BeiGene, Ltd. (NASDAQ: BGNE; HKEX: 06160), a commercial-stage biopharmaceutical company focused on developing and commercializing innovative molecularly-targeted and immuno-oncology drugs for the treatment of cancer, today announced the presentation of clinical data from two ongoing trials of its investigational Bruton’s tyrosine kinase (BTK) inhibitor, zanubrutinib, in patients with mantle cell lymphoma (MCL). The presentations were made at the 60th Annual Meeting of the American Society of Hematology (ASH), taking place December 1-4, 2018 in San Diego, CA.
Results from the pivotal Phase 2 trial of zanubrutinib in Chinese patients with relapsed or refractory (R/R) MCL (ClinicalTrials.gov Identifier: NCT03206970) were featured in an oral presentation, while updated results from the global Phase 1 trial of zanubrutinib in patients with multiple subtypes of B-cell malignancies, including treatment naïve (TN) and R/R MCL (ClinicalTrials.gov Identifier: NCT02343120), were featured in a poster presentation.
“Taken together, we believe that these two studies provide encouraging evidence for the use of zanubrutinib as a potential therapy in patients with MCL,” said Jane Huang, M.D., Chief Medical Officer, Hematology, at BeiGene. “The results from 86 patients enrolled in our pivotal Phase 2 study in Chinese patients with R/R MCL presented today at ASH, provide a thorough look into the data included in our first new drug application (NDA) in China for zanubrutinib. Additionally, the results from 48 patients with MCL enrolled in our global Phase 1 study illustrated consistent outcomes for patients studied outside of China. We are excited by the prospect that zanubrutinib may be a differentiated BTK inhibitor with deep, durable responses for patients with MCL and potentially for other B-cell malignancies.”
Zanubrutinib was discovered by BeiGene scientists, and is being developed globally as a monotherapy and in combination with other therapies to treat various hematologic malignancies. Zanubrutinib is being studied in several clinical trials as part of a broad development program and was granted Fast Track Designation by the U.S. Food and Drug Administration (FDA) for the treatment of patients with Waldenström macroglobulinemia (WM). BeiGene plans to submit an initial NDA to the FDA for zanubrutinib in 2019 or early 2020. The NDAs in China for R/R MCL and R/R chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) have been accepted by the National Medical Products Administration (NMPA, formerly known as CFDA) and the MCL filing has been granted priority review.
“Zanubrutinib was shown to be highly active in Chinese patients with R/R MCL, as evidenced by a high rate of complete responses characterized by PET-based imaging. It was also generally well-tolerated, and we are hopeful of its potential to become a new treatment option for Chinese patients with MCL and potentially other forms of B-cell lymphomas,” said Yuqin Song, M.D., Ph.D., Associate Professor of Medical Oncology, Deputy Director of the Lymphoma Department at Peking University Cancer Hospital in China, and presenter of results from the pivotal Phase 2 trial in Chinese patients.
“The outcomes observed in patients treated outside of China are generally consistent with the experiences observed in Chinese patients with R/R MCL. Importantly, the high response rates that were observed appear to extend to patients with both TN and R/R MCL,” commented Constantine Tam, M.D., Disease Group Lead for Low Grade Lymphoma and Chronic Lymphocytic Leukemia at Peter MacCallum Cancer Center and Director of Hematology at St. Vincent’s Hospital, Australia, and lead author of the poster presentation of results from the global Phase 1 trial.
Summary of Clinical Results From the Pivotal Phase 2 Trial in China
Oral Presentation Data Included in BeiGene’s NDA in China for Zanubrutinib in MCL
This single arm, open-label, multi-center, pivotal Phase 2 trial of zanubrutinib as a monotherapy in Chinese patients with R/R MCL enrolled 86 patients who had received a median of two prior lines of therapy (1-4). Patients were treated with zanubrutinib, dosed at 160 mg orally twice-daily (BID). The primary endpoint of the trial was overall response rate (ORR) assessed by independent review committee (IRC) using PET-based imaging according to the Lugano Classification 2014.
As of March 27, 2018, 85 patients with R/R MCL were evaluable for efficacy and 65 patients (75.6%) remained on study treatment. The median follow-up time for patients enrolled in the trial was 35.9 weeks (1.1-55.9). Results included:
The ORR by IRC was 83.5 percent (71/85); the complete response (CR) rate was 58.8 percent (50/85) and the partial response (PR) rate was 24.7 percent (21/85);
The 24-week progression-free survival (PFS) was estimated at 82 percent. The median PFS had not yet been reached;
With 24.1 weeks median follow-up (0.1-41.1), the median duration of response (DOR) had not yet been reached and 90 percent of responders were still in response at 24 weeks;
Zanubrutinib tolerability was generally consistent with previous reports in patients with various B-cell malignancies and the majority of adverse events (AEs) were grade 1 or 2 in severity. The most frequent AEs of any attribution were neutrophil count decreased (31.4%), rash (29.1%), upper respiratory tract infection (29.1%), and platelet count decreased (22.1%);
The most frequently reported (in >5 percent of patients) grade 3 or higher AEs were neutrophil count decreased (11.6%) and lung infection (5.8%);
Four patients (4.7%) had treatment emergent adverse events (TEAEs) leading to death (one case each of traffic accident, cerebral hemorrhage, pneumonia, and unknown cause in the setting of infection); and
Among events of special interest for BTK inhibitors, diarrhea was observed in nine patients (10.5%), all grade 1-2. Major hemorrhage was observed in 1 patient (1.2%) with blastoid variant of MCL who had intra-parenchymal CNS bleeding. No cases of atrial fibrillation/flutter were reported in this trial.
Summary of Updated Clinical Results From the Global Phase 1 Trial
This open-label Phase 1 trial of zanubrutinib as a monotherapy in patients with different subtypes of B-cell malignancies, including MCL, is being conducted in Australia, New Zealand, the United States, Italy, and South Korea. As of July 24, 2018, 48 patients with TN (n=9) or R/R (n=39) MCL have been enrolled in the trial and the median follow-up time was 12.7 months (0.7-38.0). Forty-five patients including six with TN and 39 with R/R MCL, were evaluable for efficacy in this analysis, per the Lugano 2014 classification. At the time of the data cutoff, 26 patients remained on study treatment. Updated results included:
The ORR by investigator was 88.9 percent (40/45); the CR rate was 26.7 percent (12/45) and the PR rate was 62.2 percent (28/45). The majority of patients were assessed via CT-scan; PET scans were optional per trial protocol;
The median DOR was 16.2 months and the median PFS for R/R patients was 18.0 months (0.7-30.7);
Zanubrutinib tolerability was generally consistent with previous reports in patients with various B-cell malignancies and the majority of AEs were grade 1 or 2 in severity. The most frequent AEs of any attribution were petechia/purpura/contusion (33.3%), diarrhea (33.3%), upper respiratory tract infection (29.2%), fatigue (25.0%), and constipation (18.8%);
Grade 3-5 AEs occurred in 56.3 percent of patients. Grade 3-5 AEs of any attribution reported in > three patients included anemia (8.3%), major hemorrhage (6.3%), cellulitis (6.3%), myalgia (6.3%), neutropenia (6.3%), pneumonia (6.3%); and thrombocytopenia (6.3%);
Discontinuation due to AEs occurred in 18.8 percent of patients with all but one event (peripheral edema) determined to be unrelated to study drug; and
There were four deaths due to AEs, which were all determined by the investigators to be unrelated to zanubrutinib treatment.