Phase 1b trial of tagraxofusp in combination with azacitidine with or without venetoclax in acute myeloid leukemia.

ABSTRACT: CD123, a subunit of the interleukin-3 receptor, is expressed on ∼80% of acute myeloid leukemias (AMLs). Tagraxofusp (TAG), recombinant interleukin-3 fused to a truncated diphtheria toxin payload, is a first-in-class drug targeting CD123 approved for treatment of blastic plasmacytoid dendritic cell neoplasm. We previously found that AMLs with acquired resistance to TAG were re-sensitized by the DNA hypomethylating agent azacitidine (AZA) and that TAG-exposed cells became more dependent on the antiapoptotic molecule BCL-2. Here, we report a phase 1b study in 56 adults with CD123-positive AML or high-risk myelodysplastic syndrome (MDS), first combining TAG with AZA in AML/MDS, and subsequently TAG, AZA, and the BCL-2 inhibitor venetoclax (VEN) in AML. Adverse events with 3-day TAG dosing were as expected, without indication of increased toxicity of TAG or AZA+/-VEN in combination. The recommended phase 2 dose of TAG was 12 µg/kg/day for 3 days, with 7-day AZA +/- 21-day VEN. In an expansion cohort of 26 patients (median age 71) with previously untreated European LeukemiaNet adverse-risk AML (50% TP53 mutated), triplet TAG-AZA-VEN induced response in 69% (n=18/26; 39% complete remission [CR], 19% complete remission with incomplete count recovery [CRi], 12% morphologic leukemia-free state [MLFS]). Among 13 patients with TP53 mutations, 7/13 (54%) achieved CR/CRi/MLFS (CR = 4, CRi = 2, MLFS = 1). Twelve of 17 (71%) tested responders had no flow measurable residual disease. Median overall survival and progression-free survival were 14 months (95% CI, 9.5-NA) and 8.5 months (95% CI, 5.1-NA), respectively. In summary, TAG-AZA-VEN shows encouraging safety and activity in high-risk AML, including TP53-mutated disease, supporting further clinical development of TAG combinations. The study was registered on ClinicalTrials.gov as #NCT03113643.

Prognostic and predictive role of gene mutations in chronic lymphocytic leukemia: results from the pivotal phase III study COMPLEMENT1.

Next generation sequencing studies in Chronic lymphocytic leukemia (CLL) have revealed novel genetic variants that have been associated with disease characteristics and outcome. The aim of this study was to evaluate the prognostic value of recurrent molecular abnormalities in patients with CLL. Therefore, we assessed their incidences and associations with other clinical and genetic markers in the prospective multicenter COMPLEMENT1 trial (treatment naive patients not eligible for intensive treatment randomized to chlorambucil (CHL) vs. ofatumumab-CHL (O-CHL)). Baseline samples were available from 383 patients (85.6%) representative of the total trial cohort. Mutations were analyzed by amplicon-based targeted next generation sequencing (tNGS). In 52.2% of patients we found at least one mutation and the incidence was highest in NOTCH1 (17.0%), followed by SF3B1 (14.1%), ATM (11.7%), TP53 (10.2%), POT1 (7.0%), RPS15 (4.4%), FBXW7 (3.4%), MYD88 (2.6%) and BIRC3 (2.3%). While most mutations lacked prognostic significance, TP53 (HR2.02,p<0.01), SF3B1 (HR1.66,p=0.01) and NOTCH1 (HR1.39,p=0.03) were associated with inferior PFS in univariate analysis. Multivariate analysis confirmed the independent prognostic role of TP53 for PFS (HR1.71,p=0.04) and OS (HR2.78,p=0.02) and of SF3B1 for PFS only (HR1.52,p=0.02). Notably, NOTCH1 mutation status separates patients with a strong and a weak benefit from ofatumumab addition to CHL (NOTCH1wt:HR0.50,p<0.01, NOTCH1mut:HR0.81,p=0.45). In summary, TP53 and SF3B1 were confirmed as independent prognostic and NOTCH1 as a predictive factor for reduced ofatumumab efficacy in a randomized chemo (immune)therapy CLL trial. These results validate NGS-based mutation analysis in a multicenter trial and provide a basis for expanding molecular testing in the prognostic workup of patients with CLL. ClinicalTrials.gov registration number: NCT00748189.

