Idasanutlin

Murine double minute 2 inhibition alone or with cytarabine in acute myeloid leukemia: results from an idasanutlin phase 1/1b study

Karen Yee, Cristina Papayannidis, Norbert Vey, Michael J. Dickinson, Kevin R. Kelly, Sarit Assouline, Margaret Kasner, Karen Seiter, Mark W. Drummond, Sung-Soo Yoon, Je-Hwan Lee, Steven Blotner, Lori Jukofsky, William E. Pierceall, Jianguo Zhi, Silke Simon, Brian Higgins, Gwen Nichols, Annabelle Monnet, Susanne Muehlbauer, Marion Ott, Lin-Chi Chen, Giovanni Martinelli

PII: S0145-2126(20)30194-6
DOI: https://doi.org/10.1016/j.leukres.2020.106489
Reference: LR 106489

To appear in: Leukemia Research

Received Date: 19 August 2020
Revised Date: 18 November 2020
Accepted Date: 19 November 2020

Please cite this article as: Yee K, Papayannidis C, Vey N, Dickinson MJ, Kelly KR, Assouline S, Kasner M, Seiter K, Drummond MW, Yoon S-Soo, Lee J-Hwan, Blotner S, Jukofsky L, Pierceall WE, Zhi J, Simon S, Higgins B, Nichols G, Monnet A, Muehlbauer S, Ott M, Chen L-Chi, Martinelli G, Murine double minute 2 inhibition alone or with cytarabine in acute myeloid leukemia: results from an idasanutlin phase 1/1b study, Leukemia Research (2020), doi: https://doi.org/10.1016/j.leukres.2020.106489

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

© 2020 Published by Elsevier.

Murine double minute 2 inhibition alone or with cytarabine in acute myeloid leukemia: results from an idasanutlin phase 1/1b study

Karen Yeea, Cristina Papayannidisb, Norbert Veyc, Michael J. Dickinsond, Kevin R. Kellye, Sarit Assoulinef, Margaret Kasnerg, Karen Seiterh, Mark W. Drummondi, Sung-Soo Yoonj, Je-Hwan Leek, Steven Blotnerl, Lori Jukofskyl, William E. Piercealll, Jianguo Zhim, Silke Simonn, Brian Higginso, Gwen Nicholsl, Annabelle Monnetp, Susanne Muehlbauerq, Marion Ottq, Lin-Chi Chenl, and Giovanni Martinellir

aDivision of Medical Oncology and Hematology, Princess Margaret Cancer Centre, Toronto, ON, Canada bInstitute of Hematology “L. and A. Seràgnoli,” University Hospital S. Orsola-Malpighi, Bologna, Italy cDepartment of Hematology, Aix-Marseille University, Institut Paoli-Calmettes, Marseille, France
dClinical Haematology, Peter MacCallum Cancer Centre and The Royal Melbourne Hospital, and Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, VIC, Australia
eDivision of Hematology, Keck School of Medicine of the University of Southern California, Los Angeles, CA fDivision of Hematologic Oncology, Segal Cancer Centre, Jewish General Hospital, Montreal, QC, Canada gDepartment of Medical Oncology, Thomas Jefferson University, Philadelphia, PA
hDepartment of Medicine, Division of Oncology, New York Medical College, Valhalla, NY
iDepartment of Haemato-Oncology, Beatson West of Scotland Cancer Centre, Glasgow, UK
jDivision of Hematology/Medical Oncology, Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
kDepartment of Hematology, Asan Medical Center, Seoul, Republic of Korea lTranslational Medicine-Oncology, Roche Innovation Center, New York, NY mClinical Pharmacology, Roche Innovation Center, New York, NY
nClinical Pharmacology, F. Hoffmann-La Roche, Basel, Switzerland
oProduct Development Oncology, Genentech, Inc, South San Francisco, CA pDepartment of Biostatistics Oncology, F. Hoffmann-La Roche, Basel, Switzerland qClinical Development Oncology, F. Hoffmann-La Roche, Basel, Switzerland
rIstituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST), IRCCS, Meldola, Italy

Statement of equal authors’ contribution

KY and CP contributed equally to this work.

Corresponding author

Karen Yee, Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre, 610 University Avenue, 700U 6-328, Toronto, ON M5G 2M9, Canada; email: [email protected]

Word count

Abstract: 239/250 Main text: 3329/4000
Tables and figures: 5 tables, 1 figure (limit of 6 display items)

Supplemental file: 1 (contains additional Methods, 5 supplemental tables, 4 supplemental figures, and supplemental references)

Trial registration

ClinicalTrials.gov identifier: NCT01773408.

Presented in abstract form at the 56th Annual Meeting of the American Society of Hematology, San Francisco, CA, December 6, 2014, and the 21st Congress of the European Hematology Association, Copenhagen, Denmark, June 11, 2016 [10,11].

HIGHLIGHTS

⦁ Idasanutlin (RG7388) is a novel and potent oral MDM2 antagonist [65/85 characters]

⦁ Idasanutlin alone or with cytarabine was assessed in acute myeloid leukemia [77/85 characters]

⦁ Idasanutlin showed clinical activity alone and with cytarabine in the study [77/85 characters]

⦁ Idasanutlin alone and with cytarabine had a tolerable safety profile in the study [83/85 characters]

Abstract

The prognosis remains poor for patients with relapsed or refractory (r/r) acute myeloid leukemia; thus, novel therapies are needed. We evaluated idasanutlin—a new, potent murine double minute

2 antagonist—alone or with cytarabine in patients with r/r acute myeloid leukemia, de novo untreated acute myeloid leukemia unsuitable for standard treatment or with adverse features, or secondary acute myeloid leukemia in a multicenter, open-label, phase 1/1b trial. Primary objectives were to determine the maximum tolerated dose (MTD) and recommended dose for expansion (RDE) and characterize the safety profile of idasanutlin monotherapy and combination therapy. Clinical activity and pharmacokinetics were secondary objectives. Two idasanutlin formulations were investigated: a microprecipitate bulk powder (MBP) and optimized spray-dried powder (SDP). Following dose escalation, patients (N = 122) received idasanutlin at the RDE in the extension cohorts. No formal MTD was identified. Idasanutlin was tolerable alone and in combination with cytarabine. The RDE was determined as 600 mg twice a day for the MBP formulation and 300 mg twice a day for the SDP formulation. Adverse events were mostly grade 1/2 (76.2%). The most common any-grade adverse events were gastrointestinal (including diarrhea [90.2%]). The early death rate across all patients was 14.8%. Plasma idasanutlin exposure was dose related. In TP53 wild-type patients, composite complete remission rates were 18.9% with monotherapy and 35.6% with combination therapy. Based on these results, idasanutlin development continued with further investigation in the treatment of acute myeloid leukemia.
ClinicalTrials.gov: NCT01773408.

Abbreviations: AE, adverse event; AML, acute myeloid leukemia; CI, confidence interval; CR, complete response; CRc, composite clinical remission; DLT, dose-limiting toxicity; IV, intravenously; MBP, microprecipitate bulk powder; MDM2, murine double minute 2; MTD, maximum tolerated dose; PK, pharmacokinetics; RDE, recommended dose for expansion; r/r, relapsed or refractory; SDP, spray-dried powder; WT, wild-type.

Keywords: acute myeloid leukemia; cytarabine; idasanutlin; MDM2; TP53.

