HMBeacon: A Phase 2 Study to Evaluate ALN-6400 in Adult and Adolescent Female Patients With VWD and HMB

Inclusion Criteria -

* Is an adolescent or adult patient with a diagnosis of VWD (including Type 1, Type 2, Type 3, and platelet-type VWD) and HMB for 2 cycles during screening

Exclusion Criteria -

* Has alanine aminotransferase (ALT) or aspartate aminotransferase (AST) greater than 2 times the upper limit of normal (ULN)
* Has total bilirubin greater than 1.5×ULN (except for patients with Gilbert's syndrome)
* Has an estimated glomerular filtration (eGFR) less than 30 mL/min/1.73m\^2 at screening
* Is not willing to comply with the contraceptive requirements during the study period
* Used routine factor prophylaxis (greater than or equal to 1 infusion of factor per week over 12 weeks) within 4 weeks of screening or plans use for routine factor prophylaxis during the study
* New placement of any hormonal or nonhormonal intrauterine device (IUD) or hormonal implants within 24 weeks of screening
* Known current gynecological conditions causing abnormal uterine bleeding (including infection, fibroids, endometriosis, polycystic ovary syndrome, or dysplasia)

Note: other protocol defined inclusion / exclusion criteria apply