Phase I Trial of Plerixafor and Bortezomib As a Chemosensitization Strategy in Relapsed or Relapsed/Refractory Multiple Myeloma

Abstract Abstract 1874 INTRODUCTION: This study aimed to determine the safety and activity of plerixafor (CXCR4 inhibitor) in combination with bortezomib as a chemosensitization strategy in multiple myeloma (MM). This was based on our preclinical studies showing that plerixafor (Mozobil, Genzyme Corporation, MA) induces de-adhesion of MM cells and sensitization to bortezomib in preclinical animal models. METHODS: Eligibility criteria included: 1) patients with relapsed or relapsed/refractory MM with 1–5 prior lines of therapy including bortezomib (unless patients were refractory to bortezomib), 2) measurable disease, 3) not receiving chemotherapy > 3 weeks, or biological therapy for MM > 2 weeks prior to study treatment. Eight cohorts with different doses and two treatment schedules were planned. In cohorts 1–5, patients received plerixafor at the recommended dose sq on days 1–6 of each cycle and bortezomib at the recommended dose twice a week on days 3, 6, 10, and 13 every 21 days. To test the hypothesis that higher doses and a different schedule might induce better chemosensitization, in cohort 5b–7 plerixafor was given at the recommended dose sq on days 1, 3, 6, 10, and 13 and bortezomib was given at the recommended dose twice a week on days 3, 6, 10, and 13 every 21 days. Bortezomib was given 60–90 minutes after plerixafor. Patients were assessed after every cycle by modified EBMT/UC criteria. Patients who had a response or stable disease went on to receive a total of 8 cycles with maintenance therapy for patients with at least a minimal response (MR). To examine the in vivo effect of plerixafor and bortezomib on de-adhesion of MM cells and other accessory cells of the bone marrow, peripheral blood samples were obtained from the patients at 0, 1, 2, 3, 4 and 24 hours post-dose on days 1 and 3, and time points 0, 2, and 4 hours post-dose on days 6, 10 and 13 of cycle 1. RESULTS: Twenty-five patients were enrolled in this phase I trial from June 2009 to May 2011. Median age was 60 years (range, 44–85) and median lines of prior therapy were 2 (range, 1–4) with all but 3 patients receiving prior bortezomib. The median number of cycles on therapy was 3 (1–11). Dose limiting toxicities including insomnia, restlessness, and psychosis were observed in two patients at dose level 6 (plerixafor 0.40 mg/kg and bortezomib 1.3 mg/m2). To further explore the safety of maximum tolerated dose, three additional patients were enrolled at dose level 5b (plerixafor 0.32 mg/kg and bortezomib 1.3 mg/m2). Overall, the combination proved to be well tolerated. There were no grade 4 toxicities. Grade 3 toxicities included lymphopenia (40%), hypophosphatemia (20%), anemia (10%), hyponatremia (10%), hypercalcemia (10%), and bone fracture due to myeloma bone disease (10%). One patient came off treatment due to grade 2 painful neuropathy at cycle 5. Twenty-three patients were evaluable for response, including 1 (4%) complete response (CR), 1 (4%) very good partial response (VGPR) and 3 (13%) MR, with an overall response rate (including MR) of 5 (22%) in this relapsed and refractory population. In addition, 15 (65%) patients achieved stable disease (SD), with just 3 (13%) having progressive disease (PD) as their best response. We also examined in vivo mobilization of plasma cells, CD34+ hematopoietic stem cells and other accessory bone marrow cells. Analysis of these samples showed rapid mobilization of plasma cells at 2 hours post-plerixafor with a rapid return to normal levels at 4 and 24 hours post plerixafor. Similar results were observed on days 1 and 3, but less mobilization occurred on the following days. Hematopoietic stem cell mobilization occurred at 4 hours on days 1 and 3, and was less observed with subsequent doses of plerixafor consistent with prior studies. CONCLUSIONS: The combination of plerixafor and bortezomib is generally well tolerated with minimal neuropathy or other toxicities seen to date. The responses observed are encouraging in this relapsed and refractory population. The ability to demonstrate transient de-adhesion of MM cells and accessory cells in vivo in most of the patients indicates that chemosensitization can potentially be achieved in patients with MM using this approach. Further studies are warranted and a phase 2 trial is underway. This study was supported by R01CA133799-01, and by Genzyme Corporation. Disclosures: Ghobrial: Celgene: Membership on an entity's Board of Directors or advisory committees; Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Noxxon: Consultancy, Membership on an entity's Board of Directors or advisory committees; Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Research Funding; Noxxon: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees. Off Label Use: Plerixafor in myeloma. Munshi:Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Onyx: Membership on an entity's Board of Directors or advisory committees. Schlossman:Millennium: Consultancy; Celgene: Consultancy. Anderson:Millennium: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; Acetylon: Equity Ownership. Richardson:Millennium: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Johnson & Johnson: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees.

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In Vitro and inVivo Activity of Melflufen in Amyloidosis

Blood ◽

10.1182/blood-2019-125952 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 3100-3100 ◽

Cited By ~ 2

Author(s):

Ken Flanagan ◽

Muntasir M Majumder ◽

Romika Kumari ◽

Juho Miettinen ◽

Ana Slipicevic ◽

...

Keyword(s):

