MUTATIONS IN RAS PATHWAY GENES CORRELATE WITH TYPE OF FAILURE TO AZACITIDINE : GENOMIC ANALYSIS AT RANDOMIZATION ONTO THE INSPIRE TRIAL - SLIDE PRESENTATION - ABSTRACT EP829

Abstract #EP829:

Mutations in RAS pathway genes correlate with Type

of Failure to Azacitidine: Genomic Analysis at

Randomization onto the INSPIRE Trial

Koichi Takahashi, MD1, Anna Jonasova, MD, PhD2, Selina M. Luger, MD, FRCPC3, Aref Al-Kali,

MD4, David Valcárcel, MD5, Erica D. Warlick, MD6, Wieslaw W. Jedrzejczak, MD, PhD7, María

Díez-Campelo, MD, PhD8, Patrick S. Zbyszewski, MBA9, Christopher Cavanaugh9, Richard C.

Woodman, MD9& Steven M. Fruchtman, MD9, Guillermo Garcia-Manero, MD1

1University of Texas MD Anderson Cancer Center, Department of Leukemia, Houston, TX; 21st Medical Department - Hematology, General Hospital, Prague, Czech Republic; 3Abramson

Cancer Center, University of Pennsylvania, Philadelphia, PA; 4Division of Hematology, Mayo Clinic, Rochester, MN; 5Planta Baixa, Hospital Universitari Vall d'Hebron, Barcelona, Spain; 6Division of Hematology, Oncology and Transplantation, University of Minnesota, Minneapolis, MN; 7MTZ Clinical Research, Medical University of Warsaw, Warsaw, Poland; 8Hematology Department, Institute of Biomedical Research of Salamanca, University Hospital of Salamanca, Salamanca, Spain; 9Onconova Therapeutics, Inc., Newtown, PA; 1Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX

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Introduction

• More than 45 mutations have been identified in association with HR MDS and the number of mutations increases and changes following HMA failure and leukemic transformation (Haferlach Leukemia 2014, Lindsley NEJM 2017);
• In the majority of patients with MDS (80%)co-mutations are present and the prognostic contribution of each individual mutation remains elusive, especially after adjusting for clinical variables such as IPSS-R score. Only a few mutations are predictive of poor prognosis (e.g. TP53, SF3B1) (Haferlach Leukemia 2014);
• N-RASand K-RAS mutations as well as regulators of the Ras pathway (e.g. PTPN11, NF1) are frequently observed (15-20%) in HR MDS, however their clinical impact is unclear, especially in de novo MDS (Haferlach Leukemia 2014);
• Rigosertib (RGS) is anon-ATP-competitive small molecule RAS mimetic that has the potential to block RAS-RAF-MEK-ERK and PI3K-AKT-mTOR signaling pathways (Athuluri-Divakar 2016). Rigosertib has the potential to also inhibit wildtype upregulation of RAS;
• We report here the genomic profile of 190 patients with HMA failure HR MDS at the time of study entry prior to receiving rigosertib in the INSPIRE study (NCT025622443) an ongoing phase 3 randomized global study evaluating IV rigosertib vs Physicians Choice (PC) in patients with HR MDS post HMA failure;

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INSPIRE (04-30) Study

Eligibility:

• • MDS subtypesRAEB-1,RAEB-2, or RAEB-t
  • Progression or failure to respond to HMA
  • HMA treatment duration ≤ 9 cycles in ≤
    12 months
  • < 82 years of age
• Stratification at randomization
• • VHR vs.non-VHRIPSS-R
  • By geography

2:1
R
A		Rigosertib + best
N
	supportive care
D
	N = 240
O		Primary
M			Endpoint:
I			Overall
Z			Survival
A		Physician's Choice of	(288 Events)
T		Treatment + best
I		supportive care
O		N = 120
N