Ofatumumab plus fludarabine and cyclophosphamide in relapsed chronic lymphocytic leukemia: results from the COMPLEMENT 2 trial.

In this multicenter, open-label, phase III study, patients with relapsed chronic lymphocytic leukemia (CLL) were randomized (1:1) to receive ofatumumab plus fludarabine and cyclophosphamide (OFA + FC) or FC alone; the primary endpoint being progression-free survival (PFS) assessed by an independent review committee (IRC). Between March 2009 and January 2012, 365 patients were randomized (OFA + FC: n = 183; FC: n = 182). Median IRC-assessed PFS was 28.9 months with OFA + FC versus 18.8 months with FC (hazard ratio = 0.67; 95% confidence interval, 0.51-0.88; p = .0032). Grade ≥3 adverse events (≤60 days after last dose) were reported in 134 (74%) OFA + FC-treated patients compared with 123 (69%) FC-treated patients. Of these, neutropenia was the most common (89 [49%] vs. 64 [36%]). OFA + FC improved PFS with manageable safety for patients with relapsed CLL compared with FC alone, thus providing an alternative treatment option for patients with relapsed CLL. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT00824265).

Health-related quality of life and patient-reported outcomes of ofatumumab plus fludarabine and cyclophosphamide versus fludarabine and cyclophosphamide in the COMPLEMENT 2 trial of patients with relapsed CLL.

Chronic lymphocytic leukemia (CLL) is an incurable disease. Quality of life during treatment and periods of subsequent remission is therefore vital. Health-related quality of life (HRQoL) was compared in relapsed CLL during and after treatment with ofatumumab combined with fludarabine and cyclophosphamide versus fludarabine and cyclophosphamide alone. The European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30 v3 and QLQ-CLL16 were used to assess HRQoL in this open-label, phase 3 study. Improvements in prespecified domains of patient-reported outcomes (Global Health Status [GHS]/HRQoL and B symptom scores) were recorded in both treatment arms after three cycles and were sustained after 18 months of follow-up. The two treatment arms were not significantly different at the nominal 0.05 level for GHS/HRQoL (p = .7278) or B symptoms (p = .5968). Small improvements in quality of life were maintained after therapy. The addition of ofatumumab was without any adverse impact on HRQoL (NCT00824265).

A phase 2, multicenter study investigating ofatumumab and bendamustine combination in patients with untreated or relapsed CLL.

The purpose of this study is to assess the safety and efficacy of the combination of ofatumumab and bendamustine in patients with previously untreated or relapsed chronic lymphocytic leukemia. Patients received IV ofatumumab (cycle 1: 300 mg day 1 and 1,000 mg day 8; cycles 2-6: 1,000 mg on day 1 every 28 days) and IV bendamustine 90 mg m(-2) (previously untreated) or 70 mg m(-2) (relapsed) on days 1 and 2 of each 28-day cycle, for up to 6 cycles. Forty-four previously untreated and 53 relapsed patients were enrolled. Median age was 62.5 years (previously untreated) and 68 years (relapsed); relapsed patients had received a median of 1 (range 1-11) prior therapy. The investigator-assessed overall response rate was 95% (43% complete response [CR]) for the previously untreated, and 74% (11% CR) for the relapsed patients. The regimen was well tolerated with 89% (previously untreated) and 85% (relapsed patients) receiving all 6 cycles. No unexpected toxicities were reported. Grade 3/4 events occurred in 57% of previously untreated, and 72% of relapsed patients. At ∼29 months' follow-up, the median progression-free survival (PFS) was not reached for the previously untreated population, and the 28-month PFS estimate was 72.3%. The median PFS for the relapsed population was 22.5 months (95% CI: 14.0-27.3 months). The combination of ofatumumab and bendamustine was well tolerated and effective in these previously untreated or relapsed populations. Am. J. Hematol. 91:900-906, 2016. © 2016 Wiley Periodicals, Inc.

