A Phase 1/2, Open-Label, Dose-Escalation and -Expansion Study of the Bruton Tyrosine Kinase-Targeted Protein-Degrader BGB-16673 in Patients With B-Cell Malignancies

Study consists of two main parts to explore BGB-16673 recommended dosing, a Phase 1
monotherapy dose finding comprised of monotherapy dose escalation and monotherapy safety
expansion of selected doses, and a Phase 2 (expansion cohorts)

Inclusion Criteria :

1. Confirmed diagnosis (per World Health Organization (WHO) guidelines, unless
otherwise noted) of one of the following: Marginal Zone Lymphoma (MZL) , Follicular
Lymphoma (FL), R/R Mantle Cell Lymphoma (MCL), R/R chronic lymphocytic leukemia and
small lymphocytic lymphoma (CLL/SLL), Waldenström macroglobulinemia (WM), Diffuse
large B-cell lymphoma (DLBCL), or >2 treatments per the Richter's transformation to
DLBCL.

2. Participants who have previously received a covalently-binding Bruton´s tyrosine
kinase (BTK) inhibitor (BTKi) in any line of therapy must have received treatment
with the BTK inhibitor for ≥ 8 weeks (unless reason for discontinuation is
intolerance).

3. For dose-finding and dose-expansion, participants who had previously received a
covalently-binding BTK inhibitor as monotherapy or in combination with other
anticancer agents are eligible for the study if they meet any of the following
criteria: discontinued the previous BTK inhibitor due to disease progression,
experienced disease progression after completing treatment with a BTK inhibitor or
discontinued the BTK inhibitor due to toxicity or intolerance.

4. Measurable disease by radiographic assessment or serum IgM level (WM only)

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

6. Participants enrolling in the dose finding phase of the study may be previously
treated with a BTKi or may be naïve to BTKi therapy depending on the diagnosis and
country of enrollment; participants with MCL enrolling in the expansion cohorts
(Phase 2) must have been treated with a BTKi in a prior line of therapy; CLL/SLL
participants, in addition to being treated with a BTKi in a prior line of therapy,
must also have received a Bcl-2 inhibitor in a prior line of therapy as well (Phase
2).

Exclusion Criteria:

1. Prior malignancy (other than the disease under study) within the past 2 years,
except in situ malignancies that have been curatively resected, localized breast
cancer treated with curative intent with no evidence of breast active disease for
more than 3 years and receiving adjuvant hormonal therapy, localized Gleason score ≤
6 prostate cancer undergoing observation or treatment with androgen depravation, or
any other cancer treated with curative intent, not on adjuvant treatment, and in the
opinion of the investigator is unlikely to recur.

2. Requires ongoing systemic treatment for any other malignancy

3. Requires ongoing systemic (defined as ≥ 10 mg/day of prednisone or equivalent)
corticosteroid treatment.

4. Current or history of central nervous system involvement including the brain, spinal
cord, leptomeninges, and cerebrospinal fluid (as documented by imaging, cytology, or
biopsy) by B-cell malignancy, regardless of whether participants had received
treatment for central nervous system disease

5. Known active plasma cell neoplasm, prolymphocytic leukemia, T-cell lymphoma, Burkitt
lymphoma, acquired immunodeficiency syndrome (AIDS)-related B-cell lymphoma,
Castleman disease, post-transplant lymphoproliferative disorders, hairy cell
leukemia, germinal center B-cell (GCB), DLBCL, EBV+ DLBCL NOS, primary DLBCL of the
central nervous system (CNS), primary cutaneous DLBCL - leg type, DLBCL associated
with chronic inflammation, primary mediastinal (thymic) large B-cell lymphoma,
intravascular large B-cell lymphoma, ALK+ large B-cell lymphoma, primary effusion
lymphoma, high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements,
high-grade B-cell lymphoma - NOS, B-cell lymphoma unclassifiable with features
intermediate between DLBCL and classical Hodgkin lymphoma, or history of or
currently suspected transformation of an indolent lymphoma to an aggressive
histology (except for participants with Richter Transformation to DLBCL are eligible
for Part 1a, 1c, or Phase 2 and participants with history of follicular lymphoma
transforming to non-GCB DLBCL who are eligible for Part 1a, 1c, or Phase 2).

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