A pill to flush radioactive metals from the body passed its first human safety test, Menlo Park’s SRI reports

An experimental pill designed to pull radioactive metals out of the body after a nuclear accident or a “dirty bomb” attack was safe at single doses in its first test in people, according to a study published Nov. 11 in the journal JAMA.  The researchers, from Menlo Park’s SRI International, said the results support more testing of the drug, called HOPO 14-1, as an emergency treatment that could be stockpiled and handed out to large numbers of people.

The two treatments the U.S. Food and Drug Administration has approved for this kind of contamination must be given by IV or breathed in through a nebulizer under medical supervision, and they remove only three radioactive elements:  plutonium, americium and curium, according to the study and the National Institutes of Health.  HOPO 14-1 is a capsule.  In animal studies it also removed uranium and neptunium and was up to 100 times better at binding these metals, the NIH said when the trial began in 2023.

What the trial found

• None of the 42 healthy adults had a serious side effect, and no dose was too toxic to give, up to the highest dose of 7,500 milligrams.
• The most common drug-related side effects were diarrhea (31% of participants), vomiting (14%), headache (12%) and fatigue (7%), all mild to moderate.
• Stomach and gut problems, most common at the highest doses, set the practical upper limit for a single dose, the authors wrote.
• The drug reached its peak level in the blood within about one to two hours and left the body mainly in stool, not urine.

How it works and what comes next

HOPO 14-1 is a chelator, a molecule that grabs onto metal atoms so the body can get rid of them.  Radioactive metals that are swallowed, breathed in or absorbed through wounds can lodge in the body and damage DNA and organs as they decay, so removing them quickly lowers the harm, according to the NIH.  The drug was invented at Lawrence Berkeley National Laboratory by chemists Pat Durbin, Ken Raymond and Rebecca Abergel, and SRI spent more than a decade developing it with them, SRI said.  The NIH’s National Institute of Allergy and Infectious Diseases has funded the work since 2006.

The trial gave each person one dose, at one of seven levels, and followed them for 14 days at an SRI clinic in Plymouth, Michigan, from 2023 to 2025.  It tested safety only.  It did not test whether the pill removes radioactive metals from people, and the drug is not approved for use.

Source:  Goonewardena et al., “HOPO 14-1, an Oral Actinide Chelator:  A Phase 1 Nonrandomized Clinical Trial,” JAMA, Nov. 11, 2026 (PubMed record).