A Study Evaluating the Safety, Tolerability, and Pharmacokinetics of Multiple Ascending Doses of SM04755 Following Topical Administration to Healthy Subjects

Inclusion Criteria: * Body mass index of 18 to 30 kg/m\^2 at study start * Subject must have read and understood the informed consent form, and must have signed it prior to any study-related procedure being performed * Willingness to comply with all scheduled study visits, laboratory tests, contraception requirements and other study procedures * Appropriate skin characteristics at site of application (inner thigh) (for example, consistent pigmentation, no tattoos, no scarring or noted injury, no varicose veins or structural repair) * Willing to avoid extensive sun exposure, phototherapy, or use of a tanning salon for the duration of the study Exclusion Criteria: * Women who are pregnant or lactating * Women of childbearing potential who are sexually active and are not willing to use a highly effective method of birth control during the study period that includes double barrier, intrauterine device (IUD), or hormonal contraceptive combined with single barrier, or abstinence * Males who are sexually active and not willing to use a condom, and have a partner who is capable of becoming pregnant, if neither has had surgery to become sterilized, and/or who are not willing to use double barrier or whose partner is not using a highly effective method of birth control (e.g., IUD or hormonal contraception combined with single barrier). * History of, or current, skin disease (for example, psoriasis, atopic dermatitis, seborrheic dermatitis, and skin cancer) * History of, or current, skin damage at the treatment site (inner thigh) (for example, cuts, abrasion, sunburn, sun-damage, or scarring) * Phototherapy or use of a tanning salon 2 weeks prior to study start until end of the study (Day 28) * History of, or current, allergy to investigational product/placebo ingredients * Known allergy to adhesive tape * Current evidence of malignancy or history of malignancy within the last 5 years prior to study start; prior history of in situ cancer or basal or squamous cell skin cancer, completely excised, is allowed * Treatment with an investigational product within 12 weeks prior to study start; the last date of participation in the trial, not the last date of receipt of investigational product, must be at least 12 weeks prior to study start * Use of any prescription or nonprescription drugs \[except birth control or hormone replacement therapy (HRT)\], topical skin treatments on the application site (inner thigh), vitamins, grapefruit/grapefruit juice, or dietary or herbal supplements within 14 days prior to study start * Blood donation of ≥ 1 pint (473 mL) within 56 days prior to study start or unwilling to refrain from blood donation for the duration of the study * Plasma or platelet donation within 14 days prior to study start or unwilling to refrain from plasma or platelet donation for the duration of the study * Unwilling to refrain from sperm donation for the duration of the study and until 90 days after dose administration * Prior or current latent or active tuberculosis (TB) or nontuberculous mycobacteria infection. * Evidence of active infection or illness involving fever within 7 days prior to study start * Occurrence of serious illness requiring hospitalization within 6 months prior to study start * Regular alcohol consumption exceeding 7 drinks/week for females or 14 drinks/week for men (1 drink = 5 ounces \[150 mL\] of wine or 12 ounces \[360 mL\] of beer or 1.5 ounces \[45 mL\] of hard liquor) within 6 months prior to study start * Use of tobacco- or nicotine-containing products (cigarettes, pipe, cigar, chewing tobacco or nicotine gum, lozenges or patches) within 30 days prior to study start * A history of abuse of prescription or illicit drugs within 6 months prior to study start * Marijuana use within 28 days prior to study start * Previous treatment with SM04755 * Subjects who have a current or pending disability claim, workers' compensation, or litigation(s) that may compromise response to treatment * Subjects who are immediate family members (spouse, parent, child, or sibling; biological or legally adopted) of personnel directly affiliated with the study at the investigative site, or are directly affiliated with the study at the investigative site * Subjects employed by Samumed, LLC, or any of its affiliates or development partners (that is, an employee, temporary contract worker, or designee) responsible for the conduct of the study