Recombinant hormone could REPLACE calcium supplements

By Lynda Williams, Senior medwireNews Reporter

Results from the phase III REPLACE trial of recombinant human parathyroid hormone (rhPTH) indicate the treatment can successfully combat the underlying deficit in hypoparathyroidism.

Overall, 53% of the 90 outpatients randomly assigned to receive rhPTH from a starting dose of 50 µg/day were able to reduce their daily oral calcium and active vitamin D by at least 50% while maintaining their baseline albumin-corrected serum calcium levels.

This compared with just 2% of the 44 patients given placebo, report Michael Mannstadt (Massachusetts General Hospital, Boston, USA) and co-authors.

This combined primary endpoint was assessed at 24 weeks of treatment, by which time 27% of rhPTH-treated patients had increased their dose to 75 µg/day and 52% to 100 ug/day. And the researchers report in The Lancet Diabetes & Endocrinology that titrating to a higher dose may yet have increased the number of patients who achieved this goal.

“The flexible dosing and titration algorithm can be readily implemented in an outpatient setting, which makes it immediately applicable for clinical practice,” the researchers say, noting that adverse events were similar in the rhPTH and placebo groups.

Overall, 93% of rhPTH-treated and 100% of placebo-treated patients reported at least one episode of hypocalcaemia, muscle spasm, headache, nausea, paresthesia, or other side effects, while 11% and 9% experienced serious adverse events. There was one treatment-related episode of hypercalcemia after 32 days of rhPTH and this was resolved successfully without discontinuing the hormone therapy.

Writing in an accompanying editorial, Agnès Linglart and Anya Rothenbuhler, from AP-HP Hôpital Bicêtre in Paris, France, say that the study results will “allow physicians to target normal calcium concentrations in their patients without constantly fearing hypercalciuria.”

“Replacing full-length PTH in patients with hypoparathyroidism seems, unsurprisingly, to be more appropriate than forcing absorption of calcium through the gut, and new indications and clinical development of this therapy are eagerly awaited by adult and paediatric endocrinologists,” they conclude.

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