Sustained improvement in renal function with palopegteriparatide in adults with chronic hypoparathyroidism: 2-year results from the phase 3 PaTHway-trial

The PaTHway clinical trial demonstrated sustained efficacy, safety, and tolerability of daily palopegteriparatide in the treatment of adults with hypoparathyroidism. Palopegteriparatide treatment was also associated with improvements in estimated glomerular filtration rate (eGFR) over 52 wk in a post hoc analysis, prompting further exploration of palopegteriparatide in the preservation of renal function. The current post hoc analysis evaluated the impact of palopegteriparatide treatment on renal function in adults with hypoparathyroidism through Week 104; as with prior analysis, changes in renal function were assessed using eGFR. At Week 104, 93% (76/82) of participants remained in the open-label extension. Of those, 82% had albumin-adjusted serum calcium levels in the normal range (8.3-10.6 mg/dL), 97% were independent from conventional therapy (≤600 mg/d of elemental calcium and no active vitamin D). Mean (SD) serum phosphate (3.5 (0.7) mg/dL) and albumin-adjusted calcium × phosphate product (30.7(5.1) mg2/dL2) levels were also within normal ranges. Palopegteriparatide treatment resulted in a mean (SD) increase in eGFR of 8.9 (11.0) mL/min/1.73m2 (p < .0001) from baseline to Week 52, which was sustained through Week 104, where it was 77.8 (14.8) mL/min/1.73 m2 with a mean (SD) change from baseline of 9.0 (10.3) mL/min/1.73 m2 (p < .0001). By Week 104, 45% and 34% of participants had an increase in eGFR of ≥5 mL/min/1.73 m2 and ≥10 mL/min/1.73 m2, respectively. Palopegteriparatide treatment normalized mean (SD) 24-h urine calcium within 26 wk and maintained levels below 250 mg/d through Week 104 (158.8 (90.5) mg/24 h). Most treatment-emergent adverse events were mild or moderate; no new safety signals or cases of treatment-related nephrolithiasis were reported. These findings demonstrate sustained renal safety of palopegteriparatide and suggest that PTH replacement therapy with palopegteriparatide preserves and may improve renal function in adults with chronic hypoparathyroidism after 104 wk of treatment.