Primary Objective: To compare the overall survival (OS) of patients in the rigosertib group vs PC arm in all patients and a sub-group of patients with IPSS-R very high risk;

Exploratory Objective: Correlation of overall survival and clinical responses with mutational status;

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Key Inclusion Criteria

• INSPIRE (NCT02562443) is a global randomized Ph3 trial in pts withHR-MDS after HMA failure with an overall target enrollment of 360 pts which has recently been achieved.
• Key inclusion criteria includes:
• • age < 82 years,
  • RAEB-1,RAEB-2 or RAEB-t and ≥ 1 cytopenia;
  • Higher Risk MDS perIPSS-R Intermediate risk (IR), high risk (HR) and very high risk (VHR);
  • Duration of prior HMA ≤ 9 cycles within 12 months and last dose of HMA ≤ 6 months before enrollment;
  • One of the following:
  • • Progression (2006 IWG criteria) at any time after initiation of AZA or DEC treatmentor
    • Failure to achieve complete or partial response or HI (according to 2006 IWG) after at least six4-week cycles of AZA or either four 4-week or four 6-week cycles of DEC or
    • Relapse after initial complete or partial response or HI (according to 2006 IWG criteria)or
    • Intolerance to azacitidine or decitabine;

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Methodology

• Bone marrow samples were collected at study baseline and at Months 2, 4 and 6 and every 6 months thereafter as well as at the end of treatment for mutational analysis as an exploratory endpoint;
• In this abstract we report the genomic characterization of baseline samples; future analyses will report longitudinal assessment while on therapy as well as at the time of disease progression;
• Genomic DNA was extracted from diagnostic bone marrow or peripheral blood samples and targeted capture deep sequencing of 295 genes was performed
  (median sequencing depth 500x) using Agilent's SureSelect custom panel;
• Modified Mutect and Pindel were used to identifyhigh-confidence somatic mutations;

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Table 1: Patient Demographics (N=190)

		Number of patients (%)
Sex	Female	67	(35)
	Male	121 (64)
	Unknown	2	(1)
Race	Asian	22	(12)
	Black	3	(2)
	White	152 (80)
	Other	6	(3)
	Unknown	7	(4)
Age (yr)	Median	73
	Range	54 - 82
ECOG performance Status	0	40	(21)
	1	87	(46)
	2	19	(10)
	Unknown	44	(23)
MDS type	Primary (de novo)	145 (76)
	Secondary	12 (6)
	Unknown	33	(17)
WHO/FAB classification	RAEB-1	50	(26)
	RAEB-2	78	(41)
	RAEB-t	26	(14)
	Unknown	36	(19)
Failure type after the last HMA	Progression	61	(32)
therapy
	Failure	59	(31)
	Relapse	29	(15)
	Intolerance	8	(4)
	Unknown	33	(17)
Revised IPSS score	Low		0
	Intermediate	19	(10)
	High	44	(23)
	Very High	93	(49)
	Unknown	34	(18)

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Figure 1: Genomic Profiling in Patients with HMA Failure at Baseline for INSPIRE Study

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Genomic Profiling in Patients with HMA Failure

at Baseline Assessment for INSPIRE Study

• Data is presented as blinded aggregate results for both arms of the study;
• Baseline mutations are presented for 190 pts of which 157 pts were randomized and 33 pts were screen failures;
• Median age is 73 years(54-82).IPSS-R scores for the pts randomized were: Intermediate 19 (10%), High 44 (23%) and VHR 93 (49%);
• In total 55 different mutations were identified at baseline prior to pts receiving study treatment with either IV rigosertib or PC and the median number of mutations per pt was 3;
• The most common mutations identified in pts wereASXL1 37%, TP53 26%, RUNX1 26%, TET2 23%, STAG2 21%, DNMT3A 17%, and SRSF2 17%;

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Figure 2: Pair-wise Analysis of Mutation Co-Occurrence

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Figure 3: Correlation of Mutation and