Board Of Directors ◽

Cell Lines ◽

Plasma Cell ◽

Light Chain ◽

Research Funding ◽

Plasma Cells ◽

Al Amyloidosis ◽

Advisory Committees

Background: Immunoglobulin light-chain (AL) amyloidosis is a rare disease caused by plasma cell secretion of misfolded light chains that assemble as amyloid fibrils and deposit on vital organs including the heart and kidneys, causing organ dysfunction. Plasma cell directed therapeutics, aimed at preferentially eliminating the clonal population of amyloidogenic cells in bone marrow are expected to reduce production of toxic light chain and alleviate deposition of amyloid thereby restoring healthy organ function. Melphalan flufenamide ethyl ester, melflufen, is a peptidase potentiated alkylating agent with potent toxicity in myeloma cells. Melflufen is highly lipophilic, permitting rapid cellular uptake, and is subsequently enzymatically cleaved by aminopeptidases within cells resulting in augmented intracellular concentrations of toxic molecules, providing a more targeted and localized treatment. Previous data demonstrating multiple myeloma plasma cell sensitivity for melflufen suggests that the drug might be useful to directly eliminate amyloidogenic plasma cells, thereby reducing the amyloid load in patients. Furthermore, the increased intracellular concentrations of melflufen in myeloma cells indicates a potential reduction in systemic toxicity in patients, an important factor in the fragile amyloidosis patient population. To assess potential efficacy in amyloidosis patients and to explore the mechanism of action, we examined effects of melflufen on amyloidogenic plasma cells invitro and invivo. Methods: Cellular toxicity and apoptosis were measured in response to either melflufen or melphalan in multiple malignant human plasma cell lines, including the amyloidosis patient derived light chain secreting ALMC-1 and ALMC-2 cells, as well as primary bone marrow cells from AL amyloidosis patients, using annexin V and live/dead cell staining by multicolor flow cytometry, and measurement of cleaved caspases. Lambda light chain was measured in supernatant by ELISA, and intracellular levels were detected by flow cytometry. To assess efficacy of melflufen in vivo, the light chain secreting human myeloma cell line, JJN3, was transduced with luciferase and adoptively transferred into NSG mice. Cell death in response to melflufen or melphalan was measured by in vivo bioluminescence, and serum light chain was monitored. Results: Melflufen demonstrated increased potency against multiple myeloma cell lines compared to melphalan, inducing malignant plasma cell death at lower doses on established light chain secreting plasma cell lines. While ALMC-1 cells were sensitive to both melphalan and melflufen, the IC50 for melphalan at 960 nM was approximately 3-fold higher than melflufen (334 nM). However, ALMC-2 cells were relatively insensitive to melphalan (12600 nM), but maintained a 100-fold increase in sensitivity to melflufen (121 nM). Furthermore, while 40% of primary CD138+ plasma cells from patients with diagnosed AL amyloidosis responded to melflufen treatment in vitro, only 20% responded to melphalan with consistently superior IC50 values for melflufen (Figure 1). Light chain secreting cell lines and AL amyloidosis patient samples were further analyzed by single cell sequencing. We further examined differential effects on apoptosis and the unfolded protein response in vitro in response to either melflufen or melphalan. This is of particular interest in amyloidosis, where malignant antibody producing plasma cells possess an increased requirement for mechanisms to cope with the amplified load of unfolded protein and associated ER stress. As AL amyloidosis is ultimately a disease mediated by secretion of toxic immunoglobulin, we assessed the effects of melflufen on the production of light chain invitro, measuring a decrease in production of light chain in response to melflufen treatment. Finally, we took advantage of a recently described adoptive transfer mouse model of amyloidosis to assess the efficacy of melflufen and melphalan in eliminating amyloidogenic clones and reducing the levels of toxic serum light chain in vivo. Conclusions: These findings provide evidence that melflufen mediated toxicity, previously described in myeloma cells, extends to amyloidogenic plasma cells and further affects the ability of these cells to produce and secrete toxic light chain. This data supports the rationale for the evaluation of melflufen in patients with AL amyloidosis. Figure 1 Disclosures Flanagan: Oncopeptides AB: Employment. Slipicevic:Oncopeptides AB: Employment. Holstein:Celgene: Consultancy; Takeda: Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy; Genentech: Membership on an entity's Board of Directors or advisory committees; Sorrento: Consultancy. Lehmann:Oncopeptides AB: Employment. Nupponen:Oncopeptides AB: Employment. Heckman:Celgene: Research Funding; Novartis: Research Funding; Oncopeptides: Research Funding; Orion Pharma: Research Funding.

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Phase I/II Trial of Plerixafor and Bortezomib As a Chemosensitization Strategy In Relapsed Or Relapsed/Refractory Multiple Myeloma

Blood ◽

10.1182/blood.v122.21.1947.1947 ◽

2013 ◽

Vol 122 (21) ◽

pp. 1947-1947 ◽

Cited By ~ 3

Author(s):

Irene M. Ghobrial ◽

Kenneth Shain ◽

Courtney Hanlon ◽

Ranjit Banwait ◽

Abdel Kareem Azab ◽

...

Keyword(s):

Phase I ◽

Board Of Directors ◽

Phase Ii ◽

Plasma Cells ◽

Median Number ◽

Maximum Tolerated Dose ◽

Recommended Dose ◽

Advisory Committees ◽

Post Dose ◽

Prior Therapy

Abstract Introduction This study aimed to determine the safety and activity of plerixafor (CXCR4 inhibitor) in combination with bortezomib as a chemosensitization strategy in multiple myeloma (MM). The phase I portion of this study was to determine the maximum tolerated dose (MTD). The phase II portion was designed to assess the toxicity profile and the proportion of overall confirmed response (CR + PR). This was based on preclinical studies demonstrating that plerixafor (Mozobil, Sanofi Corporation, MA) induces de-adhesion of MM cells and sensitization to bortezomib in preclinical animal models. Methods Eligibility criteria included: 1) patients with relapsed or relapsed/refractory MM with 1–5 prior lines of therapy including bortezomib (unless patients were refractory to bortezomib), 2) measurable disease, 3) not receiving chemotherapy > 3 weeks, or biological therapy for MM > 2 weeks prior to study treatment. Phase I included eight cohorts with different doses and two treatment schedules. In cohorts 1–5, patients received plerixafor at the recommended dose subcutaneously (sq) on days 1–6 of each cycle and bortezomib at the recommended dose twice a week on days 3, 6, 10, and 13 every 21 days. Cohort 5b–7 plerixafor was given at the recommended dose sq on days 1, 3, 6, 10, and 13 and bortezomib was given at the recommended dose twice a week on days 3, 6, 10, and 13 every 21 days. For the phase II portion patients received plerixafor at the MTD, 320 mcg/kg sq on days 1, 2, 3, 6, 10, and 13. Bortezomib was given 1.3 mg/m2 sq twice a week on days 3, 6, 10, 13, every 21 days. Dexamethasone was given at 40mg on days of Bortezomib. Patients in both cohorts were assessed after every cycle by IMWG criteria. Patients who had a response or stable disease went on to receive a total of 8 cycles with maintenance therapy for patients with at least a minimal response (MR). Peripheral blood samples were obtained from the patients in the phase I portion of trial at 0, 1, 2, 3, 4 and 24 hours post-dose on days 1 and 3, and time points 0, 2, and 4 hours post-dose on days 6, 10 and 13 of cycle 1. Results Twenty-five patients were enrolled in the phase I portion of trial from June 2009 to May 2011. Median age was 60 years (range, 44–85) and median lines of prior therapy were 2 (range, 1–4) with all but 3 patients receiving prior bortezomib. The median number of cycles on therapy was 3 (1–11). Dose limiting toxicities including insomnia, restlessness, and psychosis were observed in two patients at dose level 6 (plerixafor 0.40 mg/kg and bortezomib 1.3 mg/m2). To further explore the safety of maximum tolerated dose, three additional patients were enrolled at dose level 5b (plerixafor 0.32 mg/kg and bortezomib 1.3 mg/m2). There were no grade 4 toxicities. Grade 3 toxicities included lymphopenia (40%), hypophosphatemia (20%), anemia (10%), hyponatremia (10%), hypercalcemia (10%), and bone fracture due to myeloma bone disease (10%). In the phase II portion, eleven patients have been treated to date. The median age is 65 (56-80), the median lines of prior therapy were 2 (1-4). The median number of cycles on therapy was 4 (1-8). Grade 4 toxicities include lymphopenia (10%) and thrombocytopenia (20%). Grade 3 toxicities include anemia (10%), thrombocytopenia (10%), lymphopenia (20%), hyperglycemia (10%), and hypophosphatemia (10%). Ten patients are evaluable for response, including 1(10%) very good partial response (VGPR) and 3 (30%) partial response (PR), with an overall response rate (VGPR + PR) of 4 (40%) in this relapsed/refractory population. In addition, 4 (40%) patients had stable disease (SD), and 2 (20%) had progressive disease (PD). We also examined in vivo mobilization of plasma cells, CD34+ hematopoietic stem cells and other accessory bone marrow cells. Analysis of these samples showed rapid mobilization of plasma cells at 2 hours post-plerixafor with a rapid return to normal levels at 4 and 24 hours post plerixafor. Similar results were observed on days 1 and 3. Conclusions The combination of plerixafor and bortezomib was generally well tolerated in this study, with minimal neuropathy or other toxicities seen to date. The responses observed are encouraging with 40% PR or better in this relapsed and refractory population including prior bortezomib therapy. This study was supported by R01CA133799-01, and by Sanofi and Millennium/Takeda Corporations. Disclosures: Ghobrial: Onyx: Membership on an entity’s Board of Directors or advisory committees; BMS: Membership on an entity’s Board of Directors or advisory committees; BMS: Research Funding; Sanofi: Research Funding; Novartis: Membership on an entity’s Board of Directors or advisory committees. Munshi:Celgene: Consultancy; Novartis: Consultancy; Millennium: Consultancy. Anderson:celgene: Consultancy; onyx: Consultancy; gilead: Consultancy; sanofi aventis: Consultancy; oncopep: Equity Ownership; acetylon: Equity Ownership. Richardson:Millenium: Consultancy; Celgene: Consultancy; Johnson & Johnson: Consultancy; Bristol-Myers Squibb: Consultancy; Novartis: Consultancy.

