Study QEL-005-CLN-01. Phase I/II study of QEL-005 in patients with diffuse cutaneous systemic sclerosis (dcSSc) and in patients with difficult to treat rheumatoid arthritis (D2TRA).

Prior treatment

• Immunodeficiency or receiving immunoglobulin replacement therapy
• Receiving prohibited medications that cannot be stopped at screening

Other illness

• Active autoimmune diseases other than those under study
• Active infection, or recurrent chronic infection requiring intervention
• Past or current infection with Hepatitis B or C, tuberculosis (TB), syphilis or HIV.
• Participants with known clinically significant cardiac dysfunction or pulmonary disease
• History of malignancy within the past 5 years

Lab values

• Presence of a significant medical condition(s), or clinically significant laboratory abnormality, that, in the Investigator's opinion, may impact participant safety or the participant’s ability to undergo study procedures.

• Participants must be at least 18 years of age at the time of signing the informed consent.
• Specific inclusion criteria for participants with systemic sclerosis (SSc) only 1. Diagnosis of diffuse cutaneous systemic sclerosis (dcSSc) as per the 2013 ACR-EULAR criteria. 2. Serologically positive for antinuclear antibodies 3. Failure to respond sufficiently to immunomodulatory disease modifying anti-rheumatic drugs (DMARDs). 4. Skin involvement with a total modified Rodnan Skin Score of at least 15 5. Evidence of lung fibrosis based on imaging or pulmonary function testing 6. Evidence of active disease based on a validated SSc activity assessment
• Up to date vaccination schedule as per local guidance
• Adequate haematological, liver and renal function as assessed by the Investigator according to local laboratory tests
• Willing to undergo annual influenza vaccination
• Willing to enter a 15-year follow-up
• Eastern Cooperative Oncology Group (ECOG) performance status grade < 3
• Able and willing to use a highly effective method of contraception
• Participants requiring oral steroids be on a stable dose of steroid prior to screening
• Specific inclusion criteria for participants with difficult to treat rheumatoid arthritis (D2TRA) only: 1. Diagnosis of Rheumatoid Arthritis (RA) per 2010 ACR-EULAR criteria 2. Diagnosis of D2TRA per 2021 EULAR criteria 3. Evidence of clinically active disease a defined by validated clinical or laboratory results consistent with standard definitions of active RA. 4. Evidence of inflammation in target joints used for the DAS28 CRP assessment