Baseline Clinical Features

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Figure 4: Correlation With Mutations and Types of Failure

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Conclusions

• The baseline mutational analyses from the INSPIRE study provides important new insights regarding the genomic profile of patients with HMA failure, especially for the subset categorized as VHR;
• The genomic profile is representative of a cohort enriched for the VHR subset;
• RAS pathway mutations were observed more commonly in patients that progressed on HMA therapy vs patients that failed HMA therapy as defined by IWG 2006 criteria;
• Future genomic analyses of the INSPIRE study will expand the data set and will evaluate correlation of clinical responses with changes in mutational status;
• It is anticipated that these analyses will provide important new insights in the selection of mutations, including but not exclusively the RAS pathway, on the development of leukemic progression in patients with HR MDS following HMA failure and treatment rigosertib.

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Acknowledgements*

USA	Dr. Garcia-Manero, Guillermo; University of Texas MD Anderson Cancer Center	Poland	Dr. Wrobel, Tomasz; Independent Public Clinical Hospital #1 in Wroclaw, Department of
USA	Dr. Silverman, Lewis; Icahn School of Medicine at Mount Sinai		Hematology, Blood Tumors and Bone Marrow Transplanation
USA	Dr. Bejar, Rafael; The Regents of the University of California	UK	Dr. Killick, Sally; Royal Bournemouth Hospital, Department of Hematology
USA	Dr. O'Connell, Casey; USC Norris Comprehensive Cancer Center	Germany	Dr. Chromik, Joerg; Johann Wolfgang Goethe University Hospital, Center for Internal Medicine,
USA	Dr. Baer, Maria; University of Maryland Greenebaum Cancer Center		Medical Clinic II
USA	Dr. Stiff, Patrick; Loyola University Medical Center	Ireland	Dr. Enright, Helen; Adelaide and Meath Hospital Inc. National Children's Hospital, Department of
USA	Dr. Scott, Bart; Fred Hutchinson Cancer Research Center		Hematology
USA	Dr. Warlick, Erica; University of Minnesota Physicians BMT Clinic	Ireland	Dr. Cahill, Mary; Cork University Hospital
USA	Dr. Sayar, Hamid; Indiana University Melvin and Bren Simon Cancer Center	Spain	Dr. Arnan Sangerman, Montserrat; Institut Català d'Oncologia (ICO L'Hospitalet) - Hospital Duran i
USA	Dr. Luger, Selina; University of Pennsylvania,		Reynals
USA	Dr. Arana-Yi, Cecilia; New Mexico Cancer Care Alliance	Spain	Dr. Font Lopez, Patricia; General University Hospital Gregorio Maranon
USA	Dr. Schaar, Dale; Rutgers Cancer Institute of New Jersey	Spain	Dr. Rosell, Ana-Isabel; Hospital Universitario Virgen de la Victoria Hospital de Día de Hematología,
USA	Dr. Gamalski, Steven; Henry Ford Health System		1ª planta
USA	Dr. Fanning, Suzanne; GHS Cancer Institute	Spain	Dr. Diez Campelo, Maria; University Clinical Hospital of Salamanca, De partment of Hematology
USA	Dr. Moezi, Mehdi; Cancer Specialists of North Florida - Jacksonville	Spain	Dr. Valcarcel Ferreiras, David; Hospital Universitari Vall d'Hebron Servei d'Hematologia i
USA	Dr. Safah, Hana; Tulane University Hematology & Medical Oncology		Hemoteràpia
USA	Dr. Keng, Michael; University of Virginia Cancer Center	Spain	Dr. Xicoy Cirici, Blanca; ICO Badalona - Hospital Universitari Germans Trias i Pujol
USA	Dr. Yacoub, Abdulraheem; University of Kansas Cancer Center	Japan	Dr. Usuki, Kensuke; NTT Medical Center Tokyo,
USA	Dr. Al-Kali, Aref; Mayo Clinic	Japan	Dr. Suzuki, Kenshi; Japanese Red Cross Medical Center
USA	Dr. Hansen, Vincent; Northern Utah Associates LLC	Japan	Dr. Maito, Kazuyuki; Tokai Central Hospital
USA	Dr. Hansen, Vincent; Northern Utah Associates LLC	Japan	Dr. Uoshima, Nobuhiko; Japanese Red Cross Kyoto Daini Hospital
USA	Dr. Patel, Prapti; UT Southwestern Medical Center	Japan	Dr. Makita, Masanori; National Hospital Organization Okayama Medical Center
USA	Dr. Mattison, Ryan; University of Wisconsin Clinical Science Center	Japan	Dr. Nakamura, Shingen; Tokushima University Hospital
USA	Dr. Anz, Bertrand; SCRI- Tennessee Oncology- Chattanooga	Japan	Dr. Hidaka, Michihiro; National Hospital Organization Kumamoto Medical Center
