Conducting remote clinical trials with teens
Dr. Aarthi Padmanabhan has always been fascinated by the brain. As Director of Clinical Research at Limbix, Padmanabhan oversees all of Limbix’s research activities — from strategy for grant applications, to clinical trial recruitment, to data collection, analysis, and dissemination.
Raised in an Indian-American immigrant family, Dr. Padmanabhan watched friends and relatives navigate mental illness while observing the ways that both cultures stigmatized their experiences. Growing up, she recalls that it was difficult for them to voice feelings about mental health. “Not being able to talk openly about these issues early in life sort of shaped the way that I perceive them now,” Padmanabhan says.
Those lived experiences led her down a path of academic research to understand human brain function and behavior. After studying cognitive science as an undergraduate at Carnegie Mellon University, she worked as a research assistant at the National Institute of Mental Health, and then pursued a PhD in cognitive psychology at the University of Pittsburgh. There, she focused on adolescent development and autism spectrum disorders . Dr. Padmanabhan was a researcher at Stanford University before joining Limbix in 2019.
Today, study operations are her key focus. Conducting research is a mission-critical step on the way to developing a prescription digital therapeutic that can be prescribed in doctors’ offices. Padmanabhan helped oversee Limbix’s first trial, or feasibility study, from 2019 to 2020. This smaller-scale trial of up to 30 participants was meant to gauge whether the therapeutic was feasible at a baseline level. “Are teens adhering to it?” she says. “In our context… it is important to know if this is something that can even be done.”
Dr. Padmanabhan’s team looked for metrics such as completion rate of the self-guided intervention along with preliminary indicators of efficacy, like reduction of depressive symptoms. At the same time, her team conducted qualitative interviews to gain feedback, understand users’ challenges and prompt product improvements.
These days, Padmanabhan is knee-deep in Limbix’s ongoing “real-world evidence trial,” which began in 2020 and is fully virtual. Remote operation has enabled the team, which recruits through “community samples” (social media channels and word of mouth) to achieve broader reach by enrolling over 200 teens across the U.S.
Eventually, Dr. Padmanabhan imagines partnering with primary care clinics that will enroll local patients. But for now, remote operation could enhance Limbix’s equity goals. Future trials for FDA clearance will involve representative samples, and the team is thinking critically about how to serve teens from low-income communities, and racial and ethnic minority groups in particular, says Padmanabhan. Beyond data on race, ethnicity and socioeconomic status, they also track rural, urban and suburban diversity — all in the aim of creating a product that’s accessible for teens of all backgrounds.
Already, research has provided rich insights. Padmanabhan says the variability she’s seen is eye-opening, and participants’ preferences have significantly informed product design and iteration. “It’s hard to make a one-size-fits-all,” Padmanabhan says.
In fact, Spark is designed to do just the opposite, by empowering teens to determine the incremental steps that feel meaningful to them. “Personalization is really important so that people are setting goals to meet them where they’re at, and not necessarily feeling like they have to think bigger than what they’re capable of at any given moment.”
Teens may often bring varied experience with, and trust in, mental health care. For some, Spark may represent their first time seeking help for depression; others may have tried therapy through traditional means. When serving this population, considering family dynamics is especially important: people under 18 need parental consent to participate, potentially limiting options for kids with complicated family relationships, or without parental support.
Understanding nuances that shape teens’ day-to-day lives is integral to Limbix’s work. Dr. Padmanabhan knows adolescence is a critical point of development, when many disorders emerge or begin. “Intervening at that time is critical to try and alter the trajectory of illness,” she says.
And she’s energized by novelty. “Mental healthcare has not changed much in decades,” Padmanabhan says. “We’ve had talk therapy and drugs for a very long time. I really see this as a new frontier for innovation.”
