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Nano-scale liposomes are small enough to squeeze between cancer cells to distribute a radioactive isotope more evenly within the tumor, yet are large enough to stay localized in the tumor region.
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SAN ANTONIO (Sept. 4, 2008) — The University of Texas Health Science Center at San Antonio and Azaya Therapeutics Inc. on Sept. 4 announced a licensing agreement for a novel nano-scale, anti-cancer technology conceived and pre-clinically tested by Health Science Center faculty.

The tiny therapeutic agents, bubblelike structures called liposomes, are approximately 100 nanometers in size (about one-one-thousandth the width of a human hair). Nano-scale liposomes are small enough to squeeze between cancer cells to distribute a radioactive isotope more evenly within the tumor, yet are large enough to stay localized in the tumor region. They may benefit head and neck cancer patients for whom surgery and radiation is no longer an option.

The Health Science Center researchers recently discovered a way to incorporate a radioactive isotope, ¹⁸⁶rhenium, into the liposomes. The scientists also demonstrated that the radioactive liposomes could kill cancer cells.

Higher doses of radiation directly to the tumor
“Early studies indicate this method can deliver much higher radiation doses to tumors accurately while the surrounding normal tissue toxicity is minimal, which is different from external beam radiation,” said Ande Bao, Ph.D., assistant professor of radiology and otolaryngology-head and neck surgery at the Health Science Center.

If the first clinical application of ¹⁸⁶rhenium liposomes in head and neck cancer patients is successful, follow-up clinical studies may target prostate, breast and brain cancers.

Azaya Therapeutics will develop and commercialize the novel cancer treatment, which is based on the work of Dr. Bao and William T. Phillips, M.D., and Beth Goins, Ph.D., professors of radiology at the Health Science Center. All are members of the Cancer Therapy & Research Center at the UT Health Science Center. For more than 15 years, these scientists have studied ways to use liposomes for the treatment of human disease.

Nano-scale liposomes, developed by researchers at the Health Science Center, show promise in treating head and neck cancer.

Technology behind the treatment
“Nano-scale liposomes deliver short-range, powerful radiation where it is needed, sparing non-diseased tissue,” Dr. Phillips said. “This activity is so precise that it may be possible to treat the same area over and over as needed.”

External beam radiation, by contrast, can be used only once because normal tissue in the head and neck region has a lifetime dose limit that cannot be exceeded.

Another potential usage is in the operating room. It is possible ¹⁸⁶rhenium liposomes may be injected into tumors that surgeons cannot remove because of proximity to vital structures. “We could greatly increase the chance of eliminating all cancerous cells,” said Randal A. Otto, M.D., a clinical collaborator on the project, CTRC physician-in-chief and the Thomas Walthall Folbre, M.D., Endowed Chair in Otolaryngology at the Health Science Center.

Findings published in Clinical Cancer Research
This summer, the researchers presented encouraging preclinical data in the journal Clinical Cancer Research. In this study, human tumors grown in rats were partially removed, simulating a possible real-life situation of a patient with residual head and neck cancer.

The residual tumors were injected with either ¹⁸⁶rhenium-liposomes or empty liposomes. After five weeks, tumors treated with empty liposomes grew back rapidly and increased 300 percent in size, while tumors treated with ¹⁸⁶rhenium-liposomes decreased in size by three-fourths.

First license agreement for South Texas Technology Management
The exclusive license agreement is the first executed by South Texas Technology Management, the new regional technology transfer office that serves the UT Health Science Center, UT San Antonio, UT-Pan American and UT Brownsville. Kenneth W. Porter, Ph.D., directs the office, and license specialist Sean Thompson, M.S., M.B.A., played a leading role in this negotiation.

“Effective technology licensing takes time and patience,” Dr. Porter said. “Mr. Thompson recognized the complementary interests, introduced the parties a year ago and nurtured the relationship through today’s license execution. Further patience and hard work will be required to bring a new drug to market.”

“This agreement represents the best of what the Health Science Center has to offer — thorough, basic research leading to a promising new therapy for cancer patients who have few options, and the ability to license to a South Texas company that will turn it into a lifesaving product,” said Brian Herman, Ph.D., vice president for research at the Health Science Center.

Francisco G. Cigarroa, M.D., president of the Health Science Center, called the license development “a win for cancer patients and a demonstration that academic research can provide local economic development.”

Michael T. Dwyer, president and CEO of Azaya Therapeutics, said the technology nicely complements Azaya’s existing cancer therapy product pipeline.

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The University of Texas Health Science Center at San Antonio is the leading research institution in South Texas and one of the major health sciences universities in the world. With an operating budget of $668 million, the Health Science Center is the chief catalyst for the $15.3 billion biosciences and health care sector in San Antonio’s economy. The Health Science Center has had an estimated $35 billion impact on the region since inception and has expanded to six campuses in San Antonio, Laredo, Harlingen and Edinburg. More than 23,000 graduates (physicians, dentists, nurses, scientists and other health professionals) serve in their fields, including many in Texas. Health Science Center faculty are international leaders in cancer, cardiovascular disease, diabetes, aging, stroke prevention, kidney disease, orthopaedics, research imaging, transplant surgery, psychiatry and clinical neurosciences, pain management, genetics, nursing, dentistry and many other fields. For more information, visit www.uthscsa.edu.