Otsuka Pharmaceutical (TYO:4578) and Proteus Digital Health  said today that the FDA issued a complete response letter requesting more information from the companies for the combination of the Proteus “smart pill” and Otsuka’s Abilify anti-depressant drug.

The Proteus pill is designed to signal a wearable patch after it reaches the stomach, recording and time-stamping data from the pill and other patient metrics. The data can be relayed via Bluetooth to mobile devices and, with consent, to healthcare providers.

The federal watchdog is requesting new data from the companies, including information on the performance of the product under conditions it is likely to be used and further human factors investigations, the companies said.

“While we are disappointed in the FDA’s decision not to approve this Digital Medicine at this time, both Otsuka and Proteus are committed to working with the FDA to address its questions and provide the additional data that has been requested. We believe in the potential of this product to help people with serious mental illness manage their daily medication, which remains a serious unmet need,” Otsuka chief strategy officer Robert McQuade said in a prepared statement.

The FDA requested human factors testing to evalute use-related risks to confirm individuals can use the device safely and effectively, the companies said.

Last September, Otsuka Pharmaceuticals and Proteus Digital Health said that the FDA agreed to review the drug-device combo.

The companies said the FDA accepted their new drug application for the drug-device combination, using the Proteus ingestible sensor and Otsuka’s aripiprazole drug in patients with serious mental illnesses such as major depressive disorder, bipolar disorder and schizophrenia. It’s the 1st time the federal safety watchdog has reviewed a drug-device combo designed to measure adherence.