Photo courtesy of EHA
MILAN—The IDH2 inhibitor AG-221 is well-tolerated and exhibits durable clinical activity in patients with hematologic disorders, results of a phase 1 study suggest.
The drug prompted responses in patients with myelodysplastic syndromes (MDS), acute myeloid leukemia (AML), or chronic myelomonocytic leukemia (CMML).
Fourteen of 25 patients achieved a response, and 12 of those responses are ongoing.
Most adverse events (AEs) were grade 1 or 2 in nature. However, 4 patients did have serious AEs that were possibly related to treatment.
Stéphane de Botton, MD, PhD, of Institut Gustave Roussy in Villejuif, France, presented these results at the 19th Annual Congress of the European Hematology Association (EHA) as abstract LB2434.
Dr de Botton and his colleagues enrolled 35 patients who had a median age of 68 years (range, 48-81).
Twenty-seven patients had relapsed/refractory AML, 4 had relapsed/refractory MDS, 2 had untreated AML, 1 had CMML, and 1 had granulocytic sarcoma. Thirty-one patients had R140Q IDH2 mutations, and 4 had R172K IDH2 mutations.
The patients received AG-221 at 30 mg BID (n=7), 50 mg BID (n=7), 75 mg BID (n=6), 100 mg QD (n=5), 100 mg BID (n=5), or 150 mg QD (n=5). Patients completed a median of 1 cycle of treatment (range, <1-5+) and a mean of 2 cycles.
Safety data
“AG-221 was remarkable well-tolerated, and the [maximum tolerated dose] has not been reached,” Dr de Botton said. “The majority of adverse events were grade 1 and 2.”
Eighteen patients were evaluable for safety. AEs of all grades included nausea (n=4), pyrexia (n=4), thrombocytopenia (n=4), anemia (n=3), dizziness (n=3), febrile neutropenia (n=3), peripheral edema (n=3), sepsis (n=3), cough (n=2), diarrhea (n=2), fatigue (n=2), leukocytosis (n=2), neutropenia (n=2), petechiae (n=2), and rash (n=2).
Grade 3 or higher AEs included thrombocytopenia (n=3), anemia (n=1), febrile neutropenia (n=3), sepsis (n=3), diarrhea (n=1), fatigue (n=1), leukocytosis (n=2), neutropenia (n=1), and rash (n=1). Dr de Botton noted that diarrhea and rash were not expected events.
Four patients had serious AEs possibly related to treatment. One patient had grade 3 confusion and grade 5 respiratory failure. One patient had grade 3 leukocytosis, grade 3 anorexia, and grade 1 nausea. One patient had grade 3 diarrhea. And 1 patient had grade 3 leukocytosis.
Seven patients died within 30 days of study drug termination: 4 in the 30-mg cohort, 2 in the 50-mg cohort, and 1 in the 100-mg-BID cohort.
Five deaths were due to complications of disease-related sepsis (all in cycle 1), 1 complication of a humeral fracture, and 1 complication of a stroke.
Activity and response data
The researchers observed high AG-221 accumulation after multiple doses. And results were “really very similar” between the 30-mg-BID cohort and the 100-mg-QD cohort, Dr de Botton noted.
He also said AG-221 was “very efficient” at inhibiting 2-HG in the plasma. 2-HG was inhibited up to 100% in subjects with R140Q mutations and up to 60% in subjects with R172K mutations.
Twenty-five patients were evaluable for response. The remaining 10 patients did not have day-28 marrow assessments, either due to early termination (n=7) or receiving less than 28 days of treatment although they were still on the study (n=3).
In all, there were 6 complete responses (CRs), 2 CRs with incomplete platelet recovery (CRps), 1 CR with incomplete hematologic recovery (CRi), and 5 partial responses (PRs). Five patients had stable disease (SD), and 6 had progressive disease (PD).
The most responses occurred in the 50-mg group, which had 3 CRs, 1 CRi, and 1 PR. This was followed by the 30-mg group, which had 2 CRs, 1 CRp, and 1 PR.
“The majority of responses occurred in cycle 1,” Dr de Botton noted, “except in the first cohort [30 mg], where responses occurred late, at the end of cycle 3 and cycle 4.”
Twelve of the 14 responses are ongoing. Of the 8 patients who achieved a CR or CRp, 5 have lasted more than 2.5 months (range, 1-4+ months). And the 5 patients with SD remain on study.
This study is sponsored by Celgene Corporation and Agios Pharmaceuticals Inc., the companies developing AG-221.
