scholarly journals Pharmacodynamics of SEA-BCMA, a Nonfucosylated Antibody Targeting BCMA, in Patients with Relapsed/Refractory Multiple Myeloma

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1197-1197
Author(s):  
David Taft ◽  
Clark Henderson ◽  
Christine O'Day ◽  
Changpu Yu ◽  
Hong Li ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Receptor Binding ◽  
Plasma Cells ◽  
Binding Assay ◽  
Phase 1 ◽  
Receptor Occupancy ◽  
Publicly Traded ◽  
Serum Samples ◽  
Immune Effector

Abstract Patients with relapsed/triple class refractory (refractory to a proteasome inhibitor, immunomodulatory drug or anti-CD38 antibody) multiple myeloma (MM) have limited treatment options. Versatile therapies, such as unconjugated antibodies (Abs), that are well tolerated and can be combined with multiple modalities are critical for the MM treatment landscape. SEA-BCMA is an investigational, humanized, nonfucosylated IgG1 monoclonal Ab targeting B-cell maturation antigen (BCMA) on malignant plasma cells. Preclinical data show that SEA-BCMA blocks BCMA-mediated pro-survival and proliferative cell signaling and mediates antibody-dependent cellular phagocytosis and enhanced antibody-dependent cellular cytotoxicity via increased binding to activating Fc receptor, FcγRIIIa (Van Epps 2018). A phase 1, open-label, multicenter study to evaluate the safety, tolerability, and antitumor activity of SEA-BCMA in adults with relapsed or refractory MM (SGNBCMA-001; NCT03582033) is ongoing. To support maximal ligand blocking and immune effector engagement by SEA-BCMA, we investigated its binding and saturation pharmacodynamics (PD) in patients enrolled in dose escalation and currently recruiting dose expansion cohorts. Novel quantitative assays were developed to assess the BCMA target and the availability of SEA-BCMA in patients enrolled in the study. These assessments include: a liquid chromatography-mass spectrometry (LC-MS) soluble BCMA (sBCMA) assay, a BCMA receptor occupancy assay on malignant plasma cells in bone marrow aspirates, and a receptor binding assay to assess the direct binding and saturation capacity of SEA-BCMA in patients' serum samples and bone marrow aspirates to a BCMA-expressing cell in vitro. Results reported as median (min-max) values unless specified. At baseline, the median sBCMA level from patients enrolled in SGNBCMA-001 was 8.5(0.5-217.0) ng/mL. After the first dose of SEA-BCMA, a rapid and sustained increase in sBCMA was observed [32.0 (3.0-139.0) fold]. Mechanistically, because SEA-BCMA can bind to sBCMA, accumulation of sBCMA may occur due to formation of the sBCMA:SEA-BCMA complex, resulting in reduced clearance. Importantly, for patients at the dose selected for expansion (1600mg), the molar ratio of SEA-BCMA to sBCMA remained in excess (10:1-400:1), thereby overcoming the liabilities of this complex formation and supporting malignant plasma cell drug exposure. Results of a receptor binding assay using patients' serum samples also demonstrated a dose-dependent ability to saturate BCMA-expressing cells. Evaluation of receptor occupancy in patient bone marrow aspirates showed that at baseline, median unoccupied membrane BCMA (unbound by ligand) was 3,500(1,500-30,000) copies per cell with one excluded outlier that exhibited 270,000 copies per cell. On-treatment, unoccupied membrane BCMA reductions were observed ranging from 50% to 100% from baseline in majority of evaluable patients at the 1600mg dose. An on-treatment increase in total BCMA expression was also observed, which is being further investigated. Maximal ligand blocking and immune effector engagement is best achieved through saturation of a target receptor. Overall, these PD results provide insight into the saturation potential of plasma cell membrane BCMA by SEA-BCMA and informed the dose selection and schedule in expansion cohorts. Further evaluation of these relationships to patient response is ongoing as the Phase 1 study continues to enroll. Disclosures Taft: Seagen, Inc: Current Employment, Current equity holder in publicly-traded company. Henderson: Seagen, Inc: Current Employment, Current equity holder in publicly-traded company. O'Day: Seagen, Inc: Current Employment, Current equity holder in publicly-traded company. Yu: Seagen, Inc: Current Employment, Current equity holder in publicly-traded company. Li: Seagen Inc.: Current Employment, Current equity holder in publicly-traded company. Ho: Seagen Inc.: Current Employment, Current equity holder in publicly-traded company. Van Epps: Seagen, Inc: Current Employment, Current equity holder in publicly-traded company.

