The purpose of this study is to characterize the pharmacokinetic (PK) profile, safety, and tolerability of peginterferon beta-1a (BIIB017) delivered by the single-use autoinjector or prefilled syringe (PFS) in healthy volunteers to support the development of the autoinjector.

This is a randomized, open-label, 2-sequence, 2-period crossover study that will be conducted at a single site in the United States to characterize the PK profile, safety and tolerability of peginterferon beta-1a delivered by autoinjector or PFS. Participants will be randomized in a 1:1 ratio to receive a single dose of peginterferon beta-1a at Day 1 delivered by either autoinjector or PFS, followed by a single dose of peginterferon beta 1a delivered by the other device at Day 22. The total duration of study participation is up to 3 months for each participant. Participants will complete a follow-up visit at Day 50 after the end of treatment period.

Key Inclusion Criteria:

1. Must have a body mass index (BMI) of 19 to 29 kg/m^2, inclusive, and a minimum body weight of 50.0 kg

Key Exclusion Criteria:

1. History of any clinically significant laboratory abnormalities, malignancies, cardiac, endocrinologic, hematologic, hepatic, immunologic, metabolic, urologic, pulmonary, neurologic, dermatologic, psychiatric, renal, or other major diseases
2. Female subjects who are pregnant or breastfeeding
3. Any previous treatment with prescription or investigational pegylated drugs.

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.