AstraZeneca’s experimental enzyme replacement therapy efzimfotase alfa produced mixed outcomes in three late-stage trials in hypophosphatasia, a rare genetic bone disorder. The results mark another setback in the company’s pursuit of approval in a field where durable efficacy signals are required across multiple endpoints. Efzimfotase alfa has been evaluated in late-stage studies targeting the clinical manifestations of hypophosphatasia. The report highlighted that trial readouts did not deliver a clean path forward. For biotech and pharma stakeholders, the outcome reinforces the high bar for rare-disease registrational programs and the need for consistent efficacy across confirmatory studies.