In this Column Emerson Dameron, Content Marketing Director of Neoteryx (CA, USA) discusses the challenges in therapeutic drug development and monitoring.
One useful way to think about volumetric absorptive microsampling (VAMS) technology is as the next generation of traditional dried blood spot (DBS) cards. It’s a simpler method that makes it easier to collect blood and prepare it for analysis. With minimal training, the microsampling process can be self-administered anywhere, through a procedure that is less difficult and generally less expensive than working with conventional venous blood. Other benefits include a more pleasant patient experience, which leads to greater adherence and compliance, and freer access to remote areas of the world.
These benefits converge in the key areas of therapeutic drug development and monitoring.
Challenges in therapeutic drug development and monitoring
In the development of therapeutic drugs, clinical trials are necessary to measure their safety and efficacy. Though these trials are critical, they can be a burden to participants. In most cases, trial participants are required to visit the clinic multiple times to give blood for pre-screening and subsequent pharmacokinetic measurements. This is hardly convenient, especially if the clinic is far from the patient’s home or has limited operating hours. Not only are these visits inconvenient for the participant, but they are also costly for the sponsor who is covering the travel and in-clinic costs.
Likewise, for therapeutic drug monitoring (TDM), many patients need regular blood testing to monitor their health and progress. After certain procedures, such as renal transplants, physicians must be able to monitor the patient’s condition frequently through blood analysis to help ensure consistent drug concentrations in a patient’s bloodstream. Historically, it has been difficult to maintain this process without sacrificing specimen quality and accuracy or the patient’s comfort and convenience, if not both. It becomes particularly challenging when it requires participation from children, the elderly, or those who live in rural or isolated areas.
DBS technology arose, in part, in response to these challenges. And it worked somewhat well, for a long time.
DBS – A convenient, economical alternative
In December 2016, the Public Library of Science published “Cost Evaluation of Dried Blood Spot Home Sampling as Compared to Conventional Sampling for Therapeutic Drug Monitoring in Children,” a research article by scientists in the Netherlands. In a peer-reviewed scientific journal, the scientists performed a rigorous cost analysis of the savings potential achieved from using DBS rather than conventional blood testing, specifically in the context of TDM. The case studies in question involved recovering children who required TDM as part of their ongoing treatment.
This analysis addressed variables such as travel expenses (transportation, parking, and overnight stays if applicable), loss of time and productivity (for patients and caregivers), healthcare costs, laboratory costs (versus the costs of mailed-in samples taken off-site; analysis costs were assumed to be similar), and doctor feedback time (assumed to be similar in both scenarios). The travel expense portion incorporated a distance factor of 145 minutes round-trip and a total hospital visit time of 45 minutes.
In the study results, the cost of at-home DBS sampling calculated to 39.4 percent of the total cost of sampling in the clinic. The major factors contributing to the difference were additional costs of travel, lost productivity for the caregiver and the nurse’s time spent collecting samples. If weekly sampling were required over a 6month period, the total expenses and lost time differentials would compound.
Clearly, DBS is less expensive in the aggregate. But what if there were a better alternative to cards and filter paper?
Next-generation DBS, today
When DBS cards premiered more than 50 years ago, they had significant advantages over traditional wet sampling, including simplicity, low cost and ease of transportation. However, adoption has been hindered by regulatory concerns over the ‘hematocrit effect,’ along with their automation limitations. Incorrect spotting technique can lead to high sample rejection rates.
VAMS technology was developed, in part, to solve these problems. The Mitra device, based on VAMS technology, provides all the important benefits of working with dried blood, along with a volumetrically accurate, stable DBS that reduces the incidence of reworks. Using the Mitra device circumvents many practical impediments associated with DBS cards while gathering a fixed volume of blood (10 or 20 µL), every time, outside of the clinic.
Dried blood microsampling reduces time, labor, and costs. Exceptional savings can be achieved in phase II and III clinical trials; it eliminates cold-chain shipments back and forth from sites and central laboratories, along with most of the costs associated with storage and preservation. Plus, Mitra devices are available in complete at-home sampling kits that make the entire sampling process easy to execute outside of the clinic.
Furthermore, strong correlations can be built between data generated from traditional wet blood sampling and microvolumes collected with the Mitra microsampler. Compared to results generated from filter paper, results from Mitra microsamples are closer to the ‘gold standard’ associated with wet blood.
With 16 peer-reviewed publications in 2017 (so far), it’s becoming clear that Mitra microsampling technology is widely regarded as a breakthrough alternative to DBS cards and traditional venipuncture. In a world of increasingly holistic and personalized medicine, we must consider individualized options such as this that allow for better and more frequent means of getting vital information into researchers’ and doctors’ hands, while allowing clinical trial participants and patients the freedom to do so in comfort and on their own schedules. If implementation streamlines operations and saves money, all the better.