An Ascending Dose Study of PIT565 in Participants With Systemic Lupus Erythematosus (SLE).

Inclusion Criteria:

• Diagnosis of SLE according to the 2019 ACR/EULAR criteria

• Documentation of SLE autoantibodies

• Active SLE disease, as demonstrated by a SLEDAI-2K ≥ 4 at screening

• Failure to respond to standard-of-care medicines for the treatment of SLE asdetailed in the protocol

• Immunization against pneumococcus, meningococcus, influenza, and COVID-19

Exclusion Criteria:

• Severe SLE-related organ damage dysfunction or life-threatening disease atscreening.

• Any acute, severe lupus-related flare during screening that needs immediatetreatment such as acute CNS lupus (e.g., psychosis, epilepsy) or catastrophicantiphospholipid syndrome.

• Presence of severe lupus kidney disease as defined by worsening proteinuria orestimated glomerular filtration rate (eGFR) which in the opinion of the Investigatorrequires immunosuppressive induction or maintenance treatment at screening.

• History or current diagnosis of ECG or cardiac abnormalities indicating asignificant risk of safety for participants.

• Use of prohibited medication defined in the protocol.

• Clinically significant active, opportunistic, chronic or recurrent infection (including, HIV, HBV, HCV) confirmed one month prior to or during screening.

• Serious medical illness likely to interfere with participation in this clinicalstudy.

• Women of child-bearing potential, defined as all women physiologically capable ofbecoming pregnant from menarche until becoming post-menopausal, unless they areusing highly effective methods of contraception

Other protocol defined inclusion/exclusion criteria may apply.