Three male volunteers taking part in a clinical trial at the Shandon Clinic in Cork city today were hospitalised after they experienced adverse reactions.
A trial was taking place involving 12 healthy males using a drug normally taken by cancer patients when they became unwell.
The volunteers were treated in the clinic and three were transferred to Cork University Hospital as a precautionary measure. They are in a stable condition.
The men were accompanied to hospital by one of the doctors who was supervising the trial.
A second doctor remained at the clinic to attend to a further nine patients who incurred minor adverse reactions to the drug.
The trial was due to be completed next week. However, it has been terminated as a precautionary measure.
The incident has been reported to the Irish Medicines Board and the Clinical Research Ethics Committee of the Cork Teaching Hospitals in line with legal requirements.
The board said a full investigation had been launched into the test. "The trial in question was to determine the bioavailability of a drug for its potential use in the treatment of cancer and was terminated due to adverse effects on some of the volunteers," a spokeswoman added. "There are no other ongoing trials in Ireland with this investigational medicine."
Shandon Clinic has been in operation since 1990. Between 20 and 30 clinical trials are carried out onsite every year. The clinic is operated in the former University Dental Hospital in Cork.
In addition to a general ward, there are facilities for clinical pharmacology studies in which intensive monitoring of subjects may be required.