⦁ Introduction

Approximately 60% to 80% of adult patients with acute myeloid leukemia (AML) achieve complete remission following first induction chemotherapy; however, ≈20% will experience primary refractory disease, and >50% will experience relapse [1, 2]. Currently, there is no standard treatment regimen for relapsed or refractory (r/r) AML, although patients with select genetic profiles (e.g., IDH1/2 or FLT3 mutations) may benefit from recently approved therapies. In fit patients with r/r AML, complete remission rates of up to 60% have been observed following

intensive multiagent chemotherapy, but overall survival is typically limited (median, 6-9 months) [1]. In patients not able to tolerate intensive treatment, the goal of nonintensive treatment strategies is to minimize treatment-related morbidity and mortality while controlling disease progression [1]. Overall, AML remains an area of substantial unmet medical need.

The nutlins are a class of compounds that act as selective small-molecule murine double minute 2 (MDM2) inhibitors [2]. They disrupt the interaction between the transactivation domain of the tumor suppressor p53 and the E3 ligase MDM2 by binding to the p53 hydrophobic cleft on the N- terminal domain of MDM2, leading to p53 stabilization and subsequent activation [3]. MDM2 overexpression, which is detected in multiple cancers and in up to ≈50% of patients with AML, targets p53 for degradation and prevents p53-dependent cell-cycle inhibition and cell death [3-6]. Thus, inhibition of the p53-MDM2 interaction could represent a novel approach to cancer therapy.

Cytarabine is the chemotherapy backbone of the majority of treatment regimens for r/r AML [7, 8]. Preclinical evaluation of MDM2 inhibition and cytarabine in vitro and in vivo in AML models suggests synergy of the combination [9].

Idasanutlin (RG7388) is a novel and potent oral nutlin-class MDM2 antagonist [10, 11]. We describe results from a phase 1/1b trial of idasanutlin monotherapy (Idasa) and idasanutlin in combination with cytarabine (Idasa-C) in patients with AML.

⦁ Methods
⦁ Study design and participants

This study was a multicenter, open-label, phase 1/1b trial evaluating the safety, pharmacokinetics (PK), and preliminary efficacy of Idasa or Idasa-C in patients with AML (Figure 1).

Figure 1. Cohort overview. This multicenter, open-label, phase 1/1b trial enrolled patients with confirmed AML (r/r AML, de novo AML unsuitable for standard induction or with adverse features, sAML, or t-AML), regardless of TP53 mutation status. Idasanutlin was administered in an MBP or SDP (bridging cohort only) formulation. *On days 1 through 5 of a 28-day cycle. †On days 1 through 6 of a 28-day cycle. AML, acute myeloid leukemia; BID, twice a day; ECOG PS, Eastern Cooperative Oncology Group performance status; ELN, European LeukemiaNet; IV, intravenously; MBP, microprecipitate bulk powder; MTD, maximum tolerated dose; PO, orally; QD, once a day; r/r, relapsed or refractory; sAML, secondary acute myeloid leukemia; SDP, spray- dried powder; t-AML, treatment-related acute myeloid leukemia.

Eligible patients were aged ≥18 years, had confirmed AML (r/r AML, secondary AML, or treatment-related AML, or de novo AML unsuitable for standard induction or with adverse features, excluding acute promyelocytic leukemia), and had adequate hepatic and renal function. Patients were enrolled regardless of TP53 mutation status. Additional specifications regarding eligibility criteria are detailed by cohort in Online Supplementary Table S1.

The study used 2 different idasanutlin formulations. A microprecipitated bulk powder (MBP) formulation was used to establish the maximum tolerated dose (MTD) or recommended dose for expansion (RDE) for monotherapy and combination therapy. While the study was ongoing, idasanutlin formulation development continued, leading to an optimized spray-dried powder (SDP) formulation; the SDP was investigated in a separate bridging (MBP to SDP) cohort.

Across cohorts, patients received idasanutlin MBP/SDP on the schedule determined from previous studies in solid tumors (i.e., days 1-5 of a 28-day cycle) [12]. Cytarabine 1 g/m2 was administered intravenously (IV) once a day over 1 to 3 hours on days 1 through 6.

Patients received up to 2 cycles of induction with study treatment. Those who achieved clinical remission after 1 or 2 cycles could continue with additional post-remission cycles of therapy per investigator discretion following study-specific guidance for dose reduction but were required to discontinue therapy if the last cycle started >120 days after the previous cycle. Hematopoietic stem cell transplant on study was allowed. Responding patients were followed up for relapse and/or survival as long as they were receiving study treatment. Once responding patients discontinued study therapy, follow-up for relapse and/or survival ended ≈1 year after treatment initiation. Further details related to the study design are described in the Online Supplementary Methods.

This study was conducted in full accordance with the International Council for Harmonisation Guideline for Good Clinical Practice and the principles of the Declaration of Helsinki or the laws and regulations of the country in which the research was conducted, depending on which afforded the greater protection to the patient. The study protocol was reviewed and approved by the institutional review board/independent ethics committee at each institution, and all patients provided informed consent. This study is registered at ClinicalTrials.gov (NCT01773408).

⦁ Procedures and outcomes

The primary endpoint of this study was safety, which included determination of the MTD or RDE and characterization of dose-limiting toxicities (DLTs) and the overall safety profiles of Idasa and Idasa-C.

Secondary endpoints were PK and clinical activity. Clinical response was assessed per European LeukemiaNet criteria [13]. Additional information on study procedures and outcomes are included in the Online Supplementary Methods.

⦁ Statistical analysis

No formal hypothesis testing was performed in this study. Descriptive statistical analyses were performed for all study parts.

⦁ Results

Between February 21, 2013, and July 7, 2015, 122 patients with AML were enrolled. Forty-six patients (37.7%) received Idasa, and 76 (62.3%) received Idasa-C. One patient receiving Idasa-C

was found to have chronic myelomonocytic leukemia, but not AML, and therefore was not evaluable for efficacy.

Baseline characteristics are shown in Table 1 and Online Supplementary Table S2.

Table 1. Baseline patient and disease characteristics

Idasa Idasa-C All patients
(n=46) (n=76) (N=122)
Median age (range), years 67.5 (24-83) 63.0 (32-79) 64 (24-83)
Male 30 (65.2) 42 (55.3) 72 (59.0)
ELN risk
n 46 76 122
Favorable 2 (4.3) 6 (7.9) 8 (6.6)
Intermediate-1 18 (39.1) 25 (32.9) 43 (35.2)
Intermediate-2 6 (13.0) 13 (17.1) 19 (15.6)
Adverse 20 (43.5) 31 (40.8) 51 (41.8)
Not available 0 1 (1.3) 1 (<1)
No. of prior AML therapies
n 46 76 122
0 10 (21.7) 2 (2.6) 12 (9.8)
1 12 (26.1) 15 (19.7) 27 (22.1)
2 8 (17.4) 16 (21.1) 24 (19.7)
≥3 16 (34.8) 43 (56.6) 59 (48.4)
Median lines of prior AML treatment, n 1.0 2.0 1.0
Prior cytarabine >1 g/m2 21 (45.7) 55 (72.4) 76 (62.3)
Duration of response
n 34 73 107
Refractory 17 (50.0) 32 (43.8) 49 (45.8)
<3 months 6 (17.6) 5 (6.8) 11 (10.3)
3-12 months 9 (26.5) 28 (38.4) 37 (34.6)
≥12 months 2 (5.9) 8 (11.0) 10 (9.3)
TP53 mutation status
n 46 76 122
Mutant 9 (19.6) 16 (21.1) 25 (20.5)
Wild type 37 (80.4) 60 (78.9) 97 (79.5)
sAML* 17 (37.0) 12 (15.8) 29 (23.8)
AML, acute myeloid leukemia; ELN, European LeukemiaNet; Idasa, idasanutlin monotherapy; Idasa-C, idasanutlin plus cytarabine; sAML, secondary acute myeloid leukemia.
Data are n (%), unless otherwise stated. One patient in the dose-escalation cohort who received idasanutlin 400 mg once a day in combination with cytarabine did not have AML; this patient was evaluable for safety but not for response.
*Defined as AML arising from myeloproliferative disorders, myelodysplastic syndromes, or other antecedent hematologic disorders.

