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Next generation human therapeutic monoclonal antibodies (t-mAbs) are harder to quantify with the widely used bottom-up tryptic digestion method. Due to their homology with endogenous immunoglobulins, there is a lack of unique and stable 'signature' peptides that can be targeted. Middle-up two dimensional liquid chromatography high resolution mass spectrometry (2D-LC-HRMS), targeting the entire light chain, was examined as an alternative. Adalimumab (ADM) was successfully quantified in human plasma after Melon® Gel sample purification, followed by orthogonal separation on a weak cation exchange (WCX) and reversed phase column. Charge and hydrophobicity were used to separate ADM from the polyclonal immunoglobulin background. HRMS with its high resolution and exact mass was able to isotopically resolve the ADM light chain and to provide another separation dimension on the basis of mass to charge ratio. Using the targeted single ion monitoring (T-SIM) with multiplex (MSX) option, three ADM light chain precursors, 2341.80, 2129.00, and 1951.68 m/z, and one internal standard precursor 2146.39 m/z, were measured simultaneously. The Melon® Gel sample purification was found to be very efficient in removing plasma proteins that would otherwise interfere with chromatographic separation and ionization. The linearity of the method for the analysis of ADM was excellent (R 2 =0.999) between 1 - 128 mg/L with an LLOQ signal to noise ratio (S/N) of 10. Within-run and between-run precision and accuracy were in concordance with the EMA guideline. Cross-validation of the 2D-LC-HRM method with the standard peptide LC-MS/MS method showed a good agreement (R 2  = 0.86) between the methods. However, there was a bias present, possibly due to charge variant ADM formation over time. Since the presented 2D-LC-HRMS method is able to measure only the native form of ADM, it is able to provide a measure of the active form of ADM in patients., Competing Interests: Declaration of Competing Interest 2D-LC system, columns, and Melon® Gel were provided by Thermo Fisher Scientific., (Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.)

Due to the increasing number of therapeutic monoclonal antibodies (mAbs) used in the clinic, there is an increasing need for robust analytical methods to quantify total mAb concentrations in human plasma for clinical studies and therapeutic drug monitoring. We developed an easy, rapid, and robust sample preparation method for liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The method was validated for infliximab (IFX), rituximab (RTX), cetuximab (CTX), dupilumab (DPL), dinutuximab (DNX), vedolizumab (VDZ), and emicizumab (EMZ). Saturated ammonium sulfate (AS) was used to precipitate immunoglobulins in human plasma. After centrifugation, supernatant containing albumin was decanted, and the precipitated immunoglobulin fraction was re-dissolved in buffer containing 6M guanidine. This fraction was then completely denatured, reduced, alkylated, and trypsin digested. Finally, signature peptides from the seven mAbs were simultaneously quantified on LC-MS/MS together with their internal standards stable isotopically labeled peptide counterparts. The linear dynamic ranges (1 - 512 mg/L) of IFX, CTX, RTX, and EMZ showed excellent (R2 > 0.999) linearity and those of DPL, DNX, and VDZ showed good (R2 > 0.995) linearity. The method was validated in accordance with the EMA guidelines. EDTA plasma, sodium citrate plasma, heparin plasma, and serum yielded similar results. Prepared samples were stable at room temperature (20°C) and at 5°C for 3 days, and showed no decline in concentration for all tested mAbs. This described method, which has the advantage of an easy, rapid, and robust pre-analytical sample preparation, can be used as a template to quantify other mAbs in human plasma or serum., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021. Published by Elsevier B.V.)

