Sunil Iyengar

Bromodomain inhibitor OTX015 in patients with lymphoma or multiple myeloma: a dose-escalation, open-label, pharmacokinetic, phase 1 study

BACKGROUND The first-in-class small molecule inhibitor OTX015 (MK-8628) specifically binds to bromodomain motifs BRD2, BRD3, and BRD4 of bromodomain and extraterminal (BET) proteins, inhibiting them from binding to acetylated histones, which occurs preferentially at super-enhancer regions that control oncogene expression. OTX015 is active in haematological preclinical entities including leukaemia, lymphoma, and myeloma. We aimed to establish the recommended dose of OTX015 in patients with haematological malignancies. We report the results from a cohort of patients with lymphoma or multiple myeloma (non-leukaemia cohort). METHODS In this dose-escalation, open-label, phase 1 study, we recruited patients from seven university hospital centres (in France [four], Switzerland [one], UK [one], and Italy [one]). Adult patients with non-leukaemia haematological malignancies who had disease progression on standard therapies were eligible to participate. Patients were treated with oral OTX015 once a day continuously over five doses (10 mg, 20 mg, 40 mg, 80 mg, and 120 mg), using a conventional 3 + 3 design, with allowance for evaluation of alternative administration schedules. The primary endpoint was dose-limiting toxicity (DLT) in the first treatment cycle (21 days). Secondary objectives were to evaluate safety, pharmacokinetics, and preliminary clinical activity of OTX015. The study is ongoing and is registered with ClinicalTrials.gov, number NCT01713582. FINDINGS Between Feb 4, 2013, and Sept 5, 2014, 45 patients (33 with lymphoma and 12 with myeloma), with a median age of 66 years (IQR 55-72) and a median of four lines of prior therapy (IQR 3-5), were enrolled and treated. No DLTs were observed in the doses up to and including 80 mg once a day (first three patients). We then explored a schedule of 40 mg twice a day (21 of 21 days). DLTs were reported in five of six patients receiving OTX015 at this dose and schedule (all five patients had grade 4 thrombocytopenia). We explored various schedules at 120 mg once a day but none was tolerable, with DLTs of thrombocytopenia, gastrointestinal events (diarrhoea, vomiting, dysgeusia, mucositis), fatigue, and hyponatraemia in 11 of 18 evaluable patients. At this point, the Safety Monitoring Committee decided to establish the feasibility of 80 mg once a day on a continuous basis, and four additional patients were enrolled at this dose. DLTs (grade 4 thrombocytopenia) was noted in two of the patients. In light of these DLTs and other toxicities noted at 120 mg, the dose of 80 mg once a day was selected, although on a schedule of 14 days on, 7 days off. Common toxic effects reported in the study were thrombocytopenia (43 [96%] patients), anaemia (41 [91%]), neutropenia (23 [51%]), diarrhoea (21 [47%]), fatigue (12 [27%]), and nausea (11 [24%]). Grade 3-4 adverse events were infrequent other than thrombocytopenia (26 [58%]). OTX015 plasma peak concentrations and areas under the concentration versus time curve increased proportionally with dose. Trough concentrations increased less than proportionally at lower doses, but reached or exceeded the in-vitro active range at 40 mg twice a day and 120 mg once a day. Three patients with diffuse large B-cell lymphoma achieved durable objective responses (two complete responses at 120 mg once a day, and one partial response at 80 mg once a day), and six additional patients (two with diffuse large B-cell lymphoma, four with indolent lymphomas) had evidence of clinical activity, albeit not meeting objective response criteria. INTERPRETATION The once-daily recommended dose for oral, single agent oral OTX015 in patients with lymphoma is 80 mg on a 14 days on, 7 days off schedule, for phase 2 studies. OTX015 is under evaluation in expansion cohorts using this intermittent administration (14 days every 3 weeks) to allow for recovery from toxic effects. FUNDING Oncoethix GmbH (a wholly owned subsidiary of Merck Sharp & Dohme Corp).

