News has emerged from the US that the FDA has accepted, for the first time, a New Drug Application for a 'digital medicine'. This is new form of aripiprazole tablet contains an ingestible sensor, which is the result of a collaboration between Otsuka and Proteus Digital Health. The ingestible sensor relays information to a sensor patch worn by the patient, and when it reaches the stomach and this information is processed by a medical software application. The purpose of the system is to measure the adherence to aripiprazole treatment regimes of adult patients with schizophrenia and bipolar disorder associated episodes. It is also used as an adjunctive therapy for the treatment of adult major depressive disorder. Other patient metrics potentially affecting treatment regimes, such as activity and rest, may also be communicated by the sensor to the patch. The information provided by the sensor can be received by doctors on a mobile device. This is important, because the cost of administering treatments with which patients do not correctly comply, or comply at all, is estimated to be many billions.

The developments that have made this new form of aripiprazole possible are improved wireless technology and the ability to build small, sophisticated electronic systems. However, all digital medicines do not involve ingestion of a sensor and, in addition to reminding a patient when they need to take their medication, there are also digital medical devices that have applications in monitoring heart rate, respiratory rate and other vital signs. A, now traditional, example of a personalised, digital medical device is the continuous glucose monitor (CGM), used by diabetes patients. CGMs are typically attached to the patient by a disposable sensor placed under the skin. This is connected to a wireless transmitter which conducts information to a handheld device able to process and display the relevant information to the patient. CGMs can alert the patient when their glucose levels are rising or falling too quickly, predict in advance an oncoming high or low, or simply allow the patient to keep track of their glucose status throughout the day. Patients can, therefore, learn to adapt their lifestyle, to the extent possible, around their diabetes. In addition to providing this real time feedback, the data collected by a CGM can also be used with the appropriate software to establish a record of how the patient reacts to exercise, food and insulin. As with this new form of aripiprazole, the profile of a patient's disease that can be assembled in this way is an aid to clinicians advising on treatment.

Ingestible or implantable digital medicines also enable remote monitoring, such that a patient can be monitored by a hospital or other health centre from home, with treatment initiated without the patient having to first report to a clinician. Indeed, the need to monitor the vital signs of patients recovering from illness away from hospital is expected to gain in importance as the percentage of the population over 60 in many developed countries grows.

However, while digital medicines promise solutions, they also raise regulatory challenges. Chief amongst them is the need to protect personal data. Data protection law is to undergo a wholesale revision when the General Data Protection Regulation (GDPR) comes into force. Final text has now been published and will be formally adopted this year. There will then be a two year implementation period. The GDPR will include a number of measures concerning health data, including new definitions for personal data in this area. While health data is considered to be a type of "special" data (currently known as sensitive personal data), there are also a range of exceptions to the general prohibition around its use, for example, where the processing is necessary for medical diagnosis or for the purposes of preventative or occupational medicine, provided that certain safeguards are put in place around the processing. The Network and Information Security Directive (otherwise known as the Cyber Security Directive or NISD) can also be expected to have an impact on organisations processing data services where they are classed as essential service providers or digital service providers (which includes cloud computing services).

Furthermore, it is clear that the accuracy, reliability and safety of ingestible or implantable digital medicical devices will be of paramount importance. This is the concern of medical devices regulation. The existing European medical devices directives are already undergoing substantial recasting, with the current expectation being that two new Regulations are unlikely to come into force for another year.

The news from the US emphasises that issues associated with the regulation of digital medicines will soon become mainstream and the new legislation must meet this advance in technology.