Acalabrutinib monotherapy in patients with Waldenström macroglobulinemia: a single-arm, multicentre, phase 2 study

BACKGROUND

Chemoimmunotherapy is typically the standard of care for patients with Waldenström macroglobulinemia; however, infectious and hematologic toxic effects are problematic. Acalabrutinib is a selective, potent Bruton tyrosine-kinase inhibitor. The aim of this trial was to evaluate the activity and safety of acalabrutinib in patients with Waldenström macroglobulinemia.

METHODS

This single-arm, multicentre, phase 2 trial was done in 19 European academic centres in France, Italy, Greece, the Netherlands, and the UK, and eight academic centres in the USA. Eligible patients were 18 years or older and had treatment naive (declined or not eligible for chemoimmunotherapy) or relapsed or refractory (at least one previous therapy) Waldenström macroglobulinemia that required treatment, an Eastern Cooperative Oncology Group performance status of 2 or less, and received no previous Bruton tyrosine-kinase inhibitor therapy. Patients received 100 mg oral acalabrutinib twice per day in 28-day cycles until disease progression or unacceptable toxicity. The primary endpoint was investigator-assessed overall response (at least a minor response) according to the 6th International Workshop for Waldenström Macroglobulinemia (IWWM) and the modified 3rd IWWM workshop criteria. The primary outcome and safety were assessed in all patients who received at least one dose of treatment. This study is registered with ClinicalTrials.gov, number NCT02180724, and is ongoing, but no longer enrolling.

FINDINGS

Between Sept 8, 2014, and Dec 24, 2015, 122 patients were assessed for eligibility, of which 106 (87%) patients were given acalabrutinib (14 were treatment naive and 92 had relapsed or refractory disease). With a median follow-up of 27·4 months (IQR 26·0-29·7), 13 (93% [95% CI 66-100]) of 14 treatment naive patients achieved an overall response and 86 (93% [86-98]) of 92 relapsed or refractory patients per both the modified 3rd and 6th IWWM criteria. Seven (50%) of 14 treatment naive patients and 23 (25%) of 92 relapsed or refractory patients discontinued treatment on study. Grade 3-4 adverse events occurring in more than 5% of patients were neutropenia (17 [16%] of 106 patients) and pneumonia (7 [7%]). Grade 3-4 atrial fibrillation occurred in one (1%) patient and grade 3-4 bleeding occurred in three (3%) patients. The most common serious adverse events were lower respiratory tract infection (n=7 [7%]), pneumonia (n=7 [7%]), pyrexia (n=4 [4%]), cellulitis (n=3 [3%]), fall (n=3 [3%]), and sepsis (n=3 [3%]). Pneumonia (n=5 [5%]) and lower respiratory tract infection (n=4 [4%]) were considered treatment related. One treatment-related death was reported (intracranial hematoma).

INTERPRETATION

This study provides evidence that acalabrutinib is active as single-agent therapy with a manageable safety profile in patients with treatment-naive, or relapse or refractory Waldenström macroglobulinemia. Further studies are needed to establish its efficacy against current standard treatments and to investigate whether outcomes can be improved with combination therapies.

FUNDING

Acerta Pharma.

The HMG-CoA inhibitor, simvastatin, triggers in vitro anti-tumour effect and decreases IgM secretion in Waldenstrom macroglobulinaemia

Waldenstrom macroglobulinaemia (WM) is an incurable lymphoplasmacytic lymphoma with secretion of serum monoclonal immunoglobulin M (IgM). We previously showed that patients receiving cholesterol-lowering statins, had the lowest IgM value in a large cohort of patients with WM. Simvastatin, a 3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitor, induced inhibition of proliferation, cytotoxic effect and apoptosis in IgM secreting cell lines as well as in primary CD19(+) WM cells. Interestingly, those effects were reversed by addition of mevalonate and geranylgeranylpyrophosphate, demonstrating that simvastatin inhibited cell growth, survival and IgM secretion on BCWM.1 WM cells by inhibition of geranylgeranylated proteins. Furthermore, simvastatin overcame tumour cell growth induced by co-culture of WM cells with bone-marrow stromal cells. Simvastatin also decreased IgM secretion by BCWM.1 cells at an early time-point that had not affected cell survival. Simvastatin-induced cytotoxicity was preceded by a decrease in Akt (protein kinase B, PKB) and extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) pathways at 18 h. In addition, simvastatin induced an increase in stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) MAPK followed by caspase-8, -9, -3 and poly(ADP-ribose) polymerase (PARP) cleavages at 18 h, leading to apoptosis. Furthermore, simvastatin enhanced the cytotoxicity induced by bortezomib, fludarabine and dexamethasone. Our studies therefore support our earlier observation of statin-mediated anti-WM activity and provide the framework for future clinical trials testing simvastatin in WM.

