Ascendis Pharma Bone Diseases A/S

During the first 26 weeks of the trial, participants will be randomly assigned to one of two groups: one group will receive TransCon PTH and one group will receive placebo. All subjects will start with study drug at a dose of 18 mcg/day and will be individually and progressively titrated to an optimal dose in dose increments of 3 mcg/day. TransCon PTH or placebo will be administered as a subcutaneous injection using a pre-filled injection pen. Neither trial participants nor their doctors will know who has been assigned to each group. After the 26 weeks, participants will continue in the trial as part of a long-term extension study. During the extension, all participants will receive TransCon PTH, with the dose adjusted to their individual needs. This is a global trial that will be conducted in the United States, Canada, Germany, Denmark, Norway, Italy, and Hungary.