Debulking Eliminates Need for Hospitalization Prior to Initiating Frontline Venetoclax Therapy in Previously Untreated CLL Patients: A Phase 3b Study

BACKGROUND: Venetoclax is an effective oral agent for frontline treatment of patients with chronic lymphocytic leukemia (CLL). Due to the rapid induction of cell death caused by the targeted activity of venetoclax, some patients require inpatient monitoring for tumor lysis syndrome (TLS) at initiation of therapy. In the recent CLL14 study, 64% and 22% of venetoclax-treated patients were medium and high risk for TLS, respectively. This study used disease re-staging every two cycles to explore the efficacy of using of obinutuzumab, with or without bendamustine prior to initiation of venetoclax, to reduce tumor burden and thus eliminate the need for hospitalizations, as well as reduce the risk for TLS at the initiation of venetoclax therapy. METHODS: This is a single arm open-label, phase 3b trial (NCT03406156). Patients had previously untreated CLL/SLL (excluding those with 17p deletion), an Eastern Cooperative Oncology Group (ECOG) performance score of ≤1, and a medium (any lymph node 5 - RESULTS: A majority of patients were 10 cm were debulked to 30%) were infusion-related reactions (71%; all grade 1-2), nausea (39%), headache (35%) and fatigue (32%). Neutropenia (28%) and thrombocytopenia (10%) were the most frequently reported Grade 3+ AEs. AEs of TLS were reported in the debulking phase in 7% (5/69) of patients. A retrospective analysis using Howard criteria for TLS identified three additional patients with laboratory TLS: two occurred during the debulking phase and one during the venetoclax phase, all driven by phosphate and uric acid. Uric acid levels were below the institutional upper limit of normal for the patient with TLS during venetoclax treatment and did not require management. No patients were hospitalized during venetoclax ramp up. CONCLUSIONS: Two cycles of obinutuzumab prior to initiation of venetoclax was an effective debulking strategy for patients with ALC >25 × 109 /L and lymph nodes 5 cm treated with obinutuzumab or >10 cm treated with obinutuzumab plus bendamustine may need >2 cycles to achieve low tumor burden. Debulking via obinutuzumab, with or without bendamustine, may allow more patients to be administered venetoclax in the outpatient setting, eliminating the need for hospitalization during venetoclax initiation. Download : Download high-res image (173KB) Download : Download full-size image Figure . Disclosures Sharman: AstraZeneca: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Research Funding; Genentech: Consultancy, Honoraria, Research Funding; TG Therapeutics: Consultancy, Honoraria, Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding; Acerta: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding. Andorsky: Genetech: Research Funding; Gilead: Research Funding; Celgene: Research Funding; AstraZeneca: Consultancy; CTI: Research Funding. Melear: Texas Oncology: Employment; DARA: Speakers Bureau. Kolibaba: Atara Bio: Consultancy; AbbVie, Acerta, Celgene, Genentech, Gilead, Janssen, Novartis, Pharmacyclics, Seattle Genetics, TG Therapeutics: Research Funding; Verastem: Honoraria. Yimer: Clovis Oncology: Equity Ownership; Celgene: Honoraria; Seattle Genetics: Honoraria; Janssen: Speakers Bureau; AstraZeneca: Speakers Bureau; Amgen: Consultancy; Puma Biotechnology: Equity Ownership. Burke: Celgene: Consultancy; Roche/Genentech: Consultancy; Gilead: Consultancy. Fanning: Celgene: Speakers Bureau; Takeda: Speakers Bureau. Masud: AbbVie: Employment, Other: Stock/stock options. Zimmerman: AbbVie: Employment, Other: stock or options. Nielsen: AbbVie: Employment, Other: and may hold stock or stock options. Vizkelety: AbbVie: Employment, Other: stock or options. Jiang: AbbVie: Employment, Other: stock or options. Flinn: AbbVie, Seattle Genetics, TG Therapeutics, Verastem: Consultancy; TG Therapeutics, Trillum Therapeutics, Abbvie, ArQule, BeiGene, Curis, FORMA Therapeutics, Forty Seven, Merck, Pfizer, Takeda, Teva, Verastem, Gilead Sciences, Astra Zeneca (AZ), Juno Therapeutics, UnumTherapeutics, MorphoSys, AG: Research Funding; TG Therapeutics, Trillum Therapeutics, Abbvie, ArQule, BeiGene, Curis, FORMA Therapeutics, Forty Seven, Merck, Pfizer, Takeda, Teva, Verastem, Gilead Sciences, Astra Zeneca (AZ), Juno Therapeutics, UnumTherapeutics, MorphoSys, AG: Research Funding; Acerta Pharma, Agios, Calithera Biosciences, Celgene, Constellation Pharmaceuticals, Genentech, Gilead Sciences, Incyte, Infinity Pharmaceuticals, Janssen, Karyopharm Therapeutics, Kite Pharma, Novartis, Pharmacyclics, Portola Pharmaceuticals: Research Funding; F. Hoffmann-La Roche Ltd: Research Funding.