Program: Oral and Poster Abstracts
Session: 613. Acute Myeloid Leukemia: Clinical Studies: Poster I
METHODS: The AG-120 phase 1, open-label, dose-escalation and expansion study includes evaluation of safety, tolerability, maximum tolerated dose, PK/PD (including 2-HG levels) and clinical activity. Single-agent AG-120 is administered orally once (QD) or twice (BID) daily in continuous 28-day cycles. Patients included in this analysis received doses of 100 mg BID, 300 mg QD, 500 mg QD, 800 mg QD and 1200 mg QD (N=39). Blood, bone marrow and urine samples were collected at multiple time points for determination of PK/PD using qualified LC-MS/MS-based methods. Analyses were performed using WinNonLin®.
RESULTS: AG-120 exposure exceeding the predicted efficacious exposure level was demonstrated at all dose levels following oral administration. Following both single (Day -3) and multiple (Cycle 1 Day 15 [C1D15] and Cycle 2 Day 1) dose administration, mean plasma exposures of AG-120 increased less than proportionally to dose, although plasma exposures were quite variable within dose levels. Preliminary PK data revealed a mean half-life of 119 ± 104 hr. Following multiple doses, most patients achieved steady state in Cycle 1, with ~2 to 3-fold accumulation in plasma observed. Furthermore, pre-dose AG-120 trough levels were maintained above the predicted efficacious exposure level throughout treatment (up to 11 cycles). Following a single dose of AG-120, plasma 2-HG levels gradually reduced over 3 days. After multiple doses, plasma 2-HG levels were reduced to levels seen in healthy volunteers (up to 99.7% inhibition) at all dose levels tested. Steady state 2-HG inhibition was reached at approximately C1D15 in most patients, and was maintained over the course of treatment (up to 11 cycles). Mean bone marrow 2-HG levels were also substantially reduced following multiple doses of AG-120 at all dose levels tested (up to 99.9% reduction compared with baseline). Plasma 2-HG levels showed a positive correlation with levels in bone marrow (r2=0.882, p<0.001) and urine (r2=0.528, p<0.001), with a stronger correlation being observed with the former tissue. There was no clear effect of patient-intrinsic factors such as body weight or body surface area on Cmaxor AUC within the ranges tested, although the current sample size is small. Population PK and PK/PD assessments will be conducted to confirm these findings. These analyses are based on data as of 1 May 2015; updated analyses will be presented.
CONCLUSION: AG-120 exposure increased less than proportionally to dose following oral administration, with long half-life and maintenance of pre-dose levels above the predicted efficacious exposure, supporting QD dosing. In patients with IDH1 mutations, AG-120 inhibited plasma 2-HG to within levels found in healthy volunteers, and also inhibited 2-HG in bone marrow.
Disclosures: Fan: Agios Pharmaceuticals: Employment , Equity Ownership . Le: Agios Pharmceuticals: Employment , Equity Ownership . Manyak: Agios Pharmaceuticals: Employment . Liu: Agios: Employment . Prahl: Agios Pharmaceuticals: Employment , Equity Ownership . Bowden: Agios Pharmaceuticals: Employment . Biller: Agios Pharmaceuticals: Employment , Equity Ownership ; Arbutus BioPharma (formerly Tekmira): Consultancy , Equity Ownership , Membership on an entity’s Board of Directors or advisory committees ; Syros Pharmaceuticals: Consultancy , Equity Ownership , Membership on an entity’s Board of Directors or advisory committees ; Arvinas: Consultancy , Equity Ownership , Membership on an entity’s Board of Directors or advisory committees ; Denali: Consultancy , Equity Ownership , Membership on an entity’s Board of Directors or advisory committees . Agresta: Agios: Employment , Equity Ownership . Yang: Agios Pharmaceuticals: Employment , Equity Ownership .
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