The purpose of this study is to evaluate the safety, tolerability, and pharmacokinetics (PK) of VX-668 at various doses.

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:

• Participants of age between 18 to 55 years (inclusive)
• 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
• Nonsmoker or ex-smoker for at least 3 months before screening

Key Exclusion Criteria:

• Any condition possibly affecting drug absorption
• Females of childbearing potential

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/independent-research/clinical-trial-data-sharing