.0)	0	1 (16.7)	1	1 (8.3)	1
Restless arm syndrome	0 (0.0)	0	1 (16.7)	1	1 (8.3)	1
Restless legs syndrome	0 (0.0)	0	1 (16.7)	1	1 (8.3)	1
Abdominal pain upper	0 (0.0)	0	1 (16.7)	1	1 (8.3)	1
Nausea	0 (0.0)	0	1 (16.7)	1	1 (8.3)	1
Pain in extremity	1 (16.7)	1	0 (0.0)	0	1 (8.3)	1
Related treatment-emergent AEs	0 (0.0)	0	2 (33.3)	4	2 (16.7)	4
Serious AEs	0 (0.0)	0	0 (0.0)	0	0 (0.0)	0
Fatal AEs	0 (0.0)	0	0 (0.0)	0	0 (0.0)	0
AEs leading to withdrawal	0 (0.0)	0	0 (0.0)	0	0 (0.0)	0

Open in a new tab

Summary of treatment-emergent adverse events following a single dose of ilofotase alfa in the 0.8 mg/kg group, the 3.2 mg/kg group, and the overall trial population.

Abbreviations: AE, adverse event; TEAE, treatment-emergent adverse event.

Two participants (16.7%), one in each dose group, tested negative for ilofotase alfa anti-drug antibodies at baseline (day 1, predose) but were positive on day 10; (titers <1). Additionally, one participant in the 0.8 mg/kg group was positive for ilofotase alfa anti-drug antibodies at baseline (day 1, predose; titer <1), and negative on day 10. Overall, the incidence of immunogenicity to ilofotase alfa was considered negligible.

Pharmacokinetics

The mean plasma concentration–time profile for the recombinant enzyme following a single dose of 0.8 or 3.2 mg/kg ilofotase alfa is presented in Figure 3. Peak plasma concentration (C_max) ± SD was 5037 ± 1569 and 33 920 ± 16 897 ng/mL for the 0.8 and 3.2 mg/kg groups, respectively, which reached 1 h after infusion in both groups (median t_max 1.0 [min-max: 1.0-1.0] h in both groups). The mean terminal elimination half-life (t_1/2) ± SD was 77.2 ± 9.5 and 71.2 ± 10.1 h for 0.8 or 3.2 mg/kg ilofotase alfa doses, respectively (Table S4). No major deviation from dose proportionality was observed.

Ilofotase alfa serum concentration-time profiles after a single intravenous dose of ilofotase alfa in adults with hypophosphatasia. Mean (SD) ilofotase alfa serum concentrations following a single dose of ilofotase alfa are shown across the 10-d observation period on a log scale (n = 6 per dose group).

Discussion

This Phase 1b trial explored the potential of ilofotase alfa as an enzyme replacement therapy for hypophosphatasia. The trial measured the disease-specific biomarker response in 12 adult participants after a single intravenous infusion of ilofotase alfa at 1 of 2 doses (0.8 or 3.2 mg/kg). Following single dose application over 1 h, dose-dependent reductions in concentrations of PP_i, PLP, and PEA were observed as early as 1 h after completion of the infusion. Circulating AP activity peaked at first assessment, 24 h after treatment, and remained above baseline throughout the 10 d after dosing. Further, ilofotase alfa was well-tolerated and mineral homeostasis appeared unaffected.

In hypophosphatasia, deficient AP activity leads to elevated levels of various substrates, considered to be the main cause for the multitude of clinical manifestations. Specifically, genetically deficient TNAP activity in hypophosphatasia leads to elevated levels of PPi, PLP, and PEA.

In interventional studies, reducing PPi has been proven crucial for facilitating hydroxyapatite formation and restoring bone mineralization.²⁸ Accordingly, clinical studies evaluating AP enzyme replacement therapy with asfotase alfa were successful in improving skeletal integrity and limiting further disease-related sequalae.³⁵

