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792 citation(s) found for "Lacy, M".

Recovery of polyclonal immunoglobulin serum levels to normal levels after autologous stem cell transplantation predicts disease free survival in patients with multiple myeloma
Geyer, S., Markovic, S. N. , Gertz, MA, Lacy, M. , Kumar, Srishti , Hayman, S. R., Gastineau, D A, Porrata, Luis, João, Cristina , Dispenzieri, Angela

Journal of Clinical Oncology | March 9, 2020 | Volume: 24 | Issue: 18_suppl | Pages: 10088-10088

10.1200/jco.2006.24.18_suppl.10088 Get It

10088 Background: The ability of the immune system to recover its components after autologous stem cell transplantation (ASCT) is known to predict survival in patients with different types of neoplasms. Also, our previous work showed that polyclonal immunoglobulin can be used to improve T cell diversity and, consequently, T cell function in animal models. The aim of this retrospective study was to understand if the recovery of the polyclonal compartment of immunoglobulin in patients with multiple myeloma (MM) at day 100 (± 40d) after ASCT is a predictor factor for survival in MM patients who were subject to ASCT. Methods: From294 patients with IgG-MM subject to ASCT at the Mayo Clinic, Rochester, MN since October, 1993 until June, 2004, 143 patients were studied. The rational to select this group of patients was the fact that they had levels of serum IgM collected at day 100 ± 40 after ASCT recorded. Progression free survival (PFS) was assessed from the day of the transplant. PFS was studied using Kaplan-Meier curves and the univariate and multivariate analysis were done using age-adjusted proportional Cox. The prognostic variables in the multivariate model were: recovered of IgM at day 100, B2 microglobulin, age, conditioning regimen and disease status at the time of transplant. Results: There were 59 females in the study. The median age of the cohort was 58 y (33–75). The median follow up of the study was 26 mo (range, 2-111). PFS was significantly higher in the group who recovered normal serum levels of IgM at D100 compared to the pts who did not. This corresponds to a survival that is 1.5 longer in the group of patients who recovered normal levels of IgM at day100 after ASCT versus the patients who did not (median: 34 to 23 mo, respectively; p=0.05). By univariate analysis, those who did not recover normal serum levels polyclonal immunoglobulin by day 100 after ASCT had a risk of relapse 65% higher than the risk of the patients who recovered. Multivariate analysis suggests that recover the normal levels of polyclonal immunoglobulin after ASCT is an independent prognostic factor for PFS for MM patients after ASCT. Conclusions: These results suggest that polyclonal immunoglobulin is a major factor promoting immunity after ASCT. No significant financial relationships to disclose.
Phase 1 first-in-human dose escalation study of cp-751,871, a specific monoclonal antibody against the insulin like growth factor 1 receptor
Lacy, M. , Alsina, Melissa , Melvin, C., Roberts, Luisa, Yin, D., Petersen, Jane, Birgin, Ann, Poutney, S., Sharma, A. , Yin, D., Petersen, J. F., Gualberto, Antonio

Journal of Clinical Oncology | March 9, 2020 | Volume: 24 | Issue: 18_suppl | Pages: 7609-7609

10.1200/jco.2006.24.18_suppl.7609 Get It

7609 Background: Multiple lines of evidence indicate that the Insulin Like Growth Factor 1 Receptor (IGF-1R) plays a key role in the progression of multiple myeloma (MM). IGF-1 is a growth factor for MM cells. It promotes survival to the cytotoxic effects of chemotherapy in animal models of MM and its blood levels has been shown to correlate with those of paraprotein in MM patients. CP-751,871, a fully human monoclonal antibody, is a highly specific and potent inhibitor of the autophosphorylation of IGF-1R. Methods: Based on its mechanism of action and the potential relevance of IGF-1R in MM, a Phase 1 First-in-Human dose escalation study was initiated with the objective to define the safety and tolerability, and to characterize the pharmacokinetic and pharmacodynamic properties of CP-751,871 in this patient population. Patient’s eligibility included previously treated multiple myeloma in relapse or refractory phase and/or less than complete remission following autologous stem cell transplant or tandem transplant. Results: Following informed consent and screening, 10 dose-escalation cohorts of patients received from 0.025 to 10 mg/kg of CP-751,871 by iv infusion on Day 1 of 4-week cycles. In patients with a suboptimal response to CP-751,871 alone, oral dexamethasone was added to the treatment regimen. Patients received up to 14 cycles of CP-751,871 therapy, alone or in combination with dexamethasone. No dose limiting toxicities have been identified to date. Plasma CP-751,871 exposure increases with dose, and the pharmacokinetic characteristics are consistent with target-mediated disposition. Pharmacodynamic measurements indicate complete target saturation by CP-751,871 for the complete length of the dosing period. One near CR and 2 PR in combination with dexamethasone have been reported. Conclusions: These data indicate that CP-751,871 is well tolerated and may constitute a therapeutic approach for patients with multiple myeloma. [Table: see text]
Prediction of survival using absolute lymphocyte count for newly diagnosed patients with multiple myeloma
Ege, Hilmi, Lacy, Martha Q. , Hayman, Suzanne R. , Kumar, Shaji , Litzow, Mark R. , Gastineau, D A, Porrata, Luis F. , Gertz, Morie A. , Markovic, Svetomir N. , Dispenzieri, Angela