The median age in the overall population was 64 years, and the majority of patients had intermediate-risk (50.8% [n=62/122]) or adverse-risk (41.8% [n=51/122]) features per 2010 European LeukemiaNet criteria. The TP53 mutation rate was 20.5% (n=25/122). Across all dosing cohorts and study parts, most patients (90.2% [n=110/122]) had received ≥1 prior therapy following their diagnosis of AML, and more than half of all patients (54.1% [n=66/122]) had >2 prior cancer therapies. Prior cytarabine exposure was reported in 79.5% of patients (n=97/122), with 65.2% of those treated with monotherapy and 88.2% treated with combination therapy. Prior treatment with hypomethylating agents was reported in 30.3% of patients (n=37/122), with 39.1% of those treated with monotherapy and 25% treated with combination therapy. Comparing the Idasa and Idasa-C cohorts, fewer patients treated with Idasa received prior AML therapy (73.9% [n=34/46] vs 96.1% [n=73/76]), with a median of 1 vs 2 prior lines of treatment, and fewer had exposure to intermediate- or high-dose (>1 g/m2) cytarabine (45.7% [n=21/46] vs 72.4% [n=55/76], respectively). The proportion of patients with refractory disease or response duration of
<3 months after frontline induction was higher in the Idasa cohort than in the Idasa-C cohort (67.6% [n=23/34] vs 50.6% [n=37/73], respectively). Fewer patients in the Idasa cohort had a response duration to prior regimens of 3 to 12 months (26.5% [n=9/34] vs 38.4% [n=28/73]) or
>12 months (5.9% [n=2/34] vs 11.0% [n=8/73]). The proportion of patients with TP53 mutations was comparable in the Idasa and Idasa-C cohorts (19.6% [n=9/46] and 21.1% [n=16/76]); the proportion of patients with secondary AML (i.e., arising from antecedent hematologic disorders) was higher in the Idasa cohort than in the Idasa-C cohort (37.0% [n=17/46] vs 15.8% [n=12/76]). Patient dispositions are summarized in Online Supplementary Table S3.

⦁ DLTs and determination of MTD

Overall, 1 patient experienced a DLT during monotherapy dose escalation. The patient received Idasa 800 mg MBP twice a day and experienced grade 3 bone marrow failure (bone marrow biopsy specimen showed ongoing aplastic marrow without evidence of residual leukemia and globally hypocellular bone marrow without myeloid proliferation). A formal MTD was not reached during monotherapy dose escalation. However, in discussion with investigators, 800 mg MBP twice a day was deemed as intolerable, principally because of gastrointestinal adverse events (AEs) in all patients: 50.0% of patients (n=6/12) experienced grade ≥3 diarrhea as a dose-limiting event, although not fulfilling the protocol definition of a DLT. For dose escalation with combination therapy, 33.3% of patients (n=2/6) treated with Idasa 600 mg MBP twice a day and cytarabine experienced grade ≥3 diarrhea. Although this also did not meet the DLT protocol definition, further dose escalation was not performed, in agreement with investigators. Idasa 600 mg MBP twice a day was thereby identified as the RDE for both the signal-agent and combination regimens.

In the bridging cohort, 6 DLTs were reported by the investigator in 1 patient treated with Idasa 400 mg SDP twice a day (grade 3 diarrhea, nausea, abdominal pain, lethargy, and hyperbilirubinemia; and grade 5 neutropenic colitis). No DLT occurred with Idasa 300 mg SDP twice a day.

⦁ Safety

Across the monotherapy cohorts, 67.4% of patients (n = 31/46) received 1 cycle of treatment, 26.1% (n=12/46) received 2 cycles, and 6.5% (n=3/46) received ≥3 cycles. Across the combination therapy cohorts, 68.4% (n=52/76), 19.7% (n=15/76), and 11.8% (n=9/76) received 1, 2, or ≥3 treatment cycles, respectively.

A safety summary for the Idasa and Idasa-C cohorts is provided in Online Supplementary Table S4. All patients in the Idasa and Idasa-C cohorts experienced ≥1 AE, and 67.4% (n=31/46) and 90.8% (n=69/76) experienced ≥1 grade 3 AE, respectively. Based on the total number of any- grade AEs (n=2082) and grade ≥3 AEs (n=496) reported, most events (76.2%) were grade 1/2 in severity. Serious AEs occurred in 52.2% (n=24/46) of patients treated with Idasa and in 63.2% (n=48/76) of patients treated with Idasa-C. The majority of AEs were manageable; 17.4% (n=8/46) of patients in the Idasa cohort and 18.4% (n=14/76) in the Idasa-C cohort withdrew from treatment because of an AE (mainly because of hematologic toxicity or infection/sepsis). Of note, 10 of the patients who withdrew because of an AE were in the dose-escalation cohorts and received Idasa at doses above the RDE.

The most common all-grade and grade ≥3 AEs (of any cause) across all treatment cohorts are reported in Tables 2-3.

Table 2. Most common AEs (in ≥20% of patients in any dose cohort)
Idasa

Dose escalation Extension* Extension† Total

400 mg
MBP QD 400 mg
MBP BID 800 mg
MBP BID 600 mg
MBP BID 600 mg
MBP BID
(n=46)
(n=2) (n=6) (n=12) (n=9) (n=17)
Diarrhea 1 (50.0) 6 (100.0) 11 (91.7) 9 (100.0) 15 (88.2) 42 (91.3)
Nausea 1 (50.0) 4 (66.7) 11 (91.7) 5 (55.6) 13 (76.5) 34 (73.9)
Decreased appetite 1 (50.0) 2 (33.3) 6 (50.0) 6 (66.7) 7 (41.2) 22 (47.8)
Hypokalemia 1 (50.0) 3 (50.0) 7 (58.3) 3 (33.3) 4 (23.5) 18 (39.1)
Vomiting 1 (50.0) 3 (50.0) 8 (66.7) 1 (11.1) 5 (29.4) 18 (39.1)
Febrile neutropenia 0 3 (50.0) 5 (41.7) 5 (55.6) 3 (17.6) 16 (34.8)
Asthenia 0 1 (16.7) 3 (25.0) 2 (22.2) 8 (47.1) 14 (30.4)
Fatigue 2 (100.0) 1 (16.7) 3 (25.0) 4 (44.4) 3 (17.6) 13 (28.3)
Anemia 0 1 (16.7) 8 (66.7) 1 (11.1) 2 (11.8) 12 (26.1)
Edema peripheral 1 (50.0) 1 (16.7) 2 (16.7) 3 (33.3) 3 (17.6) 10 (21.7)
Hypomagnesemia 1 (50.0) 2 (33.3) 3 (25.0) 1 (11.1) 3 (17.6) 10 (21.7)

Pyrexia 0 1 (16.7) 2 (16.7) 3 (33.3) 3 (17.6) 9 (19.6)
Thrombocytopenia 1 (50.0) 1 (16.7) 6 (50.0) 0 1 (5.9) 9 (19.6)
Abdominal pain 0 3 (50.0) 3 (25.0) 0 2 (11.8) 8 (17.4)