Preclinical studies and clinical observations have shown distinct substrate affinity and catalytic activity of different AP isoenzymes.²⁸ The efficacy of ilofotase alfa in reducing substrates and improving mineralization has thus far only been demonstrated in preclinical studies using TNAP-knockout mice.³⁰ The results reported here confirm for the first time that ilofotase alfa dose-dependently reduces plasma PPi and PLP, as well as urinary PEA in humans, suggesting a potential benefit for patients with hypophosphatasia. In this study, the mean (SD) maximal reduction of PPi 2 h post-infusion, was −2.4 (±1.6) and −4.4 (±1.6) μM for the low and high doses, respectively. This is around the magnitude of the least-squares mean change (SE) of −2.6 (0.2), −3.8 (0.2), and −4.5 (0.2) reported for the 0.5, 2.0, and 3.0 mg/kg doses of asfotase alfa in adults with hypophosphatasia from baseline through week 9 when applied subcutaneously 3 times per week.³⁶ Combined with the observation that levels only returned to baseline after 38.7 and 77.3 h, these findings suggests that a positive effect on mineralization could be expected with recurrent dosing of ilofotase alfa.

Alkaline phosphatase hydrolyses phosphorylated forms of vitamin B6, specifically the principal circulating form PLP, to PL.⁵ The serum ratio of PL and PLP is postulated to be a good indicator of the effect of AP enzyme replacement therapy²⁷: a shift in the ratio toward PL after dosing indicates drug-related PLP conversion. In this trial, we observed a dose-dependent increase in the PL/PLP ratio after ilofotase alfa treatment, which steadily returned to near baseline levels across the 10-d period. This shift in ratio appears to be largely driven by changes in PL levels following the initial reduction in PLP. However, PLP levels generally returned to above ULN within the same day of treatment and remained stable throughout the rest of the 10-d period. The latter observation could be a result of PLP backflow from supersaturated tissues bringing circulating levels of PLP backup following single dose ilofotase alfa treatment. Further investigation in future studies with recurrent dosing are needed to better understand this effect and reveal if continuous treatment will eventually yield sustainable normalization of PLP levels and the PL/PLP ratio in both tissues and circulation.

While the pathophysiological significance of elevated PEA levels on clinical manifestations of hypophosphatasia is not yet clear, this study confirms that initially elevated levels return toward physiological levels following single-dose application of ilofotase alfa.

The immediate early onset of substrate reduction in this study, with progressive tapering over subsequent days, aligns with previous reports on intravenous applications of soluble AP formulations.³⁷ While this is a limitation regarding the need for sustained enzyme activity, efficacy may be prolonged through subcutaneous application that allows for protracted liberation into the circulation. Conversely, the lack of a high affinity, tissue-specific anchoring moiety could eventually prove advantageous in terms of ubiquitous, tissue-independent efficacy and controllable dose adjustments according to individual signs and symptoms.

Preclinical data, as well as clinical data from studies investigating ilofotase alfa for the prevention and treatment of AKI, confirm particular efficacy of ilofotase alfa toward some of these substates.²⁸^,³² This suggests further beneficial effects on disease-related metabolism in hypophosphatasia and establishing these markers in clinical practice for routine assessment of the disease will be important to improve and individualize treatment modalities for hypophosphatasia patients.

Studies in healthy volunteers and in patients with sepsis-associated AKI showed that in over 500 participants, ilofotase alfa has a good safety profile, and may have renal protective effects.³²^,^38–41 Our trial further supports the safety profile of ilofotase alfa, and also highlights its low immunogenicity. In the 2 participants who developed antidrug antibodies in this study, titers were very low and no new safety signals were identified.

Currently, asfotase alfa is the only approved treatment option for hypophosphatasia patients with pediatric onset of the disease and, according to the European label, to treat the bone manifestation of the disease. While open-label studies have shown effectiveness of asfotase alfa treatment in adults and adolescents with pediatric-onset disease, including effects on physical performance and health-related quality of life, evidence is lacking regarding patients who only become symptomatic later in life and who predominantly suffer from extra skeletal manifestations of the disease.³⁶^,⁴² Accordingly, there is a clear unmet need for treatment options that specifically address clinical manifestations observed in adult patients since patient perceived burden of the disease in this population appears independent of whether symptoms were diagnosed in, or retrospectively assigned to childhood, or involve bone manifestations.¹¹^,¹² Considering the wide range of substrates and mechanisms involved in the pathophysiology of signs and symptoms of hypophosphatasia, treatment options with distinct pharmacokinetic and pharmacodynamic profiles will be required to enable individually optimized treatment strategies, specifically for the large population of adult patients with predominantly extra skeletal manifestations of the disease.