[Interferences by a monoclonal IgM in biochemical analyses: detection and recommendations]

We present a case of analytical interference on three parameters (lactate dehydrogenase, uric acid and alkalin phosphatase), caused by a monoclonal IgM, evidenced in a patient with Waldenström disease. Mechanism of interference was probably related to the formation of complexes between paraprotein and lithium heparin, which result in precipitation during clinical chemistry assays, inducing a bias in the results. Management recommendations in case of suspicion of interference in clinical chemistry analysis are detailed. Are discussed for the case report, clinical consequences, possible mechanisms and evolution of interference under treatment, according to the concentration of the monoclonal protein.

Protein kinase C inhibitor enzastaurin induces in vitro and in vivo antitumor activity in Waldenstrom macroglobulinemia

Waldenström macroglobulinemia (WM) is an incurable lymphoplasmacytic lymphoma with limited options of therapy. Protein kinase Cbeta (PKCbeta) regulates cell survival and growth in many B-cell malignancies. In this study, we demonstrate up-regulation of PKCbeta protein in WM using protein array techniques and immunohistochemistry. Enzastaurin, a PKCbeta inhibitor, blocked PKCbeta activity and induced a significant decrease of proliferation at 48 hours in WM cell lines (IC(50), 2.5-10 muM). Similar effects were demonstrated in primary CD19(+) WM cells, without cytotoxicity on peripheral blood mononuclear cells. In addition, enzastaurin overcame tumor cell growth induced by coculture of WM cells with bone marrow stromal cells. Enzastaurin induced dose-dependent apoptosis at 48 hours mediated via induction of caspase-3, caspase-8, caspase-9, and PARP cleavage. Enzastaurin inhibited Akt phosphorylation and Akt kinase activity, as well as downstream p-MARCKS and ribosomal p-S6. Furthermore, enzastaurin demonstrated additive cytotoxicity in combination with bortezomib, and synergistic cytotoxicity in combination with fludarabine. Finally, in an in vivo xenograft model of human WM, significant inhibition of tumor growth was observed in the enzastaurin-treated mice (P = .028). Our studies therefore show that enzastaurin has significant antitumor activity in WM both in vitro and in vivo, providing the framework for clinical trials to improve patient outcome in WM.

Molecular sequelae of histone deacetylase inhibition in human malignant B cells

Histone acetylation modulates gene expression, cellular differentiation, and survival and is regulated by the opposing activities of histone acetyltransferases (HATs) and histone deacetylases (HDACs). HDAC inhibition results in accumulation of acetylated nucleosomal histones and induces differentiation and/or apoptosis in transformed cells. In this study, we characterized the effect of suberoylanilide hydroxamic acid (SAHA), the prototype of a series of hydroxamic acid-based HDAC inhibitors, in cell lines and patient cells from B-cell malignancies, including multiple myeloma (MM) and related disorders. SAHA induced apoptosis in all tumor cells tested, with increased p21 and p53 protein levels and dephosphorylation of Rb. We also detected cleavage of Bid, suggesting a role for Bcl-2 family members in regulation of SAHA-induced cell death. Transfection of Bcl-2 cDNA into MM.1S cells completely abrogated SAHA-induced apoptosis, confirming its protective role. SAHA did not induce cleavage of caspase-8, -9, or -3 in MM.1S cells during the early phase of apoptosis, and the pan-caspase inhibitor ZVAD-FMK did not protect against SAHA. Conversely, poly(ADP)ribose polymerase (PARP) was cleaved in a pattern indicative of calpain activation, and the calpain inhibitor calpeptin abrogated SAHA-induced cell death. Importantly, SAHA sensitized MM.1S cells to death receptor-mediated apoptosis and inhibited the secretion of interleukin 6 (IL-6) induced in bone marrow stromal cells (BMSCs) by binding of MM cells, suggesting that it can overcome cell adhesion-mediated drug resistance. Our studies delineate the mechanisms whereby HDAC inhibitors mediate anti-MM activity and overcome drug resistance in the BM milieu and provide the framework for clinical evaluation of SAHA, which is bioavailable, well tolerated, and bioactive after oral administration, to improve patient outcome.