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Final Results of the Phase I/II Study of Chemosensitization Using the CXCR4 Inhibitor Plerixafor in Combination with Bortezomib in Patients with Relapsed or Relapsed/Refractory Multiple Myeloma

Blood ◽

10.1182/blood.v126.23.4256.4256 ◽

2015 ◽

Vol 126 (23) ◽

pp. 4256-4256 ◽

Cited By ~ 1

Author(s):

Irene M. Ghobrial ◽

Kenneth H. Shain ◽

Jacob Laubach ◽

Patrick Henrick ◽

James Vredenburg ◽

...

Keyword(s):

Phase I ◽

Board Of Directors ◽

Phase Ii ◽

Research Funding ◽

Plasma Cells ◽

Response Rate ◽

Phase Ii Study ◽

Median Number ◽

Recommended Dose ◽

Advisory Committees

Abstract PURPOSE: This study aimed to determine activity and safety of the CXCR4 inhibitor plerixafor in combination with bortezomib and dexamethasone in patients with relapsed or refractory Multiple Myeloma (MM). This was based on our preclinical studies showing that plerixafor (Mozobil, Sanofi Corporation) induces de-adhesion of MM cells and sensitization to bortezomib in preclinical animal models. PATIENTS AND METHODS: Theprimary endpoint of the phase I study was the maximum tolerated dose (MTD) and for the phase II study, the safety and response rate of the combination. Eligibility criteria included patients with relapsed or relapsed/refractory MM with 1-5 prior lines of therapy including bortezomib (unless patients were refractory to bortezomib). The phase I included 8 cohorts with different doses and two treatment schedules. In cohorts 1-5, patients received plerixafor at the recommended dose sq on days 1-6 of each cycle and bortezomib at the recommended dose twice a week on days 3, 6, 10, and 13 every 21 days. In cohort 5b-6, plerixafor was given at the recommended dose sq on days 1, 3, 6, 10, and 13 and bortezomib was given at the recommended dose twice a week on days 3, 6, 10, and 13 every 21 days. For the phase II portion patients received plerixafor at the MTD established in phase I of trial, 320 mcg/kg sq on days 1, 2, 3, 6, 10, and 13. Bortezomib was given 1.3 mg/m2 IV or sq twice a week on days 3, 6, 10, 13, every 21 days. Dexamethasone was given at 40mg on days of Bortezomib. RESULTS: A total of 58 patients were enrolled on this study from June 2009 to March 2015, with 25 on the phase I and 33 on the phase II study. In the phase I study, the median age was 60 years (range, 43-85), the median number of prior therapies was 2 (range, 1-4), with all but 3 patients receiving prior bortezomib. The median number of cycles on therapy was 4 (1-12). Dose limiting toxicities including insomnia, restlessness, and psychosis were observed in two patients at dose level 6 (plerixafor 0.40 mg/kg and bortezomib 1.3 mg/m2). Therefore, 3 additional patients were enrolled at dose level 5b (plerixafor 0.32 mg/kg and bortezomib 1.3 mg/m2). There were no grade 4 toxicities. Grade 3 toxicities included lymphopenia (40%), hypophosphatemia (20%), anemia (10%), hyponatremia (10%), hypercalcemia (10%), and bone fracture due to myeloma bone disease (10%). Twenty-three patients were evaluable for response, including 1 (4%) complete response (CR), 1 (4%) very good partial response (VGPR), 1 partial remission (PR) and 2 (9%) MR, and 15 (65%) having stable disease with only 3 (13%) progressive disease (PD). In the phase II study, the median age was 63 (46-83). The median number of prior therapies was 2 (1-5), with 22 (66%) who have received prior bortezomib. The median number of cycles on therapy is 5 (1-24). The response rate included 5 VGPR (16%), 11 PR (35%) with an overall response rate of 51% and another 11 (35%) stable disease. Grade 3/4 toxicities included thrombocytopenia (68%), lymphopenia (6%), hypophosphatemia (2%), anemia (4%), infections (4%), hyponatremia (2%), hypercalcemia (2%) and neurological toxicity (2%). We also examined in vivo mobilization of plasma cells, CD34+ hematopoietic stem cells and other accessory bone marrow cells. Analysis of these samples showed rapid mobilization of plasma cells at 2 hours post-plerixafor with a rapid return to normal levels at 4 and 24 hours post plerixafor. CONCLUSIONS: The combination of plerixafor and bortezomib is generally well tolerated with minimal neuropathy or other toxicities seen to date. The responses observed are strongly encouraging with 51% ORR in this relapsed and refractory population. This study was supported by R01CA133799-01, and by Sanofi and Takeda Corporations. Disclosures Off Label Use: Plerixafor in myeloma. Azab:Verastem: Research Funding; Selexys: Research Funding; Karyopharm: Research Funding; Cell Works: Research Funding; Targeted Therapeutics LLC: Other: Founder and owner . Schlossman:Millennium: Consultancy. Richardson:Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; Gentium S.p.A.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium Takeda: Membership on an entity's Board of Directors or advisory committees.

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Role of TORC1 and TORC2 in Multiple Myeloma

Blood ◽

10.1182/blood.v118.21.1815.1815 ◽

2011 ◽

Vol 118 (21) ◽

pp. 1815-1815

Author(s):

Patricia Maiso ◽

Yi Liu ◽

Abdel Kareem Azab ◽

Brittany Morgan ◽

Feda Azab ◽

...

