Phase 1 study of the selective BTK inhibitor zanubrutinib in B-cell malignancies and safety and efficacy evaluation in CLL.

Article Details

Citation

Tam CS, Trotman J, Opat S, Burger JA, Cull G, Gottlieb D, Harrup R, Johnston PB, Marlton P, Munoz J, Seymour JF, Simpson D, Tedeschi A, Elstrom R, Yu Y, Tang Z, Han L, Huang J, Novotny W, Wang L, Roberts AW

Phase 1 study of the selective BTK inhibitor zanubrutinib in B-cell malignancies and safety and efficacy evaluation in CLL.

Blood. 2019 Sep 12;134(11):851-859. doi: 10.1182/blood.2019001160. Epub 2019 Jul 24.

PubMed ID
31340982 [ View in PubMed
]
Abstract

Zanubrutinib is a potent and highly selective inhibitor of Bruton tyrosine kinase (BTK). In this first-in-human, open-label, multicenter, phase 1 study, patients in part 1 (3 + 3 dose escalation) had relapsed/refractory B-cell malignancies and received zanubrutinib 40, 80, 160, or 320 mg once daily or 160 mg twice daily. Part 2 (expansion) consisted of disease-specific cohorts, including treatment-naive or relapsed/refractory chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). The primary end points were safety and tolerability, and definition of the maximum tolerated dose (part 1). Additional end points included pharmacokinetics/pharmacodynamics and preliminary efficacy. Reported herein are results from 144 patients enrolled in the dose-finding and CLL/SLL cohorts. No dose-limiting toxicities occurred in dose escalation. Median BTK occupancy in peripheral blood mononuclear cells was >95% at all doses. Sustained complete (>95%) BTK occupancy in lymph node biopsy specimens was more frequent with 160 mg twice daily than 320 mg once daily (89% vs 50%; P = .0342). Consequently, 160 mg twice daily was selected for further investigation. With median follow-up of 13.7 months (range, 0.4-30.5 months), 89 CLL/SLL patients (94.7%) remain on study. Most toxicities were grade 1/2; neutropenia was the only grade 3/4 toxicity observed in >2 patients. One patient experienced a grade 3 subcutaneous hemorrhage. Among 78 efficacy-evaluable CLL/SLL patients, the overall response rate was 96.2% (95% confidence interval, 89.2-99.2). Estimated progression-free survival at 12 months was 100%. Zanubrutinib demonstrated encouraging activity in CLL/SLL patients, with a low incidence of major toxicities. This trial was registered at www.clinicaltrials.gov as #NCT02343120.

DrugBank Data that Cites this Article

Drugs
Drug Targets
DrugTargetKindOrganismPharmacological ActionActions
ZanubrutinibCytoplasmic tyrosine-protein kinase BMXProteinHumans
Unknown
Inhibitor
Details
ZanubrutinibEpidermal growth factor receptorProteinHumans
Unknown
Inhibitor
Details
ZanubrutinibReceptor tyrosine-protein kinase erbB-2ProteinHumans
Unknown
Inhibitor
Details
ZanubrutinibReceptor tyrosine-protein kinase erbB-4ProteinHumans
Unknown
Inhibitor
Details
ZanubrutinibTyrosine-protein kinase BlkProteinHumans
Unknown
Inhibitor
Details
ZanubrutinibTyrosine-protein kinase BTKProteinHumans
Yes
Inhibitor
Details
ZanubrutinibTyrosine-protein kinase ITK/TSKProteinHumans
Unknown
Inhibitor
Details
ZanubrutinibTyrosine-protein kinase JAK2ProteinHumans
Unknown
Inhibitor
Details
ZanubrutinibTyrosine-protein kinase TecProteinHumans
Unknown
Inhibitor
Details