Introduction L-asparaginase is considered to be the most important component in the treatment of acute lymphoblastic leukemia (ALL). Intensifying the use of L-asparaginase during treatment for ALL has resulted in a significant rise in the percentage of children and adolescents who are cured of the disease. Asparaginase trough activity more than or equal to 100 IU/L on day 7 has been found to be the desired activity level in all childhood leukemia patients. Objectives Due to the paucity of data on biosimilar pegaspargase in the upfront setting, we planned this prospective pilot study to evaluate the levels of serum asparaginase activity (SAA) after biosimilar pegaspargase infusion. Materials and Methods It is a prospective, single-center, pilot study of 10 pediatric ALL patients for the duration of 6 months. All children less than 18 years with ALL on treatment with curative intent and receiving pegaspargase and who provided informed consent were included in this study. The enzymatic spectrophotometric method was used to determine SAA, and it was measured on the 7th and 14th days after the first dosage of pegaspargase-asparaginase, as well as on the 14th day after the second dose of pegaspargase-asparaginase, while toxicity was charted according to Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Results From 10 patients with a median age of 5.5 years, a grand total of 29 samples were taken for analysis. Children who received pegaspargase had either B-ALL or T-ALL. After the first dose, mean ± SD (standard deviation), SAA levels at day 7 was 131.3 ± 38 IU/L and at Day 14 was 94.8 ± 8 IU/L. After the second dose, mean ± SD SAA level at day 14 was 86.1 ± 15 IU/L. No patient had clinical hypersensitivity reaction and no patient reported any asparaginase-related toxicity. One patient died due to sepsis, infection with multidrug-resistant gram-negative bacteria. Conclusions Biosimilar pegaspargase maintained good SAA levels 7 and 14 days after infusion. Drug Trial Registration: Clinical Trial Registry of India vide reference CTRI/2021/08/036033 and available at https://ctri.nic.in/Clinicaltrials/pmaindet2.php?trialid=59285&EncHid=&userName= The abstract of this text was published in the Supplementary issue: Abstracts of the 25th Annual Conference of the Pediatric Hematology Oncology chapter of the Indian Academy of Pediatrics (PHOCON 2022), N Delhi in November 2022 with doi: 10.1016/j.phoj.2022.10.176 The manuscript has been read and approved by all the authors, that the requirements for authorship (Pg. 18) have been met, and that each author believes that the manuscript represents honest work, if that information is not provided in another form. None. This study was approved by Institutional Ethics Committee at Kasturba Hospital, Manipal and the procedures used in this study adhere to the tenets of the Declaration of Helsinki. All procedures performed in studies involving human participants were in accordance with the ethical standards and by approval from the Kasturba Medical College and Kasturba Hospital Institutional Ethics Committee (DHR Registration No. EC/NEW/INST/2019/374, Dated 14^th April 2021, IEC: 356/2021) and was registered at CTRI- REF/2021/08/046121. It was performed in line with the latest Helsinki Declaration's guiding principles from 2013. Vasudeva Bhat K conceptualized and designed the study. Archana M.V., Arjun Asok, and Krishnananda Prabhu helped in data acquisition and manuscript preparation. Article published online: 18 September 2023 © 2023. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/) Thieme Medical and Scientific Publishers Pvt. Ltd. A-12, 2nd Floor, Sector 2, Noida-201301 UP, India

Background/Objectives: Fatty acids, the building blocks of lipids, contribute to numerous crucial life processes and are implicated in numerous disease pathologies. Circulating fatty acids can be extracted/trans-esterified to their respective methyl ester forms and quantified from a variety of biological samples. This study aims to identify quantifiable fatty acids (through alkali trans-esterification) in human circulation, assess the correlation of the detectable fatty acid methyl esters (FAMEs) compounds between whole blood, serum and plasma matrices and propose the most ideal matrix for quantification of FAMEs. Methods: This anonymised study was carried out in a tertiary hospital after obtaining ethical approval and involved analysis of residual fasting whole blood, serum and plasma samples obtained from 20 apparently healthy subjects attending the routine health check services at the study centre. Fatty acids were converted to its methyl ester form by methanolic KOH trans-esterification and subjected to GCMS analysis. Paired t test, Pearsons’s correlation, linear regression and Bland Altman test were employed to assess the agreeability between matrices. Results: 9 out of 37 FAME compounds were detected in all three matrices. Strong correlations and statistically significant regression equations were obtained for the 9 compounds between plasma and serum matrices. Undecanoate, pentadecanoate, linolenate, and palmitate levels were lowest in plasma, while stearate, heptadecanoate levels were highest in whole blood. Myristate was highest in serum, dodecanoate was highest in plasma while docosahexanoate was found to be comparable in all three matrices. Methyl ester forms of dodeconate, myristate, pentadecanoate, palmitate, heptadecanoate, stearate, and linolenate were observed in higher concentrations in plasma when compared to serum. Conclusions: The current study shows similar & correlating FAME concentrations between serum and plasma matrix; however, whole blood FAME concentrations appear significantly different. Plasma serves as the most ideal matrix for detection and quantification of circulating fatty acids.

The advent of newborn screening across India has led to an increase in the early diagnosis of inborn errors of metabolisms (IEMs). Aminoacidopathies, the group of inherited disorders of amino acid metabolisms are of particular important because of the ease of early diagnosis and the availability of effective treatment options. Unfortunately, the biological reference intervals for amino acids vary widely between different ethnic groups and geographical locations, thereby necessitating the need to establish a population specific reference interval for optimal diagnosis.