Osteoporosis patients could soon ditch daily injection pens for an implantable microchip that releases medication at the push of a remote-controlled button, reports a new study appearing in the journal Science Translational Medicine.
The clinical trial, composed of a group of women with osteoporosis in Denmark, is the first to test a wirelessly controlled microchip capable of releasing drugs into the body at any time.
“Patients will be freed from having to remember to take their medication and don’t have to experience the pain of multiple injections,” said Robert Farra, President and Chief Operating Officer of MicroCHIPS, Inc., the Massachusetts-based company behind the device. Farra is a co-author of the study, along with colleagues from MIT, Harvard Medical School, OnDemand Therapeutics Inc and Case Western Reserve University.
Unlike most drug delivery devices, which release small amounts of drug slowly over time, the microchip releases medication on command from an external wireless device. This controlled system gets medicine into the bloodstream quickly, similar to an injection.
“Physicians will be able to seamlessly adjust their patients’ therapy using a computer or cell phone,” said Farra.
The authors figure the microchip may be a more appealing and possibly cheaper alternative to long-term use of prefilled daily injection pens.
Patients with severe osteoporosis often have to give themselves daily injections of medication that requires refrigeration. Aside from the psychological burden of daily injections, older people may have arthritis or other problems that make injections physically difficult.
Moreover, since osteoporosis is a “silent” disease – affected individuals don’t feel better or worse as their bone density decreases – many patients simply stop taking medication to avoid the hassle of daily injections.
The implant could help circumvent the high drop off in compliance and dramatically boost the quality of life for millions of osteoporosis patients. The device may also be useful for treating other chronic diseases like multiple sclerosis, heart disease or even cancer.
Roughly the size of a pacemaker, the device holds daily doses of a drug inside tiny wells that pop open either on a pre-programmed schedule or via a wireless signal.
“The drugs are in different wells. Each of these wells is covered by a nano-thin layer of gold which protects the drug for years if needed and prevents it from being released,” said Robert Langer, Professor at MIT and co-author of the Science Translational Medicine paper.
Sending a wireless signal to the well causes the gold to dissolve, freeing medication into the bloodstream.
Adapting microchip technology for human use is no small feat. The team first had to figure out a way to seal each reservoir airtight at room temperature. They developed a special compression welding process designed to provide a long-term seal. The researchers also developed the gold layer, which is strong enough to protect the contents of each reservoir, but thin enough to dissolve on command.
Despite the microchip’s proven ability to deliver drugs in the lab, once it was implanted into animals, a fibrous collagen-based membrane tended to develop around the device.
The researchers were concerned that this fibrous tissue could potentially slow down the absorption of medication, and one of the aims of this study was to determine if the membrane decreased effectiveness.
The researchers implanted the microchip just below the waistline, into seven women between the ages of 65 and 70. The procedure can be performed in a doctor's office with local anesthetic.
Tracking the women for 12 months, the team showed that the implant delivered the drug teriparatide just as effectively as daily injections, although the fibrous membrane did form around the device. Treatment improved bone formation and reduced the risk of bone fracture, as evidenced by the presence of biochemical markers signaling bone formation, bone mass and bone resorption.
“And there is much less variation from dose to dose than injections, so it's safer and more effective in that sense,” Langer said. The chip was removed from participants at the end of the one-year treatment.
The company hopes to make the device available for mainstream use in five years.
Date: February 16, 2012
Source: American Association for the Advancement of Science