This is a Phase 2s multicenter randomized study to evaluate the efficacy, safety and tolerability of GS-5178 in participants with Cutaneous Lupus Erythematosus. Participants who meet eligible criteria will be randomized in a 2:1 ratio to one of the two treatment groups: GS-5178 2 15mg tablets once daily or Placebo to match 2 15mg tablets once daily. The duration of intervention if upto 12 weeks.

Who can Participate

Male and nonpregnant female between the ages of 18 years to 75 years. Must have active CLE at the time of screening and day 1. Participants should be willing to undergo punch biopsy at 2 time points while in the study. Participants must have documented prior intolerance or inadequate response to at least one- a) Topical corticosteroid or topical calcineurin inhibitors b) Oral corticosteroid c) Any other nonbiologic standard-of-care therapy, including, but not limited to: chloroquine, quinacrine, hydoxychloroquine, azathioprine, mycophenolate mofetil (MMF), leflunomide, dapsone, or methotrexate (MTX). Participants must have a BMI between 18 and 35 kg/m2 inclusive. Participants must agree to use protocol specified methods of contraception. Participants must not have presence of active skin conditions other than cutaneous lupus that may interfere with assessing lupus-specific skin lesion(s) (eg, psoriasis, drug-induced lupus). Participants meeting any of the following criteria will be excluded: a) Prior use of interleukin-1 receptor associated kinase 4(IRAK4) inhibitor or degrader at any time. b) Exposure to cyclophosphamide within 60 days c) Exposure to JAK inhibitor (eg, tofacitinib, baricitinib, upadacitinib) within 60 days. d) Use of oral prednisone > 10mg/day within 28 days, or rituximab within 180 days. e) Use of injectable corticosteroids within 28 days f) Use of 2 or more non-biologic standard of care therapies within 28 days Additional inclusions and exclusions apply.

Study ID