Following publication of the idea that the CaR itself serves as a parathyroid PO4 sensor, the clinical trials that had previously demonstrated efficacy for Cinacalcet and Etelcalcetide (used to lower PTH levels in end-stage renal disease) were reanalysed with regards to the prevailing serum PO4 concentrations in the patients (Goodman et al., 2022). Here, PTH is linked to chronic kidney disease.