Updated Preliminary Results of a Phase 1b Dose Escalation and Dose Expansion Study of Tirabrutinib in Combination with Entospletinib in Patients with B-Cell Lymphoma
Authors: Salles Gilles , Dyer Martin J.S. , Hodson Daniel James , Bouabdallah Krimo , Ysebaert Loic , Cartron Guillaume , Davies Andrew John , Danilov Alexey V , Fegan Christopher , Kio Ebenezer A , Huang Xi , Mitra Siddhartha , Rule Simon , Morschhauser Franck 
Published: October 2019

Introduction: Tirabrutinib (TIRA; GS/ONO-4059) is a selective Bruton's tyrosine kinase (BTK) inhibitor. Entospletinib is a selective inhibitor of spleen tyrosine kinase (SYK). Both have single agent activity in lymphoma and updated results from the combination of TIRA+ENTO from this ongoing phase 1b study (NCT02457598) are reported here.

Methods: Patients with previously treated non-germinal-center B-cell type (non-GCB) diffuse large B-cell lymphoma (DLBCL) or two prior lines of therapy for follicular lymphoma (FL), small lymphocytic lymphoma (SLL), mantle cell lymphoma (MCL), marginal zone lymphoma (MZL), or Waldenstrom's macroglobulinemia (WM) and no prior exposure to targeted inhibitors were eligible for enrollment. Patients were enrolled using a 3+3 dose escalation design with either ENTO 200mg or 400mg QD and doses of TIRA ranging from 20mg to 160mg QD. Cohorts were subsequently enrolled at multiple dose levels to evaluate disease-specific safety and efficacy.

Results: As of March 5, 2018, 72 patients have enrolled on the combination. The median age was 67.5 years (range: 30-90) and the disease subtypes for patients enrolled were non-GCB DLBCL (n=32), FL (18), MZL (5), WM (7), SLL (2), MCL (8). No maximum tolerated dose and no dose-response relationship was observed with daily dosing of both agents at the dose levels evaluated.

For patients with non-GCB DLBCL (n=32), the median number of prior therapies is 3 (range 1-7). The median duration of treatment is 8 weeks (range 2-98.1) with 6 patients still on treatment. 6/27 (22%) of the evaluable patients achieved a response; best overall response is shown in table 1.

For patients with indolent NHL (n=40), the median number of prior therapies is 3 (range 1-6). The median duration of treatment is 36 weeks (range 0.1-116), with 29 patients still on treatment. 19/31 (61%) of the evaluable patients achieved a response with best overall response by indication shown in table 1.

The most common treatment-emergent adverse events (AEs) are listed in table 2. Of the 71 patients who have received treatment on study, AEs led to treatment interruption or discontinuation of both study drugs in 10 and 1 patients, respectively. There have been 4 deaths on study, all due to disease progression.

Conclusion: Once-daily dosing of TIRA up to 160 mg in combination with ENTO up to 400 mg QD was safe and well tolerated. Early results show activity in combination across all indications treated.

Disclosures

Salles: Novartis: Consultancy, Honoraria; Epizyme: Honoraria; Abbvie: Honoraria; Servier: Honoraria, Other: Advisory Board; Celgene: Honoraria, Other: Advisory Board, Research Funding; Pfizer: Honoraria; Merck: Honoraria; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; Gilead: Honoraria, Other: Advisory Board; BMS: Honoraria, Other: Advisory Board; Morphosys: Honoraria; Acerta: Honoraria; Janssen: Honoraria, Other: Advisory Board; Servier: Honoraria; Takeda: Honoraria; Amgen: Honoraria. Dyer:Gilead Sciences, Inc.: Honoraria, Research Funding. Hodson:Gilead Sciences, Inc.: Research Funding. Ysebaert:Roche: Consultancy, Research Funding; Gilead Sciences, Inc.: Consultancy, Research Funding; Janssen: Consultancy, Research Funding. Cartron:Sanofi: Honoraria; Celgene: Consultancy, Honoraria; Janssen: Honoraria; Roche: Consultancy, Honoraria; Gilead Sciences: Honoraria. Davies:Acerta Pharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead Sciences, Inc.: Honoraria, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Research Funding; ADC-Therapeutics: Research Funding; Janssen: Honoraria; Karyopharma: Membership on an entity's Board of Directors or advisory committees. Danilov:Aptose Biosciences: Research Funding; Gilead Sciences: Consultancy, Research Funding; Verastem: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Bayer Oncology: Consultancy, Research Funding; Takeda Oncology: Research Funding; TG Therapeutics: Consultancy; Astra Zeneca: Consultancy. Fegan:Roche: Honoraria; Abbvie: Honoraria; Gilead Sciences, Inc.: Honoraria; Napp: Honoraria; Janssen: Honoraria. Huang:Gilead Sciences, Inc.: Employment. Mitra:Gilead Sciences, Inc.: Employment. Rule:Roche: Honoraria; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Gilead Sciences, Inc.: Membership on an entity's Board of Directors or advisory committees; Celltrion: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau. Morschhauser:Janssen: Other: Scientific Lectures; Epizyme: Consultancy; Roche: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees.