Publications by authors named "John Marcelletti"

10 Publications

  • Page 1 of 1

Evidence of a role for functional heterogeneity in multidrug resistance transporters in clinical trials of P-glycoprotein modulation in acute myeloid leukemia.

Cytometry B Clin Cytom 2019 01 17;96(1):57-66. Epub 2018 Oct 17.

Oncology Department, Albert Einstein College of Medicine, Bronx, New York.

Background: Multidrug resistance (MDR) transporter proteins such as P-glycoprotein (P-gp) efflux a variety of chemotherapeutic drugs from acute myeloid leukemia (AML) blasts leading to clinical drug resistance.

Methods: This study examined heterogeneity of MDR functional efflux by AML blasts using two flow cytometry bioassays. Bone marrow specimens (N = 50) from elderly patients with newly diagnosed AML were analyzed for CD34+ blasts with MDR efflux function. Efflux was measured with a fluorescent dye (DiOC ) as a surrogate for oncology drugs that are substrates for MDR efflux. P-gp-mediated efflux was differentiated from non-P-gp MDR activities using zosuquidar, a highly selective P-gp modulator. The bioassays included a zosuquidar-dependent DiOC accumulation bioassay that measured only P-gp. The second method, termed the efflux bioassay, could detect P-gp and other non-P-gp efflux depending on bioassay culture conditions.

Results: Sixty-two percent of the specimens were considered positive for blasts with P-gp function, and 26% of such P-gp-positive specimens also exhibited zosuquidar-resistant (i.e., non-P-gp) MDR efflux activity; 37% of P-gp-negative AML blast specimens displayed zosuquidar-resistant MDR function in the efflux bioassay.

Conclusions: These results confirm the heterogeneous nature of MDR efflux pumps in AML blasts, and provide support for the hypothesis that non-P-gp MDR contributed to negative results with zosuquidar in AML trials like ECOG-ACRIN E3999. © 2018 International Clinical Cytometry Society.
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http://dx.doi.org/10.1002/cyto.b.21737DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6340737PMC
January 2019

11th GCC Closed Forum: cumulative stability; matrix stability; immunogenicity assays; laboratory manuals; biosimilars; chiral methods; hybrid LBA/LCMS assays; fit-for-purpose validation; China Food and Drug Administration bioanalytical method validation.

Bioanalysis 2018 Apr 27;10(7):433-444. Epub 2018 Apr 27.

Worldwide Clinical Trials, Austin, TX, USA.

The 11th Global CRO Council Closed Forum was held in Universal City, CA, USA on 3 April 2017. Representatives from international CRO members offering bioanalytical services were in attendance in order to discuss scientific and regulatory issues specific to bioanalysis. The second CRO-Pharma Scientific Interchange Meeting was held on 7 April 2017, which included Pharma representatives' sharing perspectives on the topics discussed earlier in the week with the CRO members. The issues discussed at the meetings included cumulative stability evaluations, matrix stability evaluations, the 2016 US FDA Immunogenicity Guidance and recent and unexpected FDA Form 483s on immunogenicity assays, the bioanalytical laboratory's role in writing PK sample collection instructions, biosimilars, CRO perspectives on the use of chiral versus achiral methods, hybrid LBA/LCMS assays, applications of fit-for-purpose validation and, at the Global CRO Council Closed Forum only, the status and trend of current regulated bioanalytical practice in China under CFDA's new BMV policy. Conclusions from discussions of these topics at both meetings are included in this report.
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http://dx.doi.org/10.4155/bio-2018-0014DOI Listing
April 2018

Update on biomarkers in neuromyelitis optica.

Neurol Neuroimmunol Neuroinflamm 2015 Aug 23;2(4):e134. Epub 2015 Jul 23.

Stanford University (E.M., M.H.H.), Stanford, CA; Johns Hopkins University (M.L.), Baltimore, MD; University of Oxford (P.J.W.), UK; Tohoku University (D.K.S.), Sendai, Japan; University of São Paulo (D.K.S.), Brazil; University of Colorado (J.L.B.), Denver; Mt. Sinai University (G.R.J.), New York, NY; Thomas Jefferson University (D.C.H.), Philadelphia, PA; IDIBAPS (A.S.), Barcelona, Spain; Montreal Neurological Institute and Hospital (A.B.-O.), McGill University, Montreal, Quebec, Canada; Research Institute and Hospital of National Cancer Center (H.J.K.), Goyang, Korea; KS Hegde Medical Academy (L.P.), Nitte University, Mangalore, India; Oxford University Hospital (M.I.L.), Oxford, UK; University of Southern Denmark (N.A.), Odense; Vejle Hospital (N.A.), Denmark; University Hospital (N.K.), Marrakech, Morocco; MS Center (R.H.), Erasmus MC University Medical Center, Rotterdam, the Netherlands; Service de Neurologie A (R.M.), Hôpital Neurologique Pierre Wertheimer, Hospices Civils de Lyon, Bron, France; Molecular Neuroimmunology (S.J.), Department of Neurology, University Hospital Heidelberg, Germany; Tandem Labs (J.M.), San Diego, CA; University of Michigan Medical School (T.J.S.), Ann Arbor, MI; and David Geffen School of Medicine (M.R.Y.), University of California, Los Angeles.

