Ultrasound mediated
drug delivery
(Image courtesy of Philips)

Philips hopes ultrasound unlocks potential of gene therapy

June 17, 2010
by Brendon Nafziger, DOTmed News Associate Editor
An experimental therapy that offers hope for treating disease by shutting off targeted genes might work if controlled with ultrasound pulses, according to Philips Healthcare.

Last week, Andover, Mass-based Philips inked a deal with biomed company RXi Pharmaceuticals to research using ultrasound to activate the therapy, known as RNA interference, or RNAi, which could help block genes implicated in several diseases.

The agreement is part of Philips' effort to move beyond diagnosis to therapy planning and image-guided intervention, the company told DOTmed News.

"Our decision to jointly research RNAi-based therapies with RXi is driven by our belief that patient care will ultimately benefit from the combination of novel drugs and advanced medical imaging technologies," Henk van Houten, senior vice president of Philips Research and head of its health care research program, said in a statement.

RNA is a chemical messenger used by DNA to carry out its commands, such as building proteins. In RNA interference, snippets of double-stranded RNA break off and attach to other strands of messenger RNA, stopping them in their tracks and effectively blocking the effects of the genes whose bidding they're doing.

The therapeutic promise of the technique is great since the goal is to shut off genes implicated in diseases such as cancers, Dr. Craig Mello, a professor at University of Massachusetts Medical School in Worcester and a founder of Worcester-based RXi, told DOTmed News.

Mello shared the Nobel Prize in Physiology and Medicine in 2006 with Andrew Z. Fire of Stanford University for his discovery of RNA interference.

"The numbers of possible products are [only] limited by the number of genes there are in the human," he said. RNAi can be developed to knock down genes involved in inflammation, cancer, and neurodegenerative disorders, Mello observed.

However, there is a massive obstacle to bringing the therapy into the clinic: making sure the therapeutic drugs go where they're supposed to go, and nowhere else.

"You have to get this into the cell for it to work," Mello said.

If injected, drugs relying on RNAi could deactivate genes throughout the body, and not just at the targeted site such as a tumor.

"So, the challenge for the whole field is delivery," Mello said, "and what Philips brings to this is technology for delivering and releasing drugs in a very precise region."

What Philips and RXI plan to do is research using ultrasound to ensure the drugs get activated only where they're supposed to.

In the planned joint therapy, the specially designed RNAi drug would be injected with micro-bubbles. The clinician would then deliver focused ultrasound pulses at the tumor or other target. The pulses would break up the micro-bubbles, causing them to make micro-tears in the surrounding tissue where the ultrasound pulse was delivered, allowing the drug to get absorbed. The doctors can also use ultrasound to image this action to ensure the drug goes to the right target.

"We can visualize the arrival of the bubbles in the target organ, the focused ultrasound pulse and the subsequent rupturing of the bubbles," said Steve Klink, a spokesman for Philips. "It's a great combination of two technologies, one which is extremely potent at getting the drug into the cell once it contacts the cell; the other one is capable of keeping the drug internalized and releasing it at its target in the body."

Philips said, in the long run, the company is interested in researching cardiology and oncology. "But we are still at this early stage. So at this point, it's not focused on a particular disease yet," Klink said.

The partnership comes after similar collaborations with Celsion and GlyGenix Therapeutics, as well as the launch of the Philips-led SonoDrugs project, which all involve using experimental drugs activated by Philips' equipment, the company said.

Read More from DOTmed News:

Philips Leads European "Sonodrugs" Project

Philips Combines Ultrasound With Cancer Drug Delivery

An Interview With Dr. Barry Goldberg