Keyword(s):

Cell Cycle ◽

Bone Marrow ◽

Board Of Directors ◽

Cell Lines ◽

Stromal Cells ◽

Research Funding ◽

Plasma Cells ◽

Advisory Committees ◽

Cycle Arrest

Abstract Abstract 1815 Mammalian target of rapamycin (mTOR) is a downstream serine/threonine kinase of the PI3K/Akt pathway that integrates signals from the tumor microenvironment. Mechanistically, mTOR operates in two distinct multi-protein complexes, TORC1 (Raptor) and TORC2 (Rictor). TORC1 leads to the phosphorylation of p70S6 kinase and 4E- BP1, while TORC2 regulates phosphorylation of Akt and other kinases. In multiple myeloma (MM), PI3K/Akt plays an essential role enhancing cell growth and survival and is activated by the loss of the tumor suppressor gene PTEN and by the bone marrow microenvironment. Rapamycin and its analogues have not shown significant activity in MM, likely due to the lack of inhibition of TORC2. In this study, we dissected the baseline activity of the PI3K/Akt/mTOR pathway TORC1/2 in MM cell lines with different genetic abnormalities. Methods: Eight different MM cell lines and BM samples from MM patients were used in the study. The mechanism of action was investigated by MTT, Annexin V, cell cycle analysis, immunochemistry, Western-blotting and siRNA assays. For the in vivo analyses, Luc+/GFP+ MM.1S cells (2 × 106/mouse) were injected into the tail vein of 30 SCID mice and tumor progression was detected by bioluminescence imaging. In vivo homing was checked by in vivo flow. Nanofluidic proteomic immunoassays were performed in selected tumors. Results: Raptor (TORC1) and Rictor (TORC2) knockdowns led to significant inhibition of proliferation of MM cells even in the presence of bone marrow stromal cells, this effect was also accompanied by inactivation of p-Akt, p-rS6 and p-4EBP1. We used INK128, a dual and selective TORC1/2 kinase inhibitor with similar effects to Raptor plus Rictor knockdown. We examined the protein expression levels of both mTOR complex and their downstream effectors in MM plasma cells from patients and cell lines. mTOR, Akt, pS6R and 4E-BP1 are constitutively activated in all samples. We showed that dual TORC1/2 inhibition is much more active than TORC1 inhibition alone (rapamycin) even in the presence of cytokines or stromal cells. INK128 induced cell cycle arrest, autophagy and apoptosis in cell lines and primary plasma cells even in the presence of bone marrow stromal cells (BMSCs). INK128 also showed a significant effect inhibiting cell adhesion in our in vivo homing model. Oral daily treatment with INK128 highly decreased the percentage of CD138+ tumor plasma cells in mice implanted with MM cells and reduced the levels of p-Akt and p-4EBP. These results suggest that potent and complete blockade of mTOR as part of TORC1 and TORC2 is potential therapeutic strategy to induce cell cycle arrest, apoptosis and disruption of MM cells interaction with the BM microenvironment. Conclusion: Dual inhibition of TORC1 and TORC2 represent a new and promising approach in the treatment of MM and its microenvironment. The ability of INK128 to inhibit both TORC1 and TORC2 strongly supports the potential use of this compound in MM patients. Disclosures: Liu: Intellikine: Employment. Roccaro:Roche: Research Funding. Rommel:Intellikine: Employment. Ghobrial:Celgene: Consultancy; Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Research Funding; Noxxon: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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The Transmembrane Receptor Roundabout 1 (ROBO1) Is Necessary for Multiple Myeloma Proliferation and Homing to the Bone Marrow Niche

Blood ◽

10.1182/blood-2019-128778 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 507-507

Author(s):

Giada Bianchi ◽

Peter G. Czarnecki ◽

Matthew Ho ◽

Aldo M. Roccaro ◽

Antonio Sacco ◽

...

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Tumor Volume ◽

Plasma Cells ◽

P Value ◽

Advisory Committees ◽

Bm Niche ◽

C Terminus ◽

Necessary And Sufficient

Introduction Multiple myeloma (MM) is characterized by dissemination and accumulation of plasma cells in the bone marrow (BM), which promotes tumor cell growth and therapy resistance. ROBO1 is a conserved transmembrane receptor of the Ig superfamily with no intrinsic catalytic activity, and its role in MM pathogenesis is unknown. Material and Methods We first analyzed ROBO1 expression via western blot and/or immunohistochemistry (IHC). Gene expression profiling in a cohort of 170 newly diagnosed MM patients (IFM170) was used to compare ROBO1 expression across primary MM and BM stroma cells (BMSC), and normal BM plasma cells (PC). We used short hairpin RNA (shRNA) for stable ROBO1 knock down (KD) and CRISPR-Cas9 for ROBO1 knock out (KO). For protein structure-function and rescue studies, ROBO1 KO MM cells were transduced with a lentiviral vector expressing either full-length (FL) or truncated ROBO1 mutants devoid of extracellular (Cyt) or intracellular domain (DeltaCyt), including patient-derived truncating mutations, with a C-terminus triple FLAG tag. FLAG immunoprecipitation (IP) followed by mass spectrometry or western blotting and immunofluorescence (IF) were used to identify ROBO1 interacting partners and ROBO1 cellular localization. We used a hydrogel encapsulation system to study proliferation in a 3D system. To study extramedullary and intramedullary MM growth in vivo, WT and ROBO1 KO OPM2 were injected either subcutaneously (plasmacytoma model) or intra-medullary in femoral bones of donor mice which were then implanted subcutaneously in recipient SCID mice (µ-SCID model). PET-CT was used to assess tumor volume. Mouse tumors were retrieved for IHC and RNA extraction followed by RNA sequencing. To study dissemination and homing, KO and FL addback OPM2 cells were injected intravenously in SCID mice. Femurs and plasmacytoma were retrieved at endpoint for IHC. Results ROBO1 is highly expressed in human MM cell lines and primary MM cells with highest expression in cells carrying the high risk t(4;14) cytogenetic and low/absent expression in normal PC. Of human cancer cell lines, ROBO1 expression was limited to late B cell lineage; and ROBO1 KD was selectively cytotoxic against MM, but not other hematologic cancers. ROBO1 KO significantly decreases proliferation in a 3D culture system and tumor growth in extramedullary (mean tumor volume KO versus WT plasmacytoma: 457 versus 1323 mm3, p value= 0.02) and intramedullary (mean tumor volume KO versus WT: 823 versus 2684 mm3, p value= 0.001) murine models of human MM. ROBO1 KO MM cells show decreased adhesion to BM endothelial and BMSC, which is fully rescued by FL ROBO1 addback. To address whether ROBO1 loss alters dissemination/homing of MM cells in vivo, we injected mice intravenously with ROBO KO or FL addback OPM2 cells. While ROBO1 KO resulted in a modest, non-statistically significant prolongation in mouse OS (90 versus 75 days, respectively, p value 0.2), the pattern of disease was strikingly different. As expected, ROBO1 FL mice developed hindlimb paralysis with extensive BM infiltration with MM. Importantly, ROBO1 KO mice demonstrated reduced BM infiltration and developed solitary plasmacytoma. We next showed that ROBO1 C-terminus domain is necessary and sufficient to rescue ROBO1 KO proliferative defect while expression of ROBO1 truncations, including patient-derived frameshift mutations, acted as dominant negative. IP showed avid interaction of ROBO1 with ABL1. Interestingly, we showed that the cytosolic domain of ROBO1 undergoes cleavage and translocates to the nucleus, where its function is now being studied. Conclusions We show that ROBO1 is necessary for MM homing to the BM niche and for MM growth within and outside the BM space. ROBO1 cytosolic domain undergoes proteolytic cleavage and translocates to the nucleus and is necessary and sufficient to rescue ROBO1 KO defective proliferation. Based on our data, we propose a dual model for ROBO1 in MM: the full transmembrane receptor is involved in regulating adhesion, dissemination and homing of MM cells within the BM niche; the cleaved intracellular C-terminus domain participates in transcriptional regulation, promoting MM proliferation. These data suggest that ROBO1 C-terminus may be a novel molecular target in MM. Disclosures Roccaro: Celgene: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Associazione Italiana per al Ricerca sul Cancro (AIRC): Research Funding; Associazione Italiana per al Ricerca sul Cancro (AIRC): Research Funding; European Hematology Association: Research Funding; Transcan2-ERANET: Research Funding; European Hematology Association: Research Funding; AstraZeneca: Research Funding; Transcan2-ERANET: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Research Funding. Ghobrial:Takeda: Consultancy; Sanofi: Consultancy; Amgen: Consultancy; BMS: Consultancy; Celgene: Consultancy; Janssen: Consultancy. Anderson:Sanofi-Aventis: Other: Advisory Board; Bristol-Myers Squibb: Other: Scientific Founder; Oncopep: Other: Scientific Founder; Amgen: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau.