Abnormal expression of hyaluronan synthases in patients with Waldenstrom's macroglobulimenia

Little is known about the biology or spread of Waldenstrom's macroglobulinemia (WM), a lymphoplasmo-proliferative disorder. Hyaluronan synthases (HASs), plasma membrane proteins, synthesize the extracellular matrix molecule hyaluronan (HA), which plays a role in malignant cell migration and the spread of many cancers. Three isoenzymes of HAS-HAS1, HAS2, and HAS3-are detected in humans. Aberrant expression of the HASs is coupled with different abnormalities. We have analyzed the expression pattern of HASs in WM patients. HAS3 was expressed in all patients and healthy donors tested, whereas the expression of HAS1 and HAS2 varied among the WM patients. Additionally, in WM patients, we have detected novel variants of HAS1, one of which was also detected in multiple myeloma (MM) patients. We speculate that HAS1 variants synthesize the intracellular HA ligand for RHAMM (a receptor for HA). RHAMM contributes to genetic instability in MM; therefore, we speculate that it may also contribute to genetic instability in WM. Furthermore, we suggest that overexpression of HAS1 and its variants in combination with HAS3 may form an HA matrix around WM cells, thus preventing their elimination by the immune system, and it promotes their migration and may facilitate the spread of disease.

Hyaluronidase activity in serum of patients with monoclonal gammapathy

Hyaluronidase and hyaluronic acid, two substances thought to be strongly implicated in carcinogenesis, were assessed in the plasma of 35 patients with newly documented monoclonal gammapathy and in 25 control patients. A significant increase was found in plasma hyaluronidase activity in the patients with monoclonal gammapathy. A statistically significant positive correlation was found between hyaluronidase activity and monoclonal immunoglobulin levels in plasma. An increase in serum hyaluronidase activities may be a response to the deleterious effect of hyaluronic acid in cell migration and tumor progression. Further studies are needed to assess the value of hyaluronidase activity as a marker of tumor progression.

Separation of biosynthetic oligosaccharide branch isomers using high-performance liquid chromatography on a porous two-dimensional graphite stationary phase

Oligomannosidic branch isomers (structures differing only in the branch location of a single residue) which are biosynthetic intermediates in yeast and higher eukaryotics have been separated using high-performance liquid chromatography (HPLC) on porous graphatized carbon (PGC) columns, a stationary phase of two-dimensional crystalline carbon. A mixture of two Man6GlcNAc isomers from IgM, which was determined from 1H NMR analysis, was completely separated by PGC-HPLC. Mixtures of larger yeast oligomannosidic branch isomers were also chromatographically resolved using PGC-HPLC. Man10GlcNAc and Man11GlcNAc species from invertase expressed in Pichia pastoris showed three and five peak fractions, respectively, by PGC-HPLC in agreement with the number of isomeric forms from one- and two-dimensional 1H NMR analyses of the individual sized fractions (Trimble, R. B., Atkinson, P. H., Tschopp, J. R., Townsend, R. R., and Maley, F. (1991) J. Biol. Chem. 266, 22807-22817). Selected peak fractions were further analyzed to confirm assignments using matrix- assisted laser-desorption mass spectrometry after digestion with an alpha(1 --> 2)-specific mannosidase (Aspergillus saitoi). PGC-HPLC should prove invaluable for the preparation of singular oligosaccharides to define exoglycosidase and glycosyl transferase branch specificity and for preparing standards to develop more sensitive methods for structural elucidation of oligosaccharides.

Serum concentration and localization in tumor cells of proteasomes in patients with hematologic malignancy and their pathophysiologic significance

The pathophysiologic significance of proteasomes in hematologic malignancies was examined by comparison of the proteasome levels in normal subjects and patients with benign liver diseases. The serum proteasome level measured by enzyme-linked immunosorbent assay was found to be positively correlated with the tumor burden of the patients with hematologic malignancies such as acute leukemia, chronic myelogenous leukemia, non-Hodgkin's lymphoma, and myeloma. Immunohistochemical staining showed that proteasomes were strongly expressed in these tumor cells, especially in the nuclei. These data suggest that the elevated levels of serum proteasomes in these patients are derived from tumor cells, reflect the tumor burden, and so provide prognostic information. However, in patients with benign liver diseases, serum proteasome levels correlated with serum alanine aminotransferase activities, suggesting that in hematologic malignancies associated with liver injury some of the serum proteasomes may originate from hepatocytes. The marked production of proteasomes by malignant blood cells may be involved in transformation and proliferation of these cells.