scholarly journals The Effects of BCMA Expression, Soluble BCMA, and Combination Therapeutics on the Anti-Tumor Activity of HPN217, a BCMA-Targeting Tri-Specific T Cell Engager Against Multiple Myeloma

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1185-1185
Author(s):  
Patrick P Ng ◽  
Wade Aaron ◽  
Evan Callihan ◽  
Golzar Hemmati ◽  
Che-Leung Law ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Cell Surface ◽  
Half Life ◽  
Plasma Cells ◽  
Target Cells ◽  
Publicly Traded ◽  
Anti Tumor Activity

Abstract Introduction B-cell maturation antigen (BCMA) is a cell surface receptor highly and selectively expressed on normal plasma cells and transformed plasma cells in multiple myeloma (MM) patients. Upon ligand binding, BCMA initiates signals that promote the survival of MM cells and the production of immunosuppressive factors. Therapeutics that target BCMA are being investigated in the clinic, with encouraging preliminary results. HPN217 is a Tri-specific T Cell-Activating Construct (TriTAC) specific to BCMA, to serum albumin for half-life extension, and to CD3ε for redirecting T cells against MM cells. It is currently being evaluated in a phase 1 /2 clinical trial for relapsed or refractory MM (NCT04184050). Herein, we describe translational studies to examine factors that may impact the therapeutic efficacy of HPN217, including the target BCMA, in membrane-bound or soluble form, and concomitant or combination therapeutics such as γ-secretase inhibitor (GSI) and dexamethasone. Results To evaluate the effects of HPN217 against primary MM cells, we used a patient-derived 3D-culture system (3DTEBM) designed to recapitulate the biology within the bone marrow microenvironment. 3DTEBM seeded with bone marrow accessory cells and autologous plasma recreate niches along an oxygen gradient that enable the survival and expansion of autologous MM cells without additional nutrient supplements. 3DTEBM's were established from 5 MM patients with varying ratios of autologous CD3+ T cells to MM cells (0.15-0.6). Although the functional competence of the T cells was unknown, HPN217 was able to mediate MM cell killing in 80% of the cultures with up to 71% of MM cells eliminated at a T cell/MM cell ratio of 0.45. The anti-tumor efficacy of HPN217 correlated strongly (R 2 = 0.99) with BCMA expression on the MM cells as measured by flow cytometry, suggesting the number of target receptors can be a limiting factor in efficacy. Consistent with this result, pre-incubation of target cells with 1 or 10 μg/mL anti-BCMA reduced the activity of HPN217 in T cell-dependent cellular cytotoxicity (TDCC) assays using healthy donor T cells and MM cell lines. Soluble BCMA (sBCMA) is produced when the extracellular domain of BCMA is cleaved by γ-secretase. It may act as a sink for HPN217. There was no correlation between the activity of HPN217 and the quantity of sBCMA in 3DTEBM. However, in TDCC assays, the addition of 6.25, 25 and 100 nM recombinant BCMA respectively led to 4-, 9- and 28-fold increases in the EC 50 of HPN217. Taken together, these data underscore the importance of preserving BCMA on MM cells and reducing sBCMA in circulation. Interestingly, treatment of MM cell line RPMI8226 with the GSI LY-3039478 for 24 hours increased the cell surface expression of BCMA by 3.6 folds. Using RPMI8226 as target cells in the 3DTEBM system, LY-3039478 increased the killing efficacy of HPN217-redirected primary T cells by 1.9 folds. Dexamethasone (Dex) is used with other therapeutics for treating MM. It is also commonly given to manage cytokine release syndrome (CRS) caused by T cell engagers. We conducted TDCC assays in the presence of 0.07-300 nM Dex to simulate plasma concentrations relevant to dose levels of Dex premedication for CRS. The highest Dex concentrations caused ≤3-fold increases in the EC 50 of HPN217. Considering this and the plasma half-life of i.v. injected Dex at <5 h, the suppressive effect of Dex on the anti-tumor activity of HPN217-redirected T cells may be limited. We then evaluated if MM.1S-Luc cell line xenografts in NCG mice would be a suitable model to extend the above in vitro findings to an in vivo setting. Lesions in the spine, skull and femur in NCG mice treated with vehicle could be detected by bioluminescent imaging. All mice succumbed to the disease within 40 days. By contrast, animals treated with HPN217 were protected in a dose-dependent manner. Mice that received the highest dose remained 100% disease-free at the end of the study (Figure 1). Conclusions We demonstrated HPN217 mediated BCMA-dependent primary MM cell killing by autologous T cells, and that the density of BCMA target on the surface of MM cells and sBCMA affected the efficacy of HPN217 in cultures. GSI, which increased the expression of BCMA on MM cells, enhanced the efficacy of HPN217. On the other hand, Dex had limited negative effect. HPN217 in combination with approved and experimental MM therapeutics is being evaluated in the 3DTEBM and MM.1S-Luc models. Figure 1 Figure 1. Disclosures Ng: Harpoon Therapeutics: Current Employment, Current equity holder in publicly-traded company. Aaron: Harpoon Therapeutics: Current Employment, Current equity holder in publicly-traded company. Callihan: Harpoon Therapeutics: Current Employment, Current equity holder in publicly-traded company. Hemmati: Harpoon Therapeutics: Current Employment, Current equity holder in publicly-traded company. Law: Harpoon Therapeutics: Current Employment, Current equity holder in publicly-traded company. Azab: Cellatrix, LLC: Current Employment, Current holder of individual stocks in a privately-held company. Sun: Harpoon Therapeutics: Consultancy, Current equity holder in publicly-traded company, Ended employment in the past 24 months.

