Chinese regulatory authorities agreed to review a request that BeiGene’s Bruton’s tyrosine kinase (BTK) inhibitor zanubrutinib be approved to treat patients with relapsed or refractory chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL/SLL) in that country.
The decision to accept the company’s New Drug Application was based on results from an ongoing Phase 2 study (NCT03206918), where 80% of CLL/SLL patients, all of whom had failed prior therapies, responded to zanubrutinib.
The open-label trial, taking place in China, has enrolled 91 patients with at least one prior treatment regimen. Each are being given 160 mg of zanubrutinib in capsule form.
After a median follow-up of 9.1 months, 80% showed a reduction in tumor burden. Among these patients, 2% had a complete response with no further evidence of cancer, 9% had a partial response, and 40% had a partial response but still showed high lymphocyte – white blood cell – counts.
The median duration of response has not yet been reached, as a majority of the participants are still responding to zanubrutinib. To date, the safety profile of the treatment has been consistent with previous clinical reports for zanubrutinib.
Additional follow-up clinical data collected from the trial will be submitted to the Chinese regulatory agency as supplementary information for zanubrutinib’s marketing application. These results are also expected to be presented at an upcoming medical conference.
“We are delighted that the submission for zanubrutinib in patients with relapsed-refractory CLL/SLL was accepted … in China, and we are excited to announce the top-line pivotal data for zanubrutinib in these patients, which demonstrated a high overall response rate of 80 percent despite a relatively short follow-up,” Xiaobin Wu, PhD, general manager of China and president of BeiGene, said in a press release. “These results in China are also consistent with the data from our global studies.”
Zanubrutinib is a second-generation molecule that blocks the BTK protein, which is needed for B-cells to thrive and proliferate. It is designed to be more specific and yield stronger anti-cancer activity than the first-generation BTK inhibitor Imbruvica (ibrutinib).
In China, Beigene is also seeking the approval of zanubrutinib as a treatment for mantle cell lymphoma patients who failed prior treatments.
Zanubrutinib has also received Fast Track Designation by the U.S. Food and Drug Administration (FDA) for patients with Waldenström macroglobulinemia, based on results from a global Phase 1 study (NCT02343120). Beigene is now planning to submit a marketing application in the U.S. for this indication in the first half of 2019.
“We are hopeful that these submissions, if approved, could further transform BeiGene as well as bring important new treatment options to cancer patients,” said John Oyler, co-founder, CEO, and chairman of BeiGene.
The company is exploring zanubrutinib in a broad global program. It includes a Phase 3 trial (NCT03053440) for patients with Waldenström macroglobulinemia, a Phase 3 trial (NCT03336333) for previously untreated CLL/SLL patients, and an open-label Phase 2 trial (NCT03520920) for patients with relapsed or refractory follicular lymphoma.
BeiGene is also planning a Phase 3 trial to compare zanubrutinib to Imbruvica in patients with relapsed or refractory CLL/SLL.