Pilot Trial of Single Dose Ilofotase Alfa in Hypophosphatasia

The goal of this clinical trial is to compare the effectiveness of two doses of ilofotase alfa, an enzyme replacement treatment, in patients with hypophosphatasia (HPP). The main question it aims to answer is if the harmful accumulating levels of extracellular inorganic pyrophosphate (PPi) and pyridoxal 5'-phosphate (PLP) can be reduced with ilofotase alfa. Researchers will compare the two doses of ilofotase alfa to see if treatment effects differ between the doses.

Recombinant human alkaline phosphatase (ilofotase alfa) is a full-length human chimeric alkaline phosphatase (ALP) that could benefit patients with hypophosphatasia (HPP), which is characterized by low activity of tissue-nonspecific isoenzyme of alkaline phosphatase (TNSALP). This is a pilot trial for a potential future trial aimed at identifying whether treatment with ilofotase alfa can normalize circulating levels of PPi, PLP and other biochemical markers of TNSALP deficiency along with the safety/tolerability of different doses of ilofotase alfa. The trial is designed as a single-center, open-label, randomized, parallel group clinical trial in adult patients with HPP. Two different dose levels (0.8 mg/kg and 3.2 mg/kg) of ilofotase alfa will be assessed. Participants will receive a single dose of ilofotase alfa, administered as a 1-hour intravenous infusion on Study Day 1. Participants will stay at the research center for a total of 12 days; from 2 days before study drug administration (run-in) to 10 days after treatment. An additional follow-up assessment is scheduled 14 days after administration of ilofotase alfa. Blood and urine samples will be taken daily for drug concentration and laboratory measurements assessing safety and effectiveness of treatment. In addition physical examinations will be performed on Day 1 and as needed afterwards.