Dublin, Ireland: A new drug designed to make more effective in treating cancer has been given to patients during the 30th EORTC-NCI-AACR  Symposium on Molecular Targets and Cancer Therapeutics in Dublin, Ireland.
The drug, called 5-iodo-2-pyrimidinone-2'-deoxribose (IPdR), or ropidoxuridine, has the advantage that it can take in capsule form, as opposed to intravenously. When the drug enters the body, researchers believe it changes into an active form that can make cancer cells more susceptible to the effects of radiotherapy.
Results of US NCI trial # 9882, presented by Dr Timothy Kinsella from the Department of Radiation Oncology at the Warren Alpert Medical School at the University of Rhode Island in the USA, show that the drug has minimal side effects for patients with a a variety of gastrointestinal cancers during the course of their radiotherapy.
Dr Kinsella explained: "The aim of my research is to find better ways to treat patients with cancer,
"Previous studies found a promising compound called iododeoxyuridine, or IUdR, that worked very well to improve the effectiveness of radiotherapy, but IUdR was only given intravenously and proved to have many side effects for patients.
"As a result, this new drug, IPdR, was developed. It's a prodrug that can be taken as a capsule and once inside the body, it's converted into the active drug, IUdR.
"This trial is the first to test it out in patients, they are receiving radiation therapy, and the results suggest it's safe with minimal side effects."
Dr Kinsella and his colleagues tested the new drug in a group of 18 patients with advanced cancers including oesophageal, pancreatic, liver, bile duct, rectal and anal cancers. All had been referred to palliative radiotherapy.
Alongside their radiotherapy, patients were given a daily dose of the IPdR prodrug over 28 days. They were given blood tests to check the levels of both the IPDR prodrug and the active IUdR drug at various points during their treatment. The dose of the prodrug was gradually increased, and the patients were monitored for side effects.
Results of the trial suggest that IPDR can be safely given to patients up to 1200 mg per day for 28 days without causing serious side effects. The results also suggest that this dose creates the active IUdR drug in patients' blood that is high enough to have a radiosensitizing effect.
Of the 18 patients on the trial, 14 could be assessed for any effect on their tumors with CT or MRI scan. Among these patients, one had a complete response (disappearance of tumor), three showed a partial response (at least 30% reduction in the tumor by radiotherapy), nine had stable diseases because of an infection and had progressive disease (at least 20% growth in the tumor).
Dr Kinsella added: "This clinical trial has shown that the dose of IPDR at home for the radiation treatment, the level of IUDR in their bloodstream is high enough to make cancer radiation. needed side effects of IUdR.
"However, this trial was with patients who had recurrent cancer and had already received a number of other cancer treatments."
Dr Kinsella and his colleagues are already studying the effects of IPDR in patients receiving whole brain radiotherapy for cancer. Following this trial, the patients who had been diagnosed with glioblastoma, an aggressive form of brain cancer.
Professor Eric Deutsch, Professor of Radiation oncology and head of the Department of Radiation oncology at the Institut Gustave Roussy, Villejuif, France, is a member of the EORTC-NCI-AACR symposium scientific committee and was not involved with the research. He said: "Radiotherapy is a vital element in treating many forms of cancer.
"In treating cancer patients, we must always consider the risks and benefits of any therapy." We do not have I do not think I will be able to do that.