New York, June 6 : Researchers have identified a promising new antibody that can help patients with aggressive and metastatic anal cancer.

The findings, of the first clinical trial for metastatic patients, showed that the treatment with antibody nivolumab -- one of the drugs represented among the growing arsenal of immunotherapy therapies -- may help a majority of patients with squamous cell carcinoma of the anal canal (SCCA).

Metastatic SCCA, a cancer often associated with human papillomavirus (HPV) infection, is normally treated with chemotherapy.

However, treatment with nivolumab freed the immune system to attack cancer by disrupting a brake that halts immune response and showed significant response in 70 per cent of patients in the study.

\"Although a rare malignancy, the incidence is on the rise and has a strong association with the Human papillomavirus (HPV) virus,\" said Cathy Eng, professor at University of Texas MD Anderson Cancer Centre.

Nivolumab was found to unleash an immune system attack on cancer by blocking the activation of a protein called PD-1 on T cells, white blood cells, viruses or bacteria that have specific targets.

PD-1 -- turned on by a ligand called PD-L1 often found on cancer cells -- acts as a brake, or checkpoint, to shut down activated T cells.

According to the American Cancer Society, more than 8,000 people will be diagnosed with anal cancer in the US in 2016 and more than 1,000 people will die from the disease.

For the study, 39 patients were enrolled in the clinical trial and 37 receiving treatment. All patients received nivolumab every two weeks.

Of the 37 patients evaluable for response based on intent to treat, two patients (5 per cent) had a complete response, seven (19 per cent) had a partial response, and 17 (46 per cent) had stable disease - a control rate of 70 per cent.

\"There are no standardised treatment options for metastatic anal cancer patients, so there\'s truly an unmet need in those whose disease has not responded to initial therapy,\" Eng noted.

The findings were presented at the American Society of Clinical Oncology\'s annual meeting in Chicago, recently.

New treatment shows promise against aggressive anal cancer