Agios leukemia drug demonstrates impressive response rate: study

Forty percent of patients, most with a particularly aggressive form of leukemia, responded to an experimental Agios Pharmaceuticals Inc drug, including several who experienced complete remission, according to data presented at a medical meeting on June 12. New data from the ongoing Phase I clinical trial appears to confirm the early promise seen with the Agios drug, AG-221.
Patients in the study either had the aggressive bone marrow cancer acute myelogenous leukemia (AML), or the pre-leukemic blood disorder myelodysplastic syndrome (MDS).
Among 63 patients who responded to the treatment out of 158 who were evaluated, 26, or 16 percent, had no sign of cancer in the bone marrow and a return to normal blood cell counts.
Another three patients were in remission without recovery of normal platelet count, while 16 more had also cleared leukemia from bone marrow without full restoration of other types of blood cells, such as infection-fighting neutrophils.
Forty percent response "is remarkably exciting in this kind of patient population," said Dr. Eytan Stein, from Memorial Sloan Kettering Cancer Center in New York, who presented the data at the European Hematology Association meeting in Vienna.
Patients with advanced AML typically have a response rate of under 10 percent, Stein explained. "This drug appears to be transformative for patients who receive it."
In addition to complete remission categories, 18 patients experienced partial remission, defined as at least a 50 percent reduction in leukemia cells with normal platelets and neutrophils.
"If you normalise someone's platelet count and give someone an immune system with this drug that works to transform leukemia cells into healthy adult infection-fighting cells, then you have really done the patient tremendous good," Stein said.
Of the 14 MDS patients in the trial, half had some form of complete remission.
Three quarters of those who responded to AG-221 have been on the drug for at least 6 months, the longest for nearly 16 months, Stein said. Overall survival data was not available.
The safety profile of AG-221 appears to be similar to what was seen earlier in the study with fewer patients. Serious adverse side effects possibly related to the drug were reported in 27 patients.
"There has been no hint of any new safety concerns that I have seen in the data or the patients that I have treated in the trial," Stein said. Agios and partner Celgene Corp are planning a large Phase III AML study of AG-221.