Venetoclax in Previously Treated Waldenström Macroglobulinemia.

Purpose: BCL2 is overexpressed and confers prosurvival signaling in malignant lymphoplasmacytic cells in Waldenström macroglobulinemia (WM). Venetoclax is a potent BCL2 antagonist and triggers in vitro apoptosis of WM cells. The activity of venetoclax in WM remains to be clarified.
Patients and Methods: We performed a multicenter, prospective phase II study of venetoclax in patients with previously treated WM (NCT02677324). Venetoclax was dose-escalated from 200 mg to a maximum dose of 800 mg daily for up to 2 years.
Results: Thirty-two patients were evaluable, including 16 previously exposed to Bruton tyrosine kinase inhibitors (BTKis). All patients were MYD88 L265P -mutated, and 17 carried CXCR4 mutations. The median time to minor and major responses was 1.9 and 5.1 months, respectively. Previous exposure to BTKis was associated with a longer time to response (4.5 v 1.4 months; P < .001). The overall, major, and very good partial response rates were 84%, 81%, and 19%, respectively. The major response rate was lower in those with refractory versus relapsed disease (50% v 95%; P = .007). The median follow-up time was 33 months, and the median progression-free survival was 30 months. CXCR4 mutations did not affect treatment response or progression-free survival. The only recurring grade ≥ 3 treatment-related adverse event was neutropenia (n = 14; 45%), including one episode of febrile neutropenia. Laboratory tumor lysis without clinical sequelae occurred in one patient. No deaths have occurred.
Conclusion: Venetoclax is safe and highly active in patients with previously treated WM, including those who previously received BTKis. CXCR4 mutation status did not affect treatment response.
Competing Interests: Jorge J. CastilloConsulting or Advisory Role: Janssen, Roche/Genentech, Beigene, AbbVie/PharmacyclicsResearch Funding: Pharmacyclics (Inst), AbbVie (Inst), Janssen (Inst), BeiGene (Inst), TG Therapeutics (Inst) John N. AllanHonoraria: AstraZeneca, AbbVie, Pharmacyclics/Janssen, BeiGeneConsulting or Advisory Role: AbbVie/Genentech, Pharmacyclics, Ascentage Pharma, BeiGene, Janssen Oncology, Epizyme, AstraZeneca, TG Therapeutics, ADC TherapeuticsResearch Funding: Genentech, Janssen, Celgene, TG Therapeutics Tanya SiddiqiConsulting or Advisory Role: Juno Therapeutics, AstraZeneca, BeiGene, Celgene, Pharmacyclics, Bristol Myers Squibb/CelgeneSpeakers' Bureau: Pharmacyclics/Janssen, AstraZeneca, BeiGene, Bristol Myers Squibb/CelgeneResearch Funding: Juno Therapeutics (Inst), Kite, a Gilead company (Inst), Acerta Pharma (Inst), TG Therapeutics (Inst), BeiGene (Inst), Pharmacyclics (Inst), Celgene (Inst), Oncternal Therapeutics (Inst), Bristol-Myers Squibb/Sanofi (Inst) Ranjana H. AdvaniConsulting or Advisory Role: Genentech/Roche, Seattle Genetics, Takeda, Portola Pharmaceuticals, Celgene, Sanofi, Kura Oncology, Merck, Karyopharm Therapeutics, ADC Therapeutics, Daiichi Sankyo, Bristol Myers Squibb/Celgene, Epizyme, IncyteResearch Funding: Millennium (Inst), Seattle Genetics (Inst), Genentech/Roche (Inst), Pharmacyclics (Inst), Janssen (Inst), Merck (Inst), Kura Oncology (Inst), Forty Seven (Inst), Cyteir (Inst) Catherine A. FlynnConsulting or Advisory Role: Pharmacyclics, Karyopharm Therapeutics Shayna SarosiekResearch Funding: Acrotech Biopharma (Inst) Andrew R. BranaganConsulting or Advisory Role: Pharmacyclics/Janssen, Genzyme, Adaptive Biotechnologies, BeiGene, Karyopharm Therapeutics, CSL Behring Xia LiuEmployment: Merck (I) Guang YangEmployment: AbbVie (I), Blueprint MedicinesStock and Other Ownership Interests: Blueprint MedicinesHonoraria: Janssen Matthew S. DavidsHonoraria: Research to PracticeConsulting or Advisory Role: Genentech, Janssen, Pharmacyclics, TG Therapeutics, AbbVie, AstraZeneca, Celgene, MEI Pharma, Adaptive Biotechnologies, Verastem, Ascentage Pharma, BeiGene, Lilly, Novartis, Takeda, Bristol Myers SquibbResearch Funding: Genentech (Inst), TG Therapeutics (Inst), Pharmacyclics (Inst), Surface Oncology (Inst), MEI Pharma (Inst), Verastem (Inst), Ascentage Pharma (Inst), AstraZeneca (Inst), Novartis (Inst)Travel, Accommodations, Expenses: TG Therapeutics, Janssen, AbbVie, BeiGene, Genentech Richard R. FurmanHonoraria: Janssen, AstraZeneca, Pharmacyclics, Janssen Biotech, Genentech/Roche, Loxo, TG Therapeutics, Verastem, Acerta Pharma, AstraZeneca, Beigene, Incyte, OncoTracker, AbbVie, MorphoSys, SanofiResearch Funding: Acerta Pharma, TG TherapeuticsExpert Testimony: AbbVie, Janssen OncologyTravel, Accommodations, Expenses: TG Therapeutics, Janssen OncologyOther Relationship: Incyte, Janssen Biotech Steven P. TreonHonoraria: Abbvie/Pharmacyclics, Janssen Oncology, BeiGeneConsulting or Advisory Role: Janssen, Pharmacyclics, Beigene, X4 Pharmaceuticals, Bristol Myers SquibbResearch Funding: Pharmacyclics, Bristol Myers Squibb (Inst), X4 Pharmaceuticals (Inst), Lilly (Inst), Beigene (Inst), AbbVie (Inst)Patents, Royalties, Other Intellectual Property: My institution holds patents related to use of MYD88 and CXCR4 testing for which a predetermined financial distribution to the laboratory and individuals is provided. I have not received any income to this date related to these patents (Inst)Travel, Accommodations, Expenses: Janssen OncologyOther Relationship: Janssen, Pharmacyclics, BeigeneNo other potential conflicts of interest were reported.