Tobacco Plants Could Offer Vaccine to Treat Non-Hodgkin’s Lymphoma

Tobacco plants may provide a new way of treating non-Hodgkin’s lymphoma, a cancer that will strike an estimated 56,800 Americans this year. Scientists at Stanford University and Biosource Technologies are developing a customized lymphoma vaccine produced in tobacco plants that are being grown indoors at the biotechnology company’s Vacaville, Calif., facility.

The most common form of non-Hodgkin’s lymphoma affects cells that produce antibodies to infectious disease. For a decade, a Stanford team led by Dr. Ronald Levy has been treating patients by using antibodies produced by the patients’ tumor cells to trick the patients’ immune systems into attacking the tumors. Levy has reported that half of lymphoma patients tested respond to the treatment with longer remissions and added years of survival.

The experimental vaccine is given following standard therapy, which can include chemotherapy, radiation and the new drug Rituxan, which was also developed at Stanford and is marketed by IDEC Pharmaceuticals of San Diego and Genentech of South San Francisco.

But producing an individualized anti-lymphoma vaccine is slow and expensive.

The Stanford researchers reported in the Proceedings of the National Academy of Sciences that they have developed a rapid way to make a similar vaccine in tobacco plants and that it successfully protected mice from a lethal dose of mouse lymphoma tumors. The researchers reported that 80% of the mice treated with the vaccine survived, while all of the untreated mice died.

Biosource CEO Robert L. Erwin said the vaccine is produced by taking a gene from the patient’s lymphoma cells and splicing it to a tobacco virus that is then sprayed onto growing plants. Six weeks later, leaves are harvested from the infected plants and the protein extracted.

Even though the vaccine must be customized for each patient, Erwin believes the privately held company will be able to keep costs comparable to those for other forms of cancer therapy. The company hopes to begin testing the safety of the plant-grown vaccine in lymphoma patients this fall.