Abstract: Introduction Zanubrutinib is a highly specific, potent BTK inhibitor with minimal off-target inhibition of other kinases such as EGFR, JAK3, TEC and ITK. Zanubrutinib has shown 100% BTK occupancy, sustained over 24-hours, in both the peripheral blood and lymph node biopsies from patients treated at 160 mg twice daily and achieves durable responses in patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) (Tam 2019). In a phase 2 study conducted in patients with relapsed/refractory (R/R) CLL/SLL, treatment with zanubrutinib resulted in an overall response rate (ORR) of 85%. In addition, duration of response (DOR), progression free survival (PFS) and overall survival (OS) of zanubrutinib monotherapy at 12 months were 93%, 87% and 96%(Xu 2020). Here, we present the pooled analysis to evaluate the impact of number of prior lines of therapy on outcomes of zanubrutinib treatment for CLL/SLL patients. Methods Our analysis was based on a pooled data including CLL/SLL patients treated with zanubrutinib monotherapy in two phase 1 studies (ClinicalTrials.gov NCT02343120, and ClinicalTrials.gov NCT03189524) and one phase 2 study (ClinicalTrials.gov NCT03206918), with median study follow-up time of 29.2, 21.1 and 15.1 months, respectively. Firstly, efficacy and safety outcomes were compared between the treatment naïve (TN) and relapsed/refractory (R/R) groups. Secondly, patients with 1 prior therapy were compared to patients with ≥ 2 prior therapies within the R/R setting. To control confounding in each analysis, entropy balancing was used to create a weighted sample where the baseline covariates were balanced between groups (Hainmueller 2012). In each weighted sample, the efficacy outcomes of zanubrutinib included complete response rate (CRR), ORR (defined as the achievement of complete response [CR], or CRi, partial response [PR] , nodular PR, PR with lymphocytosis), PFS and OS. The difference between groups in CRR and ORR was investigated by logistic regression, and those in PFS and OS by Cox proportional hazards models and log-rank test. The 24-month PFS and OS rates were calculated by the Kaplan-Meier method. The extent of exposure and safety profile of each group were summarized. Results The analysis data consisted of 19 TN patients, 93 patients with 1 prior therapy, and 99 patients with ≥ 2 prior therapies. Seven patients were excluded due to missing baseline covariates. In the weighted samples, all baseline covariates were balanced between groups. After weighting, the effective sample sizes were 19 and 31 for the TN and the R/R groups respectively. The median follow-up times were 31.3 and 20.9 months for the TN and R/R group, respectively; 54.4%, 18.8% and 26.8% of the patients in the R/R group had 1, 2 and & gt;2 prior lines of therapy. The ORR and CRR were higher in TN group, compared with R/R groups (100% vs. 92.1% in ORR [p & lt;0.001] and 21.05% vs. 6.7% in CRR [p=0.09] ). PFS of the TN group was superior to the R/R group (p = 0.13; HR 0.33 [95% CI: 0.10, 1.09]; Figure 1a). The 24-month PFS rate was 100% in the TN group and 79.1% in the R/R group. The OS was comparable between two groups. And safety profile was similar for both groups. After weighting, the effective sample sizes were 77 and 85 for the 1 prior therapy and the ≥ 2 prior therapies groups respectively. The median follow-up times were 17.1 and 15.8 months for the 1 prior therapy and the ≥ 2 prior therapies groups; 56.5%, 20.6% and 22.9% of the patients in the ≥ 2 prior therapies group were treated with 2, 3 and & gt;3 prior lines of therapy. The ORR was numerically higher in the 1 prior therapy group, compared with ≥ 2 prior therapies group (97.0% vs. 88.3%; p=0.05). The CRR was comparable in two groups (9.8% vs. 8.4%; p=0.75). The PFS of 1 prior therapy group was significantly longer than that in ≥ 2 prior therapies group (p & lt;0.001; HR 0.15 [95% CI: 0.05, 0.45]; Figure 1b), and 24-month PFS rates were 94.6% and 75.3%, respectively. The OS was comparable between two groups. And safety profile was similar for both groups. Conclusion Zanubrutinib administered in the early lines, including treatment of naïve patients and patients with 1 prior therapy, led to higher overall response rates and greater durability of therapeutic benefit. Safety profile was similar across all lines of therapy. References Tam CS, et al. Blood. 2019; 134 (11): 851-859. Xu W, et al. J Hematol Oncol. 2020; 13 (1): 48. Hainmueller, J. Political Analysis. 