The FDA recently hosted a Patient Focused Drug Development meeting on Chronic Pain, and the public is invited to provide comments about the information presented, as well as their own experiences with pain. The XLH Network, Inc., provided a full statement on behalf of our community, and a small portion of that statement is included below. We want to encourage our members to review the PFDD information at https://www.fda.gov/Drugs/NewsEvents/ucm603093.htm and to write their own responses and comments if they believe the information will help the XLH community. You can submit your comments here: https://www.regulations.gov/document?D=FDA-2018-N-1621-0001. Comments are due by September 10th.
Pain is a life-long part of the XLH experience that includes chronic bone pain (either due to fractures or due to mineralization defects without fractures), osteoarthritis at an earlier age than the general population due to cartilage thinning, dental pain from spontaneous abscesses, neurological pain from calcifications that impinge on the spinal canal, and pervasive, early-onset bone spurs (enthesophytes) that affect many of the tendon and ligament insertion sites throughout the skeleton and spine.
The most significant downsides to the available current treatments for the pain of individuals with XLH are as follows: 1) they not effective in some patients; 2) they work somewhat but cause significant adverse effects from the drug; 3) they work but at the risk of addiction or stomach, kidney, or liver damage; 4) generally they don't completely resolve the pain, just dull it a bit; and 5) they are a treatment and not a cure, because they don't get to the root cause of the pain.
Some individuals with XLH report having difficulty getting effective dosages or sufficient quantities of pharmacological treatments to handle the extreme severity of pain they experience. Other patients report being viewed as drug-seeking or having a psychosomatic complaint because their pain is both diffuse and severe. In addition, the origin of pain often evolves from time to time without an obvious clinical cause to explain the source of the pain. Finally, many health care providers are unaware that XLH is associated with pain and/or are unaware that there is such a thing as bone pain in the absence of trauma, and this may result, too often, in accusations of drug-seeking behavior or as having psychological issues.