P110α-mediated constitutive PI3K signaling limits the efficacy of p110δ-selective inhibition in mantle cell lymphoma, particularly with multiple relapse

Phosphoinositide-3 kinase (PI3K) pathway activation contributes to mantle cell lymphoma (MCL) pathogenesis, but early-phase studies of the PI3K p110δ inhibitor GS-1101 have reported inferior responses in MCL compared with other non-Hodgkin lymphomas. Because the relative importance of the class IA PI3K isoforms p110α, p110β, and p110δ in MCL is not clear, we studied expression of these isoforms and assessed their contribution to PI3K signaling in this disease. We found that although p110δ was highly expressed in MCL, p110α showed wide variation and expression increased significantly with relapse. Loss of phosphatase and tensin homolog expression was found in 16% (22/138) of cases, whereas PIK3CA and PIK3R1 mutations were absent. Although p110δ inhibition was sufficient to block B-cell receptor-mediated PI3K activation, combined p110α and p110δ inhibition was necessary to abolish constitutive PI3K activation. In addition, GDC-0941, a predominantly p110α/δ inhibitor, was significantly more active compared with GS-1101 against MCL cell lines and primary samples. We found that a high PIK3CA/PIK3CD ratio identified a subset of primary MCLs resistant to GS-1101 and this ratio increased significantly with relapse. These findings support the use of dual p110α/p110δ inhibitors in MCL and suggest a role for p110α in disease progression.

EZH2 Y641 mutations in follicular lymphoma

We would like to acknowledge Martina Seiffert, Danilo Allegra, Angela Philippen, Bettina Klohs, Lars Bullinger, Stefan Fröhling and Claudia Scholl for helpful discussions and Frederic Blond for the bioinformatics support. We would also like to acknowledge the excellent collaboration with Bernd Korn from the German Cancer Research Center core facility Genome and Proteome. This work was supported by funding from DJCLS SP 08/05, DJCLS R 06/13, the Helmholtz Alliance for Systems Biology and the Max-Eder-Nachwuchsgruppenprogramm of the Deutsche Krebshilfe (No. 107239).

Efficacy of venetoclax monotherapy in patients with relapsed, refractory mantle cell lymphoma post BTK inhibitor therapy

Mantle cell lymphoma (MCL), an aggressive B-cell malignancy accounting for 6% of non-Hodgkin lymphomas, remains incurable with standard therapy. Despite the approval of bortezomib,[1][1] temsirolimus,[2][2] lenalidomide,[3][3] ibrutinib[4][4] and acalabrutinib,[5][5] patients with relapsed,

Guideline for the treatment of chronic lymphocytic leukaemia: A British Society for Haematology Guideline

Anna H. Schuh, Nilima Parry-Jones, Niamh Appleby, Adrian Bloor, Claire E. Dearden, Christopher Fegan, George Follows, Christopher P. Fox, Sunil Iyengar, Ben Kennedy, Helen McCarthy, Helen M. Parry, Piers Patten, Andrew R. Pettitt, Ingo Ringshausen, Renata Walewska and Peter Hillmen NIHR BRC Oxford Molecular Diagnostic Centre, Oxford University Hospitals NHS Trust and Department of Oncology, University of Oxford, John Radcliffe Hospital, Oxford, Department of Haematology, Aneurin Bevan University Health Board, Abergavenny, Haematology, Christie Hospital, Manchester, Haematology, Royal Marsden Hospital NHS Trust, London, Cardiff & Vale University Health Board, Cardiff, Haematology, Addenbrooke’s Hospital, Cambridge, Clinical Haematology, Nottingham University Hospitals NHS Trust, Nottingham, Haematology, Royal Marsden NHS Trust, Sutton, Department of Haematology, University Hospital Leicester, Leicester, Haematology, Bournemouth and Christchurch Hospitals, Bournemouth, NIHR-ACL Haematology, University of Birmingham, Birmingham, Kings College Hospital, London, UK, Clatterbridge Cancer Centre NHS Foundation Trust, Liverpool, University of Cambridge, Cambridge, and Haematology, Leeds Teaching Hospital NHS Trust, Leeds, UK

