The purpose of the study is to evaluate the long term safety and efficacy of orally administered M5049 in participants with subacute cutaneous lupus erythematosus (SCLE), discoid lupus erythematosus (DLE) and/or systemic lupus erythematosus (SLE) who have completed the 24 week treatment period of Willow study (MS200569_0003 [NCT05162586]).

Inclusion Criteria:

• Are SCLE, DLE and/or SLE that have completed the 24 week Treatment of the Willow Study
• Have a Body Mass Index (BMI) within the less than or equal to (<=) 40 kilograms per meter square (inclusive) at Screening
• Participants who had successfully completed Week 48 of the Part 1 will have the opportunity to participate in the LTE Part 2. In exceptional cases and after Sponsor review, participants who have completed the Week 48 visit of the Part 1 within the previous 4-weeks may be considered for Part 2 participation based on eligibility review. Previous 4-weeks will be calculated from the Week 48 visit of Part 1
• Other protocol defined inclusion criteria could apply

Exclusion Criteria:

• Participants who experienced serious event(s) related to the study intervention during the WILLOW study
• Other severe acute or chronic medical or psychiatric condition or laboratory abnormality that may increase the risk associated with Long Term Extension (LTE) study participation
• Ongoing or active clinically significant viral (including Severe acute respiratory syndrome coronavirus 2 [(SARS-CoV-2)], bacterial or fungal infection, or any major episode of infection requiring hospitalization
• Received LTE prohibited medication during the WILLOW study or after the WILLOW study Week 24
• Participation in any other investigational drug study after the WILLOW study Week 24
• Other protocol defined exclusion criteria could apply

We are committed to enhancing public health through responsible sharing of clinical trial data. Following approval of a new product or a new indication for an approved product in both the US and European Union, the study sponsor and/or its affiliated companies will share study protocols, anonymized patient data and study level data, and redacted clinical study reports with qualified scientific and medical researchers, upon request, as necessary for conducting legitimate research. Further information on how to request data can be found on our website bit.ly/IPD21

Within six months after the approval of a new product or a new indication for an approved product in both the United States and the European Union

Qualified scientific and medical researchers can request the data. Such requests must be submitted in writing to the company's portal and will be internally reviewed regarding criteria for researchers' qualification and legitimacy of the research proposal.