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Germline Runx1 Mutations Induce Inflammation in Hematopoietic Stem and Progenitor Cells and Predispose to Hematologic Malignancies

Blood ◽

10.1182/blood-2021-153433 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 2201-2201

Author(s):

Mohd Hafiz Ahmad ◽

Mahesh Hegde ◽

Waihay J. Wong ◽

Andrew Dunbar ◽

Anneliese Carrascoso ◽

...

Keyword(s):

Bone Marrow ◽

Dna Damage ◽

Progenitor Cells ◽

Board Of Directors ◽

Research Funding ◽

Bone Marrow Cells ◽

Hematologic Malignancies ◽

Advisory Committees ◽

Hematopoietic Stem

Abstract Patients with Familial Platelet disorder (FPD) have a germline RUNX1 mutation and are at high risk to developing hematologic malignancies (HM), primarily myelodysplastic syndrome and acute myeloid leukemia (lifetime risk~40%). To understand how germline RUNX1 mutations predispose to HM in vivo, we developed a Runx1 R188Q/+ mouse strain , mimicking the FPD-associated R201Q missense mutation. Analysis of the bone marrow cells in Runx1 R188Q/+ mice revealed a significant increase in the total number of bone marrow cells. Immunophenotypic analysis using Sca-1 and Cd86 markers revealed a significant increase in Sca-1 expression in hematopoietic stem and multi-potential progenitor cells, indicating a systemic inflammation in the bone marrow. In addition, the frequency of common-myeloid, granulocytic-monocytic and granulocytic progenitor cells were found significantly increased in the Runx1 R188Q/+ bone marrow. Accordingly, their colony-forming unit capacity was increased when compared to wildtype controls (wt/Runx1 R188Q/+ CFU average = 45/85), indicating a myeloid bias. The number and size of platelets were not altered in Runx1 R188Q/+ mice. However, platelet function was significantly reduced. The activation of the Cd41/Cd61 fibrinogen receptor complex in membrane after thrombin treatment was reduced in Runx1 R188Q/+ platelets. Similarly, the translocation of P-selectin by alpha granules and the secretion of serotonin by the dense granules were also reduced. Hematopoietic progenitor cells isolated from Runx1 R188Q/+ mice revealed a significant reduction in DNA-damage repair response in vitro. Quantitative analysis of nuclei with 53bp1-positive foci in response to ionizing radiation showed a marked increase in 53bp1-positive foci in Runx1 R188Q/+ nuclei, suggesting that Runx1 R188Q/+ cells have a defective repair of double strand DNA breaks. Furthermore, expression of DNA-damage repair pathway-associated Pmaip1 (Noxa) was significantly reduced in irradiated Runx1 R188Q/+ hematopoietic progenitor cells. To understand underlying mechanism responsible for the observed myeloid bias in Runx1 R188Q/+ cells, transcription profiling analysis was performed in myeloid progenitors from wildtype and Runx1 R188Q/+ mice, utilizing RNA-sequencing. A total of 39 genes were significantly deregulated (> 1.5 FC; FDR<0.05), including 8 up- and 31 down-regulated genes. The expression of three repressed genes with important function in hematopoietic differentiation and malignancy (Cdh1, Gja1, and Fcer1a) were validated by qRT-PCR. To study the FPD-associated pre-leukemic process in vivo, wildtype and Runx1 R188Q/+ mice were monitored for 20 months. Although Runx1 R188Q/+ mice remained healthy for 18 months, somatic mutations in their leukocytes were evident at 12 months. Targeted sequencing of 578 cancer genes (mIMPACT panel) in leukocyte DNA of two Runx1 R188Q/+ mice identified somatic mutations in Kdm6a, Setd1b, Amer1, and Esco1 (variant allele frequencies between 0.5% and 2.8%). These mutations were confirmed at stable frequency for eight following months. Since loss of the second Runx1 allele is a frequent somatic event in progression to FPD/HM, we evaluated the predisposition to HM in Mx1Cre-Runx1 R188Q/fl mice over time. Unlike Runx1 R188Q/+ mice, Runx1 R188Q/Δ mice succumbed to myeloid leukemia with a median latency of 37.5 weeks and full penetrance. In addition, the expression of oncogenic Nras-G12D, in Runx1 R188Q/Δ mice reduced the median latency to 14.7 weeks. These studies demonstrate that FPD-associated Runx1 germline mutations induce inflammation in hematopoietic stem cells, induce myeloid expansion with defective DNA-damage response and predispose to HM over time. These studies suggest that anti-inflammatory therapies in pre-symptomatic FPD patients may reduce clonal expansion and predisposition to HM. Disclosures Ebert: Exo Therapeutics: Membership on an entity's Board of Directors or advisory committees; Skyhawk Therapeutics: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Deerfield: Research Funding; GRAIL: Consultancy. Levine: Isoplexis: Membership on an entity's Board of Directors or advisory committees; Auron: Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Membership on an entity's Board of Directors or advisory committees; Zentalis: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; QIAGEN: Membership on an entity's Board of Directors or advisory committees; Ajax: Membership on an entity's Board of Directors or advisory committees; Imago: Membership on an entity's Board of Directors or advisory committees; Mission Bio: Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria; Prelude: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy; Lilly: Honoraria; Morphosys: Consultancy; Roche: Honoraria, Research Funding; Incyte: Consultancy; Astellas: Consultancy; Amgen: Honoraria.

