(±)-Zanubrutinib induces dose-dependent anti-tumor effects against REC-1 MCL xenografts engrafted either subcutaneously or systemically via tail vein injection in mice. In the subcutaneous xenografts. Preliminary 14-day toxicity study in rats shows that (±)-Zanubrutinib is very well tolerated and maximal tolerate dose (MTD) is not reached when it is dosed up to 250mg/kg/day.