A Study of DS-1211b in Individuals With PseudoXanthoma Elasticum

DS-1211b, a potent small-molecule inhibitor of tissue-nonspecific alkaline phosphatase, is being developed for the treatment ectopic calcification diseases such as PXE. This study will assess DS-1211b (low-, middle-, and high-dose tablets) administered once daily for 12 weeks in individuals with PXE.

Key Inclusion Criteria:

• Signed and dated informed consent
• Male or female participants aged 18 to 75 years at screening
• Have an established diagnosis of PXE
• Fully vaccinated for coronavirus disease 2019 (COVID-19) per current Center for Disease Control and Prevention guidelines

Key Exclusion Criteria:

• Have a history of bone fracture in the past 6 months
• Have a history of active metabolic bone disease, excluding osteopenia or osteoporosis without fragility fracture
• Have a history of calcium pyrophosphate deposit disease
• Have a history of hypophosphatasia
• Have a history of untreated hyperparathyroidism
• Participated in another interventional research study in the past 60 days.
• Used bisphosphonate in the preceding 12 months or had plans to use bisphosphonate during the study.
• Received Vitamin B6 supplementation >5 mg/day in the month prior to screening and during the study
• Initiated or changed dose of Vitamin D in the preceding month prior to screening
• Have an alkaline phosphatase <lower limit of normal (LLN) range
• Have a QTcF interval duration >450 ms at screening
• Have moderate to severe renal insufficiency
• Are pregnant or breast-feeding women
• Are female participants unwilling to use contraceptive methods
• Have any elective surgery planned during the study period
• Have any other significant condition (medical, psychiatric, social, or medication) that, in the judgment of the Investigator, would prevent full participation or would be inappropriate for the study