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Phase I Trial of Plerixafor and Bortezomib as a Chemosensitization Strategy In Relapsed or Relapsed/Refractory Multiple Myeloma

Blood ◽

10.1182/blood.v116.21.1943.1943 ◽

2010 ◽

Vol 116 (21) ◽

pp. 1943-1943 ◽

Cited By ~ 1

Author(s):

Irene Ghobrial ◽

Abdel Kareem A. Azab ◽

Jacob P. Laubach ◽

Ranjit Banwait ◽

Meghan Rourke ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Board Of Directors ◽

Plasma Cells ◽

Advisory Committees ◽

Accessory Cells ◽

Dose Levels ◽

Higher Doses ◽

Active Disease

Abstract Abstract 1943 Introduction: Plerixafor (Mozobil®), a potent CXCR4 inhibitor, is approved in combination with G-CSF to mobilize hematopoietic stem cells (HSCs) for autologous transplantation in multiple myeloma (MM) and non Hodgkin's lymphoma (NHL). Another area of investigation consists of exploring whether disruption of the CXCR4 pathway by plerixafor could potentiate the effect of chemotherapy in active disease. This study aimed to establish the maximum tolerated dose (MTD) of plerixafor in combination with bortezomib in patients who have active relapse/refractory MM. This was informed by preclinical studies showing that plerixafor induces de-adhesion of MM cells with sensitization to combination therapy with bortezomib in pre-clinical animal models. Methods: Eligibility criteria include: 1) patients with relapsed or relapsed/refractory MM with any prior lines of therapy including bortezomib, 2) measurable disease, 3) not receiving chemotherapy> 3weeks, or biological/novel therapy for MM > 2 weeks. Patients with active disease received plerixafor at the recommended dose sc on days 1–6 of every cycle. Dose levels include 0.16, 0.24, 0.32, 0.40, and 0.48 mg/kg. Bortezomib was given at the recommended dose twice a week on days 3, 6, 10, and 13 every 21 days. Dose levels include 1.0 and 1.3 mg/m2. Bortezomib was given 60–90 minutes after plerixafor. Patients were assessed after every cycle. Patients who had response or stable disease went on to receive a total of 8 cycles without planned maintenance therapy. 4 dose levels were initially planned at a maximum of 0.24 mg/kg plerixafor. The protocol was then modified to include 3 higher doses of plerixafor, to further evaluate the hypothesis that higher doses may induce better chemosensitization. To examine the in vivo effect of plerixafor and bortezomib on de-adhesion of MM cells and other accessory cells of bone marrow, blood samples were obtained from patients at 0, 2, 4 and 24 hours post-plerixafor injection on days 1 and 3, and time points 0, 2, and 4 hours on days 6, 10 and 13 of cycle 1 and examined for the presence of plasma cells or CD34+ cells using flow cytometry. Results: Thirteen patients have been treated to date, three in each cohort with cohort 5 currently enrolling. The median age is 60, the median lines of prior therapy is 2. All of the patients received prior bortezomib. Three patients were assessed by light chain, two patients had extramedullary disease. The median number of cycles on therapy was 5 (1-8). None of the patients came off study due to toxicity. To date, there have been no dose-limiting toxicities. Overall, the combination is very well tolerated. Grade 3 possibly related toxicities include lymphopenia (30%), hypophosphatemia (15%), anemia (8%), and hyponatremia (8%). No grade 2 or higher neuropathy has been noted in these patients. Twelve patients are evaluable for response, including 1 (8%) complete remission (CR) and 1 (8%) minimal response (MR), with an overall response rate including MR of 2 (16%) in this relapsed/refractory population. In addition, 8 (66%) patients had stable disease (SD), and 2 (18%) had progressive disease (PD). We also examined the number of plasma cells, CD34+ HSCs, and other accessory bone marrow cells (including endothelial progenitor cells and plasmacytoid dendritic cells) in the peripheral blood. Analysis of these samples is ongoing, but preliminary data indicate de-adhesion of plasma cells. Conclusions: : The combination of plerixafor and bortezomib is very well tolerated with minimal neuropathy or other toxicities. The responses observed are encouraging in this relapsed/refractory population. The ability to demonstrate transient de-adhesion of MM cells and accessory cells in vivo indicates that these cells can be separated from their protective stromal environment which may make them more sensitive to chemotherapy. This study was supported by R01CA133799-01, and by Genzyme. Disclosures: Ghobrial: Celgene: Membership on an entity's Board of Directors or advisory committees; Millennium: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Munshi:Millennium Pharmaceuticals: Honoraria, Speakers Bureau. Anderson:Millennium Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Richardson:Celgene: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees.

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Long-Term Experience with Large Granular Lymphocytic Leukemia Evolving after Solid Organ and Hematopoietic Stem Cell Transplantation

Blood ◽

10.1182/blood-2019-130167 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1226-1226

Author(s):

Hassan Awada ◽

Reda Z. Mahfouz ◽

Jibran Durrani ◽

Ashwin Kishtagari ◽

Deepa Jagadeesh ◽

...

