Researchers in the United States are trying to coax from tobacco plants a drug that could be used to prevent cervical cancer in India.
The vaccine would be similar to Gardasil, made by Merck & Co., which was approved last year by the United States government to halt strains of sexually transmitted diseases that cause cervical cancer. Two of the researchers who helped invent Gardasil, Dr A. Bennett Jenson and Shin-je Ghim, are working on the tobacco-based vaccine.
The tobacco-based vaccine still in the works would cost an estimated $3 for three doses, compared with $360 for three doses of Gardasil. This would make it affordable for developing countries like India.
Jenson, Ghim and an Indian researcher, Dr Partha Basu, plan to test an experimental treatment for late-stage cervical cancer.
Late diagnoses common
Basu, head of the department of gynaecologic oncology at Chittaranjan National Cancer Institute in Calcutta, said 120 000 new cervical cancer cases are detected annually in India, with about 80% so advanced they cannot be treated.
The problems in India are similar to problems throughout the developing world, where poverty, lack of screening and spotty access to health care lead to late diagnoses and early death, said Kenneth Palmer, a researcher working with Jenson and Ghim.
"I have seen how ordinary people struggle so to remain healthy, and how there is just so little resource for them to get access to basic, primary health care, let alone treatment for cancer," Palmer told The Courier-Journal newspaper. "We could make a big difference." The researchers started by identifying a target for the vaccine, a protein called "L-2" in the sexually transmitted human papilloma virus (HPV).
To make the vaccine, they create a synthetic gene that expresses the same protein in plants, then insert that gene into a tobacco virus, which is used to infect plants and "grow" the vaccine inexpensively.
Six to 10 days later, they begin the long process of separating out parts of the tobacco until they are left with pure protein.
That protein is designed to induce antibodies that protect against at least 13 HPV strains known to cause cervical cancer. It is different from the protein used to make Gardasil, which targets two strains that cause 70% of cervical cancer cases.
Successful testing of vaccine
The tobacco-based vaccine has worked in five dogs, who were protected when researchers tried to infect them with oral canine HPV, Palmer said.
The first phase of human clinical trials could start by the end of 2008 in the United States, Palmer said. When development is further along, Basu said Indian scientists, doctors and funding agencies can discuss whether to do a trial in his country. - (SAPA)
When cervical cancer strikes
Treat cervical cancer early