Single-agent mosunetuzumab shows durable complete responses in patients with relapsed or refractory B-cell lymphomas: Phase I dose-escalation study

PURPOSE: Mosunetuzumab is a bispecific antibody targeting CD20 and CD3 that redirects T cells to engage and eliminate malignant B cells and is being developed for relapsed or refractory (R/R) B-cell non-Hodgkin lymphomas (B-NHLs). METHODS: This first-in-human trial (ClinicalTrials.gov identifier: NCT02500407) evaluated the safety and tolerability and efficacy of mosunetuzumab in patients with R/R B-NHL and established the recommended phase II dose. Data from dose escalation are presented. Single-agent mosunetuzumab was administered intravenously in 3-week cycles, at full dose in cycle 1 day 1 (group A) or with ascending (step-up) doses during cycle 1 on days 1, 8, and 15 (group B), for eight or 17 cycles on the basis of tumor response. RESULTS: Two hundred thirty patients were enrolled. Doses up to 2.8 mg and 60 mg were assessed in groups A and B, respectively; maximum tolerated dose was not exceeded. In group B (n = 197), common adverse events (≥ 20% of patients) were neutropenia (28.4%), cytokine release syndrome (27.4%), hypophosphatemia (23.4%), fatigue (22.8%), and diarrhea (21.8%). Cytokine release syndrome was mostly low-grade (grade ≥ 3: 1.0%) and mainly confined to cycle 1. Across the doses investigated (group B), best overall response rates were 34.9% and 66.2% in patients with aggressive and indolent B-NHL, respectively, and complete response rates were 19.4% and 48.5%. Among patients with a complete response, the median duration of response was 22.8 months (95% CI, 7.6 to not estimable) and 20.4 (95% CI, 16 to not estimable) in patients with aggressive and indolent B-NHL, respectively. CONCLUSION: Mosunetuzumab, administered with step-up dosing, has a manageable safety profile and induces durable complete responses in R/R B-NHL. The expansion stage of the study is ongoing at the dose level of 1/2/60/60/30 mg selected for further study

Dose-finding study of ibrutinib and venetoclax in relapsed or refractory mantle cell lymphoma

Relapsed Mantle cell lymphoma (MCL) is often treated with Bruton\u27s tyrosine kinase inhibitors (BTKi); however, post-BTKi relapse can be challenging. Adding venetoclax (VEN) to ibrutinib (IBR) has shown synergy in preclinical MCL models. Prior MCL studies of the combination show promising efficacy but have conducted limited dose finding. We sought to identify the optimal dosing combination, based on efficacy and toxicity, utilizing a continual reassessment method of 6 combinations of IBR (280 mg, 420 mg, and 560 mg by mouth daily) and VEN (max dose of 200 mg and 400 mg by mouth daily). Eligible participants were not previously exposed to BTKi and not high risk for tumor lysis syndrome (TLS). VEN, initiated first at 100 mg, then at 20 mg by mouth daily after a TLS event, was started prior to adding IBR and ramped-up based on the dose level assigned. Combination treatment continued for six 28-day cycles. Thirty-five participants were enrolled and treated. One TLS event occurred with starting dose of 100 mg VEN; no TLS was seen with 20 mg. The optimal dosing combination was considered to be VEN 200 mg and IBR 420 mg with an overall response rate (ORR) of 93.8% (95% CI: 73.6% to 99.7%) and DLT incidence of 6.2% (95% CI: 0.3% to 26.4%). ORR for all arms was 82.3% (28/34; 95% CI: 65.5% to 93.2%) with a complete response (CR) rate of 42.4% (14/33; 95% CI: 25.5% to 60.8%). A participant was not allocated to IBR 560 mg and VEN 400 mg. ORR benefit was not seen with higher dosing combinations and toxicity was higher; a comparison made within the limitations of small cohorts. Resistance was seen in nearly all arms. This trial was registered at www.clinicaltrials.gov #NCT02419560

Bendamustine, etoposide, and dexamethasone to mobilize peripheral blood hematopoietic stem cells for autologous transplantation in non-Hodgkin lymphoma