Lactic dehydrogenase estimation in haematological malignancies

Earlier studies have indicated a role for serum lactic dehydrogenase (LDH) in haematological and other malignancies. As this is still not a routine test in many units, its value has been re-examined in a retrospective analysis of serum LDH levels in 278 patients with haematological malignancies managed in a single unit. Abnormal levels at diagnosis were found in 42% of these disorders; yet analysis of over 23,000 routine requests for a biochemical screen showed only 4% with an abnormal LDH level. The estimation was also valuable in follow-up of those haematological patients, with rising levels often indicating progressive or relapsing disease even in cases which had shown a normal LDH at diagnosis.

Vacuolated plasma cell: ultrastructural distribution of acid phosphatase and intracellular immunoglobulin

In two cases of vacuolated plasma cells, one of which was associated with primary macroglobulinemia and the other was with kappa-chain Bence Jones multiple myeloma, we examined the immunopathological features of the vacuoles in order to know whether the Ig-secreting system or the lysosomal system is of importance in the process of vacuole formation. Immunofluorescent studies detected no Ig in the vacuoles. Detection of intracellular Ig by immunoelectron microscopic technique revealed that Ig was localized only in a small portion of the vacuoles but not in most vacuoles. Even when Ig was included in the vacuoles, only the contents of the vacuoles were positive for Ig but their demarcating membrane was negative for Ig. In contrast, electron microscopic studies of acid phosphatase activity revealed the presence of its activity in all vacuoles. These findings suggest that the lysosomal system but not the Ig-secreting system may play a major role in vacuolation of these myeloma cells.

Acid hydrolases as markers of maturation in B-cell chronic lymphocytic leukemia

Malignant lymphocytes from 30 B-cell chronic lymphocytic leukemia (B-CLL) patients were studied for the cytochemical localization of two acid hydrolases, alpha-naphthyl acetate esterase (ANAE) and acid phosphatase (AT). The large majority of the cells stained for both ANAE and AP in 7 cases, for AP only in 18 cases, and were negative for both the enzymes in 5 cases. Ultrastructural analysis revealed that the cells that displayed more mature morphological features, such as well developed smooth and rough membrane compartments, were those positive for acid hydrolases. That ANAE and AP are expressed by B cells at late stage of maturation was confirmed by the finding that some lymphocytes and all of the plasmacytoid lymphocytes and plasma cells from Walderström's macroglobulinemia, from mixed cryoglobulinemia, and from multiple myeloma patients stained strongly for both ANAE and AP. Using the expression of acid hydrolases and certain ultrastructural features as markers of cell differentiation, it was possible to demonstrate a process of maturation within the single B-CLL clones with accumulation of the cells at stages that differed in the various cases.

Existence of tartrate-resistant acid phosphatase activity in differentiated lymphoid leukemic cells

Acid phosphatase (AcP) in neoplastic cells from various lymphoid leukemias was examined. In the cytochemical studies, tartrate-resistant AcP (T-rAcP) activity was observed in the neoplastic cells from well-differentiated lymphoid leukemias such as adult T-cell leukemia (ATL), B-cell chronic lymphocytic leukemia (B-CLL), T-cell chronic lymphocytic leukemia (T-CLL), and hairy-cell leukemia (HCL). T-rAcP activity was also detected in a small number of leukemic cells obtained from T-cell acute lymphoblastic leukemia (T-ALL), while it was not detected in the neoplastic cells from null-ALL, macroglobulinemia, and multiple myeloma (MM). In the electrophoretical studies, fraction 1 (F-1), F-3, F-3b, and F-4 were completely tartrate-sensitive, while F-2 was partially resistant and F-5 was completely resistant. T-rAcP activity (F-5) was observed in ATL cells, B-CLL cells, and HCL cells, while it was not detected in ALL cells, macroglobulinemia cells, and MM cells. The present study indicates that T-rAcP activity is observed not only in HCL cells but also in the well-differentiated lymphoid cells such as ATL cells, B-CLL and T-CLL cells except the most highly differentiated forms of B-cells of MM and macroglobulinemia.

