A drug used for the treatment of skin cancer can help patients survive longer, a new study says.

Researchers found that ipilimumab, a drug used for treating melanoma, increased the life expectancy of a patient from three to ten years after diagnosis.

Melanoma is a cancer that starts in the cells that produce the melanin pigment. Melanoma can be identified through visible changes in size or colour of a mole.

A protein receptor known as Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4), are naturally capable of fighting skin cancer by destroying cancer cells. However, the CTLA-4's function is often disturbed by an inhibitory mechanism in the body. Ipilimumab helps the body's natural immune system fight cancer by turning off the inhibitory mechanism.

For the study, professor Stephen Hodi from the Dana-Farber Cancer Institute in the US and his research team included 4846 cases of melanoma - both from clinical trials (1861) and outside (2985 patients). The patients were treated with ipilimumab.

In both cases, around 22 percent of the patients survived after three years and survival rates improved considerably after seven years.

"There were no deaths among patients who survived beyond seven years, at which time the overall survival rate was 17%. The longest overall survival follow-up in the database is 9.9 years," said Professor Hodi. "The plateau, which started at three years and continued through to ten years, was observed regardless of dose (3 or 10 mg/kg), whether the patients had received previous treatment or not, and whether or not they had been kept on a maintenance dose of the drug."

This is not the first study to show the drug's effectiveness in improving survival rate.  A previous study had shown that the drug can assure a survival rate of 18 percent after five years.

Hodi, who worked along with researchers from different countries, including Germany and France, expected that their findings will help bring hope to people affected with the cancer. "Our findings demonstrate that there is a plateau in overall survival, which begins around the third year and extends through to the tenth year," said Hodi. "

"These results are important to healthcare providers and patients with advanced melanoma since they provide a perspective on long-term survival for ipilimumab patients who are alive after three years of treatment. Our data, which represent the longest follow-up of the largest numbers of patients on any globally approved melanoma therapy, will provide a benchmark for future medicines for advanced melanoma."

Hodi presented his findings at the 2013 European Cancer Congress (ECC2013), Amsterdam, Netherlands on Saturday.