Ensysce’s Bet: Combining Two Risky Drug Technologies That Add Up

5/9/13Follow @tanseyverse

At one edge of the sprawling Texas Medical Center in south central Houston, near a slew of hospitals and research hubs including the renowned MD Anderson Cancer Center, three floors of an office tower are reserved to nurture startup companies.

The incubator is one of the initiatives that have sprung up in Texas to expand the state’s community of life sciences companies, a sector that is growing but can’t yet match the established business ecosystems around cities such as San Francisco and Boston.

However, fledgling companies such as Ensysce Biosciences have taken root at the incubator space, the Biotechnology Commercialization Center at the University of Texas Health Science Center at Houston. There, Ensysce researchers can maintain their close collaboration on nanotechnology drug delivery tactics with scientists at Rice University and other nearby labs.

Ensysce is working on experimental cancer treatments that combine two cutting edge technologies: RNA interference and carbon nanotubes. The company is trying to prove that nanotubes offer a superior drug delivery system that will help fulfill the somewhat tarnished promise of the compounds known as siRNA’s, or small interfering RNA molecules. These chains of about 20 to 25 nucleotides can be designed to short-circuit the expression of damaging genes that cause disease.

Just five years ago, when Ensysce was founded, the scientific world was galvanized by the potential of siRNA’s, which silence the messages sent out by genes in the form of messenger RNA. A siRNA can interfere with the production of proteins from the coded instructions in messenger RNA molecules transcribed from a target gene. As one sign of the excitement over the new technology in 2006, Merck (NYSE: MRK) bought San Francisco-based startup Sirna Therapeutics for the stunning price of $1.1 billion to acquire its pioneering program in siRNA’s. The compounds were seen as a way to fight diseases that couldn’t be effectively treated with existing small-molecule chemical drugs, or biotech products made through conventional genetic engineering.

Even so, drug developers knew they’d need to find a way to get the bulky siRNA nucleotide chains delivered inside cells, where they could go to work. And hitches with drug delivery have in fact hindered progress with siRNA therapies.

Carbon nanotubes seemed like the perfect siRNA delivery vehicle to Ensysce founder Bob Gower, who financed the startup himself in 2008. It was a spinout of a company, Carbon Nanotechnologies, that he had formed in 2000 with Richard Smalley, who shared the Nobel Prize in Chemistry in 1996 for the discovery of the “buckyball,” a hollow sphere of 60 carbon atoms that looks like a soccer ball because the carbon atoms form the points of six-sided hexagons. Carbon nanotubes are made of curled sheets of these hexagons, so they look like rolled-up chicken wire.

Lynn Kirkpatrick, CEO of Ensysce Biosciences

Gower saw the thin, minuscule carbon nanotube as a lattice where chemists could attach drug molecules such as siRNA’s for protected transport through the bloodstream to a target tissue or tumor. The lattice, he hoped, would shield the siRNA from enzymes in the bloodstream that would otherwise chop it up and render it ineffective before it could get inside cells. In addition, the nanoscale ends of the tubes could penetrate cell membranes like a needle—a phenomenon later nicknamed “nanospearing.”

In 2009, Gower recruited CEO Lynn Kirkpatrick, a medicinal chemist who had co-founded small molecule drug developer ProlX Pharmaceuticals, which was sold in 2006 to become part of a merged company Oncothyreon (NASDAQ: ONTY) of Seattle, WA. Kirkpatrick says she was intrigued by Ensysce’s cutting-edge goals, but she faced a significant learning curve.

“I knew nothing about carbon nanotubes,” says Kirkpatrick, who has since presided over Ensysce’s work to adapt the nanotubes as elements of a drug preparation.

The potential of carbon nanotubes is easy to see in fields such as electronics—their molecular structure is a hundred times stronger than steel, they conduct heat, and no liquid can dissolve them. But the idea of piercing cells … Next Page »

Bernadette Tansey is a freelance journalist based in Berkeley, CA. Follow @tanseyverse

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