Image copyright Getty Images Image caption President Putin: Vials of the vaccine have been dispatched to St Petersburg
Russia’s president, Vladimir Putin, has revealed he took part in an experiment that combined immunotherapy with a synthetic steroid and hormones.
The experiment was not conducted in a hospital but behind closed doors on Mr Putin’s own lips, he said.
The Valshenko procedure, which has been hailed as a breakthrough by Russian doctors, uses a nasal vaccine to treat lung and throat cancers.
It consists of five injections into the face between two and five years.
Writing in the state-run TASS news agency, Mr Putin said he took part in the trial in the early 2000s when he was first diagnosed with an irregular heartbeat, which led to an irreversible decline in his speech.
In 2015, he was told he also had lung cancer, which had spread to his lymph nodes. He had to have a course of radiotherapy, but the growth in his lung tissue had stopped.
In March 2016, the Kremlin ordered a project to give him a new surgical and preventive therapy.
Mr Putin did not say when or where the drug was given, but said he had always been open about it.
The Russian president also said other patients had also been involved in the trial, which was designed to simulate the effects of a dose of the drug with steroid and hormonal therapy in the workplace.
Image copyright AFP Image caption Doctors in Russia are said to be involved in developing the drug
However, BBC medical correspondent Dan Jarvis said that while the trial may have been real, there are likely to be a number of caveats.
One issue is that iodine – a common ingredient – can lead to serious side effects, including depression, memory loss and even an increased risk of coronary heart disease.
Image copyright Getty Images Image caption Experts say the immunotherapy in the Valshenko trial will make a significant difference for some people
Another is that the technique involves oral antistatic injections, which might affect stomach capacity and lead to complaints of upset stomachs, dehydration and depression.
There are also questions about why the Russian president would want to participate in such an experimental clinical trial behind closed doors.
“A man who has amassed an empire in his self-belief and power might be inclined to believe he could control a process involving human life and death,” said our correspondent.
“It might seem an interesting experiment to do but not so much that it’s worth hiding.”
In recent years, Russians have complained about receiving invasive medical procedures without discussing them beforehand with their relatives.