This trial was an exploratory, uncontrolled, Phase 1b trial in 12 participants, and therefore has some limitations. Despite randomization, participants in the 0.8 mg/kg group had lower baseline AP activity—and consequently a higher mean PLP and PPi—than participants in the 3.2 mg/kg cohort. We cannot exclude that these differences may have influenced the results, since AP replacement is sensitive to the amount of substrate present, per the Michaelis–Menten equation. Furthermore, we did not eliminate the active enzyme from blood samples using a chemical inhibitor of ilofotase alfa before assessing the substrates in this study. Instead, samples were processed immediately, using a filter with a pore size small enough to withhold the active compound.

In conclusion, these data show that a single intravenous dose of ilofotase alfa increased AP activity levels over the 10-d trial period, and induced a dose-dependent, substantial reduction in all primary disease-specific biomarkers (PPi, PLP, and PEA). Ilofotase alfa was well tolerated, and mineral homeostasis appeared unaffected. Future research with prolonged subcutaneous administration is needed to investigate whether reduced serum PPi and PLP, and urine PEA levels can improve the clinical manifestations of hypophosphatasia in adults.

Supplementary Material

12NOV25_Supplementary_materials_REVISED_1-5_CLEAN_zjaf185

12nov25_supplementary_materials_revised_1-5_clean_zjaf185.pdf^{(660.4KB, pdf)}

Acknowledgments

We would like to thank the participants and their families for participating in this trial. We would also like to thank the site staff for their engagement and support. We thank Sophie Briggs from InterComm International, UK for medical writing support for this manuscript. We like to thank Liesbeth Hof and Matthias Winkel for support with the analysis of the data and conduct of the trial. We would like to thank Kristie Bass Clemmer for her support with the conduct of the trial. This trial was funded by AM-Pharma B.V.

Contributor Information

Lothar Seefried, Osteology/Clinical Trial Unit, University of Wuerzburg, 97074 Wuerzburg, Germany.

Juliane Bernholz, AM-Pharma, Stadsplateau 6, 3521 AZ Utrecht, The Netherlands.

Maarten Kraan, AM-Pharma, Stadsplateau 6, 3521 AZ Utrecht, The Netherlands.

Yvonne Nitschke, Department of General Pediatrics, Muenster University Children's Hospital, Albert-Schweitzer-Campus 1, 48149 Münster, Germany; INTEC Network of Ectopic Calcification, Center for Medical Genetics Ghent, Corneel Heymanslaan 10, 9000 Ghent, Belgium.

Frank Rutsch, Department of General Pediatrics, Muenster University Children's Hospital, Albert-Schweitzer-Campus 1, 48149 Münster, Germany; INTEC Network of Ectopic Calcification, Center for Medical Genetics Ghent, Corneel Heymanslaan 10, 9000 Ghent, Belgium.

Markus Mallek, MVZ Dr Eberhard & Partner Dortmund GbR (UEBAG), PO box 10 10 40, 44010 Dortmund, Germany.

Sina Kleinert, MVZ Dr Eberhard & Partner Dortmund GbR (UEBAG), PO box 10 10 40, 44010 Dortmund, Germany.

Franca Genest, Osteology/Clinical Trial Unit, University of Wuerzburg, 97074 Wuerzburg, Germany.

Author contributions

Lothar Seefried (Conceptualization, Formal analysis, Investigation, Methodology, Project administration, Writing—original draft, Writing—review & editing), Juliane Bernholz (Formal analysis, Funding acquisition, Project administration, Writing—original draft, Writing—review & editing), Maarten Kraan (Conceptualization, Formal analysis, Funding acquisition, Methodology, Project administration, Writing—original draft, Writing—review & editing), Yvonne Nitschke (Formal analysis, Writing—original draft, Writing—review & editing), Frank Rutsch (Formal analysis, Writing—original draft, Writing—review & editing), Markus Mallek (Data curation, Formal analysis, Writing—original draft, Writing—review & editing), Sina Kleinert (Data curation, Investigation, Writing—original draft, Writing—review & editing), and Franca Genest (Formal analysis, Investigation, Project administration, Writing—original draft, Writing—review & editing)

Funding

This study was funded by AM-Pharma B.V.

