First-line daratumumab shows high efficacy and tolerability even in advanced AL amyloidosis: the real-world experience

Background

Daratumumab was the first monoclonal CD38 antibody with single-agent activity approved for the treatment of multiple myeloma. Moreover, daratumumab demonstrated high response rates in relapsed immunoglobulin light-chain (AL) amyloidosis.

Patients and methods

In our single-center retrospective real-life case series, we analyzed the efficacy and safety of daratumumab as first-line treatment. Daratumumab was administered with low-dose dexamethasone alone or in combination with other multiple myeloma therapeutics

Results

Fourteen patients were eligible, including nine patients with cardiac stage IIIa or IIIb. Overall hematologic response rate was 100%, with 64.3% achieving complete response after a median of 16 cycles of treatment. Median time to hematologic response was 1.4 months. Organ response rates were 45.5% after a median of 4.0 months and 66.7% after a median of 10.0 months, for heart and kidney involvement, respectively. After a median follow-up of 20.5 months, two patients underwent successful autologous stem cell transplantation (ASCT), while another three patients were in preparation for ASCT. Three patients remained on daratumumab at the last follow-up. There were no unexpected toxicities and no grade III or IV adverse events, although more than half of our patients were in stage IIIa or IIIb.

Conclusion

Daratumumab proved to be highly effective in newly diagnosed AL amyloidosis with excellent hematologic and organ response rates, a remarkable safety profile, and good tolerability even in patients with advanced stage of disease.

•

Daratumumab yields high hematologic response rates in untreated AL amyloidosis.

•

Treatment is well tolerated even in advanced disease stages.

•

No unexpected toxicity was observed.

Molecular classification of tumour cells in a patient with intravascular large B-cell lymphoma

BACKGROUND

Intravascular large B-cell lymphoma (IVLBCL) is a rare type of extranodal LBCL. It is characterized by the proliferation of tumour cells exclusively intraluminally in small blood vessels of different organs. The clinical manifestation depends on the type of organ affected; additionally, a haemophagocytic syndrome can be observed in some patients.

OBJECTIVES

The aim was to further understand the nosology of this lymphoma as, due to its rarity and in spite of detailed immunohistochemical investigations, its exact nosology is only incompletely understood.

METHODS

We used microarray-based analysis of gene expression of tumour cells isolated from a patient with primary manifestation of the lymphoma in the skin and compared it with various other diffuse LBCLs (DLBCLs) as well as a previously published DLBCL classifier.

RESULTS

In unsupervised analyses, the tumour cells clustered together with non-germinal centre B-cell (non-GCB) DLBCL samples but were clearly distinct from GCB-DLBCL. Analogous to non-GCB DLBCL, molecular cell-of-origin classification revealed similarity to bone-marrow derived plasma cells.

CONCLUSIONS

The IVLBCL of this patient showed molecular similarity to non-GCB DLBCL. Due to the prognostic and increasingly also therapeutic relevance of molecular subtyping in DLBCL, this method, in addition to immunohistochemistry, should also be considered for the diagnosis of IVLBCL in the future.

Enumeration and immunohistochemical characterisation of bone marrow basophils in myeloproliferative disorders using the basophil specific monoclonal antibody 2D7

BACKGROUND

Basophils are highly specialised granulocytes that express a unique profile of antigens and increase in myeloproliferative disorders (MPD). In chronic myeloid leukaemia (CML), basophilia is a diagnostic and prognostic determinant. So far, however, no reliable approach for routine detection and enumeration of bone marrow basophils has become available.

OBJECTIVE

To detect and enumerate basophils in bone marrow sections in patients with CML and other MPD.

METHODS

The anti-basophil antibody 2D7 was applied to paraffin embedded bone marrow sections from normal/reactive subjects (n = 31), patients with CML (chronic phase, n = 37; accelerated phase, n = 9), and other MPD (chronic idiopathic myelofibrosis (CIMF), n = 20; polycythaemia vera (PV), n = 20; essential thrombocythaemia (ET), n = 20; indolent systemic mastocytosis (ISM), n = 7).

RESULTS

As assessed by serial section staining, 2D7(+) cells were found to co-express myeloperoxidase, histidine decarboxylase, CD9, and CD43, but did not express B cell or T cell restricted antigens. 2D7(+) bone marrow cells were found to increase in CML compared with normal/reactive bone marrow and other MPD (median numbers of 2D7(+) cells/mm(2): CML, 33; normal/reactive bone marrow, 6; CIMF, 10; PV, 6; ET, 5; ISM, 3; p<0.05). The highest basophil counts were recorded in accelerated phase CML (115/mm(2)).

CONCLUSIONS

A novel immunohistochemical procedure has been established for basophil detection in normal bone marrow and MPD. This approach should help in the quantification of bone marrow basophils at diagnosis and during anti-leukaemic treatment.