Idasa-C
Dose escalation Extension Bridging Total
400 mg 400 mg 600 mg 600 mg 300 mg 400 mg
MBP QD MBP BID MBP BID MBP BID SDP BID SDP BID (n=76)
(n=10) (n=7) (n=6) (n=21) (n=19) (n=13)
Diarrhea 7 (70.0) 7 (100.0) 6 (100.0) 19 (90.5) 17 (89.5) 12 (92.3) 68 (89.5)
Nausea 3 (30.0) 4 (57.1) 4 (66.7) 17 (81.0) 10 (52.6) 11 (84.6) 49 (64.5)
Hypokalemia 7 (70.0) 3 (42.9) 3 (50.0) 7 (33.3) 7 (36.8) 8 (61.5) 35 (46.1)
Vomiting 3 (30.0) 4 (57.1) 2 (33.3) 11 (52.4) 7 (36.8) 8 (61.5) 35 (46.1)
Fatigue 3 (30.0) 3 (42.9) 4 (66.7) 4 (19.0) 8 (42.1) 4 (30.8) 26 (34.2)
Febrile neutropenia 5 (50.0) 3 (42.9) 2 (33.3) 5 (23.8) 5 (26.3) 6 (46.2) 26 (34.2)
Pyrexia 2 (20.0) 2 (28.6) 2 (33.3) 8 (38.1) 5 (26.3) 5 (38.5) 24 (31.6)
Decreased appetite 3 (30.0) 4 (57.1) 2 (33.3) 6 (28.6) 5 (26.3) 3 (23.1) 23 (30.3)
Hypomagnesemia 6 (60.0) 2 (28.6) 2 (33.3) 6 (28.6) 3 (15.8) 3 (23.1) 22 (28.9)
Asthenia 2 (20.0) 2 (28.6) 1 (16.7) 7 (33.3) 2 (10.5) 5 (38.5) 19 (25.0)
Thrombocytopenia 3 (30.0) 2 (28.6) 1 (16.7) 4 (19.0) 6 (31.6) 2 (15.4) 18 (23.7)
Abdominal pain 2 (20.0) 1 (14.3) 2 (33.3) 1 (4.8) 6 (31.6) 5 (38.5) 17 (22.4)
Edema peripheral 1 (10.0) 3 (42.9) 0 5 (23.8) 4 (21.1) 2 (15.4) 15 (19.7)
Anemia 1 (10.0) 1 (14.3) 1 (16.7) 2 (9.5) 6 (31.6) 3 (23.1) 14 (18.4)
AE, adverse event; BID, twice a day; Idasa, idasanutlin monotherapy; Idasa-C, idasanutlin plus cytarabine; MBP, microprecipitate bulk powder; QD, once a day; SDP, spray-dried powder.
Data are n (%), unless otherwise stated.
*Monotherapy extension in elderly unfit patients with no prior acute myeloid leukemia (AML) therapy.
†Monotherapy extension in patients with relapsed or refractory AML (Figure 1).

Table 3. Grade ≥3 hematologic and nonhematologic AEs (in ≥5% of patients in any dose cohort)
Idasa
Dose escalation Extension* Extension† Total

(n=2) (n=6) (n=12) (n=9) (n=17)
Hematologic events
Anemia 0 0 8 (66.7) 1 (11.1) 1 (5.9) 10 (21.7)
Thrombocytopenia 1 (50.0) 1 (16.7) 6 (50.0) 0 1 (5.9) 9 (19.6)
Neutropenia 0 0 2 (16.7) 0 1 (5.9) 3 (6.5)
Nonhematologic events
Febrile neutropenia 0 3 (50.0) 5 (41.7) 4 (44.4) 3 (17.6) 15 (32.6)
Hypokalemia 0 1 (16.7) 5 (41.7) 2 (22.2) 3 (17.6) 11 (23.9)
Diarrhea 0 1 (16.7) 6 (50.0) 2 (22.2) 2 (11.8) 11 (23.9)
Sepsis 0 0 3 (25.0) 2 (22.2) 2 (11.8) 7 (15.2)
Pneumonia 0 2 (33.3) 0 2 (22.2) 0 4 (8.7)
Hypophosphatemia 0 1 (16.7) 3 (25.0) 0 0 4 (8.7)
Decreased appetite 0 0 1 (8.3) 2 (22.2) 0 3 (6.5)
Fatigue 0 1 (16.7) 0 1 (11.1) 0 2 (4.3)
Neutropenic sepsis 0 0 2 (16.7) 0 0 2 (4.3)

Idasa-C
Dose escalation Extension Bridging Total

400 mg MBP QD
400 mg MBP BID
800 mg MBP BID
600 mg MBP BID
600 mg MBP BID
(n=46)

(n=10) (n=7) (n=6) (n=21) (n=19) (n=13)
Hematologic events
Thrombocytopenia 3 (30.0) 2 (28.6) 1 (16.7) 4 (19.0) 6 (31.6) 2 (15.4) 18 (23.7)
Anemia 1 (10.0) 1 (14.3) 1 (16.7) 2 (9.5) 5 (26.3) 2 (15.4) 12 (15.8)
Neutropenia 1 (10.0) 3 (42.9) 1 (16.7) 2 (9.5) 4 (21.1) 1 (7.7) 12 (15.8)
Nonhematologic events
Febrile neutropenia 5 (50.0) 3 (42.9) 2 (33.3) 5 (23.8) 5 (26.3) 6 (46.2) 26 (34.2)
Hypokalemia 2 (20.0) 0 2 (33.3) 5 (23.8) 2 (10.5) 6 (46.2) 17 (22.4)
Diarrhea 0 1 (14.3) 2 (33.3) 3 (14.3) 4 (21.1) 5 (38.5) 15 (19.7)
Sepsis 1 (10.0) 1 (14.3) 1 (16.7) 4 (19.0) 1 (5.3) 2 (15.4) 10 (13.2)
Pneumonia 1 (10.0) 0 1 (16.7) 2 (9.5) 3 (15.8) 1 (7.7) 8 (10.5)
Hypophosphatemia 1 (10.0) 1 (14.3) 1 (16.7) 0 3 (15.8) 0 6 (7.9)
Fatigue 0 1 (14.3) 2 (33.3) 2 (9.5) 1 (5.3) 1 (7.7) 7 (9.2)
Neutropenic sepsis 1 (10.0) 2 (28.6) 0 1 (4.8) 0 1 (7.7) 5 (6.6)
Decreased appetite 0 1 (14.3) 1 (16.7) 2 (9.5) 0 0 4 (5.3)

400 mg MBP QD
400 mg MBP BID
600 mg MBP BID
600 mg MBP BID
300 mg SDP BID
400 mg SDP BID

(n=76)

AE, adverse event; BID, twice a day; Idasa, idasanutlin monotherapy; Idasa-C, idasanutlin plus cytarabine; MBP, microprecipitate bulk powder; QD, once a day; SDP, spray-dried powder.
Data are n (%), unless otherwise stated.
*Monotherapy extension in elderly unfit patients with no prior acute myeloid leukemia (AML) therapy.

†Monotherapy extension in patients with relapsed or refractory AML (Figure 1).

The most commonly reported AEs were gastrointestinal AEs (particularly diarrhea), hematologic AEs, and AEs related to infections and infestations. Diarrhea was consistently reported with monotherapy (91.3% [n=42/46]) and combination therapy (89.5% [n=68/76]), with most patients experiencing grade 1/2 events limited to the 5 days of dosing. In 2 patients, the dose was modified because of diarrhea; however, no patient withdrew. Nausea was also commonly reported with monotherapy (73.9% [n=34/46]) and combination therapy (64.5% [n=49/76]) and was primarily grade 1/2. The majority of gastrointestinal events were considered treatment related (data not shown).

