This is a Phase 1b, randomized, placebo-controlled, participant- and investigator- blinded, two-part non-confirmatory multiple ascending dose (MAD) study in adult patients aged 18-65 (inclusive) with active SLE disease (mild-moderate).This MAD study will be conducted in two parts, Part A and Part B sequentially.~In Part A, after a screening period of up to 6 weeks, participants will be randomized (in a 3:1 ratio) to MHS552 or placebo administered subcutaneously (s.c.) weekly for four weeks of treatment. Part A will consist of up to 3 cohorts (low, medium, high dose), with approximately 4-8 participants completing each cohort (total of approximately 16 participants). Participants will be followed-up during 8 weeks post last dose. The total duration of study participation of Part A is approximately 120 Days.~In Part B, after a screening period of up to 28 days, approximately 12 participants will be randomized (in a 2:1 ratio) to MHS552 or placebo administered s.c. weekly for 12 weeks of treatment (dose to be confirmed). Participants will be followed-up during 8 weeks post last dose with End of Study (EoS) visit at Day 134. The total duration of study participation of Part B is approximately 162 Days.
The purpose of this two-part multiple ascending dose study is to evaluate the safety and tolerability of multiple doses of MHS552 in adults with mild to moderately active Systemic Lupus Erythematosus (SLE). Participants will be treated for 4 or 12 weeks followed by an 8-week follow-up period.