A Phase 2, Randomized, Double-blinded, Placebo-controlled, Dose Range-finding, Multicenter Study to Evaluate the Efficacy, Safety, and Pharmacokinetics of ALXN2420, a Growth Hormone Receptor Antagonist, Administered Subcutaneously in Combination With Somatostatin Analogs in Adult Participants With Acromegaly

Inclusion Criteria: * Documented diagnosis of acromegaly, that is, historically documented evidence of a GH-secreting pituitary adenoma based on MRI or pathology report * Must be receiving maximum, or maximally tolerated dose per treating physician judgment, of long-acting SSAs (octreotide or lanreotide LAR) and meet both of the following: 1. Received for ≥ 6 months prior to screening 2. Receiving a once-monthly regimen (approximately every 4 weeks). Note: participants on stable regimens of other durations (for example, every 3 or 6 weeks) are not eligible * Must be a partial responder t…