IC50: ~16 nM for IDH2 R140Q mutant

AG-221 (Enasidenib) is a mutant isocitrate dehydrogenase 2 (IDH2) inhibitor.

The somatic mutations of IDH1 and IDH2 are found in patients with acute myeloid leukemia. Leukemia-associated IDH1/2 mutations lead to aberrant accumulation of the oncometabolite 2-hydroxyglutarate (2-HG).

In vitro: AG-221 was found to be able to reduce 2-HG levels by >90%, reverse in-vitro histone and DNA hypermethylation, and induce differentiation in leukemia cell model as well. In addition, a dose dependent proliferative burst of the human specific CD45+ blast cells was observed by the treatment of AG-221, as measured by the expression of CD11b, CD14, CD15 and cell morphology [1].

In vivo: The efficacy of AG-221 in a primary human AML xenograft model with the IDH2 R140Q mutation was studied, and the results showed that AG-221 could reduce 2-HG in the plasma, bone marrow, and urine of engrafted mice potently. In addition, the treatment of AG-221 could also induce a significant and dose dependent survival benefit as demonstrated by that all mice in the high dose treatment of AG-221 survived to the end of study [1].

Clinical trial: A phase 1, multicenter, dose-escalation, safety, PK, PD, and clinical activity study of AG-221 in patients with advanced hematologic malignancies with an IDH2 mutation has been conducted [2].

References:
[1] Kate Ellwood-Yen, Fang Wang, Jeremy Travins, Yue Chen, Hua Yang, Kim Straley, Sung Choe, Marion Dorsch, Sam Agresta, David Schenkein, Scott Biller, Michael Su.  AG-221 offers a survival advantage in a primary human IDH2 mutant AML xenograft model. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3116. doi:10.1158/1538-7445.AM2014-3116
[2] https://clinicaltrials. gov/ct2/show/NCT02577406term=Enasidenib&rank=1