Parathyroid hormone-related protein and response to pamidronate in tumour-induced hypercalcaemia

Abstract To find out if the concentration of parathyroid hormone-related protein (PTHrP) predicts the response of tumour-inducing hypercalcaemia (TIH) to pamidronate, we studied 44 patients. Pretreatment measurements of serum PTHrP, calcium and phosphate, nephrogenous cyclic AMP, tubular threshold for calcium and phosphate (TmP), and the presence of bone metastases were correlated with response to pamidronate. Response was considered good (normal calcium concentration corrected for albumin [CCa] for >14 days), or poor (failure of CCa to fall, or a rise above normal ≤ 14 days). PTHrP correlated significantly with response (good vs poor, p=0·02). Undetectable PTHrP (