France	Dr. Fenaux, Pierre; Saint-Louis Hospital, Department of Hematology Seniors	Japan	Dr. Yamauchi, Takahiro; University of Fukui Hospital
France	Dr. Wattel, Eric; Centre Hospitalier Lyon Sud	Japan	Dr. Ishitsuka, Kenji; Kagoshima University Hospital
France	Dr. Thepot, Sylvain; Centre Hospitalier Universitaire, Angers	Japan	Dr. Matsumura, Itaru; Kindai University Hospital
France	Dr. Quesnel, Bruno; Claude Huriez Hospital, Department of Hematology	Japan	Dr. Choi, Ilseung; National Hospital Organization Kyushu Cancer Center,
France	Dr. Legros, Laurence; Archet 1 Hospital, Department of Clinical Hematology	Japan	Dr. Fujita, Hiroyuki; Saiseikai Yokohamashi Nanbu Hospital
France	Dr. Clouseau, Thomas; Archet 1 Hospital, Department of Clinical Hematology	Canada	Dr. Yee, Karen; Princess Margaret Cancer Centre
France	Dr. Natarajan-Ame, Shanti; Hôpital Civil	Canada	Dr. Buckstein, Rena; Sunnybrook Research Institute, Odette Cancer Center
Croatia	Dr. Mandac Rogulj, Inga; Clinical Hospital Merkur, Clinic of Internal Medicine, Department of Hematology	Canada	Dr. Assouline, Sarit; Jewish General Hospital
Czech Republic	Dr. Jonasova, Anna; General University Hospital in Prague, 1st Internal Clinic - Clinic of Hematology	Belgium	Dr. Beckers, Marielle; University Hospital Leuven, Campus Gasthuisberg
Czech Republic	Dr. Belohlavkova, Petra; University Hospital Hradec Kralove, 4th Internal Clinic of Hematology	Belgium	Dr. Graux, Carlos; Hôpital Universitaire Mont-Godinne
Czech Republic	Dr. Hajek, Roman; University Hospital Ostrava, Department of Hematooncology	Belgium	Dr. Mazure, Dominiek; University Hospital Ghent
Czech Republic	Dr. Machova, Renata; University Hospital Olomouc	Belgium	Dr. Selleslag, Dominik; General Hospital Saint-Jan
Germany	Dr. Giagounidis, Aristoteles; Marien Hospital Duesseldorf GmbH	Sweden	Dr. Broliden, Per Anders; Karolinska University Hospital, Department of Hematology
Germany	Dr. Platzbecker, Uwe: University Hospital Carl Gustav Carus	Russia	Dr. Doronin, Vadim; State Institution of Healthcare of Moscow City Clinical Hospital # 40 of Moscow
Germany	Dr. Sockel, Katja; University Hospital Carl Gustav Carus		Healthcare department
Italy	Dr. Lunghi, Monia; University Hospital "Maggiore della Carita" of Novara, Department of Oncology, Operating Unit of	Russia	Dr. Kosinova, Marina; State Autonomous Healthcare Institution of Kemerovo Region Kemerovo
	Hematology		Regional Clinical Hospital named after S.V. Belyayev
Italy	Dr. Cavo, Michele; Polyclinic S. Orsola-Malpighi, Department of Hematology, Oncology and Laboratory Medicine,	Russia	Dr. Gritsaev, Sergey; FSI Russian Scientific Research Institute of Hematology and Transfusiology
	Operative Unit of Hematology - Cavo	Russia	Dr. Dudina, Galina; State Budget Healthcare Institution of Moscow "Moscow Clinical Scientific
Italy	Dr. Ferrero, Dario; University Hospital San Giovanni Battista of Turin, Complex Structure of Hematology - U		Centre"
Italy	Dr. Liberati, Anna Marina; Hospital S. Maria of Terni, Department of Medicine and Medical Specialties, Complex	Russia	Dr. Volodicheva, Elena; State Healthcare Institution of Tula Reegion "Tula Regional Clinical Hospital"
	University Structure of Oncohematology	Hungary	Dr. Rejtő, László; Szabolcs-Szatmár-Bereg Megyei Kórházak és Egyetemi Oktató Kórház, Jósa András
Italy	Dr. Rossi, Giuseppe; Civil Hospital of Brescia, Department of Clinical Oncology, Operative Unit of Hematology		Oktatókórház Hematológiai Osztály
Italy	Dr. Voso, Maria Teresa; Polyclinic Tor Vergata, Department of Medicine, Complex Operative Unit of Hematology	Estonia	Dr. Viigimaa, Iige; North Estonia Medical Centre
Italy	Dr. Niscola, Pasquale; Hospital S. Eugenio	Switzerland	Dr. Bonadies, Nicolas; University Hospital of Hematology and Hematology Central Laboratory (UKH-
Poland	Dr. Jedrzejczak, Wieslaw; MTZ Clinical Research Inc.		HZL)
Poland	Dr. Halka, Janusz; Oncology Center of Warmia and Mazury in Olsztyn, Teaching Department of	Australia	Dr. Harrup, Rosemary Anne; Royal Hobart Hospital (RHH), Department of Hematology and
	Hematology		Oncology
Poland	Dr. Urbanowicz, Alina; Dr. Ludwik Rydygier Provinicial Hospital in Suwalki, Department of Clinical	Austria	Dr. Pfeilstoecker, Michael; Hanusch Hospital
	Oncology and Hematology