Serum Pleiotrophin Is a New Multiple Myeloma Tumor Marker That Also Predicts Clinical Status.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3417-3417
Author(s):  
Howard S. Yeh ◽  
Haiming Chen ◽  
Steven J. Manyak ◽  
Regina A. Swift ◽  
Richard A. Campbell ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Tumor Marker ◽  
Plasma Cells ◽  
Clinical Status ◽  
Constitutive Expression ◽  
Disease Status ◽  
Heparin Binding ◽  
Serum Samples ◽  
Control Subjects

Abstract Pleiotrophin (PTN), an 18 kD heparin-binding protein, has been found to be expressed in some solid tumors whereas it has not been previously evaluated in hematologic malignancies. Constitutive expression of PTN promotes tumor expansion and may increase metastatic potential. This protein binds to syndecan-1 (CD138) and stimulates angiogenesis. Its role in multiple myeloma (MM), thus far, has not been evaluated. Recently, we showed that PTN was strongly expressed in MM cell lines and malignant plasma cells from fresh bone marrow samples but not in normal control bone marrow specimens. Since PTN has been shown to be elevated in the serum of some solid tumor patients, we determined whether PTN may be elevated in the serum of MM patients, and correlated these levels with the patients’ disease status. By using a highly sensitive and specific enzyme-liked immunosorbent assay (ELISA) for PTN, we tested 270 different serum samples [MM (n=194), MGUS (n=18) and age-matched healthy control subjects (n=58)]. Serum samples from MM patients were obtained at the time of diagnosis as well as during the course of their disease. Serum PTN levels were higher in MM patients than in the control subjects (median=1.44 ng/ml vs 0.42 ng/ml, p <0.0001). In addition, among patients with MGUS and smoldering myeloma, serum PTN was also higher than in the controls (median=1.14 ng/ml vs 0.42 ng/ml, p <0.0001) but lower than among patients with active MM (p <0.0001). Patients with untreated MM showed serum PTN levels similar to those patients who received prior treatment. Among previously treated patients, the group with progressive disease at the time of evaluating their PTN level had higher serum concentrations of this protein than patients with responsive or stable disease (median=1.73 ng/ml vs 1.16 ng/ml, p <0.0001). Evaluation of patients who had a change in disease status showed that the serum PTN level increased at the time of progression when compared with their baseline level (median=1.76 ng/ml vs 1.01 ng/ml, p=0.009). Conversely, patients who responded to anti-MM therapy exhibited significant decreases of PTN as compared with their pre-treatment PTN values (median=0.95 ng/ml vs 1.90 ng/ml, p=0.007). These results suggest that serum PTN may be a new tumor marker for MM, and monitoring of this protein may be useful to follow the responsiveness to therapy and disease status of MM patients. We are now undertaking studies to evaluate PTN as a prognostic marker in a large cohort of newly diagnosed MM patients.

miRNA in Serum and Bone Marrow Plasma Cells From Multiple Myeloma Patients.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2921-2921
Author(s):  
Andrew Stiff ◽  
Alberto Rocci ◽  
Craig C. Hofmeister ◽  
Paola Omedè ◽  
Susan Geyer ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Peripheral Blood ◽  
Plasma Cells ◽  
Immunoglobulin M ◽  
Differentially Expressed ◽  
Healthy Controls ◽  
Circulating Mirnas ◽  
Serum Samples ◽  