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Viral Infections ◽

De Novo ◽

Post Transplantation ◽

Advisory Committees ◽

Hematopoietic Stem ◽

Post Transplant ◽

Stat3 Mutations

T-cell large granular lymphocyte leukemia (T-LGLL) is a clonal proliferation of cytotoxic T lymphocytes (CTL). T-LGLL mainly manifest in elderly and is associated with autoimmune diseases including rheumatoid arthritis (RA), B cell dyscrasias, non-hematologic cancers and immunodeficiency (e.g., hypogammaglobulinemia). LGL manifestations often resemble reactive immune processes leading to the dilemmas that LGLs act like CTL expansion during viral infections (for example EBV associated infectious mononucleosis). While studying a cohort of 246 adult patients with T-LGLL seen at Cleveland Clinic over the past 10 years, we encountered 15 cases of overt T-LGLL following transplantation of solid organs (SOT; n=8) and hematopoietic stem cell transplantation (HSCT; n=7). Although early studies reported on the occurrence of LGL post-transplant, these studies focused on the analysis of oligoclonality skewed reactive CTL responses rather than frank T-LGLL. We aimed to characterize post-transplantation T-LGLL in SOT and HSCT simultaneously and compare them to a control group of 231 de novo T-LGLL (cases with no history of SOT or HSCT). To characterize an unambiguous "WHO-defined T-LGLL" we applied stringent and uniform criteria. All cases were diagnosed if 3 out of 4 criteria were fulfilled, including: 1) LGL count >500/µL in blood for more than 6 months; 2) abnormal CTLs expressing CD3, CD8 and CD57 by flow cytometry; 3) preferential usage of a TCR Vβ family by flow cytometry; 4) TCR gene rearrangement by PCR. In addition, targeted deep sequencing for STAT3 mutations was performed and charts of bone marrow biopsies were reviewed to exclude other possible conditions. Diagnosis was made 0.2-27 yrs post-transplantation (median: 4 yrs). At the time of T-LGLL diagnosis, relative lymphocytosis (15-91%), T lymphocytosis (49-99%) and elevated absolute LGL counts (>500 /µL; 93%) were also seen. Post-transplantation T-LGLL were significantly younger than de novo T-LGLL, (median age: 48 vs. 61 yr; P<.0001). Sixty% of post-transplantation T-LGLL patients were males. Fifteen% of patients had more cytogenetic abnormalities compared to de novo T-LGLL, had a lower absolute LGL count (median: 4.5 vs. 8.5 k/µL) and had less frequent neutropenia, thrombocytopenia and anemia (27 vs. 43%, 33 vs. 35% and 20% vs. 55%; P=.01). TCR Vb analysis identified clonal expansion of ≥1 of the Vb proteins in 60% (n=9) of the patients; the remaining 40% (n=6) of the cases had either a clonal process involving a Vb protein not tested in the panel (20%; n=3) or no clear expansion (20%; n=3). Signs of rejection were observed in 20% (n=3/15) and GvHD in 13% (n=2/15) of the patients. Post-transplantation, 27% of cases presented with neutropenia (absolute neutrophil count <1.5 x109/L; n=4), 33% with thrombocytopenia (platelet count <150 x109/L; n=5) and 25% with anemia (hemoglobin <10 g/dL; n=3). T-LGLL evolved in 10 patients (67%; 10/15) despite IST including cyclosporine (n=5), tacrolimus (n=4), mycophenolate mofetil (n=5), cyclophosphamide (n=1), anti-thymocyte globulin (n=1), and corticosteroids (n=6). Lymphadenopathy and splenomegaly were seen in 13% (n=2) and 33% (n=5) of the patients. Other conditions observed were MGUS (20%; n=3) and RA (7%; n=1). Conventional cytogenetic showed normal karyotype in 89% (n=11, tested individuals 13/15). Somatic STAT3 mutations were identified in 2 patients. Sixty% of cases (n=9) were seropositive for EBV when tested at different time points after transplant. Similarly, 53% (n=8) were seropositive for CMV, of which, 5 were positive post-transplantation and 3 pre-/post-transplantation. The complexity of T-LGLL expansion post-transplantation might be due to several mechanisms including active viral infections, latent oncogenic viral reactivation and graft allo-antigenic stimulation. However, in our cohort graft rejection or GvHD was encountered in a few patients (2 allo-HSCT recipients). Autoimmune conditions were present in 50% of SOT recipients (n=4/ 8, including RA, ulcerative colitis, systemic lupus erythematosus). Some of our patients also had low immunoglobulin levels. Overt EBV (post-transplant lymphoproliferative disorder) and CMV reactivation was diagnosed in only 27% (4/15) of the patients. In sum we report the long term follow up of a cohort of T-LGLL and emphasize the expansion of T-LGLL post-transplant highlighting the difficulty in assigning one unique origin of LGLL. Disclosures Hill: Genentech: Consultancy, Research Funding; Takeda: Research Funding; Celegene: Consultancy, Honoraria, Research Funding; Kite: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Seattle Genetics: Consultancy, Honoraria; Amgen: Research Funding; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; TG therapeutics: Research Funding; AstraZeneca: Consultancy, Honoraria. Majhail:Atara Bio: Consultancy; Mallinckrodt: Honoraria; Nkarta: Consultancy; Anthem, Inc.: Consultancy; Incyte: Consultancy. Sekeres:Syros: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Maciejewski:Alexion: Consultancy; Novartis: Consultancy.

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Pegaspargase Can Safely be Administered in Adults Age 40 and Older with Acute Lymphoblastic Leukemia

Blood ◽

10.1182/blood-2019-124727 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 3816-3816 ◽

Cited By ~ 2

Author(s):

Ryan J. Daley ◽

Sridevi Rajeeve ◽

Charlene C. Kabel ◽

Jeremy J. Pappacena ◽

Sarah E. Stump ◽

...

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Board Of Directors ◽

Research Funding ◽

Lymphoblastic Leukemia ◽

Philadelphia Chromosome ◽

Hypersensitivity Reactions ◽

Newly Diagnosed ◽

Advisory Committees ◽

Hematopoietic Stem ◽

Frontline Treatment

Introduction: Asparaginase (ASP) has demonstrated a survival benefit in pediatric patients (pts) with acute lymphoblastic leukemia (ALL) and is now part of standard-of-care frontline treatment. As a result, asparaginase preparations have been incorporated into the treatment of adult ALL to improve outcomes. Pegaspargase (PEG-ASP), a modified version of asparaginase with prolonged asparagine depletion, appears to be safe in adults up to age 40 (Stock, et al., Blood, 2019), but is associated with a unique spectrum of toxicities, the risks of which appear to increase with age. Therefore, the safety of PEG-ASP remains a significant concern in older adults w/ ALL. Methods: We conducted a single center retrospective chart review of pts age ≥40 years who received PEG-ASP as part of frontline induction/consolidation or reinduction, between March 2008 and June 2018 at Memorial Sloan Kettering Cancer Center. The primary objective was to evaluate the tolerability and toxicity of PEG-ASP based on the incidence and severity of ASP-related toxicities (hypersensitivity reactions, hypertriglyceridemia, hyperbilirubinemia, transaminitis, pancreatitis, hypofibrinogenemia, etc) according to the Common Terminology Criteria for Adverse Events, version 4.03. Laboratory values recorded were either the peak or the nadir, the more appropriate for toxicity assessment, within a 4-week period following PEG-ASP administration. Secondary objectives were to determine the total number of doses of PEG-ASP administered in comparison to the number of doses intended, and to characterize the rationale for PEG-ASP discontinuation when applicable. Fisher's exact test was used to compare the incidence of PEG-ASP toxicities with respect to pt and treatment characteristics (regimen, age, BMI, gender, Philadelphia chromosome positive (Ph+) vs. Ph-, presence of extramedullary disease, PEG-ASP dose). P values were not adjusted for multiple comparisons. Results: We identified 60 pts with ALL (40 B-ALL and 20 T-ALL) who received at least one dose of PEG-ASP. Nine pts were Ph+. The median pt age at initiation of the treatment was 53, (range, 40 to 80), and 19 pts had a BMI ≥30 kg/m2. Forty-four pts received treatment for newly diagnosed ALL, and 16 pts for relapsed disease. Table 1 lists pt baseline characteristics. Among the 44 pts with newly diagnosed ALL, 27 pts received PEG-ASP as part of pediatric or pediatric-inspired regimens at doses of 2000 - 2500 units/m2, and 1 pt received a modified dose of 1000 units/m2 due to age. The remaining 16 pts received PEG-ASP at doses of 1000 - 2000 units/m2 for consolidation, per established adult regimens (ALL-2 and L-20; Lamanna, et al., Cancer, 2013). Grade 3/4 ASP-related toxicities with a >10% incidence included: hyperbilirubinemia, transaminitis, hypoalbuminemia, hyperglycemia, hypofibrinogenemia, and hypertriglyceridemia. Frontline treatment regimens in which PEG-ASP was used in consolidation cycles only (ALL-2, L-20) were associated w/ a lower incidence of hyperbilirubinemia (p=0.009) and hypertriglyceridemia (p<0.001) compared to those regimens that included PEG-ASP during induction (pediatric/pediatric-inspired regimens) (Table 2). Younger age (40-59 vs. ≥60 years) was associated with a greater risk of hypertriglyceridemia (p<0.001) and higher PEG-ASP dose (≥2000 vs. <2000 units/m2) was associated with a greater risk of hypertriglyceridemia and hypofibrinogenemia (p=0.002 and p=0.025, respectively). Thirty-eight pts (63%) received all intended doses of PEG-ASP. Six pts stopped PEG-ASP to proceed to allogeneic hematopoietic stem cell transplantation (5 in CR1, 1 in CR2), and 7 pts stopped for hypersensitivity reactions. Hepatotoxicity was the only ASP-related toxicity that led to PEG-ASP discontinuation occurring in 5 pts (hyperbilirubinemia, N=4; transaminitis, N=1). The total number of intended doses of PEG-ASP based on regimens used was 186, and 112 were administered. Conclusion: PEG-ASP was incorporated into the treatment of 60 adult ALL pts age ≥40, with manageable toxicity. Seven pts discontinued PEG-ASP due to hypersensitivity reactions and 5 discontinued due to hepatotoxicity, but other reported toxicities did not lead to PEG-ASP discontinuation and the majority of the pts completed all intended doses of PEG-ASP. This study suggests that with careful monitoring, PEG-ASP can safely be administered in adults ≥40 years of age. Disclosures Rajeeve: ASH-HONORS Grant: Research Funding. Tallman:UpToDate: Patents & Royalties; Oncolyze: Consultancy, Membership on an entity's Board of Directors or advisory committees; Delta Fly Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Rigel: Consultancy, Membership on an entity's Board of Directors or advisory committees; Cellerant: Research Funding; Tetraphase: Consultancy, Membership on an entity's Board of Directors or advisory committees; Nohla: Consultancy, Membership on an entity's Board of Directors or advisory committees; BioLineRx: Consultancy, Membership on an entity's Board of Directors or advisory committees; Orsenix: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; ADC Therapeutics: Research Funding; Biosight: Research Funding; Jazz Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; KAHR: Consultancy, Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees. Geyer:Dava Oncology: Honoraria; Amgen: Research Funding. Park:Takeda: Consultancy; Allogene: Consultancy; Amgen: Consultancy; AstraZeneca: Consultancy; Autolus: Consultancy; GSK: Consultancy; Incyte: Consultancy; Kite Pharma: Consultancy; Novartis: Consultancy.

