So many new journal articles! Nothing terribly earthshattering, but every little tidbit helps.
You’ve heard my rant about case reports seldom offering much new information on XLH, but the two I’m highlighting today are different, because there’s virtually no research on the use of burosumab during pregnancy, so we (and pediatric endocrinologists) can learn from clinical experiences with individual patients. First, there’s “Continuation of burosumab during pregnancy in a patient with X-linked hypophosphatemia” Conclusion: “Although no apparent short-term maternal or fetal adverse events were observed, the safety of burosumab use during pregnancy is uncertain, and more clinical data, particularly with long-term follow-up, are needed.” Second, there’s “Prolonged neonatal phosphate retention and transient hypercalcemia following antenatal Burosumab exposure: a pharmacovigilance alert.” Conclusion: “This case demonstrates that … Burosumab exposure [in the womb] can result in prolonged postnatal alterations in calcium-phosphate homeostasis. Careful biochemical monitoring is warranted in exposed infants, and continuation of Burosumab beyond mid-pregnancy should be approached with caution.”
My takeaway from those two case reports is that anyone who has XLH and is pregnant REALLY needs to consult an expert to decide the best treatment option after discussing the pros, cons, and unknowns. It’s not an issue I have any personal experience with, but it must be a really difficult decision, doing what’s best for the child without doing any permanent damage to the mother’s health.
I also found this case report interesting, not so much for patients who have lived experience on the subject, for clinicians who may not fully understand the progressive nature of XLH and the ongoing need for treatment, regardless of where the patient is in that progression. “Three Generations of X-Linked Hypophosphataemia: The Inter-generational Impact of Burosumab Across the Lifespan.” Conclusion: “This three-generation familial case series uniquely illustrates the varying clinical phenotype and disease burden at different stages of life … [and] highlights the cascading intergenerational impact of burosumab whereby treatment uptake is promoted when benefits are observed in affected family members ….” Patients (who aren’t spontaneous cases like I am) have direct, lived experience with the multi-generational impacts of XLH, and they will undoubtedly see themselves in these patients. I think it’s even more important though that clinicians get to experience these impacts vicariously through articles like this one, since pediatric specialists in particular seldom see the effects of XLH later in life, and even those clinicians who treat adults may not see enough of us to observe the whole range of the progression of symptoms.
In non-case-report articles, we’ve got “Burosumab for XLH and TIO in adults” It doesn’t add much to the existing literature, but it’s a good overview if you need one for your clinician, especially if you get any resistance to pursuing adult treatment. It makes a strong case for adult treatment, something that’s still more of an afterthought for most clinicians. Plus, it talks about TIO, which gets a lot less attention than XLH does. I think it’s important to talk about the two together, since it refocuses attention on the root problem, hypophosphatemia, rather than the better-known bone symptoms (rickets/osteomalcia), perhaps shattering some pre-conceived and extremely limited notions about XLH being purely a matter of height and bowed legs.
Finally, speaking of TIO, there have been several journal articles about it in recent months. There are too many to summarize here (and most offer little actionable information for patients), but you can see them all at pubmed: https://pubmed.ncbi.nlm.nih.gov/?term=tumor%20induced%20osteomalacia&sort=date One in particular really caught my attention, because the title is so stark, and it’s similar to the experience of a TIO patient I met in person once: “Phosphaturic Mesenchymal Tumor: From Invisibility to Bedridden Morbidity” Most journal articles/titles tend to be so distant and objective that it’s easy to forget how much the patient is suffering and how badly their quality of life is affected. There’s a lot of bad experiences (especially misdiagnoses) in all the articles, but there’s also some good news insofar as burosumab is being prescribed and is helping those patients who can’t be cured by surgery.
And that gets us caught up through the end of September!
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Please note that the author is a well-read patient, not a doctor, and is not offering medical or legal advice.
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