Screening Analysis

Abstract Abstract 2921 Background: Multiple myeloma (MM) is a clonal B-cell malignancy characterized by the aberrant expansion of clonal plasma cells (PCs) within the bone marrow. Malignant PCs produce intact or partial monoclonal immunoglobulin (M protein) and cause organ damage. More than 20,000 new cases of multiple myeloma (MM) are diagnosed every year in the US with approximately 10,700 deaths occurring. The pathogenesis of MM is still largely unclear, but several reports suggest that interaction of tumor cells with the bone marrow microenvironment and microRNAs (miRNAs) deregulation may play a role in the etiology and progression of MM. miRNAs are small non-coding RNAs capable of regulating protein expression by binding to mRNA, and have been implicated in the development of MM. First identified inside cells, miRNAs can also be detected in body fluids, including serum and plasma, and may be a valid biomarker. Few studies have investigated the agreement between circulating miRNAs and intracellular myeloma PC miRNAs at diagnosis. Methods: Using Nano-String nCounter technology we first performed a screening analysis on serum samples obtained from MM patients and healthy controls. We identified a candidate set of miRNAs differentially expressed in the serum of MM patients. The levels of these miRNA markers were validated by RT-PCR in both serum and bone marrow PCs from the same cohort. Agreement of the quantitative miRNA marker levels between sample types was evaluated using intraclass correlation coefficients (ICC) (both for normalized and log2 measures). Results: Thirty-nine MM patients (21 male, 18 female) with a median age of 72 years (range: 65 – 83) were included in the analysis. Most were ISS stage I or II (59% vs. 41% ISS stage III) and 39% were high risk according to FISH abnormalities – 21% of patients carried del17p, 24% t(4;14) and 5% t(14;16). Medians and ranges for lab markers were as follows: hemoglobin 10.0 g/dl (7.2 to 15.1), beta2-microglobulin 5.18 ug/ml (1.38 – 12.1), creatinine 0.94 mg/dl (0.65 – 2.49), CRP = 1.6 mg/dl (0.02 – 116.0). Nine age-matched healthy controls were also used for the analysis. After the screening analysis, the following miRNAs were differentially expressed between healthy subjects and MM patients in serum samples: miR-92a, miR-451, miR-19b, miR-21, miR-16, miR-25, miR-30a, and miR-126. There was no significant agreement or correlation between serum and myeloma cell samples using either untransformed as well as log2measures (all p>0.40) (Table 1). Conclusion: Our preliminary results suggest a difference between circulating miRNAs in myeloma patients from controls. This indicates that future studies are needed to better define the role of miRNAs in the peripheral blood as a prognostic and even diagnostic biomarker in myeloma. From our preliminary data it also appears that circulating miRNAs are not simply secreted into the peripheral blood by myeloma PCs as it seems that circulating miRNAs do not reflect those of myeloma PCs. Differential expression could be determined by other cells that can release and or modify their miRNA expression in response to MM. Ongoing studies are examining the origin and function of miRNAs in the peripheral blood. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Potent in vitro and in vivo activity of an Fc-engineered humanized anti-HM1.24 antibody against multiple myeloma via augmented effector function

