In the meantime, if you're considering participating in the trials, you can review the inclusion/exclusion criteria (available here: https://clinicaltrials.gov/ct2/show/NCT02526160?term=XLH&rank=1 ) and discuss your participation with trusted advisers.
You might also find the following sites useful for background information on participating in clinical trials and questions to ask:
Board member Kathy Buchanan, who has extensive experience as a clinical research nurse and is a certified clinical research coordinator, suggests that anyone considering participation in a trial should read all of the documents carefully, especially the consent form. Some questions that ought to be addressed by the paperwork, but that you may wish to ask about are: 1) how much time your involvement will require, 2) how often you'll be required to travel, 3) how often bloodwork and other lab work will be done, 4) what side effects may occur and how/when to report them. Finally, if payment is offered for participation, make sure you understand when the monies will be paid (e.g., at the end of the study or at shorter intervals).
Note that, as always, the XLH Network, Inc. does not endorse or critique specific clinical trials, and does not counsel individual patients either for or against participation in any specific clinical trial. Prospective volunteers should always carefully review the clinical trial's informed consent documentation, and discuss the pros and cons of their participation with trusted advisers, including their health care providers and family members.