BACKGROUND: Bendamustine is a chemotherapeutic agent that has shown broad activity in patients with lymphoid malignancies. It contains both alkylating and nucleoside analog moieties, and thus, is not commonly used for stem cell mobilization due to concerns that it may adversely affect stem cell collection. Here we describe the lymphoma subset of a prospective, non-randomized phase II study of bendamustine, etoposide, and dexamethasone (BED) as a mobilization agent for lymphoid malignancies. METHODS: This subset analysis includes diffuse large B-cell lymphoma (N=3), follicular lymphoma (N=1), primary mediastinal B-cell lymphoma (N=1), and NK/T-cell lymphoma (N=1). Patients received bendamustine (120 mg/m(2) IV d 1, 2), etoposide (200 mg/m(2) IV d 1-3), and dexamethasone (40 mg PO d 1-4) followed by filgrastim (10 mcg/kg/d sc. through collection). RESULTS: We successfully collected stem cells from all patients, with a median of 7.9x10(6)/kg of body weight (range, 4.4 to 17.3x10(6)/kg) over a median of 1.5 days (range, 1 to 3) of apheresis. All patients who received transplants were engrafted using kinetics that were comparable to those of other mobilization regimens. Three non-hematologic significant adverse events were observed in one patient, and included bacterial sepsis (grade 3), tumor lysis syndrome (grade 3), and disease progression (grade 5). CONCLUSION: For non-Hodgkin lymphoma, mobilization with bendamustine is safe and effective

Bendamustine (Treanda®), Etoposide and Dexamethasone (BED) Followed by GCSF Effectively Mobilizes Autologous Peripheral Blood Hematopoietic Stem Cells

Abstract 4126 Background: High dose chemotherapy followed by autologous stem cell transplantation (ASCT) is a standard of care for patients with advanced or treatment refractory multiple myeloma (MM) and non-Hodgkin lymphoma (NHL). Stem cell proliferation and mobilization can be enhanced though the addition of myelosuppressive chemotherapy to GCSF administration. Chemotherapeutic agents without cross resistance to prior therapies may support peripheral blood stem cell (PBSC) collection and improve patient outcomes by exacting a more potent direct anti-tumor effect prior to ASCT. Bendamustine (Treanda®) is a synthetic chemotherapeutic agent that shares structural similarities to both purine analog and alkylating agents without significant cross resistance to other compounds in either drug class. Bendamustine appears to have low stem cell toxicity in vitro, is well tolerated, and has activity in MM and NHL. We hypothesized that bendamustine9s activity in patients with disease resistant to first line therapies makes it a logical candidate for chemotherapy based PBSC mobilization. Methods: Patients were eligible if they had relapsed or refractory MM, B-cell NHL or T-cell NHL and were candidates for ASCT. Other criteria included: age >18 years, ANC >1,500/mm 3 , platelets >100,000/mm 3 , adequate renal and hepatic function, 2 IV d 1, 2 - provided along with financial support for this study by Teva Pharmaceuticals), etoposide (200 mg/m 2 IV d 1– 3), dexamethasone (40 mg PO d 1– 4), delivered as an outpatient, followed by filgrastim (10 mcg/kg/day; starting on d 5 through end of collection)]. Apheresis was initiated when peripheral blood CD34 cell counts were >5/μL. The primary endpoint was successful mobilization, defined as collection of >2.0 × 10 6 CD34 cells/kg. Adverse events (AEs) were graded using the CTCAE v4.0. Results: Twenty patients (16 MM, 3 B-cell NHL, 1 NK/T-cell NHL) were treated. The median age was 59 years (range 43–70), and the median number of prior therapies was 1 (range 1–3) for MM and 2 (range 2–3) for NHL patients. All patients (20/20) were successfully mobilized. The median number of CD34 + cells collected was 19.11 × 10 6 /kg (Mean 22.49; range 4.35 to 55.51 × 10 6 ). All MM patients collected >10 × 10 6 CD34 + cells/kg. The median time from BED mobilization therapy to the first day of CD34 stem cell collection was 12 days (mean 12.05; range 10 to 20 days). The median number of days of apheresis was 1 (mean 1.45; range 1 to 4). A predictable pattern of leucocyte nadir and recovery was demonstrated (88% of patients started apheresis between days 10–12). One patient (5%) was given plerixafor and for 2 patients (10%) the dose of GCSF was increased to 16 mcg/kg twice daily. Among the 20 patients mobilized and collected, 12 have thus far undergone ASCT and 100% (12/12) have achieved an unsupported neutrophil count >500/μL at an average of 14.3 days after PBSC infusion and a platelet count >20K/μL at an average of 10 days. Serious AEs (SAEs) were observed in 5 patients and 1 patient died due to disease progression. No unexpected grade 3 or greater treatment related SAEs were seen. Disease response assessments are ongoing. The original protocol design involved 3 agents (bendamustine, dexamethasone and GCSF [BDG]). After the first 3 patients enrolled, the mobilization regimen was modified to include etoposide because BDG did not yield a predictable pattern of leucocyte nadir and recovery, thus complicating timing for apheresis (median time to collection 22 days). The first 3 patients were censored from the analysis, however all 3 patients were successfully mobilized and collected. Conclusions: The initial experience with PBSC mobilization after BED in this phase II study suggests the regimen is safe and effective, while the use of BDG does not yield predictable CD34 kinetics. Time to neutrophil and platelet engraftment after ASCT appears unimpaired when compared with other chemotherapy based mobilization regimens. Large numbers of stem cells were rapidly mobilized and resulted in short durations of apheresis. No patient with MM collected 6 CD34 + cells/kg (sufficient for 2 ASCTs). The regimen was very well tolerated and these findings suggest that the role of bendamustine in PBSC mobilization should be further explored. Disclosures: Green: Teva Pharmaceuticals: Research Funding. Holmberg: Millenium: Research Funding; Otsuka: Research Funding; Merck: Research Funding; Seattle Genetics: Research Funding; Sanofi: Research Funding. Budde: Teva Pharmaceuticals: Research Funding. Gopal: Teva Pharmaceuticals: Research Funding