Neuromyelitis optica (NMO) (and NMO spectrum disorder) is an autoimmune inflammatory disease of the CNS primarily affecting spinal cord and optic nerves. Reliable and sensitive biomarkers for onset, relapse, and progression in NMO are urgently needed because of the heterogeneous clinical presentation, severity of neurologic disability following relapses, and variability of therapeutic response. Detecting aquaporin-4 (AQP4) antibodies (AQP4-IgG or NMO-IgG) in serum supports the diagnosis of seropositive NMO. However, whether AQP4-IgG levels correlate with disease activity, severity, response to therapy, or long-term outcomes is unclear. Moreover, biomarkers for patients with seronegative NMO have yet to be defined and validated. Collaborative international studies hold great promise for establishing and validating biomarkers that are useful in therapeutic trials and clinical management. In this review, we discuss known and potential biomarkers for NMO.
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http://dx.doi.org/10.1212/NXI.0000000000000134DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4516398PMC
August 2015

Calculations for Adjusting Endogenous Biomarker Levels During Analytical Recovery Assessments for Ligand-Binding Assay Bioanalytical Method Validation.

AAPS J 2015 Jul 23;17(4):939-47. Epub 2015 Apr 23.

Immunoanalytical Operations, Tandem Labs, Laboratory Corporation of America® Holdings, 13112 Evening Creek Drive South, San Diego, California, 92128, USA,

It is often necessary to adjust for detectable endogenous biomarker levels in spiked validation samples (VS) and in selectivity determinations during bioanalytical method validation for ligand-binding assays (LBA) with a matrix like normal human serum (NHS). Described herein are case studies of biomarker analyses using multiplex LBA which highlight the challenges associated with such adjustments when calculating percent analytical recovery (%AR). The LBA test methods were the Meso Scale Discovery V-PLEX® proinflammatory and cytokine panels with NHS as test matrix. The NHS matrix blank exhibited varied endogenous content of the 20 individual cytokines before spiking, ranging from undetectable to readily quantifiable. Addition and subtraction methods for adjusting endogenous cytokine levels in %AR calculations are both used in the bioanalytical field. The two methods were compared in %AR calculations following spiking and analysis of VS for cytokines having detectable endogenous levels in NHS. Calculations for %AR obtained by subtracting quantifiable endogenous biomarker concentrations from the respective total analytical VS values yielded reproducible and credible conclusions. The addition method, in contrast, yielded %AR conclusions that were frequently unreliable and discordant with values obtained with the subtraction adjustment method. It is shown that subtraction of assay signal attributable to matrix is a feasible alternative when endogenous biomarkers levels are below the limit of quantitation, but above the limit of detection. These analyses confirm that the subtraction method is preferable over that using addition to adjust for detectable endogenous biomarker levels when calculating %AR for biomarker LBA.
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http://dx.doi.org/10.1208/s12248-015-9756-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4476982PMC
July 2015

Recommendations on incurred sample stability (ISS) by GCC.

Bioanalysis 2014 Sep;6(18):2385-90

Quintiles Bioanalytical & ADME Labs, Ithaca, NY, USA.

The topic of incurred sample stability (ISS) has generated considerable discussion within the bioanalytical community in recent years. The subject was an integral part of the seventh annual Workshop on Recent Issues in Bioanalysis (WRIB) held in Long Beach, CA, USA, in April 2013, and at the Global CRO Council for Bioanalysis (GCC) meeting preceding it. Discussion at both events focused on the use of incurred samples for ISS purposes in light of results from a recent GCC survey completed by member companies. This paper reports the consensus resulting from these discussions and serves as a useful reference for depicting ISS issues and concerns, summarizing the GCC survey results and providing helpful recommendations on ISS in the context of bioanalytical method development and application.
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http://dx.doi.org/10.4155/bio.14.155DOI Listing
September 2014

A phase I trial of continuous infusion of the multidrug resistance inhibitor zosuquidar with daunorubicin and cytarabine in acute myeloid leukemia.

Leuk Res 2009 Aug 23;33(8):1055-61. Epub 2008 Dec 23.

Hematologic Malignancies Program, H Lee Moffitt Cancer Center, Tampa, FL, USA.

Zosuquidar is a potent and specific inhibitor of P-glycoprotein (P-gp). In preliminary experiments, blockade of P-gp for at least 12 h was required to reverse daunorubicin resistance. Because of the short half-life of zosuquidar, we performed a phase I trial of this drug as a 72-h infusion (CIV) in 16 patients during leukemic induction with daunorubicin and cytarabine. Study goals were to establish safety and determine the dose required for P-gp inhibition in NK cells and AML blasts. > 90% P-gp inhibition was achieved within 2h at a plasma threshold of 132 ng/ml zosuquidar. The recommended phase II dose of zosuquidar is 700 mg/day.
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http://dx.doi.org/10.1016/j.leukres.2008.09.015DOI Listing
August 2009

Leukemic blast and natural killer cell P-glycoprotein function and inhibition in a clinical trial of zosuquidar infusion in acute myeloid leukemia.

