Wireless Drug Delivery Prototype Completes Clinical Trials
There are two competing methods for next-generation drug delivery. On the one hand, you can send a tiny robot into the bloodstream of the patient, to analyse the environment there, and determine when to release some of its drug payload, and when to request resupply. On the other, you have the concept of a dumb waldo drug capsule, that routinely drops X amouint of drug into the bloodstream on command from an external device. Both approaches are being develloped, and both are at time of writing, just starting to enter clinical trials in different hospitals around the world.
This device however, has completed its first round of clinical trials, and is the first of either type to do so. It is of the externally controlled dumb capsule type, and was created by the company MicroCHIPS, in conjunction with researchers at MIT. About 15 years ago, MIT professors Robert Langer and Michael Cima had the idea to develop a programmable, wirelessly controlled microchip that would deliver drugs after implantation in a patient’s body. This is the direct result of a decand and a half of work.
The device is, as is to be expected, rather primitive, and only capable of holding one type of drug at a time. The hope is eventually to have an entire pharmacy available in a device, with it dispensing chemicals into the bloodstream when the doctor directs it to, as opposed to it making its own decisions. In February, the scientists reported they had successfully used the device to administer daily doses of an osteoporosis drug normally given by injection. They used the programmable implants to deliver an osteoporosis drug called teriparatide to seven women aged 65 to 70. The study found that the device delivered dosages comparable to injections, and there were no adverse side effects.
“Compliance is very important in a lot of drug regimens, and it can be very difficult to get patients to accept a drug regimen where they have to give themselves injections,” says Cima, the David H. Koch Professor of Engineering at MIT. “This avoids the compliance issue completely, and points to a future where you have fully automated drug regimens.”
The human clinical trial began in Denmark in January 2011. Chips were implanted during a 30-minute procedure at a doctor’s office using local anesthetic, and remained in the patients for four months. The implants proved safe, and patients reported they often forgot they even had the implant. Each had enough drug stored inside for no more than twenty doses, individually sealed in tiny reservoirs about the size of a pinprick.Each dose was capped with a tiny seal of platinum and titanium that melted when a small electrical current was applied, by an attached electrode. In short, it was essentially a small array, 4 x 5 of drug doses, each of which had its own unique address in the chip's memory.
Because the chips are programmable, dosages can be scheduled in advance or triggered remotely by radio communication over a special frequency called Medical Implant Communication Service (MICS). Current versions work over a distance of a few inches, but researchers plan to extend that range. Ultimately, a goal is to have true telemedicine systems in place, with signals being transmitted over the internet, to a MICS tranceiver in the patient's house or car, which sends the command to the implant. It is even conceivable eventually, to include the tranceiver on the implant itself, thus connected it to the body's BAN network, and to the internet via the smartphone. This in conjunction with an implant that can carry many drugs at once, would allow doctors to update prescriptions with immediate effect, bypassing the need to use a pharmacy entirely.
In the Science Translational Medicine study, the researchers measured bone formation in osteoporosis patients with the implants, and found that it was similar to that seen in patients receiving daily injections of teriparatide. Another notable result is that the dosages given by implant had less variation than those given by injection. Henry Brem, professor of neurosurgery, ophthalmology, oncology and biological engineering at Johns Hopkins University School of Medicine, called the results “stunning.” “It’s very rare to find a paper that is really a breakthrough in technology,” says Brem, who was not part of the research team. “It fulfills the promise of polymer drug delivery and the incredible sophistication of microchip capabilities.” Once a version of the implant that can carry a larger number of doses is ready, MicroCHIPS plans to seek approval for further clinical trials.