Surovatamig as Consolidation Therapy in Participants With Chronic Lymphocytic Leukaemia or Small Lymphocytic Lymphoma With Unmutated Immunoglobulin Heavy Chain Variable (IGHV)

The purpose of this study is to evaluate the therapeutic benefit and safety of subcutaneous (SC) Surovatamig monotherapy as consolidation therapy in patients with Chronic Lymphocytic Leukaemia (CLL)/ Small Lymphocytic Lymphoma (SLL) with unmutated IGHV (uIGHV).

This is a Phase III global, randomised, open-label, multicentre study. The study will consist of 2 sequential parts- the Dose Optimisation and Safety Run-in part and the Phase-III part. During the dose optimisation and safety run-in part, Surovatamig will be initiated in 2 dose levels. This part will help to determine the recommended phase III dose (RP3D) of Surovatamig to be used in Phase III part. Phase III would comprise of 2 arms, Arm A where the Surovatamig dose (RP3D) will be administered as a consolidation therapy (post standard of care \[SOC\] induction therapy) and Arm B where participants will be observed. In Phase 3 participants will be randomized in a 1:1 ratio to Arm A or Arm B.

Inclusion Criteria: * Documented diagnosis of CLL/SLL with genomic features defined by unmutated IGHV. * Treatment received and response at the end of 1L (first-line) finite therapy. * Participants with SLL (except those in CR in Phase III part) must have measurable disease (nodal or extranodal) with at least one measurable target lesion. * ECOG performance status of 0 to 2. * Adequate haematologic, liver, renal and cardiac function. * Female participants: must be either women not of childbearing potential or must use a highly effective form of contraception. * Male participants who intend to be sexually active with females of childbearing potential must agree to use barrier contraception (eg, condoms). Exclusion Criteria: * Suspected or confirmed transformation of CLL/SLL to a more aggressive form of lymphoma (ie, Richter's transformation, prolymphocytic leukaemia, or DLBCL). * Evidence of active or history of Central Nervous System (CNS) involvement by CLL/SLL. * History of or ongoing confirmed progressive multifocal leukoencephalopathy. * Participants who have any concurrent or history of malignancy. * Participants with: * Active or uncontrolled infection (including Epstein-Barr virus-EBV) requiring systemic therapy. * Participants with known history of Heamophagocytic lymphohistiocytosis (HLH). * Human Immunodeficiency Virus (HIV) infection, or participants with chronic or active infection with Hepatitis B Virus (HBV) or Hepatitis C Virus (HCV). * Major cardiac abnormalities. * Prior CLL/SLL-specific therapies. * Requires chronic immunosuppressive therapy for active autoimmune/inflammatory condition or prior allogeneic stem cell or solid organ transplant. * Major surgical procedure. * Known hypersensitivity to surovatamig or any of the excipients of the product.