Journal of Clinical Oncology | March 9, 2020 | Volume: 24 | Issue: 18_suppl | Pages: 7605-7605

10.1200/jco.2006.24.18_suppl.7605 Get It

7605 Background: In the setting of autologous stem cell transplantation (ASCT) in multiple myeloma (MM), it has been shown that peripheral blood absolute lymphocyte count (ALC) on day 15 is an independent prognostic factor for clinical outcomes. Recently the International Staging System (ISS) for MM has been developed as a simple staging system to assess survival in newly diagnosed MM patients. The role of ALC on survival in newly diagnosed MM patients is unknown. Methods: Between 1994 and 2002, 1,835 consecutive MM patients were evaluated at the Mayo Clinic, Rochester. Of these patients, we retrospectively analyzed 584 MM patients that were originally diagnosed and followed at the Mayo Clinic. The primary end point was to assess the role of ALC at the time of MM diagnosis on overall survival (OS). OS was measured from the date of diagnosis to time of death or last follow-up. ALC was analyzed as a continuous variable and dichotomized based on finding the optimal cut point based on the log-rank statistic. ALC was then compared to the ISS. Results: The median age of the cohort was 67 years (range: 29–94 years), including 234 females and 350 males. The median follow-up was 32 months (range: 1–136 months). The median ALC at diagnosis was 1.2 x 109/L (range: 0.12–5.44 x 109/L). ALC, as a continuos variables was identified as a prognostic factor for OS (HR= 0.466, 95%CI= 0.396–0.547, p < 0.0001). MM patients with an ALC ≥ 1.3 x 109/L experienced a superior OS compared with MM patients with an ALC < 1.3 x 109/L (55.5 months versus 22.6 months, p< 0.0001). In the multivariate analysis, ALC was independent prognostic factor when compared to the ISS (HR = 0.580, 95%CI=0.518–0.647, p< 0.0001). Conclusions: Our study shows that ALC at diagnosis for MM is an independent prognostic factor for OS, suggesting how the host immune status plays a critical role in the survival of patients with MM. No significant financial relationships to disclose.
Outcome after second stem cell transplantation for relapsed multiple myeloma
Simpson, Lijo, Verma, Rajanshu , Kumar, Shaji , Lacy, Martha Q. , Hayman, Suzanne R. , Litzow, Mark R. , Dispenzieri, Angela , Rajkumar, S. Vincent , Gertz, Morie A.

Journal of Clinical Oncology | March 6, 2020 | Volume: 25 | Issue: 18_suppl | Pages: 8118-8118