Association of exposure with the grade of AEs was analyzed using a univariate logistic regression. The probability of developing an infection (grade ≥3) or diarrhea (grade ≥3) in all patients treated with Idasa-C was calculated. No significant relationship was noted between drug exposure and grade ≥3 infection or grade 3 diarrhea. No grade 4 diarrhea was reported.

Across all treatment cohorts, 27 deaths (22.1%) were reported (Table 4) and were due to progressive disease (n=11), infection-related AEs (sepsis, pneumonia, other infections; n=14), and cerebral ischemia and hepatic failure (n=1 each). The early death rate (deaths ≤30 days from treatment initiation) among all patients was 14.8% (n=18/122) and was similar with monotherapy (15.2% [n=7/46]) and combination therapy (14.5% [n=11/76]).

Table 4. On-treatment mortality

Idasa Idasa-C All
patients

400 mg MBP QD 400 mg MBP BID 800 mg MBP BID 600 mg MBP BID 600 mg MBP BID
(n=46) 400 mg MBP QD 400 mg MBP BID 600 mg MBP BID 600 mg MBP BID 300 mg SDP BID 400 mg SDP BID
(n=76)
(N=122)
(n=2) (n=6) (n=12) (n=9) (n=17) (n=10) (n=7) (n=6) (n= 21) (n=19) (n=13)
All deaths 1 (50.0) 2 (33.3) 4 (33.3) 4 (44.4) 0 11 (23.9) 4 (40.0) 1 (14.3) 1 (16.7) 5 (23.8) 1 (5.3) 4 (30.8) 16 (21.1) 27 (22.1)
Early deaths
(≤30 days after 0
first dose intake)
1 (16.7)
3 (25.0)
3 (33.3)
0
7 (15.2)
2 (20.0)
1 (14.3)
1 (16.7)
5 (23.8)
1 (5.3)
1 (7.7)
11 (14.5)
18 (14.8)
Early deaths 0 0 2 (16.7) 2 (22.2) 0 4 (8.7) 1 (10.0) 1 (14.3) 1 (16.7) 4 (19.0) 0 1 (7.7) 8 (10.5) 12 (9.8)
Early deaths 0 1 (16.7) 1 (8.3) 1 (11.1) 0 3 (6.5) 1 (10.0) 0 0 1 (4.8) 1 (5.3) 0 3 (3.9) 6 (4.9)

Dose escalation Extension* Extension† Total Dose escalation Extension Bridging Total Total

due to AEs due to PD
AE, adverse event; BID, twice a day; Idasa, idasanutlin monotherapy; Idasa-C, idasanutlin plus cytarabine; MBP, microprecipitate bulk powder; PD, progressive disease; QD, once a day; SDP, spray-dried powder.
Data are n (%), unless otherwise stated.
*Monotherapy extension in elderly unfit patients with no prior acute myeloid leukemia (AML) therapy.
†Monotherapy extension arm in patients with relapsed or refractory AML (Figure 1).

⦁ Clinical activity

Composite clinical remission (CRc) was observed across all treatment cohorts in the TP53-WT population (Table 5).

Table 5. Best overall hematologic response in patients with TP53-WT

Idasa Idasa-C
400 mg
MBP QD 400 mg
MBP BID 800 mg
MBP BID 600 mg
MBP BID 600 mg
MBP BID
(n=37) 400 mg
MBP QD 400 mg
MBP BID 600 mg
MBP BID 600 mg
MBP BID 300 mg
SDP BID 400 mg
SDP BID
(n=59)
(n=2) (n=4) (n=11) (n=6) (n=14) (n=8) (n=5) (n=4) (n=17) (n=15) (n=10)
Evaluable
patients 2
TP53-WT
3
9
5
14
33
7
5
4
14
15
10
55
CR 1 (50.0) 0 1 (9.1) 1 (16.7) 1 (7.1) 4 (10.8) 1 (12.5) 3 (60.0) 1 (25.0) 5 (29.4) 7 (46.7) 2 (20.0) 19 (32.2)
CRp 0 0 0 0 0 0 0 0 0 0 0 1 (10.0) 1 (1.7)
CRi 0 1 (25.0) 1 (9.1) 1 (16.7) 0 3 (8.1) 0 0 0 0 1 (6.7) 0 1 (1.7)
CRc: CR+
CRp + 1 (50.0)
CRi
1 (25.0)
2 (18.2)
2 (33.3)
1 (7.1)
7 (18.9) 1 (12.5)
3 (60.0)
1 (25.0)
5 (29.4)
8 (53.3)
3 (30.0)
21 (35.6)
MLFS 0 0 1 (9.1) 0 0 1 (2.7) 0 1 (20.0) 0 0 1 (6.7) 1 (10.0) 3 (5.1)
PR 1 (50.0) 0 2 (18.2) 0 0 3 (8.1) 1 (12.5) 0 1 (25.0) 1 (5.9) 0 0 3 (5.1)
HI 0 1 (25.0) 2 (18.2) 1 (16.7) 3 (21.4) 7 (18.9) 1 (12.5) 0 0 0 0 1 (10.0) 2 (3.4)
PD 0 1 (25.0) 2 (18.2) 2 (33.3) 10 (71.4) 15 (40.5) 4 (5.0) 1 (20.0) 2 (50.0) 8 (47.1) 6 (40.0) 5 (50.0) 26 (44.1)

Dose escalation Extension* Extension† Total Dose escalation Extension Bridging Total

with

BID, twice a day; CR, complete response; CRc, composite clinical remission; CRi, complete response with insufficient recovery of peripheral counts; CRp, complete response without platelet recovery; HI, hematologic improvement; Idasa, idasanutlin monotherapy; Idasa-C, idasanutlin plus cytarabine; MBP, microprecipitate bulk powder; MLFS, morphological leukemia-free state; PD, progressive disease; PR, partial remission; QD, once a day; SDP, spray-dried powder; WT, wild type.
Data are n (%), unless otherwise stated. The 400-mg QD cohort of the combination therapy dose-escalation group excludes 1 patient without acute myeloid leukemia (AML).
*Monotherapy extension in elderly unfit patients with no prior AML therapy.
†Monotherapy extension in patients with relapsed or refractory AML (Figure 1).

CRc rates were 18.9% (n=7/37 [95% confidence interval (CI), 8.0-35.1]) with Idasa and 35.6% (n=21/59 [95% CI, 23.5-49.1]) with Idasa-C. Of the 7 responding patients in the Idasa cohort, 4 had r/r AML and 3 had previously untreated AML (sAML, n = 2/3). All of the responding patients in the Idasa-C cohort (n=21) had r/r AML. Most responding patients achieved complete response (CR), with CR rates of 10.8% (n=4/37) and 32.2% (n=19/59) in those receiving Idasa and Idasa-C, respectively (Online Supplementary Figure S1). In the 300-mg SDP twice-a-day Idasa-C cohort, the rates of CRc and CR were 53.3% (n=8/15) and 46.7% (n=7/15), respectively. The majority of CRc patients treated with monotherapy or combination therapy (71.4% [n=20/28]) achieved their best response after 1 treatment cycle. The change from baseline in bone marrow blasts achieved with combination therapy across cohorts in patients with TP53-WT is shown in Online Supplementary Figure S2.
The CRc rate in patients with TP53 mutations was 4.0% (n=1/25). The responding patient carried a TP53 M243R mutation and achieved a CR with Idasa-C. Additionally, 5 patients carrying TP53 mutations achieved hematologic improvement as best response (Idasa, n=2; Idasa-C, n=3).
In TP53-WT patients achieving CRc, the median duration of response was 234 days (7.7 months; range, 26-700 days) in the monotherapy group and 260 days (8.5 months; range, 34-357 days) in the combination therapy group. The median duration of response across all patients who achieved CRc was 234 days (7.7 months; range, 26-700 days) in the monotherapy group and 254 days (8.4 months; range, 34-357 days) in the combination therapy group. Six of 28 patients (21.4%) who achieved CRc proceeded to successful allogeneic stem cell transplant (Idasa, n=1; Idasa-C, n=5).