Extramedullary haematopoiesis in chronic lymphocytic leukaemia

A 69-year-old man with refractory chronic lymphocytic leukaemia (CLL) presented with shortness of breath 1 month after starting treatment with the Bruton Tyrosine Kinase inhibitor, ibrutinib. CLL had been diagnosed 26 years previously; after a period of expectant management the patient had been treated sequentially with chlorambucil, fludarabine, cyclophosphamide-doxorubicin-vincristine-prednisolone, high dose methylprednisolone, and rituximab with bendamustine. In terms of prognostic markers, CD38 was positive by flow cytometry, while molecular genetics demonstrated a mutated IGHV gene. On his most recent assessment, 66% of cells exhibited del(13q) by fluorescence in situ hybridization (FISH). There was no loss of TP53 by FISH, but molecular genetic analysis demonstrated a mutation in exon 7 of the gene. Bone marrow trephine biopsy demonstrated hypercellularity at nearly 100%; normal haematopoietic cells were largely replaced by a lymphoid infiltrate, consistent with CLL, which constituted 60–70% of the cellularity. There was grade 2/4 fibrosis. Computerized tomography (CT) scanning demonstrated widespread small volume lymphadenopathy, with gross splenomegaly at 21 cm. In addition, multiple lobulated pleural masses were noted bilaterally, measuring between 3 9 and 8 1 cm in diameter, with moderate bilateral pleural effusions (left – arrows indicate pleural masses). On re-presentation with progressive dyspnoea 4 weeks after starting ibrutinib, chest radiography demonstrated a large left-sided pleural effusion, which was drained. The pleural fluid was bloodstained and immunophenotyping showed the presence of clonal B lymphocytes consistent with CLL. However, a repeat CT scan showed that, while the spleen and lymph nodes had reduced in size, consistent with a good response to ibrutinib, the lobulated pleural masses had not changed. Owing to concern that the pleural lesions could represent a second pathological process, a CT-guided biopsy was undertaken. Histological examination of the biopsy revealed aggregates of small lymphocytes admixed with scattered megakaryocytes, together with clusters of immature myeloid and erythroid cells. There was no evidence of a second malignancy. The small lymphocytes were CD20positive B cells co-expressing CD5 and CD23; the findings were those of B-CLL with associated extramedullary haematopoiesis (right). Isolated pleural extramedullary haematopoiesis is uncommon. On questioning, the patient gave a history of trauma to the ribs several years previously. There are isolated case reports of trauma-related extramedullary haematopoiesis, but these have only been in the pelvis, which is the most active site of haematopoiesis. In this case, therefore, it seems most likely that the pleural extramedullary haematopoiesis was a result of the patient’s known heavy bone marrow infiltration; the history of rib fractures is the only plausible explanation for this being the site at which the extramedullary haematopoiesis occurred.

Abstract 4489: The activity of novel, potent, selective PI3K/mTOR pathway inhibitors in B-cell malignancies

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Background: Activation of the PI3K pathway is implicated in a number of tumour types, including haematological malignancies. Agents that target this pathway at different levels (e.g. RTK, PI3K, mTOR etc) have shown promising activity in preclinical models and in early phase trials. We have therefore investigated the activity of novel, potent, pan- and isoform-selective PI3K pathway inhibitors in lymphoma and myeloma models. Methods: Compounds studied included those with selectivity for mTOR (INK128, mTOR IC50 1.6 nM), PI3Kδ/γ (INK713, INK1048, IC50s 50 nM for others) and PI3Kδ/γ/β (INK1138, IC50s <10 nM for each isoform). IC87114 (δ- selective), GDC-0941 (α/δ selective), rapamycin and doxorubicin were included as comparators. Agents were studied in a panel of lymphoma and myeloma cell lines, in normal PBMCs and in primary tumours cultured with stromal cells. Effects on cell viability and proliferation were assessed using the Guava Viacount assay, on apoptosis induction by annexin V labelling, and on cell cycle distribution by flow cytometry. PI3K pathway activity and inhibition was determined by Western blotting as well as mass spectrometry. Results: In cell lines, inhibition of mTOR by INK128 resulted in potent inhibition of cell proliferation, in many at concentrations as low as 10 nM. Selective PI3K inhibitors were less potent anti-proliferative agents, although activity was seen in cells with activation of the PI3K pathway as determined by western blot analysis. For all compounds tested, the major impact was on cell proliferation rather than cell viability. PI3K inhibitors showed little effect on cell viability at concentrations < 1µM. The effect of these compounds in primary mantle cell lymphoma, follicular lymphoma, chronic lymphocytic leukaemia and myeloma samples was variable, both between and within tumour types, possibly due to differences in basal PI3K pathway activity. Effects in normal PBMCs were markedly different to those seen in tumour cells, with a concentration-dependent increase in cell number with either mTOR or PI3K inhibition. Conclusion: Selective PI3K pathway inhibition, particularly at the level of mTOR, results in cytostatic, and at higher concentrations cytotoxic, responses in haematological malignancies. The variable activity of these compounds between cell lines and primary samples suggests it will be important to characterise the activity of the PI3K pathway in individual tumours to identify patients likely to benefit from such agents. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4489.