Rapid Acute Coronary Syndrome Evaluation Over One Hour With High-Sensitivity Cardiac Troponin I: A United States-Based Stepped-Wedge, Randomized Trial.

STUDY OBJECTIVE: The real-world effectiveness and safety of a 0/1-hour accelerated protocol using high-sensitivity cardiac troponin (hs-cTn) to exclude myocardial infarction (MI) compared to routine care in the United States is uncertain. The objective was to compare a 0/1-hour accelerated protocol for evaluation of MI to a 0/3-hour standard care protocol. METHODS: The RACE-IT trial was a stepped-wedge, randomized trial across 9 emergency departments (EDs) that enrolled 32,609 patients evaluated for possible MI from July 2020 through April 2021. Patients undergoing high-sensitivity cardiac troponin I testing with concentrations less than or equal to 99th percentile were included. Patients who had MI excluded by the 0/1-hour protocol could be discharged from the ED. Patients in the standard care protocol had 0- and 3-hour troponin testing and application of a modified HEART score to be eligible for discharge. The primary endpoint was the proportion of patients discharged from the ED without 30-day death or MI. RESULTS: There were 13,505 and 19,104 patients evaluated in the standard care and accelerated protocol groups, respectively, of whom 19,152 (58.7%) were discharged directly from the ED. There was no significant difference in safe discharges between standard care and the accelerated protocol (59.5% vs 57.8%; adjusted odds ratio (aOR)=1.05, 95% confidence interval [CI] 0.95 to 1.16). At 30 days, there were 90 deaths or MIs with 38 (0.4%) in the standard care group and 52 (0.4%) in the accelerated protocol group (aOR=0.84, 95% CI 0.43 to 1.68). CONCLUSION: A 0/1-hour accelerated protocol using high-sensitivity cardiac troponin I did not lead to more safe ED discharges compared with standard care.

Is rapid acute coronary syndrome evaluation with high-sensitivity cardiac troponin less costly? An economic evaluation.

Objective: Protocols to evaluate for myocardial infarction (MI) using high-sensitivity cardiac troponin (hs-cTn) have the potential to drive costs upward due to the added sensitivity. We performed an economic evaluation of an accelerated protocol (AP) to evaluate for MI using hs-cTn to identify changes in costs of treatment and length of stay compared with conventional testing. Methods: We performed a planned secondary economic analysis of a large, cluster randomized trial across nine emergency departments (EDs) from July 2020 to April 2021. Patients were included if they were 18 years or older with clinical suspicion for MI. In the AP, patients could be discharged without further testing at 0 h if they had a hs-cTnI < 4 ng/L and at 1 h if the initial value were 4 ng/L and the 1-h value ≤7 ng/L. Patients in the standard of care (SC) protocol used conventional cTn testing at 0 and 3 h. The primary outcome was the total cost of treatment, and the secondary outcome was ED length of stay. Results: Among 32,450 included patients, an AP had no significant differences in cost (+$89, CI: -$714, $893 hospital cost, +$362, CI: -$414, $1138 health system cost) or ED length of stay (+46, CI: -28, 120 min) compared with the SC protocol. In lower acuity, free-standing EDs, patients under the AP experienced shorter length of stay (-37 min, CI: -62, 12 min) and reduced health system cost (-$112, CI: -$250, $25). Conclusion: Overall, the implementation of AP using hs-cTn does not result in higher costs.

A sensitive LC-MS/MS assay to quantitate free payload Aur0101 from ADC PYX-201 in rat and monkey plasma.

Aim: Aur0101 is a cytotoxic and small-molecule microtubule depolymerizing agent, and is the payload conjugated to antibody-drug conjugate PYX-201. Developing and validating a sensitive bioanalytical method to quantitate Aur0101 was novel and crucial in preclinical PYX-201 studies. Materials & methods: Reference standard Aur0101 and its stable isotope labelled internal standard Aur0101-d8 were used in this LC-MS/MS method. Results: This sensitive assay was validated at a lower limit of quantitation of 15 pg/ml and successfully applied to support preclinical rat and monkey toxicology studies. Preclinical plasma toxicokinetic parameters were presented. Conclusion: A sensitive and robust LC-MS/MS assay was validated for Aur0101 in rat and monkey plasma.

A sensitive and rapid LC-MS/MS assay for quantitation of free payload Aur0101 from antibody drug conjugate (ADC) PYX-201 in human plasma.

