The FDA has granted BGB-3111 (zanubrutinib, BeiGene, Ltd.) a breakthrough therapy designation for the treatment of adult patients with mantle cell lymphoma (MCL) who have received at least one prior therapy.
More than 1,300 patients worldwide have been treated with zanubrutinib, an investigational small molecule inhibitor of Bruton’s tyrosine kinase (BTK). Currently, it’s being developed in a broad clinical program that includes seven phase 3 or pivotal trials conducted globally or in China.
The designation is based in part on phase 2 data presented at the 2018 American Society of Hematology meeting. Results from a single-arm, open-label, multicenter Chinese trial showed an overall response rate (ORR) of 83.5%.2 In addition, the responses appeared to be durable.
The one-year progression-free survival (PFS) rate in patients receiving zanubrutinib was 90% and the two-year PFS was 82%.
Zanubrutinib’s benefit was consistent across trial subgroups, including patients with and without the blastoid variant form of MCL, those with and without bulky disease, and those who had received <3 or 3 or more previous lines of therapy.
The most frequent adverse events included decreased neutrophil count, upper respiratory tract infection, rash, decreased platelet count, and decreased white blood cell count.