2012; 20(1): 25-46. Disclosures Tam: BeiGene: Honoraria; AbbVie: Honoraria, Research Funding; Janssen: Honoraria, Research Funding. Seymour:Morphosys: Consultancy, Honoraria; Mei Pharma: Consultancy, Honoraria; Gilead: Consultancy; AstraZeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Research Funding; F. Hoffmann-La Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Nurix: Honoraria. Zhou:Henan Cancer Hospital: Current Employment. Opat:Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BeiGene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZenca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; CSL Behring: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Epizyme: Research Funding. Trotman:Celgene: Research Funding; Takeda: Research Funding; BeiGene: Research Funding; F. Hoffmann-La Roche: Research Funding; PCYC: Research Funding. Huang:BeiGene: Current Employment, Current equity holder in publicly-traded company. Lu:BeiGene: Current Employment, Current equity holder in publicly-traded company. OffLabel Disclosure: Zanubrutinib in treatment-naive CLL/SLL

Abstract: Mantle cell lymphoma (MCL) is a mature B-cell neoplasm with a high initial response rate followed almost invariably by relapse. Here we report the pooled data from 2 studies, BGB-3111-AU-003 and BGB-3111-206, to explore the efficacy of zanubrutinib monotherapy in relapsed/refractory (R/R) MCL. A total of 112 patients were included. Median follow-up durations were 24.7 and 24.9 months for BGB-3111-AU-003 and BGB-3111-206, respectively. Overall response rate (ORR) and complete response (CR) rate were 84.8% and 62.5%, and median duration of response, progression-free survival (PFS) and overall survival (OS) were 24.9, 25.8 and 38.2 months, respectively. After weighting, the PFS (median: NE vs. 21.1 months, P  = 0.235) and OS (median: NE vs. 38.2 months, P  = 0.057) were similar but numerically better in the second-line than later-line group. Zanubrutinib was well-tolerated with treatment discontinuation and dose reduction for adverse events in 12.5% and 2.7% of patients, respectively. Hypertension, major hemorrhage and atrial fibrillation/flutter rates were 11.6%, 5.4% and 1.8%, respectively. Zanubrutinib is efficacious in R/R MCL, with a favorable safety profile.

Abstract: Background: The Bruton tyrosine kinase (BTK) inhibitor zanubrutinib,has demonstrated greater selectivity for BTK versus other TEC- and EGFR-family kinases in biochemical assays and favorable pharmacokinetic/pharmacodynamic properties in preclinical studies. In a phase 1 clinical trial, zanubrutinib showed complete and sustained 24-hour BTK occupancy in both blood and lymph node biopsies from patients treated at 160 mg twice daily (bid; Tam et al. Blood 2016;128:642), and was associated with durable responses in patients with non-Hodgkin lymphoma (Tam et al. Blood 2017;130:152). Here, we present initial safety and efficacy data from a phase 2 trial of zanubrutinib in patients with relapsed or refractory mantle cell lymphoma (R/R MCL). Methods: Conducted in China, BGB-3111-206 (clinicaltrials.gov NCT03206970) is a pivotal, single-arm, open-label, multicenter phase 2 study. Patients with R/R MCL aged 18-75 years and with 1-4 prior treatment regimens received zanubrutinib 160 mg bid until disease progression (PD) or unacceptable toxicity. The primary objective is to evaluate the efficacy of zanubrutinib as measured by overall response rate (ORR) assessed by an Independent Review Committee (IRC). Response was assessed with PET-CT scans (in subjects with FDG-avid disease) and CT or MRI scans (in subjects with FDG non-avid disease) at each response assessment and for confirmation of complete response (CR) per the International Conference on Malignant Lymphoma (Lugano) criteria (Cheson, 2014). Key secondary endpoints included progression free survival (PFS), time to response (TTR), duration of response (DOR) and safety. Treatment-emergent adverse events (TEAEs) were assessed according to NCI CTCAE v4.03. Results: As of 27 March 2018, 86 patients with R/R MCL were enrolled and treated. Patient characteristics are summarized in the Table. Over one-half (52.3%) of patients were refractory to their last prior therapy. Median follow-up was 36 weeks (range,1-56) at the data cut. Twenty-one patients discontinued zanubrutinib (13 for PD; 6 for TEAEs; 1 withdrew consent; and 1 per investigator's discretion). One patient was