10.1200/jco.2007.25.18_suppl.8118 Get It

8118 Background: Autologous stem cell transplantation (ASCT) improves survival and remains the standard of care for patients with newly diagnosed myeloma considered eligible for transplant. However, ASCT is not curative and patients relapse after a median interval of 24–30 months. While new therapeutic options have become available for relapsed MM, repeat ASCT remains an option especially when previously collected stem cells are available. The outcome of pts going to a second SCT in the relapsed setting has not been studied extensively. Methods: We identified pts with myeloma who received a second SCT from a prospectively maintained database. Planned tandem ASCTs were excluded. 56 pts received a second SCT for relapsed MM, including 11 allogeneic SCTs. Among the 45 second ASCTs, 5 were followed by reduced intensity allogeneic SCT and were analyzed with the allogeneic group. Results: The median age at second ASCT was 60.2 yrs (range, 41.3–74.4) and 27 (68%) were males. The median time to second ASCT from diagnosis, first ASCT and relapse were 47.4 mos (22.8–158.6), 36.3 mos (13.5–129.8) and 7.2 mos (1–32) respectively. Among patients receiving second APBSC, 14 (35%) patients were alive with a median follow up of 10.5 mos (1–45 mos). All patients received melphalan conditioning. The median time to neutrophil engraftment was 15 days and platelet engraftment was 16 days. The median hospitalization was 4 days (range 0–33) and there was one transplant related death in the group. The best response included 13 pts with CR (33%), 4 with VGPR (10%), and 19 with PR (48%). MM has relapsed in 22 (55%) pts with a median PFS of 12.5 mos from second ASCT. The median estimated OS from diagnosis, first ASCT and second ASCT were 100.5 mos, 65.9 mos, and 30.6 mos respectively. Among the 16 pts receiving allogeneic SCT, 8 pts (50%) were alive at analysis with a median PFS and OS from transplant of 17.9 mos and 33.5 mos respectively. Conclusions: Second ASCT as salvage therapy for relapsed MM is a viable approach and has a favorable outcome in this selected group of patients. The toxicity, engraftment kinetics, hospitalization and the response rates are comparable to patients undergoing initial ASCT. Allogeneic SCT with or with out a preceding ASCT results in comparable survival in selected patients with high risk disease. No significant financial relationships to disclose.
Cytogenetic analysis using multiple myeloma targets in POEMS syndrome
Kyle, Robert A. , Lust, John A., Lacy, Martha Q. , Greipp, Philip R., Witzig, TE, Bryce, Alan H. , Ketterling, Rhett P. , Gertz, Morie A. , Fonseca, Rafaël , Witzig, T.E. , Rajkumar, S. Vincent , Dispenzieri, Angela

Journal of Clinical Oncology | March 6, 2020 | Volume: 25 | Issue: 18_suppl | Pages: 8116-8116

10.1200/jco.2007.25.18_suppl.8116 Get It

8116 Background: POEMS syndrome, or osteosclerotic myeloma, is an uncommon plasma cell disorder associated with Peripheral neuropathy, Organomegaly, Endocrinopathy, M protein, and Skin changes, as well as bone lesions, Castlemans disease, and edema. The pathogenesis of POEMS is poorly understood, and its clinical course is distinct from Multiple Myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS). While various cytogenetic abnormalities have been well described in MM and MGUS, we provide the first report of testing for these abnormalities in POEMS syndrome. Methods: Using a prospectively held dysproteinemia database, we reviewed all cases of POEMS seen at our institution, identifying 36 with metaphase cytogenetic testing results, and 9 with fluorescence in situ hybridization (FISH) testing results. Combined cytoplasmic immunoglobulin/FISH testing (cIg- FISH) was performed with fluorescent-tagged antibodies to kappa/lambda immunoglobulin and FISH probes corresponding to the following anomalies: trisomies 3, 7, 9, 11, 15 and 17; del13/del13q; 14q32 split/del14; and t(11;14). Results: Five patients had insufficient plasma cells for cIg-FISH, and 9 were adequate for testing. Monosomy 13 was seen in 5 of the 9 cIg-FISH samples of which 2 of these cases also had apparent monosomy 14. cIg-FISH in one patient revealed trisomy 3 and 7. No abnormalities were seen at 11q13 (CCND1), 17p13 (p53) or translocations involving 14q32 (IGH). Thrity-eight total karyotypes analyses were attempted, though two showed an insufficient number of suitable metaphases. Of the 36 karyotype analyses, 31 were normal, 2 displayed characteristic plasma cell anomalies (hyperdiploid with structural anomalies), 2 treated patients displayed del20q anomalies and 1 patient had a constitutional 13;14 translocation. Conclusion: We are the first to report del13 as a possibly common abnormality in POEMS syndrome, detected by cIg-FISH in 5 of 9 (55%) samples with sufficient plasma cells, similar to the rate observed in MM and MGUS. The lack of abnormalities at 14q32 (IgH locus) is in contrast to MM and MGUS. Abnormal karyotypes, consistent with dividing plasma cells, are rare in POEMS, observed in only 2 of 36 (5.5%) cases. These observations could possibly lend insight into all three disorders. No significant financial relationships to disclose.
Novel therapy with 2-methoxyestradiol (2ME2) for the treatment of relapsed and plateau phase multiple myeloma
Lacy, Martha Q. , Richardson, Paul G. , Schlossman, R, Sidor, Carolyn, Richardson, Paul Gerard Guy , Gertz, Morie A. , Dispenzieri, Angela , Greipp, Patricia T. , Witzig, Thomas E. , Anderson, Kenneth C. , Rajkumar, S. Vincent

