Updated from Sunday at 10:30 am EDT with current stock price, analyst comments.
SAN DIEGO (TheStreet) -- The Agios Pharmaceuticals (AGIO) cancer metabolism drug AG-221 is demonstrating surprisingly strong clinical activity, including multiple complete remissions, in an early stage study involving patients with advanced blood cancers.
Shares of Agio were up 30% to $46.25 in Monday pre-market trading.
Agios designed AG-221 to block a mutated protein known as IDH2 which promotes the growth of cancer cells. The phase I study presented Sunday was expected to demonstrate the ability of AG-221 to decrease levels of an IDH2 biomarker as proof of early activity.
AG-221 achieved that and more. Six of 10 patients with advanced, treatment-refractory acute myeloid leukemia carrying the IDH2 mutation had objective tumor responses, including three complete remissions and two complete remissions with incomplete platelet recovery.
"We are very encouraged by these early data," said Agios CEO David Schenkein, in a statement. "The findings corroborate the use of precision medicine in genetically defined patient populations..."
The AG-221 data were presented Sunday at the American Association for Cancer Research (AACR) annual meeting.
The phase I study is enrolling patients with acute myeloid leukemia (AML) or myelodysplastic syndrome which no longer responds to multiple lines of therapy. All the patients were screened to make sure their cancer harbored the IDH2 mutation.
Ten AML patients were treated in the first two cohorts of the study with either 30 mg or 50 mg of AG-221 given orally twice per day. After a single, 28-day treatment cycle, three patients achieved a complete remission, as determined by study investigators. Two patients had a complete remission with incomplete platelet recovery and a single patients achieved a partial response.
The remaining three patients did not complete the 28-day cycle of AG-221 and died due to complications of disease-related infection.
Adverse events possibly related to AG-221 reported in the study to date include one patient with abnormally high white blood count and one patients with confusion and respiratory failure due to disease-related infection.
Patients continue to receive treatment with AG-221, including one patient in a fifth cycle of therapy. The study is continuing with additional patients enrolled and treated at higher doses of AG-221. Agios is exploring twice daily and once-per-day AG-221 dosing.
Agios is developing AG-221 under a collaboration with Celgene (CELG). The companies are also working together on AG-120, a similar drug designed to block another mutated cancer-growing protein known a IDH1.
J.P. Morgan analyst Geoff Meacham upgraded Agio to overweight from buy. "In our view, the interim phase 1 data presented at the AACR meeting yesterday were substantially de-risking for AG-221 (IDH2 program) and the broader technology platform, particularly for AG-120 (IDH1 program)," Meacham wrote in a research note.
Follow Adam Feuerstein on Twitter.