not evaluable for response due to a lack of central pathologic confirmation of MCL. Of the 85 evaluable patients, ORR per the IRC was 84% (n=71; Table), with CR reported in 59% of patients (n=50). The estimated event-free rate for responders was 90% at 24 weeks after response. In total, 12 patients have progressed; the estimated PFS rate was 82% at 24 weeks. The most frequent (≥15%) TEAEs due to any cause included decreased neutrophil count (31.4%), upper respiratory tract infection (29.1%), rash (29.1%), decreased platelet count (22.1%), and decreased white blood cell (WBC) count (17.4%). Grade ≥3 TEAEs due to any cause reported in 〉 2 patients included decreased neutrophil count (11.6%), lung infection (5.8%), anemia (4.7%), and decreased WBC count (3.5%). Petechia/purpura/contusion and hematuria were each reported in 4 patients (4.7%, all grade 1/2); major hemorrhage (serious or grade ≥3 bleeding or central nervous system bleeding of any grade)was reported in 1 patient (1.2%); no cases of atrial fibrillation/flutter or tumor lysis syndrome were reported. Six patients died within 30 days of last study treatment, 1 from PD, 4 due to Grade 5 TEAEs and 1 due to a Grade 5 event that was not treatment emergent. TEAEs leading to discontinuation of zanubrutinib included (n=1 each): infection, pneumonia, lung infection, interstitial lung disease, and twoGrade 5 TEAEs (cerebral hemorrhage and road traffic accident). Conclusions: Zanubrutinib was shown to be highly active in patients with R/R MCL, as demonstrated by a high rate of CR documented by PET-based imaging. Zanubrutinib was generally well-tolerated, consistent with previous reports of zanubrutinib treatment in patients with various B-cell malignancies. Disclosures Song: Peking University Cancer Hospital (Beijing Cancer Hospital): Employment. Zhou:Affiliated Cancer Hospital of Zhengzhou University: Employment; Health and Family Planning Commission of Henan Province: Patents & Royalties: Scientific and technological innovative talents "51282" Project leaders; Henan Cancer Hospital: Consultancy, Employment; Natural Science Foundation of China: Research Funding. Jin:College of Medicine, Zhejiang University: Employment; The National Natural Science Foundation of China: Research Funding. Guo:BeiGene (Shanghai) Co., LTD: Employment. Wang:BeiGene (Shanghai) Co., LTD: Employment. Hilger:BeiGene (Beijing) Co., Ltd.: Employment, Equity Ownership. Huang:BeiGene (Beijing) Co., Ltd.: Employment, Equity Ownership. Novotny:BeiGene (Beijing) Co., Ltd.: Employment, Equity Ownership. Osman:BeiGene USA: Employment, Equity Ownership. Zhu:Beijing Cancer Hospital: Employment.

Abstract: We conducted two indirect comparisons to estimate the efficacy of zanubrutinib versus orelabrutinib in Chinese patients with relapsed or refractory (R/R) chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) or R/R mantle cell lymphoma (MCL). An unanchored matching-adjusted indirect comparison (MAIC) was performed in R/R CLL/SLL patients. Individual patient data from zanubrutinib trial (BGB-3111-205) were adjusted to match the aggregated data from the orelabrutinib trial (ICP-CL-00103). A naïve comparison was performed in R/R MCL for the different response assessment methodology and efficacy analysis set between the zanubrutinib (BGB-3111-206) and orelabrutinib (ICP-CL-00102) trials. Efficacy outcomes included ORR and PFS. In R/R CLL/SLL patients, after matching, IRC-assessed ORR was comparable (86.6% vs. 92.5%; risk difference, -5.9% [95% CI: -15.8%-3.8%]); IRC-assessed PFS was similar with a favorable trend in zanubrutinib over orelabrutinib (HR, 0.74 [95% CI: 0.37-1.47] ) and the 18-month PFS rate was numerically higher in zanubrutinib (82.9% vs. 78.7%). In R/R MCL patients, naïve comparison showed investigator-assessed ORR was similar (83.7% vs. 87.9%; risk difference, -4.2% [95% CI: -14.8%-6.0%]), and CR rate was significantly higher in zanubrutinib over orelabrutinib (77.9% vs. 42.9%; risk difference, 35.0% [95% CI: 14.5%, 53.7%] ). Investigator-assessed PFS was similar with a favorable trend (HR, 0.77 [95% CI: 0.45-1.32]) in zanubrutinib over orelabrutinib and the 12-month PFS rate was numerically higher in zanubrutinib (77.5% vs. 70.8%). MAIC result showed zanubrutinib demonstrated favorable PFS over orelabrutinib for R/R CLL/SLL patients. The naïve comparison showed zanubrutinib had favorable PFS and higher CR rate than orelabrutinib for R/R MCL patients.

