Doctors arm immune system to fight cervical cancer cells

CHENNAI: Doctors were bewildered when they went through the case sheet of a woman who was diagnosed with advanced stage cervical

cancer

nearly 10 years ago. More than a year after a full dose of radiotherapy, cancer had spread to the lung. By then the disease should have claimed her life. Yet, she continues to visit them for periodic checks. Tests show she is free of the ailment.

When diagonosed with cancer, her oncologist at the

Cancer Institute

(WIA) here had included her name for an experimental treatment – immunotherapy. Rather than directly attacking cancer cells, this therapy strengthens and trains the patient’s own immune cells to fight the disease. “It’s like arming killers and letting them loose on specific targets,” says Dr T Rajkumar, head of the

Department of Molecular Oncology

at the institute, who led a team of researchers.

A 10-year follow up of this patient sent their hopes soaring; harnessing the immune system to fight cancer – a medical dream – could soon become a reality. On Monday, the hospital launched the second phase of the clinical trial involving 54 cervical cancer patients. The trial, which is likely to go on for nearly a year, will be a game changer in cancer therapy if it is proven to be a success, said the institute’s chairperson Dr V Shantha.

Between 2002 and 2006, the hospital conducted the first phase of the trial with 14 patients – four of them received a cellular form of immune therapy. Doctors gave them shots of “dendritic cell vaccines” to boost the patient’s immune system that defends the body against viruses, bacteria and other invaders.

Cancer cells hide from the immune system or block its ability to fight. For the therapy, scientist at the hospital drew cells called monocytes from the patient’s blood and modified them into dendritic cells – cells that have efficient antigens to stimulate the ‘fighter’ cells, or T-cells, in the body. These cells were then exposed to the

cancer cell

proteins drawn from the patient’s tumour. “In short, we reset the immune system and armed it with information to target cancer cells,” said Dr Rajkumar.

Only one of the four patients survived. Yet, the scientists concluded that Phase 1 was a success because the therapy did not cause toxicity or other side effects to any of the patients. They did not expect to see such phenomenal results on one patient either.

In December 2016, the hospital received regulatory clearances to go ahead with the second phase of the trial. Hospital director Dr T G Sagar said this trial will be larger, longer and a more detailed study.

Patients will be divided into three groups of 18 each. While the first group will receive standard therapy, which includes radiation and chemotherapy, the second group will receive the same therapy, besides a vaccine similar to the one used in phase 1 of the trial – dendritic cells primed with the patient’s own tumor cell proteins. Patients in the third group will receive the standard therapy with another vaccine – dendritic cells primed with cancer antigen SPAG9.

This antigen, discovered by New Delhi-based Dr Anil Suri of the

National Institute of Immunology

, is a potential biomarker for cervical carcinoma, bladder cancer, and lung cancer. The aim is to teach the fighter cells like T-cells and B-cells to attack cells with this biomarker. “If we succeed, this will be an important advance and an example of translational research outcome,” he said at the inauguration of the second phase of the clinical trial.

Patients will be given 10 doses of the vaccine over seven to eight months – once every two weeks for the first four doses followed by the once every month along with standard therapy. The vaccines will be given intra-dermally, from where they will travel to the lymph nodes and attack the tumour. If the results are positive, doctors will study the effect of this therapy in breast and ovarian cancers. “Many still come in the late stages of the disease. If this therapy works it will benefit them the most,” said molecular oncologist Dr T Rajkumar of the institute.

The survival rate in cervical cancer falls from 95% in the early stage to 50% in the fourth stage.