The purpose of this study is to evaluate the safety, tolerability, and pharmacokinetics of single and multiple ascending doses of VX-581.

The study is being conducted to evaluate the safety, tolerability, and pharmacokinetics of single and multiple ascending doses of VX-581 in healthy participants and consists of Screening Phase, Treatment Phase and Safety Follow-up Phase. Note: This clinical trial information was submitted voluntarily under the applicable law and, therefore, certain submission deadlines may not apply. (That is, clinical trial information for this applicable clinical trial was submitted under section 402(j)(4)(A) of the Public Health Service Act and 42 CFR 11.60 and is not subject to the deadlines established by sections 402(j)(2) and (3) of the Public Health Service Act or 42 CFR 11.24 and 11.44.).

Key Inclusion Criteria:

• Body mass index (BMI) of 18.0 to 32.0 kilogram per meter square (kg/m^2)
• A total body weight of more than (>) 50 kg
• Male and Female participants of non-childbearing potential

Key Exclusion Criteria:

• History of febrile illness or other acute illness that has not fully resolved within 14 days before the first dose of study drug
• Any condition possibly affecting drug absorption

Other protocol defined Inclusion/Exclusion criteria may apply.

Details on Vertex data sharing criteria and process for requesting access can be found at: https://www.vrtx.com/our-science/clinical-trials-data-sharing/