Tobacco aids in research to make vaccine for cancer

OWENSBORO, Ky. -- The plants stretching their leaves toward the hot Kentucky sun in a greenhouse near here look like any other ordinary tobacco plant. They are anything but. Deep inside their cells, they are furiously cranking out microscopic fragments of human tumor.

The plants are destined not for a pack of Marlboros, but for a laboratory by the Owensboro airport. There the tiny tumor fragments will be recovered and processed into vaccines designed to treat a type of cancer called lymphoma.

It's a dry run at the moment, but by this fall, vaccines produced this way are to be flown to medical suites nationwide and injected into patients, in one of the largest tests to date of whether vaccination can arrest the growth of tumors.

The shots the patients get will be not of a single, standardized vaccine, but rather of a customized product created specifically for each person's cancer.

The Kentucky project is sponsored by the California company Large Scale Biology Corp., and it chose tobacco -- actually, a close Australian relative of American field tobacco -- not for the satisfaction of using that maligned plant to treat cancer but because tobacco may be the cheapest, fastest vehicle for growing the tumor's necessary fragments.

A 'very subtle point'

The project is designed as a test of whether the long-heralded, much-delayed era of "personalized medicine" is finally at hand -- and whether a long history of commercial failure can be overcome to deliver such customized treatments at a tolerable price.

"It may be too early to say we're at the dawn" of the age of personalized medicine, said Robert Erwin, chairman and chief executive of Large Scale Biology. "We may be at that very subtle point right before the dawn, where you know it's about to happen, but nobody else does."

His company isn't the only one trying to use tobacco, or other plants, to grow drugs. Projects to grow drugs in bulk that way are progressing around the country, drawing excitement and a measure of environmental concern.

And dozens of companies are pursuing personalized medical treatments. Another company and a National Cancer Institute laboratory are well ahead of Large Scale Biology in bringing the idea to lymphoma treatment.

But the Kentucky operation is perhaps the most ambitious attempt in the country to marry the two approaches: to use potentially cheap production techniques based on plants to create pharmaceuticals customized for individual patients.

Erwin's curious plants, hundreds of them, were growing on a greenhouse bench in western Kentucky not long ago. On one bench, the specimens of Nicotiana benthamiana were making fragments from the tumor of a 58-year-old woman from Mill Valley, Calif. Plants on the opposite bench were growing tumor fragments from a 57-year-old man from Hollister, Calif.

Devil in the details

Most people think of a vaccine as a drug given ahead of time to induce immunity to a germ. That's accurate, but the term is really broader and can be applied to many drugs designed to attack disease by inducing an immune response.

For years, scientists have theorized that certain types of cancer might be particularly amenable to treatment with vaccines. By definition, a patient has cancer because his or her immune system has failed to recognize and kill cells growing out of control. What if the immune system could somehow be awakened to the threat and rallied to attack?

The technical details have bedeviled scientists, however, and no cancer vaccine has ever reached the market. But lately, the idea has been showing promise for the deadly skin cancer melanoma and lymphoma.