The biopharmaceutical industry is abuzz with talk regarding a 2011 US Food and Drug Administration (FDA) guidance on human factors and the mitigation of user-based risk in the development of medical devices (1). As expected, his talk is often accompanied by a sense of anxiety. Device developers and the growing number of biomanufacturers developing combination drug–device products now need answers to usability questions they are hardly familiar with. Wrong answers may have direct (and troubling) implications from a number of perspectives, such as regulatory approvals to business-case success and innovation.
Understanding the scope, depth, and nuance of human factors engineering and design for usability requires expert practitioners — those experienced in both the science and art of understanding human capabilities and limitations within a constantly changing regulatory framework. Thankfully for the rest of the drug delivery community, a better understanding of what this means for the development process can be gained by simply considering the subject at a higher level.
PRODUCT FOCUS: ALL BIOLOGICS
PROCESS FOCUS: MANUFACTURING
WHO SHOULD READ: PRODUCT DEVELOPMENT, FORMULATORS, PRODUCT MANAGERS, FILL AND FINISH, MARKETING
KEYWORDS: DRUG DELIVERY, DEVICE DESIGN
At the core of human factors engineering and the mitigation of user-based risk is a common-sense approach that considers design options in the context of how a human interacts with the world. For the biopharmaceutical delivery device industry, that is possible with a simple framework that uses delivery systems as a patient journey. Such a framework includes
- Understanding how human factors define and evaluate human capabilities (how patients should be considered)
- Understanding that human conditions, for which we should be designing, are not static states but series of evolutions (the journey).
Here, we delve into those points in greater detail and, in the process, reveal how usability concerns are likely to evolve as patients progress through the experience of managing their conditions.
Elements of Usability
For many professionals in the medical device development industry, usability is something that is difficult to describe, but that “you know when you see it.” If they were forced to articulate what usability means, many would mention phrases such as “simple,” “easy to use,” and “fewer steps.” Although none of those are necessarily wrong, it is important to recognize that for each disease state and use case, such concepts do not necessarily translate into the same set of device embodiments or affordances (experiences that users have with objects). Understanding usability involves understanding human capabilities and limitations in a much deeper way.
Human factors guidance and best practices provide a robust framework for categorizing four major components of usability — all inextricably linked in the context of understanding what usability means
- physical abilities, including anthropometry (the measure of bodies, such as heights or the size of hands), biomechanics (what can be accomplished physically, such as how much weight can be lifted, how firmly something can be grasped), and sensory abilities (vision, hearing, tactile sense, and so forth)
- cognitive abilities, including how brains process information, the capabilities of memory, the manner in which humans learn new things, and how habits are developed
- state of being, including the general health of expected users, disease states and comorbidities likely to challenge patients’ mental and emotional states, and motivation for learning new things
- experiences, including educational backgrounds, knowledge of particular disease states, and lifelong experiences with objects that will guide behavioral interactions with any delivery system.
Arguably, some of those items above might be components of usability that many companies that are unfamiliar with human factors engineering may not consider. However, taken as a whole, such important connections are interrelated. For example, although an asthma patient experienced in adhering to a rescue therapy regimen using a metered-dose inhaler (MDI) may be physically capable of using a maintenance therapy drug delivered through a dry-powder inhaler (DPI), that patient may struggle to shift his or her cognitive model of inhalers, even to the point of expecting immediate relief from that device when suffering an acute attack.
Usability and the Patient Journey
The patient journey concept is rooted in a notion that the elements of usability described above are not static in the context of how a patient endures the process of becoming ill, being diagnosed, and learning to manage his or her disease. Such a notion has real implications for how a delivery system should be optimized for usability over a period of time. The outline below depicts discrete stages in this journey, several of which will be examined more closely in the remainder of the article.
Initial Diagnosis: For many patients, being diagnosed with a disease is a shocking experience. Although some may experience a sense of relief because they now have an explanation for why they have been feeling ill, many will respond with deep-seated emotions of anger and depression. Often, patients will approach the need for medication with hostility, fear, or anxiety. Mentally focusing on learning-oriented tasks to facilitate their own treatment can be challenging. Patients may also suffer from symptoms that impair their ability to interact physically with objects or devices required for therapy.
Such considerations have implications for the design of drug delivery systems. Relative to this stage of the patient journey, devices should be easy to learn. Typically, that means minimizing the number of steps required to use a delivery device, but not at the expense of providing ambiguous feedback for how the device works or whether medicine has been delivered. Devices should also be easily demonstrated. Clinicians will often broker a patient’s introduction to a device and initially educate a patient in its proper use. Device interactions should not require patients to perform precise physical actuations or rely on finely tuned motor skills and sensory acuity. For example, using an insulin pen should not require precise orientation and alignment between disposable needle and pen, because a diabetic patient likely may suffer from trembling in the hands and have difficulty seeing small alignment details on system components. Rather, such components should be designed to guide the connection of discrete parts using simple motor interactions so they self-align and securely connect with minimal physical effort.
