Havana, Aug 19 (IANS): A Cuban vaccine against advanced prostate cancer will soon enter the third stage of its trial process, where it will be tested on 300 patients, specialists said in Havana.

In this stage, researchers at the Centre for Genetic Engineering and Biotechnology (CIGB), where the vaccine Heberprovac was developed, will compare its performance with that of Zoladex, a well known therapy used internationally to treat various types of neoplasms, reported Xinhua.

Researchers from CIBG on Tuesday said Heberprovac is already superior to Zoladex in its administration format, needing only seven shots.

The first four doses are given every 15 days and the rest are spread out over five months.

In comparison, Zoladex, which is also used to treat breast cancer, must be administered every three months via a sub-cutaneous implant.

The specialists say that while Heberprovac has not yet been proven to be a cure for prostate cancer, it has led to "a greater survival rate and better quality of life" in the majority of patients treated with it.

The vaccine's first phase of trial took place in 2007 and the second phase concluded in early 2015.