VIENNA, Austria (TheStreet) -- Two experimental drugs from Agios Pharmaceuticals (AGIO) designed to curb the overactive metabolism of certain kinds of mutated blood cancer cells are showing prolonged responses not normally seen in patients with advanced disease, according to new study results announced Friday.
For one of the Agios drugs, known as AG-221, more than three-quarters of responding blood cancer patients have remained on treatment for six months or longer, with the longest treatment lasting 15 months.
"This is a very high-risk patient population with life expectancy measured in weeks or just a few months, so to see this response and the duration of response is, to some extent, unheard of," said Dr. Eytan Stein of New York's Memorial Sloan Kettering Cancer Center and an investigator involved in the Agios clinical trials.
Updated results from two, phase I studies of Agios drugs AG-221 and AG-120 are being presented at a meeting of the European Hematology Association underway in Vienna.
Celgene (CELG) is partnered with Agios on the development and marketing of AG-221 and AG-120, if approved. A phase III study of AG-221 will start in the second half of this year. Meanwhile, the phase III study of AG-120 is expected to begin in the first half of 2016.
Both AG-221 and AG-120 are pills designed to block mutated, metabolic enzymes known as IDH2 and IDH1, respectively. Normally, cells use the IDH enzymes to help break down nutrients and generate energy. When mutated, the IDH enzymes alter the genetic programming of cells, preventing them from maturing and allowing them to grow uncontrollably.
Patients with certain types of blood cancer have bone marrow crowded with undifferentiated, rapidly dividing blast cells. AG-221 and AG-120 block the mutated IDH enzymes and allow the leukemic cells in bone marrow to mature into normal blood cells. Agios estimates that between 18% to 24% of certain types of leukemia contain mutated IDH enzymes.