This study will assess the safety and preliminary efficacy of the bi-specific TCE, alnuctamab (known as BMS-986349, CC-93269, EM901), targeting BCMA in patients with moderate to severe SLE, refractory to standard-of-care treatments.

The purpose of this research study is for researchers to learn if the investigational therapy called alnuctamab (known as BMS-986349, CC-93269, EM901) is safe and effective to treat refractory Systemic Lupus Erythematosus (SLE). CC-93269 is investigational, which means its safety and effectiveness have not been established and it is not approved by the U.S. Food and Drug Administration (FDA) for SLE. This will be the first study testing CC-93269 in SLE. Alnuctumab is a type of treatment known as a T cell engager. It is a special protein engineered in the laboratory, which is able to attach to T cells, a type of white blood cell that can kill other cells in the body. T cells normally protect the body from infections, for example by destroying the cells where the virus hides. In this case, alnuctumab will redirect T cells to a new target, called the plasma B cell. This is a type of white blood cell that plays an important role in activating the autoimmune response in patients with lupus. By linking T cells to the autoimmune plasma B cells, alnuctumab will allow the removal of these pathogenic cells. The goal is to evaluate whether this will be sufficient and safe to treat lupus.

Key Inclusion Criteria:

• Age 18-60 years.
• Documented diagnosis of SLE fulfilling 2019 ACR/EULAR criteria.
• Historical documentation of ANA (1:80 or greater) autoantibody on immunofluorescence as well as presence of at least 1 additional autoantibody of the type: anti-dsDNA, anti-histone, anti-chromatin, anti-Smith, anti-RNP, anti-Ro/SSA, anti-La/SSB, anti-cardiolipin (IgG), or anti-beta2-glycoprotein1 (IgG).
• History of SLE that is refractory to corticosteroids and at least 2 immunosuppressive therapies with different mechanisms of action (methotrexate, thiopurines, mycophenolate mofetil, calcineurin inhibitors, biologic agents, cyclophosphamide), including at least one biologic therapy (e.g. anti-CD20 therapy, anifrolumab, belimumab) or cyclophosphamide. Of note, hydroxychloroquine is not considered an immunosuppressive therapy, and methotrexate/azathioprine counts as a single drug class).
• Total SLEDAI-2K >6 with clinical SLEDAI-2K >4, or >1 BILAG A organ domain score, or >2 BILAG B, but without active central nervous system (CNS) disease within the past year; a maximum of two participants with only arthritis and/or rash can be included if truly disabling

Key Exclusion Criteria:

• Autoimmune disease other than SLE, except associated Sjogren's Disease if not primary contributor to symptoms; coexistent fibromyalgia will be allowed if not primary contributor to symptoms.
• TTP-like SLE; catastrophic APS; LN WHO class V as primary qualifying criterion (unless overlap with Class III or IV), rapidly progressive LN, or eGFR <40 mL/min; active CNS pathology attributable to neuropsychiatric SLE.
• Active or suspected infection, including HIV.
• O2 sat <92% on room air; ANC <1500u/L, Hgb <8g/dL, Plt <75,000/uL; ALT or AST > 2X ULN (unless attributed to active myositis), Total Bilirubin >1.5 X ULN (unless Gilbert's Disease), total B cell count <12/microliter, hypogammaglobinemia <500mg/dL.

All of the individual participant data collected during the trial, after de-identification.

Immediately following publication. No end date.

Researchers who provide a methodologically sound proposal. For individual participant data meta-analysis. Proposals may be submitted up to 36 months following article publication. After 36 months the data will be available in our University's data warehouse but without investigator support other than deposited metadata. Information regarding submitting proposals and accessing data may be found at (Link tbd).