Plant produced vaccine tackles cancer.

The first personalised cancer vaccine produced by plants has successfully completed Phase I clinical trials. This plant system could mean quick and effective therapies that are tailored to each patient's tumour.

US researchers at Stanford University Medical Center and Touro University produced the vaccine in collaboration with five pharmaceutical companies. It was created by taking tumour samples from patients with B-cell non-Hodgkin's lymphoma and isolating the gene for part of the antibody that the tumour is manufacturing. The gene was then inserted into a virus and, in turn, used to infect tobacco plants--effectively transforming them into vaccine factories.

The personalised vaccine elicited an immune response in 11 of the 16 patients in the trial and the vaccine was well tolerated (PNAS 2008, 105, 10131).

'The advantages are speed and safety,' senior author Ronald Levy, Stanford University Medical Center, explains. 'The virus spreads rapidly throughout the plant and within a week the protein can be extracted.' Because the plants' own protein-manufacturing machinery added sugars to the proteins, the trial was also a test of patients' response to modified proteins. The altered proteins did not appear to cause any adverse effects.

Charles Arntzen, whose group at Arizona State University produced a plague vaccine in plants, commented, 'We've known for a long time that each patient has a different cancer but this is the first time we have a system to allow us to go after a specific disease.'

Pete Delves, reader in immunology in the division of infection and immunity at UCL says: 'The advantage is [these types of vaccines] actually work, unlike many cancer vaccines.' One problem with personalised vaccines, however, is that they cannot be stockpiled like conventional ones. The other problem is that a new one has to be made for each patient, so the treatment is expensive.