Early Treatment and Acclimation
At this stage in the journey, patients are in a transformative state as they learn to adapt to new routines and habits
. They have yet to build up a level of experience that makes treatment regimens habitual and automatic. Forgetting steps and confusing the effects of newly learned interactions are very real possibilities. Device developers should be aware of the possibility that many patients will be acclimating to more than one prescription therapy. That can exacerbate the challenges of learning new routines and elevate the risk that patients might confuse the steps and dosing frequencies associated with different medicines.
During this stage, a minimal number of use steps is paramount. Equally important is the ability of a system to provide clear and unambiguous feedback regarding the state of the device. That will confirm that patients have successfully performed the appropriate interactions and received a proper dose, and it contributes to the creation of habits that will facilitate ease of use in the future. For example, a DPI system should be designed to indicate and differentiate discrete states, such as
- secured for transport/storage (e.g., device is closed and sealed)
- ready for preparing a dose (e.g., device is open and ready for a dose to be advanced)
- loaded and ready to deliver (e.g., dose is ready for inhale)
- successfully delivered and ready to be secured for transport/storage (e.g., dosing chamber empty, confirmation that dose has been delivered).
Ambiguity relative to any of these steps can compromise the integrity of a solution and introduce the risk of harm for a patient. Uncertainty about whether a dose is loaded and ready for delivery can result in an accidental discharge and waste. Uncertainty around whether the proper dose was delivered can lead to administration of a double dose. Complicated routines requiring medication to be extracted, measured accurately, transferred to a delivery device, and then loaded and/or primed greatly increase the potential for error, waste, and misuse. That is particularly true before patients have had the chance to perform those routines to the point where they become natural and habitual.
This stage represents a very significant shift in how patients may consider their disease state and the relationship they have with a delivery system. As time passes and therapy regimens become more established, patients often start to feel better, may be less symptomatic, and have come to terms with their disease state. Many will yearn for occasions where they can “escape” the burden of suffering from disease in an attempt to achieve a lifestyle that is commensurate with what they experienced before their diagnosis.
Aspects of device use that may have been heavily appreciated during earlier stages, such as ease of learning and demonstrability, will likely have waned in importance when users become more experienced with operating a device. Now, patients are likely to make new demands of their device around convenience of use and the impact that the prescription therapies have on lifestyle and quality of life. Devices that are quick and efficient to use, especially regarding the time required to prepare and actuate delivery, stand a better chance of encouraging adherent behavior because their impact on daily routines becomes negligible. Discreteness also becomes more important. A discrete device provides its user with a greater range of options for how to integrate a dosing regimen into daily life. It also enables use without calling undue attention to the device, which can create distractions to others or feelings of stigmatization. Delivery systems deemed inconvenient or overconspicuous can negatively affect a patient’s emotional attitude and motivation to sustain adherent behavior.
Patient Lives a Better Life
For many patients, disease management becomes a permanent fixture in their lives. In this stage, emotional attitudes can develop that create a sense of complacency, which can undermin adherence to a prescription regimen. For some disease sufferers, therapy may serve only to stabilize symptoms without eradicating them. Over time, such patients can become despondent about the hopelessness of their condition and begin to doubt the effectiveness of their medication. Others may return to a near approximation of their lifestyle before diagnosis, emboldening them to skip doses or lapse in their therapy entirely.
In either situation, lack of information regarding the benefits, value, and effects of medical therapy can contribute to a lapse in adherence. In this context, well-designed delivery systems can become platforms for helping patients and physicians monitor disease-state progression. Devices designed with enabling technologies can then support the collection of information regarding physiologic measures, use patterns, adherence, and other relevant aspects of disease management. Accordingly, that can provide clinicians with more actionable information and lead to elevated standards of care. For patients, it can provide tangible means of how their prescription therapy is providing benefits and further incentivize adherent behavior.
Why the Journey Matters for Device Developers
A user-centered perspective for device development can elevate the standard of care for sufferers of disease. There is a clear connection regarding the advantages that device manufacturers can derive from making a commitment to usability as a development and organizational strategy. Supporting usability inherently drives innovation that matters to both patients and caregivers alike. Meaningful innovation often correlates with distinctive offerings, customer loyalty, and competitive advantage. Finally, user-centered practices are critical to navigating regulatory pathways and serving as strong risk-mitigation tools, both of which have real and significant implications to a device manufacturer’s business case.
The good news for biopharmaceutical and delivery system manufacturers is that the method or steps required for sound human factors and user-centered design are well-defined and align well with a best-practice, stage-gate process. It also enables confident decision making and provides efficiencies in product development. The patient journey is a trip worth understanding for all developers and engineers in the biopharmaceutical and medical device industries.
Corresponding author Chris Evans is director of innovation, Pharmaceutical Delivery Systems, at West Pharmaceutical Services, Washington, NJ; 1-908-223-7575. Ed Geiselhart is director of product development and planning at Insight Product Development, LLC.