Leuk Res 2009 Jun 30;33(6):769-74. Epub 2008 Oct 30.

Kanisa Pharmaceuticals, San Diego, CA, United States.

A bioassay was developed to assess P-glycoprotein (P-gp) function of peripheral blood natural killer (NK) cells and AML blasts during zosuquidar infusion. Cells were incubated with the fluorescent dye DiOC(2)(3) in the presence and absence of zosuquidar, and dye accumulation measured by flow cytometry. The assay performance was assessed using NK cells and the P-gp-positive K562/R7 cell line, and then utilized to determine the function of P-gp and its inhibition by zosuquidar in AML blasts and NK cells from patients enrolled in a Phase I trial. The assay of zosuquidar-inhibitable accumulation of DiOC(2) is robust and reproducible.
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http://dx.doi.org/10.1016/j.leukres.2008.09.020DOI Listing
June 2009

HPLC determination of erythrocyte methotrexate polyglutamates after low-dose methotrexate therapy in patients with rheumatoid arthritis.

Clin Chem 2003 Oct;49(10):1632-41

Research and Development, Prometheus Laboratories, 5739 Pacific Center Blvd., San Diego, CA 92121. Division of Rheumatology, Scripps Clinic, San Diego, CA 92037, USA.

Background: Methotrexate (MTX) may produce antiarthritic effects through polyglutamation to methotrexate polyglutamates (MTXPGs), a process that covalently attaches sequential gamma-linked glutamic residues to MTX. We sought to develop an innovative HPLC method for the quantification of these metabolites in erythrocytes.

Methods: Two alternative approaches were developed. In the first approach, MTXPGs from 50 micro L of packed erythrocytes were converted to MTX in the presence of plasma gamma-glutamyl hydrolase and mercaptoethanol at 37 degrees C. In the second approach, MTXPG species (up to the hepta order of glutamation) from 100 micro L packed erythrocytes were directly quantified in a single run. In both methods, the MTXPGs were extracted from the biological matrix by a simple perchloric acid deproteinization step with direct injection of the extract into the HPLC. The chromatography used a C(18) reversed-phase column, an ammonium acetate/acetonitrile buffer, and postcolumn photo-oxidation of MTXPGs to fluorescent analytes.

Results: Intra- and interday imprecision (CVs) were <10% at low and high concentrations of analytes for both methods. The limit of quantification was 5 nmol/L. In 70 patients with rheumatoid arthritis receiving weekly low-dose MTX, the mean (SD) total MTXPG concentration measured after conversion of MTXPGs to MTX was similar to the total MTXPG concentration calculated from the sum of individual MTXPG species [117 (56) vs 120 (59) nmol/L; r = 0.97; slope = 1.0]. The triglutamate predominated over all other MTXPG species (36% of total), the pentaglutamate was the highest order of glutamation detected, and a stability study revealed no change in the polyglutamation pattern in erythrocytes 48 h after phlebotomy when the specimen was stored at 2-8 degrees C.

Conclusion: The proposed method for quantification of erythrocyte MTXPGs is rapid, sensitive, and accurate and can be applied to the routine monitoring of MTX therapy.
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http://dx.doi.org/10.1373/49.10.1632DOI Listing
October 2003

Synergistic inhibition of herpesvirus replication by docosanol and antiviral nucleoside analogs.

Antiviral Res 2002 Nov;56(2):153-66

Avanir Pharmaceuticals, 11388 Sorrento Valley Road, Suite 200, San Diego, CA 92121, USA.

Interactions between docosanol (n-docosanol, behenyl alcohol) and nucleoside or pyrophosphate analogs were investigated in vitro. The anti-HSV activity of acyclovir (ACV) was synergistically enhanced by treatment of cells with docosanol as judged by inhibition of progeny virus production and plaque formation. This drug interaction between ACV and docosanol was observed with laboratory strains of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2), oral and genital clinical isolates of HSV, cytomegalovirus (CMV), and varicella zoster virus (VZV). Near optimal concentrations of docosanol plus ACV inhibited HSV replication >99% more than either drug alone, including emergence of ACV-resistant variants. The response was observed with African Green Monkey kidney cells, normal human foreskin cells, and normal human lung cells. Treatment of cells with docosanol also synergistically intensified the inhibition of HSV production by all tested nucleoside analogs, including trifluorothymidine (TFT), adenine arabinoside (Ara-A), and ribavirin. An additive anti-HSV effect was observed with docosanol and phosphonoformate (PFA). No evidence was found for either synergistic inhibition of cellular DNA synthesis or induction of overt cellular toxicity when docosanol was combined with ACV, TFT, Ara-A, ribavirin, PFA, 8-azaguanine, or 5-fluorouracil. The ability of docosanol treatment to increase the antiviral activities of nucleoside analog antiviral drugs, coupled with a lack of toxic interactions, translates to substantial improvements in drug selectivity ratios.
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http://dx.doi.org/10.1016/s0166-3542(02)00105-5DOI Listing
November 2002