Limbix Releases Clinical Trial Data for Teen Mental Health App

Limbix's SparkRx: A Digital Therapeutic for Adolescent Depression

In October, Limbix, a developer of digital therapeutics geared towards adolescents, publicized findings from a trial concerning its innovative product, SparkRx. This program represents a self-directed therapeutic intervention for teenagers, delivered exclusively through a smartphone application.

Company Background and Funding

Established in 2016, Limbix currently employs approximately 30 individuals, with expansion plans to incorporate an additional 30 employees by the second quarter of 2022. To date, the company has secured $9 million in Series A funding, finalized in May 2020.

This funding round was spearheaded by GSR Ventures, with contributions from existing investors including Sequoia Capital, Storm Ventures, NextGen Venture Partners, and BIXINK Therapeutics.

SparkRx: Design and Functionality

SparkRx, the company’s inaugural product undergoing clinical assessment, is engineered to assist teenagers in managing symptoms of depression.

The application prompts users to record their emotional states and to engage in activities anticipated to improve their well-being. As Benjamin Alouf, Limbix’s chief medical officer, explains, “The intended usage is limited to just a few minutes each day.”

SparkRx facilitates scheduling, planning, and preparation for these activities, with users subsequently reporting on their experiences.

Clinical Trial Results

Limbix recently presented the outcomes of a clinical trial at the 2021 American Academy of Pediatrics National Conference and Exhibition Virtual Experience.

While the full study has not yet appeared in a peer-reviewed journal, TechCrunch reviewed the company’s poster presentation – a concise, data-rich summary commonly used at scientific conferences.

The study involved 160 adolescents, aged 13 to 22, who were assigned to either utilize SparkRx or an alternative application offering mental health education.

Participants in both groups exhibited varying degrees of depression symptoms, assessed using the PHQ-8 questionnaire – a standard tool in depression research.

This questionnaire gauges the frequency with which adolescents experience symptoms such as loss of interest, appetite changes, or feelings of failure, to quantify the severity of their depression.

Impact on Depression Scores

Usage of SparkRx correlated with a reduction in PHQ-8 scores among teenage participants – scores decreased by approximately five points, a change considered clinically significant.

However, this reduction did not reach statistical significance when compared to the control group receiving only mental health education.

A noteworthy difference emerged when analyzing data from teenagers who consistently completed the PHQ-8 questionnaire each week.

Among those who actively engaged with the program, SparkRx demonstrated superior performance compared to the control group.

Remission Rates

After five weeks, 21% of adolescents adhering to the study protocol achieved remission from depression, in contrast to only 4% in the control group.

Availability and Regulatory Considerations

SparkRx is currently accessible to teenagers with a referral from their healthcare provider.

This is permissible due to temporary FDA guidance issued during the pandemic, allowing the release of digital therapy programs under specific conditions – namely, that they are not marketed to individuals experiencing suicidal thoughts, nor used for self-diagnosis or treatment decisions.

Alouf notes that the majority of current users have been recruited through clinical trials, rather than through general availability.

Retention and the Mental Health App Landscape

Research indicates potential benefits from utilizing mental health applications, particularly for individuals with anxiety and depression, although effects are often modest, as highlighted in a 2020 review.

A significant challenge, however, is user retention. A review published in NPJ Digital Medicine reveals a median 15-day retention rate of approximately 3.9% for mental health apps.

SparkRx Retention Rates

The SparkRx trial demonstrates improved retention figures. Forty-two percent of teenagers used the app daily, compared to 19.5% observed in other research-focused depression applications.

Participants completed approximately 63.5% of the program on average.

Tailoring to the Teen Audience

Enhanced retention is attributed to the app’s design, specifically tailored to address the unique mental health needs and barriers faced by teenagers.

“Our studies, and published research, demonstrate that adolescents favor self-guided, autonomous, and discreet therapeutic approaches,” Alouf explains. “They prefer to engage at their own pace and convenience.”

The Importance of Autonomy

A 2021 meta-analysis of eight studies identified autonomy as a primary theme influencing teenagers’ access to therapy.

Further research confirms that the need for autonomy is a “strong barrier” preventing adolescents from seeking mental healthcare.

Alouf argues that SparkRx is designed with autonomy – and discretion, to address stigma – in mind, offering a self-guided experience requiring a healthcare provider referral.

Limitations and Future Directions

It is crucial to note that this application is not intended for teenagers experiencing suicidal ideation. The study did not include an assessment of suicidal thoughts in the PHQ-8 questionnaire.

Limbix intends to pursue FDA approval for SparkRx as a digital therapeutic, aiming for a prescription-based model.

“FDA approval will reinforce both internal and external confidence in the product’s quality and validity,” Alouf states.

The company is currently planning a pivotal trial to support this application, with Alouf indicating they are “working diligently” to launch it as soon as possible.