Zanubrutinib

Drug Overview
Zanubrutinib (BeiGene) is an oral small molecule inhibitor of Bruton’s tyrosine kinase (BTK), developed to be more selective with less off-target effects than Imbruvica (ibrutinib; AbbVie/Johnson & Johnson). BTK is part of the B-cell receptor signalling pathway, which promotes cell proliferation, adhesion, and survival in many B-cell malignancies.

Analyst Outlook
Zanubrutinib (BeiGene) is an orally administered Bruton’s tyrosine kinase (BTK) inhibitor currently under development for both treatment-naïve and relapsed/refractory chronic lymphocytic leukaemia (CLL). While early-phase trials of zanubrutinib have demonstrated promising safety and efficacy, the drug will face significant competition in both the first-line and second-line settings from more well-established therapies in this increasingly crowded indication. In particular, Imbruvica (ibrutinib; AbbVie/Johnson & Johnson) will serve as a significant barrier to market entry. Not only does Imbruvica share the same mechanism of action as zanubrutinib, but the drug is already approved and widely used in a variety of CLL treatment settings. Nonetheless, BeiGene has initiated a Phase III head-to-head trial testing zanubrutinib against Imbruvica. If zanubrutinib can demonstrate statistically significant improvements in efficacy over Imbruvica, the drug could quickly grow to become an important part of the CLL treatment algorithm.