Blood ◽  
2012 ◽  
Vol 119 (9) ◽  
pp. 2074-2082 ◽  
Author(s):  
Yu-Tzu Tai ◽  
Holly M. Horton ◽  
Sun-Young Kong ◽  
Erik Pong ◽  
Hsing Chen ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Plasma Cells ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Immune Effector ◽  
Bone Marrow Plasma ◽  
Therapeutic Monoclonal Antibodies

Abstract HM1.24, an immunologic target for multiple myeloma (MM) cells, has not been effectively targeted with therapeutic monoclonal antibodies (mAbs). In this study, we investigated in vitro and in vivo anti-MM activities of XmAb5592, a humanized anti-HM1.24 mAb with Fc-domain engineered to significantly enhance FcγR binding and associated immune effector functions. XmAb5592 increased antibody-dependent cellular cytotoxicity (ADCC) several fold relative to the anti-HM1.24 IgG1 analog against both MM cell lines and primary patient myeloma cells. XmAb5592 also augmented antibody dependent cellular phagocytosis (ADCP) by macrophages. Natural killer (NK) cells became more activated by XmAb5592 than the IgG1 analog, evidenced by increased cell surface expression of granzyme B–dependent CD107a and MM cell lysis, even in the presence of bone marrow stromal cells. XmAb5592 potently inhibited tumor growth in mice bearing human MM xenografts via FcγR-dependent mechanisms, and was significantly more effective than the IgG1 analog. Lenalidomide synergistically enhanced in vitro ADCC against MM cells and in vivo tumor inhibition induced by XmAb5592. A single dose of 20 mg/kg XmAb5592 effectively depleted both blood and bone marrow plasma cells in cynomolgus monkeys. These results support clinical development of XmAb5592, both as a monotherapy and in combination with lenalidomide, to improve patient outcome of MM.

Bone disease as the first manifestation of systemic AL-amyloidosis

2020 ◽  
Vol 92 (7) ◽  
pp. 85-89
Author(s):  
L. P. Mendeleeva ◽  
I. G. Rekhtina ◽  
A. M. Kovrigina ◽  
I. E. Kostina ◽  
V. A. Khyshova ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Bone Disease ◽  
Plasma Cells ◽  
Interventricular Septum ◽  
Bone Destruction ◽  
Amyloid Deposition ◽  
Bone Lesions ◽  
Al Amyloidosis ◽  
Linear Type