⦁ PK analyses

Idasa exposure increased linearly with doses up to 600 mg MBP twice a day. The highest tested dose of 800 mg MBP twice a day did not lead to a further increase in exposure, suggesting a saturation in intestinal absorption at this dose level. In the Idasa dose range evaluated (400-1200 mg/day), coadministration with cytarabine did not appear to have an effect on Idasa PK. Relative bioavailability of the SDP formulation was approximately twice that of the MBP formulation; Idasa exposures were similar between the 600-mg MBP twice-a-day and 300-mg SDP twice-a-day treatments. Following 5 dosing days with Idasa 300 mg SDP twice a day, maximum concentrations were achieved 4 hours postdose and decreased thereafter, with an elimination half-life of 28 hours (Online Supplementary Figure S3). The interpatient variability for the day 5 area under the plasma concentration-time curve from time 0 to 24 hours was 33.8% (Online Supplementary Table S5). No dose- or exposure-response relationship was identified.

Idasa concentrations in the bone marrow of 15 monotherapy patients were 71% ± 21% of concentrations observed in matched plasma samples.

⦁ Biomarker analyses

Macrophage inhibitory cytokine 1 (MIC-1) is a secreted protein induced by activated p53 that was used to support dose finding [14]. Increases in serum levels of MIC-1 were associated with increases in steady-state exposure levels of idasanutlin in patients with AML in the presence or absence of cytarabine.

Consistent with previous findings, [24] baseline MDM2 expression showed correlation with response (n=92; Spearman coefficient 0.3; P=0.0009; Online Supplementary Figure S4). Median MDM2 percent cell positivity at baseline was 54.70% (range, 1.2-99.2) in responders (n=25) and 8.45% (range, 0.1-99.2) in nonresponders (n=67).

⦁ Discussion

There is no standard treatment in r/r AML, but cytarabine is a mainstay [7]. Cytarabine is a cytosine analogue that interferes with DNA synthesis and causes DNA damage, which is likely to augment the antitumor activity of MDM2 inhibitors [15, 16]. Therefore, cytarabine was chosen as the combination partner for idasanutlin in this phase 1/1b study. A phase 1b study of the initial MDM2 antagonist RG7112 (RO5045337) had investigated combination therapy with cytarabine, both at low (20 mg/m2 subcutaneous) and intermediate (1 g/m2 once a day IV × 6) doses [17].
Although the study objectives for safety and efficacy were met for the 1-g/m2 dose, toxicity and lack of efficacy with low-dose cytarabine suggested that this combination was not worth pursuing. Small-molecule MDM2 antagonists were shown to be associated with myelosuppression [12, 18, 19]. Neurotoxicity is associated with higher doses of cytarabine and is more common in older patients, who were the targeted population for Idasa-C. Thus, additional evaluation of higher cytarabine doses was not considered in this study. Instead, the cytarabine dose in the combination therapy regimen was set at 1 g/m2 IV once a day on days 1 through 6 to balance the increased effects of idasanutlin with the potential for intolerable AEs in older patients. The administration of Idasa on days 1 through 5 in a 28-day cycle was chosen based on prior demonstration of efficacy with this schedule in solid tumors [12].

This study enrolled a high-risk population consisting primarily of patients with r/r disease with poor prognosis [20]. Overall, Idasa and Idasa-C were tolerable in this adverse-risk population. Although the incidences of serious AEs and grade ≥3 AEs were higher with Idasa-C, the overall AE profile in patients treated with Idasa or Idasa-C was similar. Compared with other cytarabine-containing relapse regimens, no unexplained toxicities were observed with Idasa-C [21, 22]. Gastrointestinal AEs, especially diarrhea, were frequently reported across treatment cohorts; however, antidiarrheal prophylaxis was not mandatory. Diarrhea was generally manageable: of 110 patients

who experienced diarrhea, the event resolved with supportive treatment (e.g., loperamide) in 79 patients (71.8%) or without supportive treatment in 12 patients (10.9%), and no patient withdrew because of diarrhea or other gastrointestinal AEs. The safety profile in the TP53-WT population (79.5% [n=97/122]) was mostly consistent with that of the overall population.

As anticipated in a high-risk AML population who was neutropenic at baseline, grade ≥3 infection and febrile neutropenia were common across all patient groups [23]. The early death rate with Idasa-C (14.5%) was typical for reinduction therapy in patients with r/r AML [7]. Relative to other cohorts, a higher early death rate (33.3%) was observed in the Idasa extension cohort (600 mg MBP twice a day), which enrolled elderly patients aged >70 years or 60 to 70 years with ≥1 comorbidity and no prior AML therapy. Given the caveat of the small sample size of this cohort (n=9), the age and frailty of this patient population compared with a fitter population may have contributed to the susceptibility for the side effects associated with this Idasa dose. Enrollment in this cohort was prematurely discontinued due to the limited clinical benefit observed.

CRc rates were 18.9% and 35.6% with Idasa and Idasa-C, respectively. The majority of responses were CRs (82.1%) and were achieved after only 1 treatment cycle. Furthermore, 6 patients (21.4%) were able to proceed to stem cell transplant. The median duration of response in TP53- WT patients achieving CRc was 234 days (7.7 months; range, 26-700 days) in the monotherapy group and 260 days (8.5 months; range, 34-357 days) in the combination therapy group.
Response duration ranges were largely overlapping between the 2 cohorts; because of the confounding effect of transplant or further study treatment, the contributing effect of chemotherapy to response duration cannot be estimated.

As described previously,[24] median MDM2 expression was higher in patients who responded to Idasa than in nonresponders; this finding is consistent with the postulated mechanism of action of idasanutlin. However, the dynamic range of MDM2 expression was overlapping in both responders and nonresponders, and patients with very low MDM2 expression levels still had responses.

The antitumor activity of idasanutlin depends on the reactivation of the tumor suppressor p53 protein. The TP53 gene can be mutated throughout its entire sequence. Although many of the mutations in TP53 have a detrimental functional effect, evidence suggests that some mutations are tolerated, allowing p53 to retain functionality [25, 26]. Thus, TP53-WT status was not an eligibility criterion in this study. The proportion of TP53 mutations (20.5%) was slightly higher than that previously reported in AML (4%-15%),[27] which may be due to the substantial proportion of elderly and adverse-risk patients enrolled in this study [28]. Only 1 patient with a TP53 mutation (M243R) responded to study therapy. According to the International Agency for Research on

Cancer TP53 Database, this mutation is classified as functional [29]. Because this patient had received Idasa-C, clinical remission cannot unequivocally be attributed to idasanutlin. Future research is therefore important to distinguish deleterious mutations in TP53 from those that are likely to remain functional when considering patient eligibility for idasanutlin treatment.