* Represents sites that contributed patient samples used in this analysis

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References

• Athuluri-DivakarSK, Vasquez-Del Carpio R, Dutta K, et al. A small molecule RAS-mimetic disrupts RAS association with effector proteins to block signaling. Cell 2016;165:643-55
• Haferlach T, et al. Landscape of genetic lesions in 944 patients with myelodysplastic syndromes. Leukemia 2014;28(2):241-247.
• Onconova Therapeutics, Inc. (2018). Controlled Study of Rigosertib Versus Physician's Choice of Treatment in MDS Patients After Failure of an HMA (INSPIRE). Clinical Trials.gov Identifier: NCT02562443. Retrieved from: https://clinicaltrials. gov/ct2/show/NCT02562443.
• Lindsley et al. Prognostic Mutations in Myelodysplastic Syndrome afterStem-Cell Transplantation. NEJM 2017; 376:536-547. DOI: 10.1056/NEJMoa1611604
• Mufti, G. J., Best, S., Lea, N., Silverman, L. R., et al. (2014). Mutational Profile and Karyotypic Abnormalities of a Cohort of Clinical Trial Patients withHigher-Risk Myelodysplastic Syndromes (MDS) Following Failure of Hypomethylating Agents (HMAs): Impact on Response to Rigosertib Therapy. Blood, 124(21),3258.

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