To evaluate the safety, tolerability, pharmacokinetics and pharmacokinetics of multi-dose APG-2575 in mild-to-moderate systemic lupus erythematosus (SLE).

This is a randomized, double-blind, placebo-controlled Phase I/II study. About 40 participants will be recruited to receive either APG-2575 or a placebo, with doses from 200mg up to 800mg.

Inclusion Criteria:

• 1. Diagnosis of systemic lupus erythematosus for at least 6 months.
• 2. On stable treatment for systemic lupus erythematosus before first dose at least 28 days.
• 3. SLEDIA-2000 score: 4-12
• 4.Other than systemic lupus erythematosus, subject should be in general good health.

Exclusion Criteria:

• 1. Severe systemic lupus erythematosus.
• 2. Significant autoimmune disease other than lupus.
• 3. Significant, uncontrolled or unstable disease in any organ.