The SDP idasanutlin formulation, which became available during the conduct of the study, was investigated only as combination therapy because preliminary study data had already demonstrated the superiority of Idasa-C over Idasa. The bioavailability of the SDP formulation was shown to be double that of the previously used MBP formulation (Online Supplementary Table S5). The 300-mg SDP twice-a-day treatment demonstrated drug exposure comparable to that of the 600-mg MBP twice-a-day treatment, which had been identified during dose escalation as the dose to be investigated in the extension phase. In addition, no DLT was observed with 300 mg SDP twice a day, and efficacy was supportive. Idasa 300 mg SDP twice a day was therefore selected for further clinical development in combination with cytarabine in a phase 3 study of r/r AML (NCT02545283; MIRROS).[30]

Contributions

S.B., L.J., J.Z., B.H., G.N., L.-C.C., and G.M. contributed to the design of the study and development of the methodology. K.Y., C.P., M.J.D., K.R.K., S.A., M.K., S.-S.Y.,
J.-H.L., L.J., B.H.,G.N., L.-C.C., and G.M. contributed to data collection. K.Y., C.P., M.J.D., K.R.K., S.A., K.S., M.W.D., S.-S.Y., J.-H.L., S.B., L.J., W.E.P., J.Z., S.S., B.H., G.N., A.M., S.M., M.O., L.-
C.C., and G.M. contributed to data analysis and interpretation. All authors contributed to the writing of the manuscript, approved the final version, and agree to be accountable for all aspects of the report. All authors verify that this study was conducted per protocol and vouch for the accuracy and completeness of the data.

Competing interests statement

All authors received support from F. Hoffmann-La Roche Ltd during the conduct of the study. Editorial support, provided by an independent medical writer and under the guidance of the authors, was funded by the sponsor. K.Y. received funding to conduct clinical trials from Agensys, Astex, MedImmune, Merck, Millennium, and Roche/Genentech; participated in advisory boards for Celgene, Otsuka, Shire, Takeda, Novartis, and Pfizer; and received honoraria from Novartis and Pfizer (outside the submitted work). N.V. received personal fees from Roche, Novartis, and Amgen (outside the submitted work). M.J.D. received grants, personal fees, and nonfinancial support from Roche (during the conduct of the study); grants, personal fees, and nonfinancial support from Novartis; personal fees and nonfinancial support from Gilead; personal fees from

Takeda; and grants from Celgene (outside the submitted work). K.R.K. received personal fees from Genentech, Janssen, Seattle Genetics, Celgene, Pharmacyclics, Agios, AstraZeneca, and Verastem (outside the submitted work). S.A. reports personal fees from Janssen, AbbVie, and Pfizer (outside the submitted work). M.K. received personal fees for advisory board participation from Jazz; grants and personal fees to conduct clinical trials and for participation in advisory boards from Daiichi, Astellas, and Otsuka; and grants to conduct clinical trials from Pfizer and ONO (outside the submitted work). K.S. received personal fees from Novartis, Celgene, Incyte, and Astellas (outside the submitted work). S.B., L.J., W.E.P., J.Z., S.S., B.H., G.N., A.M., S.M., M.O., and L.-C.C. report employment and received stock from Roche/Genentech during the conduct of the study. C.P., M.W.D., S.-S.Y., J.-H.L., and G.M. have nothing to disclose.

Acknowledgements

The authors would like to thank Xiao Yu Mo for assistance with generating data outputs; Steven A. Middleton for project oversight and guidance; Katia Gamel for scientific assistance with manuscript writing; and Huang Huang, Petra Auclair, Anastasiia Oparii, Nicki Maloney, Sudhakar Katakam, Denise Guimaraes, Sandra Inge Ott, and Andrii Yurovskyi for assistance with biostatistical analyses. Support for third-party writing assistance for this manuscript—furnished by Kia C. E. Walcott, PhD, of Health Interactions, Inc—was provided by F. Hoffmann-La Roche Ltd.

Role of the funding source

F. Hoffmann-La Roche Ltd sponsored this study. The principal investigators, co-investigators, and representatives from the sponsor designed this study, and all investigators and coauthors were involved in the data collection, analysis, and interpretation. Full access to the raw data was provided to all authors. The corresponding author had the final responsibility for the decision to submit for publication.

Data sharing statement

Qualified researchers may request access to individual patient-level data through the Clinical Study Data Request platform at www.clinicalstudydatarequest.com. Further details on Roche’s criteria for eligible studies are available at https://clinicalstudydatarequest.com/Study- Sponsors/Study-Sponsors-Roche.aspx. For further details on Roche’s Global Policy on Sharing of Clinical Study Information and how to request access to related clinical study documents, visit https://www.roche.com/research_and_development/who_we_are_how_we_work/clinical_trials/our
_commitment_to_data_sharing.htm.

References

⦁ J.E. Megias-Vericat, D. Martinez-Cuadron, M.A. Sanz, P. Montesinos, Salvage regimens using conventional chemotherapy agents for relapsed/refractory adult AML patients: a systematic literature review, Ann. Hematol. 97(7) (2018) 1115-1153.

⦁ H. Dohner, E. Estey, D. Grimwade, S. Amadori, F.R. Appelbaum, T. Buchner, H. Dombret, B.L. Ebert, P. Fenaux, R.A. Larson, R.L. Levine, F. Lo-Coco, T. Naoe, D. Niederwieser, G.J. Ossenkoppele, M. Sanz, J. Sierra, M.S. Tallman, H.F. Tien, A.H. Wei, B. Lowenberg, C.D. Bloomfield, Diagnosis and management of AML in adults: 2017 ELN recommendations from an international expert panel, Blood. 129(4) (2017) 424-447.

⦁ L.T. Vassilev, MDM2 inhibitors for cancer therapy, Trends Mol. Med. 13(1) (2007) 23-31.

⦁ C.E. Bueso-Ramos, Y. Yang, E. deLeon, P. McCown, S.A. Stass, M. Albitar, The human MDM- 2 oncogene is overexpressed in leukemias, Blood. 82(9) (1993) 2617-2623.

⦁ A. Quintas-Cardama, C. Hu, A. Qutub, Y.H. Qiu, X. Zhang, S.M. Post, N. Zhang, K. Coombes,
S.M. Kornblau, p53 pathway dysfunction is highly prevalent in acute myeloid leukemia independent of TP53 mutational status, Leukemia. 31(6) (2017) 1296-1305.

⦁ M. Prokocimer, A. Molchadsky, V. Rotter, Dysfunctional diversity of p53 proteins in adult acute myeloid leukemia: projections on diagnostic workup and therapy, Blood. 130(6) (2017) 699-712.
⦁ N.R. Ramos, C.C. Mo, J.E. Karp, C.S. Hourigan, Current Approaches in the Treatment of Relapsed and Refractory Acute Myeloid Leukemia, J. Clin. Med. 4(4) (2015) 665-695.

⦁ B. Lowenberg, Sense and nonsense of high-dose cytarabine for acute myeloid leukemia, Blood. 121(1) (2013) 26-28.

⦁ B. Higgins, C. Tovar, K. Glenn, A. Walz, Z. Filipovic, Y.-E. Zhang, M. Dangl, B. Graves, L. Vassilev, K. Packman, Antitumor activity of the MDM2 antagonist RG7388, Mol. Cancer Ther. 12(11 Supplement) (2013) B55.

⦁ K. Yee, G. Martinelli, N. Vey, M.J. Dickinson, K. Seiter, S. Assouline, M. Drummond, S.Y. Yoon, M. Kasner, J.H. Lee, K. Kelly, S. Blotner, B. Higgins, S. Middleton, G. Nichols, G. Chen, H. Zhong, W.E. Pierceall, J. Zhi, L.C. Chen, Phase 1/1b Study of RG7388, a Potent MDM2 Antagonist, in Acute Myelogenous Leukemia (AML) Patients (Pts), Blood. 124(21) (2014) 116.