Urinary excretion of beta-hexosaminidase in different forms of proteinuria

The urinary excretion of beta-hexosaminidase was studied in different forms of proteinuria. Patients with tubular proteinuria showed a very large increase in beta-hexosaminidase only in the acute stage of the renal disease, while patients with chronic tubular dysfunction did not show any greater degree of beta-hexosaminidase excretion. The same findings were noted in glomerular disease, in which patients with a very high degree of disease activity showed a marked increase in enzyme excretion. There was a good correlation between enzyme excretion and level of proteinuria. In Bence-Jones proteinuria it seems possible to determine the grade of renal injury caused by the light chain.

Activity of adenosine deaminase and of purine nucleoside phosphorylase in peripheral lymphocytes from patients with acquired immunological disorders

The activity of adenosine deaminase (ADA) and of purine nucleoside phosphorylase (PNP) was determined in the peripheral lymphocytes of patients with diseases associated with acquired partial dysfunction of the immune response. Increase ADA activity was found in patients with Waldenstrom's macroglobulinemia and in some patients with non-Hodgkin's lymphoma. Increased PNP activity was found in patients with non Hodgkin's lymphoma whereas decreased PNP activity was fund in patients with connective tissue disorders. The alternations found in ADA and PNP activities probably reflect changes in the lymphocyte subpopulations and do not seem to have an etiological role in the pathogenesis of the disturbed immune response.

Red cell pyrimidine 5'-nucleotidase and glutathione in myeloproliferative and lymphoproliferative disorders

Red cell reduced glutatione (GSH) and pyrimidine 5'-nucleotidase (Pry 5'-NT) were measured in a variety of myeloproliferative and lymphoproliferative disorders. Raised levels of GSH were found in chronic lymphocytic leukaemia, Hodgkin's disease, non-Hodgkin's lymphoma, Waldenstrom's macroglobulinaemia and myeloma. Decreased activity of Pyr 5'-NT was found in acute myeloblastic leukaemia, acute lymphoblastic leukaemia, chronic granulocytic leukaemia, chronic lymphocytic leukaemia, Hodgkin's disease and non-Hodgkin's lymphoma. There was no correlation between the raised GSH levels and decrease Pry 5'-NT levels.

[Studies of lysozyme activity in serum, urine and blood smears from patients with haematological diseases]

Lysozyme activity was studied in blood smears, serum, and urine of patients suffering from leukaemia or other haematological diseases. Increased enzyme activity was found in myelocytic, myelomonocytic and monocytic leukaemia and equally in secondary granulocytosis and polycythaemia vera. Reduced rates were found in lymphocytie leukaemia, malignant lymphoma with bone marrow involvement, and myelophthisic conditions. A rise in urinary lysozyme occurred when the serum level exceeded 50 microgram/ml. Abundant activities were found in myelomonocytic and monocytic leukaemias. Using the bacteriolytic method in blood smears, no enzyme activity was demonstrated in cells of acute or chronic lymphocytic leukaemia, in monocytic leukaemia however, almost all cells show strong reaction. In acute myelocytic or myelomonocytic leukaemia, the portion of positive cells changes from case to case depending on the degree of cell differentiation and maturation. In chronic myelocytic leukaemia there was no difference as compared to enzyme activity of myelocytes in bone marrow of control cases. Thus the bacteriolytic demonstration of lysozyme in blood smears may additionally contribute to distinction of different types of blastic leukaemias, and serum lysozyme also may allow more reliable insight into granulocytic and monocytic myelopoiesis than morphologic studies of blood or bone marrow smears can do, e.g. in agranulocytosis and pancytopenia.

5' nucleotidase activity in leukaemic lymphocytes

The enzyme 5' nucleotidase (E.C.3.1.3.5.) is present in lymphocytes isolated from the blood of normal subjects. The activity was extremely low in lymphocytes from 17 patients with B lymphocytic leukaemias. Removal of normal lymphocytes from the B-cell leukaemic samples decreased further the enzyme activity. Moderately low values were observed in three cases of T-ALL and in the cells from a case of Sézary syndrome. In contrast, normal or high values were observed in three cases of ALL in which T and B markers were not demonstrable and in two of T-CLL. No differences were observed in partially purified subpopulations of normal B and T cells.