Our case demonstrates severe bone disease in primary AL-amyloidosis without concomitant multiple myeloma. A 30-year-old man had spontaneous vertebral fracture Th8. A computed tomography scan suggested multiple foci of lesions in all the bones. In bone marrow and resected rib werent detected any tumor cells. After 15 years from the beginning of the disease, nephrotic syndrome developed. Based on the kidney biopsy, AL-amyloidosis was confirmed. Amyloid was also detected in the bowel and bone marrow. On the indirect signs (thickening of the interventricular septum 16 mm and increased NT-proBNP 2200 pg/ml), a cardial involvement was confirmed. In the bone marrow (from three sites) was found 2.85% clonal plasma cells with immunophenotype СD138+, СD38dim, СD19-, СD117+, СD81-, СD27-, СD56-. FISH method revealed polysomy 5,9,15 in 3% of the nuclei. Serum free light chain Kappa 575 mg/l (/44.9) was detected. Multiple foci of destruction with increased metabolic activity (SUVmax 3.6) were visualized on PET-CT, and an surgical intervention biopsy was performed from two foci. The number of plasma cells from the destruction foci was 2.5%, and massive amyloid deposition was detected. On CT scan foci of lesions differed from bone lesions at multiple myeloma. Bone fragments of point and linear type (button sequestration) were visualized in most of the destruction foci. The content of the lesion was low density. There was no extraossal spread from large zones of destruction. There was also spontaneous scarring of the some lesions (without therapy). Thus, the diagnosis of multiple myeloma was excluded on the basis based on x-ray signs, of the duration of osteodestructive syndrome (15 years), the absence of plasma infiltration in the bone marrow, including from foci of bone destruction by open biopsy. This observation proves the possibility of damage to the skeleton due to amyloid deposition and justifies the need to include AL-amyloidosis in the spectrum of differential diagnosis of diseases that occur with osteodestructive syndrome.

166Ho-DOTMP plus melphalan followed by peripheral blood stem cell transplantation in patients with multiple myeloma: results of two phase 1/2 trials

Blood ◽  
2003 ◽  
Vol 102 (7) ◽  
pp. 2684-2691 ◽  
Author(s):  
Sergio Giralt ◽  
William Bensinger ◽  
Mark Goodman ◽  
Donald Podoloff ◽  
Janet Eary ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Stem Cell ◽  
Hematopoietic Stem Cell Transplantation ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Phase 1 ◽  
High Dose ◽  
Two Phase ◽  
Hematopoietic Stem

Abstract Holmium-166 1, 4, 7, 10-tetraazcyclododecane-1, 4, 7, 10-tetramethylenephosphonate (166Ho-DOTMP) is a radiotherapeutic that localizes specifically to the skeleton and can deliver high-dose radiation to the bone and bone marrow. In patients with multiple myeloma undergoing autologous hematopoietic stem cell transplantation two phase 1/2 dose-escalation studies of high-dose 166Ho-DOTMP plus melphalan were conducted. Patients received a 30 mCi (1.110 Gbq) tracer dose of 166Ho-DOTMP to assess skeletal uptake and to calculate a patient-specific therapeutic dose to deliver a nominal radiation dose of 20, 30, or 40 Gy to the bone marrow. A total of 83 patients received a therapeutic dose of 166Ho-DOTMP followed by autologous hematopoietic stem cell transplantation 6 to 10 days later. Of the patients, 81 had rapid and sustained hematologic recovery, and 2 died from infection before day 60. No grades 3 to 4 nonhematologic toxicities were reported within the first 60 days. There were 27 patients who experienced grades 2 to 3 hemorrhagic cystitis, only 1 of whom had received continuous bladder irrigation. There were 7 patients who experienced complications considered to be caused by severe thrombotic microangiopathy (TMA). No cases of severe TMA were reported in patients receiving in 166Ho-DOMTP doses lower than 30 Gy. Approximately 30% of patients experienced grades 2 to 4 renal toxicity, usually at doses targeting more than 40 Gy to the bone marrow. Complete remission was achieved in 29 (35%) of evaluable patients. With a minimum follow-up of 23 months, the median survival had not been reached and the median event-free survival was 22 months. 166Ho-DOTMP is a promising therapy for patients with multiple myeloma and merits further evaluation. (Blood. 2003;102:2684-2691)

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