Rett Syndrome, like many other neurological disorders, relies on the interpretation of symptoms by others – typically parents and clinicians, through questionnaires and interviews. This is standard for the field whether in clinical practice or clinical trials. And like other neurological disorders, Rett Syndrome suffers the inconvenience of not having direct and objective measures that correlate with severity. What does this inconvenience mean, exactly?
Well let’s take a direct and objective measure we’re all aware of as an example: blood pressure. Blood pressure is a direct and objective measure that correlates with a patient’s degree of cardiovascular health. It’s measured in the clinic in a non-invasive way, and represents a measurement in the patient (direct) such that the results are not interpreted by someone else, but simply listed (objective) – like 115 over 60, or 140 over 90. Now imagine if we had to measure and treat cardiovascular health through questionnaires and interviews instead. . . Suddenly, that direct and objective measure of blood pressure we take for granted seems pretty valuable doesn’t it?
The lack of an objective and standardized outcome measure for Rett is a major reason why there is limited pharmaceutical and biotech involvement in our disorder. Developing drugs is risky business and companies are further deterred when there are extra complications such as subjective and therefore potentially ineffective or irreproducible outcome measures.
At RSRT we have therefore made it one of our key objectives to develop more effective ways to measure Rett therapeutics in the clinic. Not only does this objective attempt to move the needle in a more comprehensive and meaningful way for therapies in clinical trials, but could also change the way we evaluate Rett every day.
Right now we are working on an initiative to develop direct and objective measures of Rett symptoms by testing non-invasive, wearable biosensors. We have piloted a number of biosensor devices that can measure things like heart rate variability, breathing, sleep quality, body position, gait, and others, just by being worn on the body. These biosensor devices collect direct and repeated measurements in an individual, much like a fitbit or apple watch, and can provide significantly more accurate data over almost any period of time than standard symptom assessments. This is our attempt at a “Rett blood pressure measure” and could represent a huge advantage over symptom observation.
Our goal is to identify which biosensors are easy to use, generate good quality data, and detect symptoms that would be valuable to measure in Rett patients. But that’s not enough - we have also partnered with industry to develop analytical programs for the data these devices collect to detect and evaluate Rett symptoms specifically.
The biosensors that are furthest along in our development initiative are all worn on the body in some way: on the wrist like a watch, or as an undershirt, or like a sticky Band-Aid, all of which have their pros and cons, may be more appropriate in certain settings, or for measuring certain symptoms in particular. But we are also working with the next generation of biosensors called invisibles, which are not worn, but collect data by being in the vicinity of the individual to remotely detect physiological outputs of interest. Very cool and totally Sci-Fi, but like the wearables, invisibles also present their own advantages and challenges.
As we continue to pursue our biosensor development initiative we are confident that direct and objective measures of Rett symptoms are only a matter of time. We expect that various biosensors may be better suited for certain situations but we are doing our best to develop a biosensor that is as all encompassing as we can currently imagine. We are excited to be spearheading this important approach in understanding Rett on a different level than ever before and creating the opportunity for new therapies to be effectively evaluated directly and objectively where it matters most – in the patient.