Journal of Clinical Oncology | March 6, 2020 | Volume: 25 | Issue: 18_suppl | Pages: 8108-8108

10.1200/jco.2007.25.18_suppl.8108 Get It

8108 Background: 2-methoxyestradiol (2ME2) is a natural endogenous product of estradiol metabolism with anti-angiogenic and anti-neoplastic properties that has demonstrated activity against multiple myeloma cell lines and xenografts in immunocompromised mice. We report results of the first phase II clinical trial of 2ME2 in pts with relapsed and plateau phase myeloma. Methods: This trial was designed with a one-stage design to accrue 60 pts in the setting of relapsed and plateau phase myeloma. 2ME2 was administered orally at a dose of 1000 mg daily. After the first 39 pts were accrued, based on the results of ongoing phase I trials, the dose of 2ME2 was increased to 800 mg twice daily for the remaining patients. Pts who were already on study at that point were also allowed to escalate their dose to 800 mg twice daily. The primary endpoint was overall response rate. Responses were assessed using Eastern Cooperative Oncology Group criteria. Results: Sixty patients were treated at Mayo Clinic and Dana Farber Cancer Institute. Median age was 60 years (range, 28–99). Thirty-one patients had relapsed/refractory myeloma and 29 patients had plateau phase myeloma. Median number of prior therapies was 4 including stem cell transplant (48%), thalidomide (62%), bortezomib (6%) and lenalidomide (3%). Therapy was well tolerated. Adverse events were anemia (35%), fatigue (35%), nausea (25%), diarrhea (20%), hot flashes (20%), headache (17%), muscle cramps (15%), and upper respiratory tract infection (15%). Most toxicities were mild (grade 1–2). Estimated progression-free survival rates for all pts at one, two, and three years are 24%, 16%, and 9% respectively. Three pts with plateau phase disease, have been on study for over 4 years without progression at 50, 60, and 63 months. Response assessment is ongoing; so far, whilst no partial responses have been seen, prolonged stable disease has been observed in 3 pts (5%). Conclusions: 2ME2 is a novel agent that appears to be safe and well tolerated. Although no responses have been seen, prolonged stable disease in some pts is promising. Preliminary pharmacokinetic data indicate that the dose of 2ME2 used in this study may be inadequate, and a new formulation with significantly better bioavailability will be tested soon in this patient population. No significant financial relationships to disclose.
Prevention of active multiple myeloma (MM) using IL-1 receptor antagonist (IL-1ra) and low-dose dexamethasone (Dex) and monitoring the high sensitivity C-reactive protein (hsCRP)
Lust, John A., Lacy, Martha Q. , Zeldenrust, Steven R., Greipp, PR, Kumar, Shaji , Geyer, Susan M. , Donovan, Kathleen A., Dispenzieri, Angela , Gertz, Morie A. , Witzig, Thomas E.

Journal of Clinical Oncology | March 6, 2020 | Volume: 25 | Issue: 18_suppl | Pages: 8105-8105

