CPX-351 Plus Enasidenib for Relapsed AML

PRIMARY OBJECTIVE:

I. To estimate the remission rate (defined as complete remission [CR]/ CR with incomplete hematologic recovery [CRi]) of the combination of liposome-encapsulated daunorubicin-cytarabine (CPX-351) plus enasidenib mesylate (enasidenib) in adults with relapsed acute myeloid leukemia (AML) characterized by a 2-hydroxyglutarate (2-HG) producing IDH2 mutations that include IDH2^R172 and IDH2^R140.

SECONDARY OBJECTIVES:

I. To evaluate persistent severe hematologic toxicity at induction day 60 in patients with a morphologic leukemia-free state (bone marrow blasts < 5%).

II. To evaluate delayed CR/CRi with enasidenib maintenance in participants with stable disease after induction with CPX-351.

III. To estimate the rate of CR plus complete remission with partial hematologic recovery (CRp) of the combination of CPX-351 plus enasidenib.

IV. To evaluate time to return of normal hematopoiesis after induction therapy. V. To evaluate 30- and 60-day survival. VI. To evaluate CPX-351 plus enasidenib as a bridge to allogeneic hematopoietic stem cell transplantation (HSCT).

EXPLORATORY OBJECTIVES:

I. To determine the co-existing mutations that are present with the IDH2 mutation and describe those that are present in patients who achieve CR/CRi.

II. To determine the depth of molecular response to induction by minimal residual disease (MRD) using next generation sequencing.

III. To estimate the subclinical cardiotoxicity of CPX-351 as measured by troponin I, electrocardiography (ECG), and echocardiography.

OUTLINE:

INDUCTION: Patients receive liposome-encapsulated daunorubicin-cytarabine intravenously (IV) over 90 minutes on days 1, 3, and 5, and enasidenib mesylate orally (PO) on days 10-60 in the absence of disease progression or unacceptable toxicity. Patients whose bone marrow is not hypoplastic receive re-induction including liposome-encapsulated daunorubicin-cytarabine IV on days 1 and 3, and enasidenib mesylate PO on days 8-60 in the absence of disease progression or unacceptable toxicity.

CONSOLIDATION: Participants who achieve CR/CRi may proceed directly to allogeneic HSCT or receive up to 4 cycles of consolidation. Patients < 60 years receive cytarabine twice daily (BID) on days 1, 3, and 5, and patients >= 60 years receive cytarabine IV once daily on days 1-5. Patients also receive enasidenib mesylate PO on days 6-55. Treatment repeats every 28-55 days for up to 4 cycles in the absence of disease progression or unacceptable toxicity. Patients who maintain CR/CRi after completion of consolidation therapy undergo allogeneic HSCT at the discretion of the treating physician.

MAINTENANCE: Participants who have stable disease (not meeting criteria for progressive disease, but also not achieving CR/CRi) at day 60 receive enasidenib mesylate PO daily in the absence of disease progression or unacceptable toxicity. Routine follow-up visits will be conducted at least once every 3 months for the duration of the trial.