Apple has kicked up its focus on health over recent years, but the company isn’t stopping just yet. According to a new report from CNBC, Apple has a secret team currently working on developing a solution for treating diabetes that would be seen as the “holy grail” for the condition…

The report, citing three people familiar with the matter, explains that Apple has hired a “small team” of biomedical engineers to work on the initiative. The team is said to be based out of an unmarked, nondescript office in Paolo Alto, California.

The initiative sees Apple working on developing sensors that can constantly monitor blood sugar levels to better treat diabetes. While specific timeline information is unclear, the company is reportedly far enough along in it testing that it has been conducting feasibility trials:

The initiative is far enough along that Apple has been conducting feasibility trials at clinical sites across the Bay Area and has hired consultants to help it figure out the regulatory pathways, the people said.

One of the sources explained that Apple is developing optical sensors, which work by shining a light through the skin to measure glucose levels. To accurately be able to measure glucose level would be a huge breakthrough for Apple and the medical industry as a whole.

Accurately detecting glucose levels has been such a challenge that one of the top experts in the space, John L. Smith, described it as “the most difficult technical challenge I have encountered in my career.”

To succeed would cost a company “several hundred millions or even a billion dollars,” DexCom executive chairman Terrance Gregg previously told Reuters.

Such an initiative was first imagined by Steve Jobs and Apple has been working on it for five years. Jobs imagined the solution being integrated into a wearable device, such as the Apple Watch.

Jobs envisioned wearable devices, like smartwatches, being used to monitor important vitals, such as oxygen levels, heart rate and blood glucose.

Apple has made a variety of acquisitions that lend credibility to this report. While specific information is still somewhat unclear, an initiative like this succeeding would not only help the success of Apple Watch, but also millions of diabetes patients.