Ofatumumab retreatment and maintenance in fludarabine-refractory chronic lymphocytic leukaemia patients.

There are limited data on retreatment with monoclonal antibodies (mAb) in patients with chronic lymphocytic leukaemia (CLL). In a pivotal study, ofatumumab (human anti-CD20 mAb) monotherapy demonstrated a 47% objective response rate (ORR) in fludarabine refractory CLL patients. From this study, a subset of 29 patients who had at least stable disease and then progressed were retreated with eight weekly ofatumumab infusions (induction treatment period), followed by monthly infusions for up to 2 years (maintenance treatment period). The ORR after 8 weeks of induction retreatment was 45% and 24% had continued disease control after maintenance at 52 weeks. Efficacy and safety of the retreated patients were compared with their initial results in the pivotal study. Response duration was 24.1 months vs. 6.8 months; time to next therapy was 14.8 months vs. 12.3 months; and progression-free survival was 7.4 months vs. 7.9 months (medians). Upon retreatment, 72% had infusion reactions, mostly Grade 1-2. Three patients had fatal infections. In summary, ofatumumab retreatment and maintenance therapy was feasible in patients with heavily pretreated CLL and appeared to result in more durable disease control than initial ofatumumab treatment in this subset of patients who may have a more favourable disease profile.

Chlorambucil plus ofatumumab versus chlorambucil alone in previously untreated patients with chronic lymphocytic leukaemia (COMPLEMENT 1): a randomised, multicentre, open-label phase 3 trial.

BACKGROUND: Treatment for patients with chronic lymphocytic leukaemia who are elderly or who have comorbidities is challenging because fludarabine-based chemoimmunotherapies are mostly not suitable. Chlorambucil remains the standard of care in many countries. We aimed to investigate whether the addition of ofatumumab to chlorambucil could lead to better clinical outcomes than does treatment with chlorambucil alone, while also being tolerable for patients who have few treatment options. METHODS: We carried out a randomised, open-label, phase 3 trial for treatment-naive patients with chronic lymphocytic leukaemia in 109 centres in 16 countries. We included patients who had active disease needing treatment, but in whom fludarabine-based treatment was not possible. We randomly assigned patients (1:1) to receive oral chlorambucil (10 mg/m(2)) on days 1-7 of a 28 day treatment course or to receive chlorambucil by this schedule plus intravenous ofatumumab (cycle 1: 300 mg on day 1 and 1000 mg on day 8; subsequent cycles: 1000 mg on day 1) for three to 12 cycles. Assignment was done with a randomisation list that was computer generated at GlaxoSmithKline, and was stratified, in a block size of two, by age, disease stage, and performance status. The primary endpoint was progression-free survival in the intention-to-treat population and assessment was done by an independent review committee that was masked to group assignment. The study is registered with ClinicalTrials.gov, number NCT00748189. FINDINGS: We enrolled 447 patients, median age 69 years (range 35-92). Between Dec 22, 2008, and May 26, 2011, we randomly assigned 221 patients to chlorambucil plus ofatumumab and 226 patients to chlorambucil alone. Median progression-free survival was 22·4 months (95% CI 19·0-25·2) in the group assigned to chlorambucil plus ofatumumab compared with 13·1 months (10·6-13·8) in the group assigned to chlorambucil only (hazard ratio 0·57, 95% CI 0·45-0·72; p<0·0001). Grade 3 or greater adverse events were more common in the chlorambucil plus ofatumumab group (109 [50%] patients; vs 98 [43%] given chlorambucil alone), with neutropenia being the most common event (56 [26%] vs 32 [14%]). Grade 3 or greater infections had similar frequency in both groups. Grade 3 or greater infusion-related adverse events were reported in 22 (10%) patients given chlorambucil plus ofatumumab. Five (2%) patients died during treatment in each group. INTERPRETATION: Addition of ofatumumab to chlorambucil led to clinically important improvements with a manageable side-effect profile in treatment-naive patients with chronic lymphocytic leukaemia who were elderly or had comorbidities. Chlorambucil plus ofatumumab is therefore an important treatment option for these patients who cannot tolerate more intensive therapy. FUNDING: GlaxoSmithKline, Genmab A/S.

