Recent clinical trials on microneedle drug delivery

Microneedles have been in development since the late 80s, but only recently have they begun appearing in clinical trials. Microneedles are micron-scaled needles that are so small, they are able to painlessly penetrate the skin. Current microneedle designs look like miniaturized beds of nails, fabricated from stainless steel, titanium, and even plastic. Although recent clinical trials have used microneedles to deliver drugs, researchers are also investigating how microneedles could be used to sample body fluids for monitoring.

Last fall Zosano Pharma presented results of a Phase II trial of microneedle delivery of parathyroid hormone (PTH) for osteoporosis. The Zosano product, the ZP-PTH patch, is a band-aid-type patch containing a bed of microneedles coated with PTH, significantly more convenient compared with the daily conventional injections required by Zosano’s competitor, Forteo. One potential downside is that the Zosano patch in the trial was applied for 30 minutes daily and then removed. What would happen if patients forget to remove the patch? Although the daily microneedle patch is convenient compared with the daily conventional injections of Forteo, other osteoporosis medications (with different mechanisms of action) are even more convenient, offering oral pills or a once-yearly injection. With yet another osteoporosis drug approved last week, it remains to be seen what the market will look like if and when the ZP-PTH patch launches.

Other clinical trials involving microneedle delivery include three studies (proof of concept, pre-phase I) by NanoPass technologies using their MicronJet microneedle technology for flu vaccines, anaesthesia, and diabetes. Similar to the Zosano patch, the MicronJet is an array of microneedles, but instead of being in band-aid form, the MicronJet connects to a conventional syringe, presumably enabling delivery of larger fluid volumes. Finally, Emory University is also conducting a Phase II/III clinical trial on using microneedles for insulin delivery in Type 1 diabetes.

For more on microneedles:

• Marlene Bourne, MEMS and nanotech industry analyst, has a great 5-minute podcast about microneedles
• Last year Dorian Liepmann, professor at UC Berkeley, gave a talk about the history, advantages, and challenges of microneedle development (the talk itself is about 16 minutes, with 10 minutes of questions afterwards)
• Mark Prausnitz’s group at Georgia Tech has been a leader in microneedle research, working on flu vaccine delivery (and many other applications)

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