BioWorld Today Contributing Writer

Fullerene carbon nanotubes are being investigated as a means to solve two important problems for many cancer therapeutics: to deliver large active agents to specific locations and to protect normal tissue from the active agent during delivery. Backed by an enormous intellectual property portfolio in carbon nanotube technology, Ensysce Biosciences Inc., hopes to corner the market using the tube-shaped molecules to deliver cancer therapeutics.

Because carbon nanotubes can traverse cell membranes and carry large payloads into cells, Ensysce has a multi-pronged development platform. The chemical structure of carbon nanotubes allows them to form stable complexes with cancer-cell targeted agents that range from small interfering RNA (siRNA) to existing cancer drugs, such as Taxol and doxorubicin.

In fact, the name Ensysce was chosen to signify the "precise" targeting of drugs "inside" cells, since nanotubes so easily penetrate cancer cells.

"We're quite different from most of the delivery companies in that they're usually looking at relatively large-diameter nanoparticles, whereas ours are very small," CEO D. Lynn Kirkpatrick told BioWorld Today. "We've been able to form stable complexes with numerous active entities – including siRNA. We believe our current research efforts to tailor their transport and release will ensure a therapeutic benefit while eliminating off-target effects."

Because siRNAs can silence gene messages and have potential to suppress messages that lead to cancer, the molecules have intriguing prospects as a cancer therapeutic if they can be delivered directly into cancer cells without degrading or interfering with other matter. Ensysce-sponsored animal studies conducted at M.D. Anderson Cancer Center in Houston have shown that carbon nanotubes can transport siRNA into cancer cells to produce a biological response without signs of toxicity.

In June, the Houston-based company received $1.5 million from the Texas Emerging Technology Fund (ETF) to move its technology into preclinical studies. (See BioWorld Today, June 14, 2010.)

"We are optimizing our first product and hope to have it [ready for an investigational new drug application] in 12 to 18 months," Kirkpatrick said.

Privately held Ensysce was spun off in 2008 by Unidym Inc., a majority-owned subsidiary of Pasadena, Calif.-based Arrowhead Research Corp., to focus specifically on the therapeutic applications. (See BioWorld Today, March 19, 2008.)

Unidym, which develops nonclinical products that incorporate carbon nanotubes, licensed its nanotech patent portfolio to Ensysce for that field of use and holds an equity position in the company.

The company's technology stems from the research of the late Richard Smalley, the 1996 Nobel Laureate for chemistry from Rice University in Houston. Unidym acquired the rights to Smalley's work in carbon nanotechnology through a merger with Smalley's firm Carbon Nanotechnologies, Inc. (CNI) in April 2007. CNI had been developing carbon nanotubes – tube-shaped molecules comprised of intricately arranged carbon atoms – for more than 10 years and owned 54 U.S. patents and several patent applications for the technology.

After the spinoff, CNI's co-founder, Robert Gower, continued to chair the new company. He recruited Kirkpatrick, co-founder of ProlX Pharmaceuticals and a former professor of chemistry and biochemistry at the University of Regina, Canada, to join Ensysce as CEO in January 2009. The company now has four employees and sponsors collaborative research in carbon nanotube technology at Stanford and Rice Universities as well as M.D. Anderson.

For example, Ensysce is supporting a research program at Rice that uses two alpha-emitting materials – astatine and actinium – complexed inside ultra-short carbon nanotubes to offer another potential delivery vehicle for cancer therapy. Holes in the walls of the ultra-short carbon nanotubes allow the alpha-emitters to enter, where they are captured and retained. Subsequent emission from the radioactive material penetrates only a two- to three-cell diameter, ensuring localization of the agents.

Although Ensysce is focusing on developing its own product stream, the academic research collaborations may also lead to enhancements of existing technologies. "We have the opportunity both to partner with companies that require the delivery technologies and to take products into trials ourselves, to develop our own pipeline," Kirkpatrick said.

Presently, the company's IP portfolio includes exclusive and nonexclusive licenses from several universities and research institutions for more than 80 issued patents, plus additional pending-patent applications. Ensysce holds the licensing rights to technology developed as part of its funded research programs and, as part of its broad license agreement with Unidym, the rights to any IP required for the use of carbon nanotubes in therapeutic applications that is developed, licensed or acquired by Unidym within the next few years.

The ETF funding is expected to take the company through 201 1 "with a highly aggressive development timeline," Kirkpatrick said. In the meantime, she's discussing downstream funding opportunities with potential partners and examining other financing mechanisms.