Variable frequencies of MALT lymphoma-associated genetic aberrations in MALT lymphomas of different sites

Although several recurrent genetic aberrations are known to occur in MALT lymphoma, no comprehensive study on the most prevalent MALT lymphoma-associated genetic aberrations is available. We therefore screened 252 primary MALT lymphomas for translocations t(11;18)(q21;q21), t(14;18)(q32;q21), and t(1;14)(p22;q32), and trisomies 3 and 18. The above-listed translocations occurred mutually exclusively and were detected overall in 13.5, 10.8, and 1.6% of the cases; trisomy 3 and/or 18 occurred in 42.1%. The frequency at which the translocations occurred varied markedly with the primary site of disease. The t(11;18)(q21;q21) was mainly detected in pulmonary and gastric tumors, whereas the t(14;18)(q32;q21) was most commonly found in lesions of the ocular adnexa/orbit, skin, and salivary glands. Trisomies 3 and 18 each occurred most frequently in intestinal and salivary gland MALT lymphomas. Our results demonstrate that the three translocations and trisomies 3 and 18 occur at markedly variable frequencies in MALT lymphoma of different sites.

Prognostic significance of molecular staging by PCR-amplification of immunoglobulin gene rearrangements in diffuse large B-cell lymphoma (DLBCL)

The prognostic value of the detection of peripheral blood (PB) and/or bone marrow (BM) involvement by polymerase chain reaction (PCR) amplification of rearranged immunoglobulin heavy chain (IgH) and immunoglobulin kappa light chain (Igkappa) genes was evaluated in 155 patients with diffuse large B-cell lymphomas (DLBCL). Immunoglobulin gene rearrangements (IgR) were detected in 35/155 (23%) patients. The presence of IgR in PB/BM was related to clinical stage (CS I-III vs CS IV; P<0.001), histopathological detection of BM involvement (P<0.001), and the International Prognostic Index (P<0.001). IgR-positive cases had a significantly lower complete remission (CR) rate (18/35, 51%) than IgR-negative patients (85/120, 71%; P=0.042), and a significantly poorer overall survival (OAS) at 5 years (25 vs 66%; P<0.001). There was a significant difference in the estimated OAS at 5 years between patients with negative BM histology and negative PCR results (66%), patients with negative BM histology but positive IgR (37%), and patients with positive BM histology (12%). Our results indicate that molecular methods improve the accuracy of staging in patients with DLBCL and define a group of patients with normal bone marrow histology who have a significantly poorer OAS due to molecular detection of PB/BM involvement.

Diffuse large B-cell lymphomas with plasmablastic/plasmacytoid features are associated with TP53 deletions and poor clinical outcome

To define reproducible criteria for subgroups of diffuse large B-cell lymphomas (DLBCL), including lymphomas with plasmablastic/plasmacytoid features (PB/PC-Fs), we investigated 66 DLBCL; the samples were categorized as either centroblastic (CB), immunoblastic (IB) or PB/PC-F applying standardized morphologic criteria. Blinded specimens were reviewed by three independent pathologists. The final consensus classification included 44 CB (67%), seven IB (10%) and 15 PB/PC-F (23%). The interobserver agreement between two centers (Vienna, Würzburg) was 93.5%. Most PB/PC-F were CD20+, cIgM+, MUM-1+, CD138+/-, bcl-6-, corresponding to an activated B-cell phenotype. Immunoglobulin-V(H) gene mutation analysis was consistent with a germinal or postgerminal center-cell origin. By fluorescence in situ hybridization analysis, 11/13 (85%) PB/PC-F had a monoallelic TP53 deletion. The pretreatment characteristics of patients with PB/PC-F included a tendency for more B symptoms, extranodal disease and a higher IPI. Importantly, PB/PC-F were resistant to standard chemotherapy (complete remission rate 47%, relapse rate 71%) and even autologous stem-cell transplantation. The median overall survival (OS) (14 months, P<0.002) and disease-free survival (6 months, P=0.02) were significantly shorter compared to patients with CB and IB. The OS difference was pronounced within the low and low-intermediate IPI risk group (P<0.001). Our data indicate a strong association of plasmablastic/plasmacytoid morphology with TP53 deletions, poor response to chemotherapy and short survival.

Analysis of SH2D1A mutations in patients with severe Epstein-Barr virus infections, Burkitt's lymphoma, and Hodgkin's lymphoma

Mutations or deletions in the SH2D1A (src homology 2 domain protein 1A) gene result in a severe immunodeficiency called X-linked lymphoproliferative (XLP) disease. XLP is primarily characterized by a defective immune response against the Epstein-Barr virus (EBV), resulting in an unusually severe and often fatal clinical course following EBV infection. The second major cause of death is the development of B cell lymphomas, both in EBV-infected and EBV-negative patients. To study whether the clinical manifestation of XLP gene defects and/or polymorphisms extends beyond the classically recognized phenotype, we analyzed patients for the presence of SH2D1A gene alterations who presented with fatal or nonfatal, yet unusually severe or chronic EBV infections, and other possibly EBV-associated diseases, such as Hodgkin's lymphomas or nonendemic Burkitt's lymphomas and Burkitt-type leukemias. We identified mutations of the SH2D1A gene only in the majority of patients presenting with fatal mononucleosis or an XLP family history, but not in any of the other patients studied. The only alteration determined was a polymorphism in the 5' region of the SH2D1A gene both in patient groups as well as in controls.