Light Sciences Oncology begins trial of photodynamic therapy for liver cancer

NOVEMBER 26, 2008--Light Sciences Oncology (Bellevue, WA) has completed enrollment in a global Phase 3 clinical trial of its Light Infusion Therapy ("Litx") as light-activated treatment for unresectable hepatocellular carcinoma (HCC), also known as hepatoma or primary liver cancer. LSO hopes to enter a New Drug Application to the U.S. FDA, EMEA, and other authorities in 2009. The single-use, disposable Litx device uses light-emitting diodes (LEDs) to activate a water-soluble drug.

NOVEMBER 26, 2008--Light Sciences Oncology, Inc. (Bellevue, WA) (LSO) has completed patient enrollment in a global Phase 3 clinical trial of its Light Infusion Therapy ("Litx") as photodynamic treatment (PDT) for unresectable hepatocellular carcinoma (HCC), also known as hepatoma or primary cancer of the liver. The two-armed, randomized clinical trial has enrolled 200 patients at sites in 11 countries. The primary endpoint of the trial is to assess survival of patients receiving Litx therapy versus those receiving standard-of-care therapies.

This is a pivotal clinical trial, according to Light Sciences Oncology president and CEO Llew Keltner, M.D., Ph.D. "We look forward to seeing a statistically significant survival benefit of Litx and proceeding with a New Drug Application to the U.S. FDA, EMEA, and other regulatory authorities in 2009."

Litx is designed as an entirely new mode of therapy compared with the older, laser-based generation of light-activated drug therapies. The single-use, disposable Litx device uses light-emitting diodes (LEDs) to activate LS11(R) (talaporfin sodium), a light-activated, water-soluble drug. An LS11 molecule activated by the Litx system results in the production of singlet oxygen, which can kill target tissues with minimal side effects. Litx uses low-intensity light that causes vascular closure and apoptosis, or "programmed cell death." Illumination with low-intensity light can activate each molecule of LS11 many times, resulting in a continuous supply of singlet oxygen molecules.

The Litx device contains a tiny array of LEDs at the end of a very narrow (only 1.2 mm wide) flexible coated micro-wire. Administering physicians insert the LED array into a tumor using a biopsy-like procedure, requiring only a mild anesthetic, followed by intravenous injection of LS11. The device emits red light at a discrete frequency and intensity, for a fixed time period, to activate LS11 and create a 2 cm by 4 cm "kill zone" around the LED array.

Litx attacks tumors from the inside out, rather than using the outside-in approach of many standard treatments. It kills all tumor cells in the kill zone, rather than only the minority of cells undergoing rapid division. The Litx treatment closes tumor blood supply vessels, starving remaining cancer cells of oxygen and nutrients. The use of multiple light sources and multiple treatments is feasible and can be tailored based on the number, size, shape and location of the target tumors.

Additionally, Litx may stimulate a patient's immune system to attack untreated tumors. Since 2007, data from a number of published animal and human studies has demonstrated that the production of large apoptotic masses in tumors with light-activated drug therapies, including Litx, yields tumor-specific clones of CD8+ T-cells that infiltrate distant, untreated tumors and destroys them. Human trials of Litx have produced images that demonstrate destruction of large tumors not directly treated with Litx.

There is no evidence that Litx produces the typical side effects from the systemic damage to rapidly-dividing normal cells caused by chemotherapy, radiation, and other cancer treatments. As a single-use disposable drug and device combination, Litx is being developed solely as a drug product through the oversight of FDA's Center for Drug Evaluation and Research (CDER).

The clinical trial includes patients at sites in 11 countries within Asia and Europe: the Philippines, Korea, India, Malaysia, Thailand, Hong Kong, Singapore, Serbia, Poland, Croatia, and Italy.

No effective treatments are available for the vast majority of HCC patients. According to the 2005 edition of Cancer, Principles & Practice of Oncology, there are approximately one million new cases of HCC worldwide each year and, according to an article published in the Journal of Hepatology in 2004, HCC kills approximately one million people worldwide each year.

Posted by Barbara G. Goode, barbarag@pennwell.com

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Light Sciences Oncology, Inc.

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