10.1200/jco.2007.25.18_suppl.8105 Get It

8105 Background: IL-6 is the central myeloma growth factor and we have shown that abnormal production of IL-1beta in the myeloma microenvironment stimulates the generation of paracrine IL-6. A Phase II trial was completed using IL-1ra, which inhibits paracrine IL-6 production, and low dose Dexamethasone (Dex), which decreases IL-1 levels through myeloma cell apoptosis, in patients with smoldering/indolent MM (SMM/IMM). These patients are at the greatest risk for progression to active MM and most likely to benefit from anti- cytokine therapy. Methods: Patients that had ≥ 10% bone marrow plasma cells and/or an IgG or IgA M-spike ≥ 3 g/dL and did not require immediate chemotherapy were eligible. A total of 47 patients received 100 mg of IL-1ra SQ qd for 6 months unless clinical progression occurred. Responding patients were allowed to continue on therapy with IL-1ra alone. Low dose Dex (20 mg qweek) was added after 6 months of IL-1ra in non-responding patients. The primary endpoint was progression-free survival (PFS). Results: The 47 patients were at high risk for progression to active MM with 98% having ≥ 10% plasma cells, 89% generating IL-1 levels consistent with myeloma (≥ 1.0), and 32% having bone lesions. All 47 patients received IL-1ra initially and 25/47 subsequently received IL-1Ra/Dex. For the group of 47 patients, the median overall progression-free survival was 37.5 months. Three patients achieved a minor response (MR) to Anakinra alone; 5 pts achieved a PR and 4 patients an MR after addition of Dex. Seven patients had a decrease in the plasma cell labeling index (PCLI; a marker of myeloma cell growth) on Anakinra alone which paralleled a decrease in the high sensitivity CRP (a marker of serum IL-6 levels). The median PFS for patients without (n=12) and with (n=35) a ≥ 15% decrease in their baseline hsCRP was 6 months and > 3 yrs, respectively (p=0.002). Conclusions: In SMM/IMM patients at high risk for progression to active myeloma, treatment with IL-1 inhibitors (IL-1ra ± Dex) results in an increased PFS in patients that demonstrate a ≥15% reduction in the baseline CRP compared to those that do not respond. No significant financial relationships to disclose.
Outcome of patients relapsing early after autologous stem cell transplantation for multiple myeloma
Mahmood, Shameem, Lacy, Martha Q. , Hayman, S. R., Litzow, Mark R. , Kumar, Santosh , Dispenzieri, Angela , Rajkumar, S. Vincent , Gertz, Morie A.

Journal of Clinical Oncology | March 6, 2020 | Volume: 25 | Issue: 18_suppl | Pages: 8022-8022

10.1200/jco.2007.25.18_suppl.8022 Get It

8022 Background: Autologous stem cell transplant (ASCT) is the standard approach for eligible patients (pts) with multiple myeloma (MM). The median time to relapse after early ASCT is 2–3 yrs and overall survival (OS) is 4–5 yrs. Though various risk factors have been identified for early relapse, the outcome of this group of pts is not clearly described. With the advent of newer therapies, it is important to understand the natural history of MM in these pts to design treatment strategies. Methods: A total of 432 pts with MM, undergoing ASCT within 12 months (mos) of diagnosis, with a minimum follow up of 12 mos were studied. Clinical and laboratory data were obtained from a prospectively maintained database and clinical records. Pts were divided into 2 groups: early relapse (relapse <12 mos from ASCT) and late relapse (either relapsed >12 mos after ASCT or disease free at last follow up). Results: There were 94 pts (22%) in the early relapse group and among the late relapse group (N=338), 171 had relapsed beyond 12 mos and 167 were disease free at last follow up. The median time to ASCT was similar in all groups. The early relapse group had a significantly shorter median OS from diagnosis (23.9 vs. 82.2 months; P < 0.001) and from transplant (17.6 mos vs. not reached; P < 0.001). The median OS from relapse was 7.9 mos in this group compared to 39.6 months for the rest. In univariate analysis, elevated CRP, high BM plasma cell%, labeling index (PCLI) >1%, abnormal cytogenetics, presence of circulating PCs at harvest and lack of CR from ASCT predicted for early relapse. In multivariate analysis, an elevated PCLI (RR=2.9; P=0.002) and failure to achieve CR (RR 2.7; P=0.002) was associated with early relapse. Conclusions: Pts who relapse within 12 mos of an ASCT have a very short survival and should be offered trials evaluating novel therapies and combinations. Survival figures from this study represent the benchmark for the comparison of novel approaches in this population. Pts with poor prognostic factors have a short PFS after ASCT and should be considered for alternative approaches. Inability to achieve CR appears to predict shorter PFS and clinical trials evaluating maintenance therapy should be offered in these pts. No significant financial relationships to disclose.
Pharmacodynamic properties of the anti-IGF-IR monoclonal antibody CP-751,871 in cancer patients
Lacy, M. Q., Lipton, A., Demers, Laurence M., Leitzel, Kim , Yin, Da , Pollak, Michaël , Bono, Johann S. de , Yin, D., Roberts, Lewis R. , Sharma, A., Gualberto, Antonio

Journal of Clinical Oncology | March 6, 2020 | Volume: 25 | Issue: 18_suppl | Pages: 3587-3587

