NEW APPROACH TO SOLID CANCER TUMOR TREATMENT; EFFICACY RESULTS PUBLISHED IN SCIENCE JOURNAL.

TUSTIN, Calif.--(BW HealthWire)--Jan. 29, 1997--Vascular Targeting Agents (VTAs), a promising cancer therapy that interrupts the blood supply necessary for a solid tumor's continued survival, were the subject of a study published in the January 24 issue of Science, the weekly journal of the American Association for the Advancement of Science.

The technology was pioneered by Philip Thorpe, M.D., Ph.D., founder of Peregrine Pharmaceuticals, which recently announced that it will be acquired by Techniclone Corporation (Nasdaq: TCLN), a cancer therapeutic company that is also pioneering treatment of solid tumors. Techniclone's most advanced product, LYM-1, is currently in PHASE II/III clinical trials for the treatment of non-Hodgkin's B-cell lymphoma.

In the mouse model study, Vascular Targeting Agents delivered a clot-inducing drug inside the tumor vasculature, resulting in the selective formation of blood clots (thrombosis) within the tumor vessels. The clots resulted in the "starvation" of the tumor (blockage of oxygen and nutrients necessary for tumor survival), causing massive tumor cell death. Complete tumor regressions were reported in 38 percent of the mice, while 24 percent achieved a partial response rate (classified as greater than 50 percent decrease in initial tumor volume).

"These results show an exciting, new approach to the treatment of large, solid tumors," said Thorpe, M.D., Ph.D., a principle investigator of the study and the Serena Simmons Distinguished Chair of Cancer Immunopharmacology at the University of Texas Southwestern Medical Center in Dallas, Texas. "Because vascular targeting agents are highly specific and anchor to endothelial cells in contact with blood, considerably less drug is needed to achieve a therapeutic effect, thus providing a less toxic, yet highly effective therapy for solid tumor treatment."

Tumor Necrosis Therapy -- Destruction of Tumor From Inside-Out

Techniclone Corporation's Tumor Necrosis Therapy (TNT) uses a monoclonal antibody which carries toxic "payloads" (such as radioisotopes) directly to the inner core of large, cancerous tumors. Preclinical trials have shown that once TNT is injected into the blood stream, it acts like a guided "smart bomb," anchoring to antigens on the DNA within the nucleus of the cell and delivering the radioactive payload specifically to the inside of the tumor -- destroying the tumor from the inside-out. Techniclone plans to begin human clinical trials for TNT this year.

Peter M. Anderson, M.D., Ph.D., senior associate consultant at the Mayo Clinic's Department of Pediatric and Adolescent Medicine, Division of Hematology and Oncology, commented, "As a practicing oncologist, I am encouraged by new and novel approaches to treating solid tumors. Vascular Targeting Agents and Tumor Necrosis Therapy have the potential to treat a variety of different tumors in a more gentle manner than is currently available."

"Innovative drug delivery systems that permit large, cancerous tumors to be destroyed without damaging surrounding healthy tissue may provide promise as a future front-line therapy for cancer patients," added Alan Epstein, M.D., Ph.D., professor of pathology at the University of Southern California Medical Center and director of scientific affairs for Techniclone.

Future Collaboration of Therapies May Provide "One-Two" Punch

Cancer cells, unlike normal tissues, undergo rapid degeneration resulting in areas of necrosis (dead tissue) where the cell membrane is "leaky" and porous -- allowing large molecules (like antibodies) to penetrate the cell. Scientists at Techniclone are currently testing the combination of VTAs and TNT in animals with large, solid tumors, and expect to enter TNT into human trials later this year.

DNA-associated antigens, which TNT anchors to, only become accessible in dead cells. Thus, by first administering VTAs (and causing massive tumor cell death), TNT can become even more effective by creating a larger "target area" into which TNT can deliver its payload and kill any remaining live tumor cells (on the outer tumor) that survived the VTA therapy.

"The synergistic opportunities of these two technologies are exciting," said Lon Stone, president and CEO of Techniclone Corporation. "Although the two technologies provide for swift and targeted tumor cell death as individual therapies, together, they represent the potential for a powerful `one-two' punch in future cancer treatments. The efficiency of these two drug delivery platforms may one day provide a more humane treatment for all solid tumor cancer patients."

Techniclone's Portfolio of Products For Future Cancer Treatments

Established in 1981 and headquartered in Tustin, Calif., Techniclone Corporation's most advanced drug development program is LYM-1, a non-Hodgkin's B-cell lymphoma therapy product currently being studied in a multi-center U.S. Phase II/III clinical trial. In addition to the TNT product (a U.S. clinical trial is scheduled to begin in 1997), the company is also planning for clinical trials for its patented Vasopermeation Enhancement and Vascular Targeting Agents products. Additional corporate and product pipeline information can be obtained on Techniclone Corporation's Internet web site (www.Techniclone.com). -0- This release contains certain forward-looking statements that involve a number of risks and uncertainties. Actual events or results may differ from the company's expectations as a result of the risk factors discussed in Techniclone's reports on file with the U.S. Securities Exchange Commission (including, but not limited to, the report on Form 10-Q for the quarter ended October 31, 1996).

CONTACT: Sheryl Seapy

Russell-Welsh, Inc.

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Nicole Scarcello

Techniclone Corporation

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