In October, Limbix, a company creating digital therapeutics for adolescents, released data from a trial on its new product: SparkRx. SparkRx is a self-guided therapy program for teens run entirely on a phone.
Limbix was founded in 2016, and has about 30 employees, with plans to add 30 more by the second quarter of 2022. So far the company has raised $9 million in Series A funding, which closed in May 2020. That round was led by by GSR Ventures, with participation from existing investors Sequoia Capital, Storm Ventures, NextGen Venture Partners and BIXINK Therapeutics.
SparkRx, which is designed to help teens manage depression, is the company’s first product to be clinically evaluated. The app encourages teens to take note of their feelings, and schedule activities that leave them feeling better.
“They’re only really intended to spend a few minutes a day with it,” says Benjamin Alouf, Limbix’s chief medical officer. “[Teens use it] to schedule, to plan, to set the stage and then to go out and do this activity. Then they report back as to how it went.”
Limbix recently unveiled the results of a clinical trial at the 2021 American Academy of Pediatrics National Conference and Exhibition Virtual Experience. It has not been published in a journal, but TechCrunch reviewed the company’s poster presentation (a dense, data-rich synopsis format used at scientific conferences) from the event.
In the study, 160 adolescents aged 13-22 were assigned to use SparkRx or another app providing mental health education. Each group had mild to severe depression symptoms, which were evaluated using a classic questionnaire in depression research, called the PHQ-8. (Essentially, the questionnaire asks teens to estimate how often they feel they have little interest in doing things, have a loss of appetite or regularly feel like a failure, to evaluate depression symptoms.) The higher the score, the worse symptoms are.
SparkRx was associated with a decline in PHQ-8 scores among teenagers — those scores dropped about five points, a decrease the study refers to as clinically meaningful. However, that reduction wasn’t statistically significant compared to a control group who just got mental health education.
Where SparkRx made a meaningful difference was when the team looked specifically at teenagers who actually filled out PHQ-8 questionnaires every week (not everyone in the treatment group did so). In the people who actually completed the program, the app outperformed the control.
After five weeks, 21% of teens who adhered to study guidelines were in remission from depression, compared to 4% of the control group.
SparkRx is actually available right now to teens who get a referral from their healthcare provider. That’s made possible through pandemic-era FDA guidance stipulating the agency wouldn’t object to the release of digital therapy programs — provided they’re not marketed toward people who are grappling with suicidal ideation, or used on their own to make clinical diagnosis or treatment decisions.
Alouf says the majority of users, however, have so far come through clinical trials, not through real-world usage.
There’s plenty of background research suggesting people can benefit from using mental health apps — particularly people with anxiety and depression, though effects tend to be small, one 2020 review paper notes. But one major barrier appears to be retention. As one review paper in NPJ Digital Medicine notes, the median 15-day retention rate for mental health apps tends to be about 3.9%.
SparkRx’s trial does show higher retention numbers. Forty-two percent of teens used the app every day (compared to 19.5% seen in other “research depression apps,” the study notes). They completed about 63.5% of the program on average.
Part of increasing retention comes down to shaping a mental health app for the teen audience. Alouf says SparkRx has specifically been tweaked to address teen-specific mental health issues and barriers that stop them from seeking treatment.
“We have found through our studies, and it’s also been published, that adolescents prefer a self-guided, somewhat autonomous and very very discrete methods of therapy. They like to do it on their own time, at their own convenience and at their own pace,” he says.
For example, 2021 meta-analysis of eight studies evaluated some of the major barriers standing between teens and therapy. Autonomy was the primary theme that emerged across studies. Other research has shown the need for autonomy is a “strong barrier” preventing teenagers from seeking mental healthcare.
Alouf’s argument is SparkRx is designed with autonomy (and discretion — stigma is also a barrier to engagement with therapy) in mind. The app is self-guided, though it needs a referral from a healthcare provider to get started.
It’s also important to mention this app is not intended for teens who have suicidal ideation. The app wasn’t evaluated on teens who indicated they had struggled with thoughts of self-harm (the PHQ-8, the form used to track depression symptoms in the study, specifically does not include a question on this).
Ultimately, SparkRx intends to submit for FDA approval of its digital therapy program. The company, says Alouf, is aiming to have SparkRx become a prescription-based digital therapeutic.
“Getting the FDA stamp of approval will just show there’s not just internal but external confidence in the quality and validity of the product,” he says.
Whether or not SparkRX will gain FDA approval will likely hinge on the results of another pivotal trial the company is planning right now. Alouf was hesitant to provide a timeline, but added the company is “working diligently” on launching that trial “as soon as we can.”
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