Conflicts of interest

L.S. has received honoraria for consultation and lectures from Alesta, Alexion/AstraZeneca, AM-Pharma, Amgen, Biomarin, Chiesi, Gedeon-Richter, Haleon/GSK, Inozyme, KyowaKirin, Mereo, Novartis, NovoNordisk, Stadapharm, Theramex, UCB, and Ultragenyx; and grants for scientific projects to the institution from Alexion/AstraZeneca, Chiesi, and KyowaKirin. J.B. is an employee of AM-Pharma and may own stocks or shares in the company. M.K. acts as a medical advisor to AM-Pharma and may own stocks or shares in the company. Y.N., M.M., and S.K. report no conflicts of interest. F.R. has received grant support and consultancy fees from Inozyme Pharma. F.G. has received speaker honoraria from Abbvie, Lilly, and Alexion.

Data availability

Data supporting this trial are available on the Clinical Trials Information System (CTIS) site here: https://euclinicaltrials.eu/search-for-clinical-trials/?lang=en&EUCT=2023-503186-35-00. This data is also available via the ClinicalTrials.gov website here: https://clinicaltrials.gov/study/NCT05890794?intr=ilofotase%20alfa&rank=2.

Ethics and consent

The trial was conducted in accordance with the principles of the Declaration of Helsinki and all applicable laws and was approved by the applicable ethics committee. All participants gave written informed consent before any study-related procedures.

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39. Pickkers P, Mehta RL, Murray PT, et al. Effect of human recombinant alkaline phosphatase on 7-day creatinine clearance in patients with sepsis-associated acute kidney injury: a randomized clinical trial. JAMA. 2018;320(19):1998-2009. 10.1001/jama.2018.14283 [DOI] [PMC free article] [PubMed] [Google Scholar]
40. Heemskerk S, Masereeuw R, Moesker O, et al. Alkaline phosphatase treatment improves renal function in severe sepsis or septic shock patients. Crit Care Med. 2009;37(2):417-23, e1. 10.1097/CCM.0b013e31819598af [DOI] [PubMed] [Google Scholar]
41. Pickkers P, Angus DC, Arend J, et al. Study protocol of a randomised, double-blind, placebo-controlled, two-arm parallel-group, multi-centre phase 3 pivotal trial to investigate the efficacy and safety of recombinant human alkaline phosphatase for treatment of patients with sepsis-associated acute kidney injury. BMJ Open. 2023;13(4):e065613. 10.1136/bmjopen-2022-065613 [DOI] [PMC free article] [PubMed] [Google Scholar]
42. Seefried L, Rak D, Petryk A, Genest F. Bone turnover and mineral metabolism in adult patients with hypophosphatasia treated with asfotase alfa. Osteoporos Int. 2021;32(12):2505-2513. 10.1007/s00198-021-06025-y [DOI] [PMC free article] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

12NOV25_Supplementary_materials_REVISED_1-5_CLEAN_zjaf185

12nov25_supplementary_materials_revised_1-5_clean_zjaf185.pdf^{(660.4KB, pdf)}

Data Availability Statement

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PERMALINK

A randomized Phase 1b trial evaluating the pharmacodynamics of ilofotase alfa in adults with hypophosphatasia

Lothar Seefried

Juliane Bernholz

Maarten Kraan

Yvonne Nitschke

Frank Rutsch

Markus Mallek

Sina Kleinert

Franca Genest

Roles

Abstract

Introduction

Materials and methods

Trial design

Trial participants

Trial objectives and assessments

Sample collection and laboratory assays

Sample collection

Trial medication

P‌Pi assay

PL/PLP assay

PEA assay

Ilofotase alfa and antidrug antibodies

Statistical analysis

Results

Demographics and baseline characteristics

Figure 1.

Table 1.

Change from baseline in hypophosphatasia-related biomarkers

Figure 2.

Safety and tolerability

Table 2.

Pharmacokinetics

Figure 3.

Discussion

Supplementary Material

Acknowledgments

Contributor Information

Author contributions

Funding

Conflicts of interest

Data availability

Ethics and consent

References

Associated Data

Supplementary Materials

Data Availability Statement

ACTIONS

PERMALINK

RESOURCES

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