⦁ G. Martinelli, C. Pappayannidis, K. Yee, N. Vey, M. Drummond, K. Kelly, M. Dickinson, J.-H. Lee, K. Seiter, S.-S. Yoon, S. Assouline, M. Kasner, G. Nichols, S. Middleton, S. Blotner, J. Zhi,
W. Pierceall, L.-C. Chen, Abstract S504: Phase 1b Results of Idasanutlin + Cytarabine (Ara-C) in Acute Myeloid Leukemia (AML) Patients (pts), Haematologica. 101(s1) (2016) 187 S504.

⦁ L.L. Siu, A. Italiano, W.H. Miller, J.Y. Blay, J.A. Gietema, Y.J. Bang, L.R. Mileshkin, H.W. Hirte, M. Reckner, B. Higgins, L. Jukofsky, S. Blotner, J. Zhi, S. Middleton, G.L. Nichols, L.C. Chen, Phase 1 dose escalation, food effect, and biomarker study of RG7388, a more potent second-generation MDM2 antagonist, in patients (pts) with solid tumors, Haematologica. 32(suppl 15) (2014) 2535.

⦁ H. Dohner, E.H. Estey, S. Amadori, F.R. Appelbaum, T. Buchner, A.K. Burnett, H. Dombret,
P. Fenaux, D. Grimwade, R.A. Larson, F. Lo-Coco, T. Naoe, D. Niederwieser, G.J. Ossenkoppele,
M.A. Sanz, J. Sierra, M.S. Tallman, B. Lowenberg, C.D. Bloomfield, L. European, Diagnosis and management of acute myeloid leukemia in adults: recommendations from an international expert panel, on behalf of the European LeukemiaNet, Blood. 115(3) (2010) 453-474.

⦁ H. Yang, Z. Filipovic, D. Brown, S.N. Breit, L.T. Vassilev, Macrophage inhibitory cytokine-1: a novel biomarker for p53 pathway activation, Mol. Cancer Ther. 2(10) (2003) 1023-1029.

⦁ J.M. Ford, Regulation of DNA damage recognition and nucleotide excision repair: another role for p53, Mutat. Res. 577(1-2) (2005) 195-202.

⦁ D.P. Lane, Cancer. p53, guardian of the genome, Nature. 358(6381) (1992) 15-16.

⦁ K. Yee, G. Martinelli, S. Assouline, M. Kasner, N. Vey, K. Kelly, M. Drummond, M. Dennis, K. Seiter, S. Blotner, L. Jukofsy, S. Middleton, J. Zhi, G. Chen, H. Zhong, G. Nichols, Phase 1b study of the MDM2 antagonist RG7112 in combination with 2 doses/schedules of cytarabine, Blood. 122(21) (2013) 498.

⦁ C. Iancu-Rubin, G. Mosoyan, K. Glenn, R.E. Gordon, G.L. Nichols, R. Hoffman, Activation of p53 by the MDM2 inhibitor RG7112 impairs thrombopoiesis, Exp. Hematol. 42(2) (2014) 137-145.

⦁ S. Wang, W. Sun, Y. Zhao, D. McEachern, I. Meaux, C. Barriere, J.A. Stuckey, J.L. Meagher,
L. Bai, L. Liu, C.G. Hoffman-Luca, J. Lu, S. Shangary, S. Yu, D. Bernard, A. Aguilar, O. Dos- Santos, L. Besret, S. Guerif, P. Pannier, D. Gorge-Bernat, L. Debussche, SAR405838: an optimized inhibitor of MDM2-p53 interaction that induces complete and durable tumor regression, Cancer Res. 74(20) (2014) 5855-5865.

⦁ J.P. Sasine, G.J. Schiller, Emerging strategies for high-risk and relapsed/refractory acute myeloid leukemia: novel agents and approaches currently in clinical trials, Blood Rev. 29(1) (2015) 1-9.

⦁ S. Faderl, V. Gandhi, S. O’Brien, P. Bonate, J. Cortes, E. Estey, M. Beran, W. Wierda, G. Garcia-Manero, A. Ferrajoli, Z. Estrov, F.J. Giles, M. Du, M. Kwari, M. Keating, W. Plunkett, H. Kantarjian, Results of a phase 1-2 study of clofarabine in combination with cytarabine (ara-C) in relapsed and refractory acute leukemias, Blood. 105(3) (2005) 940-947.

⦁ E. Archimbaud, V. Leblond, M. Michallet, C. Cordonnier, P. Fenaux, P. Travade, F. Dreyfus,
J. Jaubert, Y. Devaux, D. Fiere, Intensive sequential chemotherapy with mitoxantrone and continuous infusion etoposide and cytarabine for previously treated acute myelogenous leukemia, Blood. 77(9) (1991) 1894-1900.

⦁ H.C. Schouten, Neutropenia management, Ann. Oncol. 17 Suppl 10 (2006) x85-x89.

⦁ B. Reis, L. Jukofsky, G. Chen, G. Martinelli, H. Zhong, W.V. So, M.J. Dickinson, M. Drummond, S. Assouline, M. Hashemyan, M. Theron, S. Blotner, J.H. Lee, M. Kasner, S.S. Yoon,
R. Rueger, K. Seiter, S.A. Middleton, K.R. Kelly, N. Vey, K. Yee, G. Nichols, L.C. Chen, W.E. Pierceall, Acute myeloid leukemia patients’ clinical response to idasanutlin (RG7388) is associated with pre-treatment MDM2 protein expression in leukemic blasts, Haematologica. 101(5) (2016) e185-e188.

⦁ E. Kotler, O. Shani, G. Goldfeld, M. Lotan-Pompan, O. Tarcic, A. Gershoni, T.A. Hopf, D.S. Marks, M. Oren, E. Segal, A Systematic p53 Mutation Library Links Differential Functional Impact to Cancer Mutation Pattern and Evolutionary Conservation, Mol. Cell. 71(1) (2018) 178-190.

⦁ S. Kato, S.Y. Han, W. Liu, K. Otsuka, H. Shibata, R. Kanamaru, C. Ishioka, Understanding the function-structure and function-mutation relationships of p53 tumor suppressor protein by high- resolution missense mutation analysis, Proc. Natl. Acad. Sci. U S A. 100(14) (2003) 8424-8429.

⦁ M.B. Melo, N.N. Ahmad, C.S. Lima, K.B. Pagnano, S. Bordin, I. Lorand-Metze, S.T. SaAd,
F.F. Costa, Mutations in the p53 gene in acute myeloid leukemia patients correlate with poor prognosis, Hematology. 7(1) (2002) 13-19.

⦁ M. Moarii, E. Papaemmanuil, Classification and risk assessment in AML: integrating cytogenetics and molecular profiling, Hematology Am. Soc. Hematol. Educ. Program. 2017(1) (2017) 37-44.

⦁ International Agency for Research on, IARC TP53 Database. ⦁ http://p53.iarc.fr/TP53GeneVariations.aspx.⦁ 2019.

⦁ P. Montesinos, B.M. Beckermann, O. Catalani, J. Esteve, K. Gamel, M.Y. Konopleva, G. Martinelli, A. Monnet, C. Papayannidis, A. Park, C. Récher, R. Rodríguez-Veiga, C. Röllig, N. Vey,
A.H. Wei, S.S. Yoon, P. Fenaux, MIRROS: a randomized, placebo-controlled, Phase III trial of cytarabine ± idasanutlin in relapsed or refractory acute myeloid leukemia, Future Oncol. 16(13) (2020) 807-815.