A Study to Investigate the Efficacy and Safety of Sonrotoclax Plus Zanubrutinib Compared With Placebo Plus Zanubrutinib in Adults With Relapsed/Refractory Mantle Cell Lymphoma (CELESTIAL-RRMCL)

Inclusion Criteria:

• Histologically locally confirmed diagnosis of MCL based on the World HealthOrganization 2022 classification of Haematolymphoid Tumors (WHO-HAEM5), or based onInternational Consensus Classification (ICC)

• Ability to provide archival or fresh tumor tissue for retrospective centralconfirmation of MCL diagnosis

• Received 1 to 5 prior lines of systemic therapy including an anti-CD20 monoclonalantibody (mAb)-based immunotherapy or chemoimmunotherapy and requiring treatment inthe opinion of the investigator

• Relapsed or refractory disease after the last line of therapy

• Measurable disease defined as ≥ 1 nodal lesion that is > 1.5 cm in longest diameter,or ≥ 1 extranodal lesion that is > 1 cm in longest diameter

• Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 to 2

• Adequate organ function

Exclusion Criteria:

• Prior therapy with B-cell lymphoma-2 inhibitor (BCL2i)

• Prior therapy with BTK degraders

• Prior therapy with covalent or non-covalent Bruton tyrosine kinase inhibitor (BTKi)unless the participant was intolerant of non-zanubrutinib covalent or non-covalentBTKi. Participants with refractory disease to BTKi therapy or relapse attributed tofailure of BTKi therapy are ineligible.

• Prior autologous stem cell transplantation or chimeric antigen receptor T-celltherapy within 3 months before first dose of study drug

• Prior allogeneic stem cell transplant within 6 months of the first dose of the studydrug

• Known central nervous system involvement by lymphoma

• Clinically significant cardiovascular disease

• History of stroke or intracranial hemorrhage within 6 months before first dose ofstudy drug

Note: Other protocol defined Inclusion/Exclusion criteria may apply.