A Study to Evaluate Long-term Safety and Clinical Activity of Givosiran (ALN-AS1) in Patient With Acute Intermittent Porphyria (AIP)

Inclusion Criteria: * Completed participation in Part C of study ALN-AS1-001 (NCT02452372) * Not on a scheduled regimen of hemin * Women of child bearing potential must have a negative serum pregnancy test, not be nursing, and use acceptable contraception * Willing and able to comply with the study requirements and to provide written informed consent Exclusion Criteria: * Clinically significant abnormal laboratory results * Received an investigational agent (other than ALN-AS1) within 90 days before the first dose of study drug or are in follow-up of another clinical study * History of multiple drug allergies or intolerance to subcutaneous injection