PYX-201 is an investigational antibody drug conjugate (ADC) with an engineered, fully human IgG1 antibody, a cleavable chemical linker, and a toxin (Aur0101) with an average drug-antibody ratio (DAR) of âˆ¼ 4. A sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and fully validated to determine the presence in human plasma, of free payload Aur0101 from PYX-201 to assess drug safety and efficacy. Aur0101 and its deuterated internal standard (IS), Aur0101_d8, were extracted from 25 µL of human plasma using a solid liquid extraction (SLE) method. Chromatographic analysis was carried out on a Waters Acquity UPLC BEH C18 (2.1 mm × 50 mm, 1.7 µm, 130 A) column. Quantitation of free Aur0101 was conducted on a Sciex triple quadrupole mass spectrometer API 6500 + using multiple reaction monitoring (MRM) mode via positive electrospray ionization. The calibration curve was linear over the concentration range of 25.0 to 12,500 pg/mL with correlation coefficient, r2 ≥ 0.9988. The intra-assay %RE was between -4.3% to 14.3% with % CV was ≤ 6.2%. The inter-assay %RE was between -0.2% to 9.5% with % CV was ≤ 6.1%. The average analyte recovery was 89.7% and the average IS recovery was 88.7%. Aur0101 was found to be stable in human plasma and human whole blood under various tested conditions with and without the presence of PYX-201. To our knowledge, this is the first published fully validated assay for free, unconjugated Aur0101 in any matrix, from any species. This assay has been successfully applied to clinical sample analysis to support clinical studies.

Quantitation of total antibody (tAb) from antibody drug conjugate (ADC) PYX-201 in rat and monkey plasma using an enzyme-linked immunosorbent assay (ELISA) and its application in preclinical studies.

PYX-201 is an investigative ADC oncology drug composed of a monoclonal human immunoglobulin G (IgG) antibody targeting the extra domain B splice variant of fibronectin (EDB + FN) conjugated to an auristatin payload through a cleavable linker. Effective measurement of PYX-201 tAb is the key to ADC drug PYX-201 preclinical pharmacokinetics (PK) assessment. PYX-201 monoclonal antibody (mAb) was used as the reference standard, goat anti-human IgG polyclonal antibody (pAb) or rabbit anti-human Kappa light chain mAb was employed as the capture antibody, and mouse mAb or goat pAb anti-human IgG the crystallizable fragment (Fc) (horseradish peroxidase (HRP)) was utilized as the detection antibody in this ELISA. This assay was validated with a dynamic range 250 - 10,000 ng/mL and 250 - 6000 ng/mL in rat and monkey K2EDTA plasma, respectively. PYX-201 tAb bioanalytical ELISA assay was reported for the first time in any biological matrix. This is the first time for a bioanalytical method to be validated for a tAb from an ADC drug targeting EDB + FN in any biological matrix.

Bioanalysis of an antibody drug conjugate (ADC) PYX-201 in human plasma using a hybrid immunoaffinity LC-MS/MS approach.

PYX-201 is an anti-extra domain B splice variant of fibronectin (EDB + FN) antibody drug conjugate (ADC) composed of a fully human IgG1 antibody, a cleavable mcValCitPABC linker, and four Auristatin 0101 (Aur0101, PF-06380101) payload molecules. To better understand the pharmacokinetic (PK) profile of PYX-201 after it is administered to cancer patients, the development of a reliable bioanalytical assay to accurately and precisely quantitate PYX-201 in human plasma is required. In this manuscript, we present a hybrid immunoaffinity LC-MS/MS assay used to successfully analyze PYX-201 in human plasma. PYX-201 was enriched by MABSelect beads coated with protein A in human plasma samples. The bound proteins were subjected to "on-bead" proteolysis with papain to release the payload Aur0101. The stable isotope labelled internal standard (SIL-IS) Aur0101-d8 was added and the released Aur0101 was quantified as a surrogate for the total ADC concentration. The separation was performed on a UPLC C18 column coupled with tandem mass spectrometry. The LC-MS/MS assay was validated over the range 0.0250 to 25.0 µg/mL with excellent accuracy and precision. The overall accuracy (%RE) was between -3.8% and -0.1% and the inter-assay precision (%CV) was <5.8%. PYX-201 was found to be stable in human plasma for at least 24 h on ice, 15 days after being stored at -80 °C, as well as after five freeze/thaw cycles of being frozen at -25 °C or -80 °C and thawed on ice. The assay this paper reports on, has been successfully applied to human sample analysis to support clinical studies.

Quantification of antibody-drug conjugate PYX-201 in rat and monkey plasma via ELISA and its application in preclinical studies.

Aim: PYX-201 is a novel antibody-drug conjugate targeting the extra domain B splice variant of fibronectin in the tumor microenvironment. Accurate quantification of PYX-201 is critical for PYX-201 pharmacokinetics profiling in preclinical studies. Materials & methods: ELISA was performed using reference standard PYX-201, mouse monoclonal anti-monomethyl auristatin E antibody, mouse IgG1, mouse monoclonal anti-human IgG horseradish peroxidase and donkey anti-human IgG horseradish peroxidase. Results: This assay was validated at 50.0-10,000 ng/ml in rat dipotassium EDTA plasma and 250-10,000 ng/ml in monkey dipotassium EDTA plasma. Conclusion: This is the first time for a PYX-201 bioanalytical assay in any matrix to be reported.