An experimental drug has blocked the progression of prostate cancer in an animal model with an aggressive form of the disease, new research shows.

The agent, OSU-HDAC42, belongs to a new class of drugs called histone deacetylase (HDAC) inhibitors, compounds designed to reactivate genes that normally protect against cancer but are turned off by the cancer process.

The study showed that the agent kept mice with a precancerous condition from developing advanced prostate cancer.

Human testing of the compound is expected to begin early next year.