10.1200/jco.2007.25.18_suppl.3587 Get It

3587 Background: The Insulin like Growth Factor I receptor (IGF-IR), a tyrosine kinase, is widely expressed in human tissues. IGF- IR and its ligands (IGF-I and IGF-II) are expressed by many human cancers (e.g., breast, prostate, colorectal and non-small cell lung). Binding of the ligands to the IGF-IR activates key cellular signaling pathways important for stimulating cellular proliferation and inhibiting apoptosis. IGF- I and IGF-II are present in the circulation, but also locally expressed in neoplastic tissue. Bioavailability of these ligands is regulated by a family of IGF binding proteins (IGFBPs1–6). CP-751,871, a fully human monoclonal antibody, is a highly specific and potent inhibitor of IGF-IR activation. In vitro experiments show that binding of CP 751,871 to IGF-IR induces receptor internalization and degradation. This antibody has been shown to have antineoplastic activity using both in vivo and in vitro pre-clinical models. Methods: Blood samples were collected for characterization of the pharmacokinetic and pharmacodynamic properties of CP-751,871 in phase 1 trials of this agent given to cancer patients either alone or in combination with chemotherapy. The endpoints assessed included among others: CP-751,871 plasma concentrations, total and free IGF-I, IGFBP-3, soluble IGF-IR and IGF-IR expression on granulocytes and tumor cells. Results: CP 751,871 exposure increased with dose over the 800-fold dose range investigated. Pharmacokinetic profiles were consistent with target-mediated disposition. A dose-dependent downregulation of soluble IGF-IR serum concentration and IGF-IR expression was observed, with sustained inhibition for the entire dosing period (3–4 week cycles) observed at doses ≥ 1.5 mg/kg. As predicted for an agent that interferes with IGF-I action, IGF-I and IGFBP-3 serum levels were up-regulated in a similar dose-dependent manner. Conclusions: The pharmacodynamic endpoints of clinical trials provide evidence that CP-751,871 targets IGF-IR in granulocytes, tumor cells and tissues involved in regulation of the growth hormone -IGF-I axis. These data provide proof of principle for the use of CP-751,871 as a first-in-class therapeutic approach to inhibit the IGF-IR pathway in cancer patients. No significant financial relationships to disclose.
Utilizing multiparametric flow cytometry in the diagnosis of patients with primary plasma cell leukemia
Evans, Laura A. , Jevremović, Dragan , Nandakumar, Bharat , Dingli, David , Lacy, Martha Q. , Hayman, Suzanne R. , Kapoor, Prashant , Leung, Nelson , Fonder, Amie , Hobbs, Miriam, Hwa, Yi L. , Warsame, Rahma , Kourelis, Taxiarchis , Russell, Stephen J. , Lust, John A., Lin, Yi , Siddiqui, Mustaqeem , Kyle, Robert A. , Kumar, Shaji , Dispenzieri, Angela , Leung, Nelson , Hwa, Yi Lisa, Warsame, Rahma , Kourelis, Taxiarchis , Russell, Stephen, Gertz, Morie A , Rajkumar, S Vincent , Gonsalves, Wilson , Russell, Stephen J , Jevremovic, Dragan , Siddiqui, Mustaqeem A , Dingli, David , Lin, Yi , Dispenzieri, Angela , Buadi, Francis K. , Muchtar, Eli , Go, Ronald S. , Gertz, Morie A. , Rajkumar, S. Vincent , Gonsalves, Wilson I.

American Journal of Hematology | March 4, 2020 | Volume: 95 | Issue: 6 | Pages: 637-642

10.1002/ajh.25773 | PMID 32129510 Get It

AbstractThe diagnosis of primary plasma cell leukemia (pPCL) has been made by quantifying circulating plasma cells (cPCs) morphologically on a peripheral blood (PB) smear. However, this technique is not sufficiently sensitive. Multiparametric flow cytometry (MFC) provides a readily available and highly sensitive method to identify and quantify cPCs that could complement PB smear assessment. However, an optimal quantitative cutoff for cPCs by MFC to identify pPCL has not been established. Thus, a total of 591 patients newly diagnosed multiple myeloma (NDMM) patients who had their PB samples evaluated morphologically by PB smear, and immunophenotypically by MFC prior to beginning therapy were evaluated. The presence of ≥200 cPCs/μL by MFC (N = 25 or 5% of the total population) was chosen to identify patients with ≥5% cPCs by PB smear with a specificity of 99% and a sensitivity of 77%. For patients with ≥200 cPCs/μL by MFC compared to the remainder of the cohort, the median Time to next therapy (TTNT) was 18 vs 30 months and the median OS was 38 vs 70 months respectively. Thus, MFC assessment of PB can be utilized in conjunction with the morphological assessment of a PB smear to aid in improving the identification of pPCL among NDMM patients.