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Lower Hematopoietic Progenitor Cell Counts and Yields at Subsequent Donations Is Influenced By a Shorter Inter-Donation Interval between the First and Subsequent Mobilizations

Blood ◽

10.1182/blood-2019-123492 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1962-1962

Author(s):

Sandhya R. Panch ◽

Brent R. Logan ◽

Jennifer A. Sees ◽

Bipin N. Savani ◽

Nirali N. Shah ◽

...

Keyword(s):

Stem Cell ◽

Board Of Directors ◽

Peripheral Blood ◽

Research Funding ◽

Time Interval ◽

Advisory Committees ◽

Hematopoietic Stem ◽

Peripheral Blood Cd34 ◽

Cell Counts ◽

Cd34 Cells

Introduction: Approximately 7% of unrelated hematopoietic stem cell (HSC) donors are asked to donate a subsequent time to the same or different recipient. In a recent large CIBMTR study of second time donors, Stroncek et al. incidentally found that second peripheral blood stem cell (PBSC) collections had lower total CD34+ cells, CD34+ cells per liter of whole blood processed, and CD34+ cells per kg donor weight. Based on smaller studies, the time between the two independent PBSC donations (inter-donation interval) as well as donor sex, race and baseline lymphocyte counts appear to influence CD34+ cell yields at subsequent donations. Our objective was to retrospectively evaluate factors contributory to CD34+ cell yields at subsequent PBSC donation amongst NMDP donors. Methods. The study population consisted of filgrastim (G-CSF) mobilized PBSC donors through the NMDP/CIBMTR between 2006 and 2017, with a subsequent donation of the same product. evaluated the impact of inter-donation interval, donor demographics (age, BMI, race, sex, G-CSF dose, year of procedure, need for central line) and changes in complete blood counts (CBC), on the CD34+ cell yields/liter (x106/L) of blood processed at second donation and pre-apheresis (Day 5) peripheral blood CD34+ cell counts/liter (x106/L) at second donation. Linear regression was used to model log cell yields as a function of donor and collection related variables, time between donations, and changes in baseline values from first to second donation. Stepwise model building, along with interactions among significant variables were assessed. The Pearson chi-square test or the Kruskal-Wallis test compared discrete variables or continuous variables, respectively. For multivariate analysis, a significance level of 0.01 was used due to the large number of variables considered. Results: Among 513 PBSC donors who subsequently donated a second PBSC product, clinically relevant decreases in values at the second donation were observed in pre-apheresis CD34+ cells (73.9 vs. 68.6; p=0.03), CD34+cells/L blood processed (32.2 vs. 30.1; p=0.06), and total final CD34+ cell count (x106) (608 vs. 556; p=0.02). Median time interval between first and second PBSC donations was 11.7 months (range: 0.3-128.1). Using the median pre-apheresis peripheral blood CD34+ cell counts from donation 1 as the cut-off for high versus low mobilizers, we found that individuals who were likely to be high or low mobilizers at first donation were also likely to be high or low mobilizers at second donation, respectively (Table 1). This was independent of the inter-donation interval. In multivariate analyses, those with an inter-donation interval of >12 months, demonstrated higher CD34+cells/L blood processed compared to donors donating within a year (mean ratio 1.15, p<0.0001). Change in donor BMI was also a predictor for PBSC yields. If donor BMI decreased at second donation, so did the CD34+cells/L blood processed (0.74, p <0.0001). An average G-CSF dose above 960mcg was also associated with an increase in CD34+cells/L blood processed compared to donors who received less than 960mcg (1.04, p=0.005). (Table 2A). Pre-apheresis peripheral blood CD34+ cells on Day 5 of second donation were also affected by the inter-donation interval, with higher cell counts associated with a longer time interval (>12 months) between donations (1.23, p<0.0001). Further, independent of the inter-donation interval, GCSF doses greater than 960mcg per day associated with higher pre-apheresis CD34+ cells at second donation (1.26, p<0.0001); as was a higher baseline WBC count (>6.9) (1.3, p<0.0001) (Table 2B). Conclusions: In this large retrospective study of second time unrelated PBSC donors, a longer inter-donation interval was confirmed to be associated with better PBSC mobilization and collection. Given hematopoietic stem cell cycling times of 9-12 months in humans, where possible, repeat donors may be chosen based on these intervals to optimize PBSC yields. Changes in BMI are also to be considered while recruiting repeat donors. Some of these parameters may be improved marginally by increasing G-CSF dose within permissible limits. In most instances, however, sub-optimal mobilizers at first donation appear to donate suboptimal numbers of HSC at their subsequent donation. Disclosures Pulsipher: CSL Behring: Membership on an entity's Board of Directors or advisory committees; Miltenyi: Research Funding; Bellicum: Consultancy; Amgen: Other: Lecture; Jazz: Other: Education for employees; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Medac: Honoraria. Shaw:Therakos: Other: Speaker Engagement.

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