The purpose of this study is to determine if C fiber conduction is impacted by NAV1.8 modulation.

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 30.0 kilogram per meter square (kg/m^2)
• A total body weight >50 kg

Key Exclusion Criteria:

• Participants who have any 1 of the following criteria in the foot/ankle in which MNG will be performed:

  • Injection of local anesthetics or steroids within 35 days prior to randomization
  • Unsuitable anatomy of the superficial peroneal nerve (i.e., nerve cannot be seen or palpated at the dorsum of the foot/ankle)
  • Infection, disease (dermatologic or vascular), ongoing pain, or recent trauma or surgery that may affect study assessments

• History of febrile illness within 14 days before study drug dosing

• Any condition possibly affecting drug absorption

• Participants with Type 1 or Type 2 diabetes mellitus

• Any dermatological (generalized) or autoimmune disease that may affect C-nociceptor excitability

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