A multicentre, phase II trial of ofatumumab monotherapy in relapsed/progressive diffuse large B-cell lymphoma.

This international, multicentre phase II study was conducted to assess ofatumumab, a human anti-CD20 monoclonal antibody, in patients with relapsed/progressive diffuse large B-cell lymphoma (DLBCL) who were ineligible for autologous stem cell transplantation (TI) or who had relapse/progression after transplantation (PT). Eighty-one patients received ofatumumab 300 mg intravenously (IV) on Day 1, followed by seven weekly IV infusions of 1000 mg. Patients in the TI and PT groups had received a median of 3 (range, 1-7) and 5 (range, 2-7) prior therapies, respectively. One-third of patients did not respond to the last prior therapy, and 53% had failed two or more rituximab-containing therapies. Overall response rate was 13% for the TI group (seven partial responses) and 8% for the PT group (two complete responses). Median progression-free survival was 2·6 months, and median duration of response was 9·5 months. The most common Grade 3-4 adverse events were neutropenia (11%), leucopenia (6%), lymphopenia (6%) and thrombocytopenia (6%). Sixteen deaths have been reported, with disease progression as the most common cause of death. In conclusion, ofatumumab monotherapy was well tolerated and provided clinical benefit to some DLBCL patients in this study.

Ofatumumab, the first human anti-CD20 monoclonal antibody for the treatment of B cell hematologic malignancies.

Ofatumumab is the first human anti-CD20 monoclonal antibody to be approved for patients in the United States and the European Union. Ofatumumab received accelerated approval from the U.S. Food and Drug Administration in October 2009 and was granted a conditional marketing authorization by the European Medicines Agency in April 2010 for the treatment of patients with chronic lymphocytic leukemia (CLL) refractory to fludarabine and alemtuzumab, based on interim results of a pivotal phase 2 trial. Preliminary positive results for ofatumumab in combination with chemotherapy in patients with CLL are currently being confirmed in larger randomized trials in both the frontline setting and the relapsed/refractory setting. Ofatumumab has also shown potential in treating B cell non-Hodgkin's lymphoma, such as follicular lymphoma (FL), diffuse large B cell lymphoma (DLBCL), and Waldenström's macroglobulinemia. Additional trials are ongoing to confirm activity of ofatumumab as monotherapy and in combination with chemotherapy in patients with FL or DLBCL.

Ofatumumab is active in patients with fludarabine-refractory CLL irrespective of prior rituximab: results from the phase 2 international study.

Ofatumumab, the human CD20 monoclonal antibody that binds a distinct epitope from rituximab, has demonstrated clinical benefit as monotherapy for patients with chronic lymphocytic leukemia refractory to fludarabine and alemtuzumab (FA-ref) and patients refractory to fludarabine with bulky (> 5 cm) lymph nodes (BF-ref). To potentially gain insight into outcomes in patients previously treated with or refractory to rituximab, we performed an ad hoc retrospective analysis in the final 96 FA-ref and 111 BF-ref patients. There were 117 patients previously treated with rituximab (98 rituximab-refractory); 89 patients were rituximab-naive. For rituximab-treated, rituximab-refractory, and rituximab-naive patients, overall response rate was 43%, 44%, and 53%; median progression-free survival was 5.3, 5.5, and 5.6 months; and median overall survival was 15.5, 15.5, and 20.2 months. There were no significant differences in ofatumumab-related infusion reactions, or hematologic or infectious adverse events between subgroups. In summary, ofatumumab monotherapy was effective and well tolerated in patients with fludarabine-refractory chronic lymphocytic leukemia, including in patients with previous rituximab exposure. This trial was registered at www.clinicaltrials.gov as #NCT00349349.