A phase 2, multicentre, open‐label trial (ACE‐LY‐003) of acalabrutinib in patients with relapsed or refractory marginal zone lymphoma

Summary Acalabrutinib, a Bruton tyrosine kinase inhibitor, demonstrated greater selectivity and improved safety versus ibrutinib in a head‐to‐head trial in relapsed/refractory (R/R) chronic lymphocytic leukaemia. In the R/R marginal zone lymphoma (MZL) cohort (phase 2) of a phase 1b/2 trial (NCT02180711), 43 patients with MZL and at least one prior therapy received acalabrutinib 100 mg twice daily until disease progression or unacceptable toxicity [median age 69 years (range 42–84); median one (1–4) prior systemic regimens]. Median follow‐up was 13.3 months (range 0.5–45.5). Among 40 patients evaluable for response, investigator‐assessed overall response rate was 53% [95% confidence interval (CI) 36%–69%] with five (13%) complete responses. Tumour reduction occurred in 40 (93%) of the treated patients. Median time to response was 2.9 months (median duration of response not estimable). Estimated median progression‐free survival (PFS) was 27.4 months (12‐month PFS rate, 67%). Five patients died (disease progression, n = 4; septic shock, n = 1). Seventeen patients (40%) had grade 3 or higher adverse events (AEs), most commonly neutropenia (14%), anaemia, dyspnoea (7% each), fatigue and thrombocytopenia (5% each). Hypertension occurred in 5%; atrial fibrillation/flutter and major haemorrhage were not reported. AEs led to treatment discontinuation in three (7%) patients. Acalabrutinib was active and well tolerated in patients with R/R MZL

Combining a CD20 chimeric antigen receptor and an inducible caspase 9 suicide switch to improve the efficacy and safety of T cell adoptive immunotherapy for lymphoma.

Modification of T cells with chimeric antigen receptors (CAR) has emerged as a promising treatment modality for human malignancies. Integration of co-stimulatory domains into CARs can augment the activation and function of genetically targeted T cells against tumors. However, the potential for insertional mutagenesis and toxicities due to the infused cells have made development of safe methods for removing transferred cells an important consideration. We have genetically modified human T cells with a lentiviral vector to express a CD20-CAR containing both CD28 and CD137 co-stimulatory domains, a "suicide gene" relying on inducible activation of caspase 9 (iC9), and a truncated CD19 selectable marker. Rapid expansion (2000 fold) of the transduced T cells was achieved in 28 days after stimulation with artificial antigen presenting cells. Transduced T cells exhibited effective CD20-specific cytotoxic activity in vitro and in a mouse xenograft tumor model. Activation of the iC9 suicide switch resulted in efficient removal of transduced T cells both in vitro and in vivo. Our work demonstrates the feasibility and promise of this approach for treating CD20(+) malignancies in a safe and more efficient manner. A phase I clinical trial using this approach in patients with relapsed indolent B-NHL is planned