An experimental drug from Agios Pharmaceuticals Inc showed anti-cancer effect in a small Phase I study in patients with relapsed acute myeloid leukemia (AML), Newsmax Health reports.

Of seven patients available to be evaluated following a 28-day cycle of treatment with the drug, AG-221, six had what researchers deemed objective responses to the medicine.

Three of them achieved complete remission and two achieved complete remission with incomplete platelet recovery, meaning that the leukemia had exited their bone marrow but the blood platelet count had not yet returned to normal levels.

Study's lead investigator, Dr. Eytan Stein of Memorial Sloan Kettering Cancer Center in New York noted that in the tiny group of patients there were no observable side effects that appear related to the drug itself, "which is very different from chemotherapy."

Stein said researchers were not expecting the impact seen with the lowest doses in the first handful of patients. "We were actually kind of surprised that at the first dose level we're seeing dramatic clinical activity. That usually doesn't happen," he said.