Safety and Tolerability of CFTX-1554 in Healthy Subjects

INCLUSION CRITERIA: * Body mass index 18.0 to 30.0 kg/m2 * Females may be of childbearing potential but not pregnant or lactating, or of nonchildbearing potential; all females will be required to have a negative serum pregnancy test conducted at screening, (each) admission, and follow-up. * Female subjects of childbearing potential who have a fertile male sexual partner must agree to use adequate contraception from at least 4 weeks prior to first administration of study drug until 90 days after the follow up visit. * Male subjects, if not surgically sterilized, must agree to use adequate contraception and not donate sperm from first admission to the clinical research center until 90 days after the follow-up visit. * All prescribed medication must have been stopped at least 30 days prior to first admission to the clinical research center. * All over-the-counter medication, vitamin preparations and other food supplements, or herbal medications must have been stopped at least 14 days prior to first admission to the clinical research center. * Ability and willingness to abstain from alcohol from 48 hours before screening and first admission to the clinical research center. * Ability and willingness to abstain from methylxanthine-containing beverages or food (coffee, tea, cola, chocolate, energy drinks) and grapefruit (juice) from 48 hours before first admission to the clinical research center. * Good physical and mental health on the basis of medical history, physical examinatio…