Washington Editor

Operating under the belief that science has failed to tap into the full potential of interferons, Pestka Biomedical Laboratories Inc. has established a subsidiary to focus on developing the next generation of these molecules designed to fight cancer without producing toxic side effects.

Led by Chief Scientific Officer Sidney Pestka, among the founders of interferon technology, the new subsidiary, PBL Therapeutics, aims to develop "ultra-interferons" that can be 20 to 30 times more potent than those on the market today. In addition, PBL Therapeutics also has developed Sustained Release Protein Delivery (SuRe-PD) technology designed to deliver the interferon directly to the tumor and release the drug slowly over time. Together, the company said ultra-interferons and SuRe-PD are expected to enable PBL to develop more effective cancer treatments with dramatically reduced side effects.

"Interferons are capable of having a great impact on cancer, but they have not been utilized because there are difficulties in using them," Pestka told BioWorld Today.

The side effects are generally similar to influenza symptoms, he said.

Nevertheless, there's a $5 billion annual market for interferons, according to PBL Therapeutics. First purified and characterized in the 1970s by Pestka, interferons (proteins that regulate the human immune system) are used today to treat multiple sclerosis and viral diseases such as hepatitis B and hepatitis C.

The current interferons are given as a shot in the arm and have a systemic impact. "If you are just trying to treat a tumor in the head or in the kidney, you don't want interferon throughout the body. That's primarily what causes the side effects," said Robert Pestka, president and CEO of PBL Therapeutics and its parent company, Pestka Biomedical, both of Piscataway, N.J. "What we are developing is a way to give interferon locally, directly to the tumor."

Robert Pestka, Sidney's son, said the company's initial research will focus on some of the most serious cancers, including certain brain and head and neck cancers, as well as advanced melanoma. "These are advanced diseases for which we feel we can achieve relatively quick approval and that should receive orphan-indication designations," he added.

PBL Therapeutics likens advancements in interferon science to that of monoclonal antibodies (MAbs). According to the company, the first MAbs derived from mice were incompatible with the human immune system and caused severe allergic responses. However, a breakthrough in 1986 allowed for production of the first humanized MAbs, which were better tolerated. Today, the company said, there are 10 approved MAbs and 60 MAb-based cancer clinical trials.

"What we are saying is it took a while for monoclonal antibodies to be accepted and to overcome various technological barriers, namely their humanization," Robert Pestka said. "We believe the same is true for interferons. Even though they were developed and commercialized 20 years ago by Hoffmann-La Roche under Sid's guidance, they haven't been used effectively for cancer."

Using its sustained-release technology to delivery the drug directly to tumors, PBL Therapeutics intends to file its first investigational new drug application for SuRe-PD ultra-interferon by the end of 2003 - and optimistically, to get FDA approval four years down the road, Robert Pestka said.

The company has been awarded a $1.38 million research grant from the National Cancer Institute to continue commercialization of one its proprietary technology platforms. The work will be conducted in conjunction with the Robert Wood Johnson Medical School and the New Jersey Medical School of the University of Medicine & Dentistry of New Jersey.

Pestka Biomedical Laboratories, founded in 1990, manufactures and supplies interferon products for research purposes. Privately held Pestka Biomedical and its subsidiary, PBL Therapeutics, together employ 23 people. Pestka Biomedical has funded the first $6 million of PBL's costs. The company is seeking additional investors.