Washington, Apr 20 : In a study, led by an Indian-origin scientist, researchers have found a combination therapy, which could reduce cancer stem cells and stop the growth pancreatic cancer-one of the deadliest cancers.

Rajesh Kumar N. V., Ph. D., a faculty member at the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University, led the study.

He said that a combination therapy using tigatuzumab, a novel humanized death receptor-5 (DR-5) agonist antibody, along with gemcitabine, could result in reducing pancreatic cancer stem cells to achieve tumour remission and prevent tumour recurrence.

"Many advanced cancers, including pancreatic cancer, recur and result in patient death despite the use of chemotherapeutic and radiation modalities that initially lead to therapeutic responses," said Kumar.

He added: "A growing body of evidence supports the concept that cancer stem cells are the seeds of the most clinically deadly form of therapy-resistant human cancers. Emerging studies show that cancer stem cells are indeed more resistant to therapy than other cancer cells and might be the reason why conventional chemotherapy, while reducing tumor size, does not result in long-term cures."

For the study, the researchers examined the cancer stem cells in ten patient-derived tumours implanted in laboratory mice.

It was found that DR-5 is enriched in cancer stem cells compared to non-stem cell tumour populations.

The mice either received tigatuzumab alone; gemcitabine, the current clinical treatment for pancreatic cancer; or a combination of the two agents.

And it was discovered that treatment with gemcitabine alone reduced tumour size, but the tumour cells that remained were rich in pancreatic cancer stem cells. In nearly all cases, the tumours returned.

On the other hand, treatment with gemcitabine and tigatuzumab reduced pancreatic cancer stem cells, caused tumour remission, and significantly increased time-to-tumour progression in 50 percent of treated cases from a median of 54 days to 103 days.

The researchers claimed that targeting cancer-sustaining pancreatic cancer stem cells will be of paramount significance as there are few effective therapies for pancreatic cancer and most of the patients die within the first year of diagnosis.

"Clinically, this discovery could transform the way in which pancreatic cancer is treated and contribute towards making pancreatic cancer a more manageable disease," said Kumar.

Results of the study will be presented at the American Association for Cancer Research 100th Annual Meeting 2009. (ANI)