The addition of rabbit anti-human thymocyte globulin (ATG) to the conditioning regimen prior to allogeneic hematopoietic cell transplantation has significantly reduced the risk of graft-versus-host disease (GvHD) and graft failure. However, ATG has a small therapeutic window. Overexposure of ATG post-HCT hampers T cell immune reconstitution and has been associated with increased relapse rates and viral reactivations, whereas underexposure has been associated with an increased incidence of GvHD, both of which lead to increased mortality. Therapeutic drug monitoring of T cell binding ATG plasma levels provides a means to optimize dosing for patients at high risk for graft failure to ensure timely T cell immune reconstitution and subsequently increase survival chances. This manuscript describes the first liquid chromatography tandem-mass spectrometry (LC-MS/MS) method to quantify the pharmacologically active fraction of polyclonal ATG in plasma. This was achieved through immunoaffinity purification of active ATG from plasma with Jurkat T cells. After the binding and washing, samples were eluted, denatured, and trypsin-digested. Signature peptides originating from the IgG constant chain were measured with LC-MS/MS. Critical method parameters were optimized, and the method was successfully validated following European Medicines Agency (EMA) guidelines. The method covered the therapeutic range of ATG and was validated at a lower limit of quantification (LLOQ) of 1 AU/mL with an overall CV and bias of 11.8% and - 2.5%, respectively. In conclusion, we developed a LC-MS/MS-based method to quantify active polyclonal rabbit ATG in human plasma. We suggest that this novel assay can be used to monitor and optimize dosing of ATG in clinical practice.

The Canadian Stroke Best Practice Consensus Statement: Secondary Stroke Prevention during Pregnancy, is the first of a two-part series devoted to stroke in pregnancy. This document focuses on unique aspects of secondary stroke prevention in a woman with a prior history of stroke or transient ischemic attack who is, or is planning to become, pregnant. Although stroke is relatively rare in this cohort, several aspects of pregnancy can increase stroke risk during or immediately after pregnancy. The rationale for the development of this consensus statement is based on the premise that stroke in this group requires a specifically-tailored management approach. No other broad-based, stroke-specific guidelines or consensus statements exist currently. Underpinning the development of this document was the concept that maternal health is vital for fetal wellbeing; therefore, management decisions should be based on the confluence of two clinical considerations: (a) decisions that would be made if the patient was not pregnant and (b) decisions that would be made if the patient had not had a stroke. While empirical research in this area is limited, this consensus document is based on the best available literature and guided by expert consensus. Issues addressed in this document include general management considerations for secondary stroke prevention, the use of antithrombotics, blood pressure management, lipid management, diabetes care, and management for specific ischemic stroke etiologies in pregnancy. The focus is on maternal and fetal health while minimizing risks of a recurrent stroke, through counseling, monitoring, and the safety of select pharmacotherapy. These statements are appropriate for health care professionals across all disciplines.

Background: Liver and lungs are the two most frequent sites of metastatic spread of colorectal cancer (CRC). Complete resection of liver and/or lung metastases is the only chance of cure, and several studies have reported an improved survival after an aggressive treatment. Nevertheless, CRC liver metastases (CLM) have been recognized as a pejorative factor for patients undergoing pulmonary metastasectomy. We report our experience with patients successively operated on for CRC hepatic and pulmonary metastasis (CPM) and seek to identify prognostic factors., Methods: All consecutive patients who had resection of CPM and CLM between 2001 and 2014 were enrolled in the study. Clinicopathological and survival data were retrospectively analysed., Results: Forty-six patients underwent resections of both CLM and CPM. Hepatic resection preceded pulmonary resection in most cases (91.3%). The median intervals between the resection of the primary tumour and the hepatic recurrence and between hepatic and pulmonary recurrences were 12 months [0-72] and 21.5 months [1-84], respectively. The mortality rate following CPM resection was 4.3%. After a median follow-up of 41.5 months [0-126], 35 patients recurred of whom 14 (40%) and 11(31.4%) could benefit from repeated resection of recurrent CLM and CPM, respectively. The median and 5-year overall survivals (OS) were 53 months and 49%, respectively. No prognostic factor was identified., Conclusion: An aggressive management of CLM and CPM, including repeated resections, may provide a long-term survival comparable to survival of patients with unique metastasectomy. The absence of prognostic factor may reflect the highly selected pattern of the eligible patients.