An article published by Eric Thomas et al at Covance (now Labcorp Drug Development) and Astra Zeneca in the July 2020 issue of Bioanalysis, reported on a method to measure the MEK1/2 inhibitor selumetinib (AZD6244) from VAMS® extracts in blood collected with Mitra® devices.
Selumetinib is a class of drugs that act as an MEK1/2 inhibitor. MEK stands for mitogen-activated protein kinase kinase. A mitogen is a small molecule that induces cells to begin or enhance cell division.
The drug selumetinib acts to inhibit this activity. Indeed, selumetinib has recently been approved for the treatment of plexiform neurofibromas related to Neurofibromatosis type 1 (NF1) in pediatric patients. Neurofibromatosis type 1 is a rare genetic disorder of the nervous system that is usually diagnosed in early childhood.
It is associated with the growth of plexiform neurofibromas (tumors) along the nerves in the body, affecting skin, bone, eyes the spine and other areas. If left untreated, plexiform neurofibromas continue to grow, causing symptoms and impacting the tissue that covers and protects nerves. Most neurofibromas are noncancerous, but some may eventually become malignant.
Pharmacokinetic (PK) studies in preclinical research had been previously developed to measure selumetinib (including its metabolites) in traditional human matrices such as plasma, plasma ultra-filtrate, human dialysate, and urine.
Eric Thomas et al needed to develop a method for non-adults, namely pediatric patients, where reduced blood volume collection would be desirable.
For this purpose, they looked to whole blood sampling approaches rather than traditional plasma approaches. Several blood sampling techniques were considered, including finger-stick methods with dried blood spot (DBS) cards and Mitra devices with VAMS.
However, there were a few known concerns pertaining to DBS, including contamination risks with sub-punching as well as issues with spot homogeneity and spot size pertaining to hematocrit (%HCT). Indeed, the authors highlighted that contamination during sub-punching DBS cards had previously been reported as a concern.
Furthermore, they quoted recommendations from the EBF DBS-microsampling consortium on the requirement of blank cards to be used to punch between samples and further, to run samples in order of increasing concentration to mitigate such contamination concerns.
Nevertheless, they determined that dried blood microsampling would be desirable as this would enable remote collection by the patient or a caregiver at home without the need to visit a clinic or lab for a blood draw.
They chose Mitra due to its volumetric collection properties and stated that “This approach mitigates challenges with biases and variability, largely driven by hematocrit and nonhomogeneity, associated with sub-punches analyzed for DBS.”
They also stated that VAMS was “rapidly expanding as a replacement to traditional DBS techniques.”
There had been no previous method developed on selumetinib, so the team decided to develop and validate a robust assay using VAMS. They believed the VAMS assay would have the potential to be used in support of clinical trials.
Clinical trials are critical to allowing new medicines to be developed and commercially deployed for use. However, trials are costly, and can be burdensome and inconvenient (especially in pediatrics) for those who enroll in them.
This sometimes leads to some patients voluntarily dropping out of the trials before they reach completion. Remote microsampling provides an alternative way to run drug trials that minimize the impact on the patient yet allow for critical data to be gathered.
The work reported by Eric Thomas et al demonstrated that high-quality data can be gained from 10 µL microsamples to allow them to support future studies on selumetinib.
This study paper was summarized for our readers by James Rudge, PhD, Neoteryx Technical Director. This is curated content. To learn more about the important research outlined in this review, visit the original article published in the Journal of Pharmaceutical and Biomedical Analysis.
Visit our Technical Resource Library to read more study papers and presentations that used Mitra devices with VAMS.