Parathyroid hormone replacement effective for hypoparathyroidism treatment
LOS ANGELES — Recombinant human parathyroid hormone 1-84 lowered oral calcium and calcitriol dosage over 6 years while achieving normal range levels for albumin-corrected serum calcium in adults being treated for hypoparathyroidism, according to data presented at the AACE Annual Scientific and Clinical Congress.
“This research confirms that chronic hypoparathyroidism is treatable with long-term [recombinant human parathyroid hormone 1-84] therapy,” Bart Clarke, MD, professor of medicine at the Mayo Clinic in Rochester, Minnesota, told Endocrine Today. “These findings indicate that patients with not well-controlled hypoparathyroidism may be treated adjunctively with long-term [recombinant human parathyroid hormone 1-84].”
Clarke and colleagues examined 6-year safety and efficacy data from the RACE study. Forty-nine adults (mean age, 48.1 years; 81.6% women) from 12 centers in the U.S. were given doses of 25 µg or 50 µg per day of recombinant human parathyroid hormone 1-84 (rhPTH[1-84]; Natpara, Shire), with doses adjusted by 25 µg per day up to 100 µg per day. Participants continued the regimen for 72 months. To ensure that participants kept their albumin-corrected serum calcium levels between 8 mg/dL and 9 mg/dL, adjustments for oral calcium and calcitriol doses were allowed.
In the 34 participants who completed all 72 months, there was a 40.4% decrease in oral calcium dose and a 72.2% decrease in calcitriol dose. Participants also maintained combined albumin-corrected serum calcium levels of 8.4 mg/dL. The researchers also observed that urinary calcium excretion, serum phosphorous levels and calcium-phosphorous product levels all decreased, with the first two measures reaching the normal range. Mean serum creatinine and estimated glomerular filtration rate did not change. The researchers further noted that “no new safety concerns were identified” but that 98% of the participants had “treatment-emergent adverse events” while 26.5% had “treatment-emergent serious adverse events.”
“The findings show continued efficacy of PTH 1-84 long-term treatment in normalizing the biochemical abnormalities seen with chronic hypoparathyroidism,” Clarke said. “The most striking finding of this study was the gradual normalization of urinary calcium excretion over 6 years. The observed safety profile was consistent with the profile observed in previous reports.” – by Phil Neuffer
Bone H, et al. Safety and efficacy of recombinant human parathyroid hormone 1-84 for the treatment of adults with chronic hypoparathyroidism. Presented at: AACE Annual Scientific and Clinical Congress; April 24-28, 2019; Los Angeles.
Disclosure: Clarke reports his institution receives research funding from Shire/Takeda.