Abstract: This pooled analysis of two studies of zanubrutinib examined its efficacy and safety in the treatment of patients with recurrent/relapsed mantle cell lymphoma (MCL) in two different settings—second‐line and later‐line with long‐term follow‐up. This analysis showed that patients receiving zanubrutinib in the second‐line had significantly better overall survival than those who received it in the later‐line. The finding suggests that earlier use of zanubrutinib in the treatment line may lead to better outcomes in patients with recurrent/relapsed MCL.

Abstract: Background: Bruton tyrosine kinase (BTK) is one of the key kinases implicated in the pathogenesis of multiple B cell malignancies. Orelabrutinib is a novel, highly selective and potent irreversible BTK inhibitor with minimal activities against other kinases (ITK, EGFR, ERBB2, etc.). As thus orelabrutinib may avoid off-target related adverse events and shall have improved safety profiles comparing to other BTK inhibitors. Here we present the safety profile of orelabrutinib analyzed based on data from 5 ongoing clinical studies in B cell malignancies (Table 1). Methods: Safety data of 266 patients (pts) from 5 ongoing orelabrutinib monotherapy studies were pooled and analyzed. All pts have been treated with at least one dose of oral orelabrutinib at ≥150 mg daily. The analysis includes the frequency and severity of adverse events (AEs), AEs of special interest, and AEs leading to treatment discontinuation or dose modifications. Results: Safety data were pooled from 266 pts with median age of 60 years (range 35.0-79.0, 69.2% males). The median duration of exposure was 11.0 months (range 0.2-22.0). The most common (occurring in ≥15% of pts) AEs were neutropenia (28.6%), thrombocytopenia (25.9%), Upper respiratory tract infection (24.4%), leukopenia (18.0%), anemia (16.2%) and rash (15.8%). Treatment related serious AEs (SAEs) were reported in 14.7% pts. The most common treatment related SAEs included thrombocytopenia (3.0%), lung infection (3.0%), pneumonitis (1.9%), anemia (1.1%) and lymphadentis (0.8%), The safety profiles were comparable in pts with various subtypes of B cell malignancies. It's noted that orelabrutinib has much less frequency of BTK off-target related adverse events, such as atrial fibrillation, diarrhea, major hemorrhage etc. Among all 266 pts, only one patient was reported with one episode of transient grade 1 atrial fibrillation, and no grade ≥3 atrial fibrillation was observed. Diarrhea of any grade was 7.1% and only one case (0.4%) was reported as grade 3. The major hemorrhage, defined as serious or ≥ G3 bleeding of any site, or central nervous system bleeding of any grade, was rarely observed; as only one case of cerebral hemorrhage, in 65-year-old male patient with more than 10 years hypertension was reported; the other three cases were subcutaneous hemorrhage, vitreous hemorrhage and vitreous hemorrhage/retinal hemorrhage. The later 2 cases of vitreous hemorrhage and/or retinal hemorrhage were resulted from posterior vitreous detachment and macular degeneration and both events were assessed as unlikely related to the treatment. Among 266 pts, the second primary malignancies were reported in only one pt with r/r MCL during orelabrutinib treatment. Grade ≥3 infection occurred in 41 pts (15.4%); most common infections were upper respiratory tract infection and lung infection. Most of the AEs were occurred during the early treatment, the frequency of the new event occurrence was significantly decreased during the later cycles. Dose reductions due to AEs occurred in 15 pts (5.6%), and treatment discontinuation due to AEs in 5.3% of pts with 2.3% related to orelabrutinib. Conclusions: Orelabrutinib shows excellent safety profiles and tolerability across various B-cell malignancies in long-term treatment. These data suggested orelabrutinib as a favorable treatment choice including the combinational therapy for B-cell malignancies. . Disclosures Zhu: Beijing InnoCare Pharma Tech Co., Ltd: Current Employment. Zhao:Beijing InnoCare Pharma Tech Co., Ltd: Current Employment. Xu:Beijing InnoCare Pharma Tech Co., Ltd: Current Employment.