Rodman & Renshaw Annual Global Investment Conference

September 2011

Forward-Looking StatementsThis presentation contains forward-looking statements that involve substantial risks and uncertainties. These statements are often, but not always, made through the use of words or phrases such as "anticipates," "expects," "plans," "believes," "intends," and similar words or phrases. All statements, other than statements of historical facts, included in this presentation regarding our strategy, future operations, outlook, milestones, the success of Arno’s product development, potential advantages of Arno’s product candidates, future financial position, future financial results, plans and objectives of management are forward-looking statements. We may not actually achieve these plans, intentions or expectations and Arno cautions investors not to place undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements we make. Various important factors that could cause actual results or events to differ materially from the forward-looking statements that we make. Such factors include, among others, risks that the results of clinical trials will not support our claims or beliefs concerning the effectiveness of our product candidates, our ability to finance the development of our product candidates, regulatory risks, and our reliance on third party researchers and other collaborators. Arno is providing this information as of the date of this presentation and does not undertake any obligation to update any forward-looking statements as a result of new information, future events or otherwise.

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What Differentiates Arno Therapeutics

• Three oncology drug candidates with unique MOAs

• Highly differentiated products for unmet medical needs with substantial market potential

• Leadership team with records of success in oncology drug development and commercial outcomes

• Strong patent position on all assets

Global Product Success

Glenn R. Mattes, President & CEO 25+ years of R&D, commercialization and managerial experience ;

Taxotere®, Lovenox®, Remicade®, Prezista®, Doxil®, Procrit®/Eprex®

J. Chris Houchins, Chief Operating Officer 20+ years of global drug development experience; Celebrex®,

Aromasin®, Ellence®, Emcyt®, Temodar®, Intron®/Peg-Intron®, Caelyx®

Stefan Proniuk, PhD, MBA, Senior Director Product Development 15+ years of global CMC drug development experience, multiple

NCEs and approved products; Triaminic®, Niravam ®

Alex Zukiwski, MD, Chief Medical Officer 16+ years of global pharmaceutical industry experience; Taxotere®,

Xeloda®, Procrit®/Eprex®, Velcade®, Doxil®, Yondelis®, FluMist®/Fluenz®

Arie Belldegrun, MD, Executive Chairman of the Board Professor and Chair of Urologic Oncology, UCLA

Founder of Agensys and Cougar Biotechnology (Zytiga™) 4

Potential Labeling Drives Development

HIGHLIGHTS OF PRESCRIBING INFORMATION

These highlights do not include all the information needed to use

AR-42 safely and effectively. See full prescribing information for AR-42.

AR-42 tablets for oral administration

----------------------------RECENT MAJOR CHANGES--------------------------

Indications and Usage, XXXXXXXXXX XXXXXXX XXXXX XXXXX (1)

Warnings and Precautions, Rash (5.2)

Warnings and Precautions, Fatigue (5.2)

--------------------------INDICATIONS AND USAGE----------------------------

AR-42 is a pan-histone deacetylase (HDAC) inhibitor indicated for the treatment of patients with:

– XXXXXXXXX XXXXXXXXX XXXXXX XXXXXXX XXXXXXXXXXXXXX who require therapeutic intervention but are not candidates for curative surgical resection(1).

– XXXXXXX who require therapeutic intervention but are not candidates for curative surgical intervention or radiation therapy(1).

AR-42 in combination with XXXXXXXX is indicated for the treatment of patients with XXXXXXXXXX XXXXXXX XXXXX XXXXX after progression of at least one prior platinum containing chemotherapy regimen (1).

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Product Candidates

Hematologic Malignancies and Solid Tumors

Solid Tumors and Lymphomas

Glioblastoma MultiformeAR-67

Phase III Registration

AR-12

AR-42

Discovery Preclinical Phase IIPhase I

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AR-42 Profile

Pan-DAC inhibitor; oral formulation In vitro and in vivo activity demonstrated in

multiple tumor types– Greater potency and efficacy vs.

vorinostat in AML models– Encouraging results in multiple cancers

and leukemic stem cells Phase I/II study in hematological

malignancies and solid tumors is currently ongoing

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AR-42 Profile

Phase II program anticipated to begin in 2Q2012

Potential Indications– Non-small cell lung cancer– Prostate cancer– Cranial-spinal axis tumors – Carcinoma of the urothelium – Hepatocellular carcinoma– Acute myelogenous leukemia

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AR-42 Phase I/II Study Dose escalation phase to define MTD in study subjects

with hematological malignancies– N~20 patients

A solid tumor dose escalation arm is being added– Tumors of “interest”; N = ~21

MTD expansion phase – N~30 patients, 10 subjects in each cohort (chronic

lymphocytic leukemia, multiple myeloma and Hodgkin’s disease)

Trial Design– Standard 3+3 study dose escalation study, oral

administration 3x/week on non-consecutive for 3 consecutive weeks of a 28 day treatment cycle

– Assessment in both phases for biomarkers of target inhibition, including histone and tubulin acetylation, as well as other potential markers for treatment changes or toxicity

– Study endpoints: Safety , PK, PD, preliminary efficacy

Minimal Regrowth of Ben-Men-1-LucB Xenografts After AR-42 Treatment

+ AR-42 (months) 1 60

2 31+ Normal diet (months)

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AR-12 Profile

Potential first-in-class; targeted PDK-1 inhibitor; oral formulation

Phase I/II study in solid tumors and lymphomas currently enrolling

Potential Indications–NSCLC–Breast cancer

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AR-12 MOA

Targets PI3K/Akt Pathway

AR-12

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AR-12 Combination Potential

Preclinical data show increased activity and/or reversal of resistance when combined with:

Tarceva® (non-small cell lung cancer, in vitro and in

vivo)

Iressa® (non-small cell lung cancer, in vitro and in vivo)

Avastin ® (colon cancer, in vivo)

Herceptin ® (breast cancer, in vitro)

Tamoxifen (ER positive and negative breast cancer, in

vitro and in vivo)

Gleevec ® (chronic myelogenous leukemia, in vitro)

Nexavar ® (nasopharyngeal cancer, in vitro)

Tseng PH et al., Mol Pharmacol. 2006 Nov;70(5):1534-41Cen L et al., British J Cancer (2007) 97, 785-791Ping-Hui Tseng et al, Blood (2005) 105: 4021-4027

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AR-12 Phase I/II Study

• Dose-escalation to determine MTD and/or active biologic dose in subjects with solid tumors and lymphomas–Study is ongoing–Early evidence of biologic activity

• Phase II expansion will allow for efficacy/safety assessments in tumors of interest

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AR-67 Profile

Third-generation camptothecin analogue Phase II glioblastoma multiforme study

currently enrolling Phase II colorectal carcinoma study

scheduled to start 4Q2011 Potential Indications

– Glioblastoma multiforme – Colorectal cancer– Non-small cell lung cancer– Small cell lung cancer

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AR-67 Summary

Tert-butyl-silyl camptothecin derivative with substantially improved lactone stability, and increased lipophilicity– ~ 85% remains in active “lactone” form– potential increased central nervous system

penetration– potential for more predictable

metabolism/toxicity

Phase I study demonstrated anti-tumor activity; acceptable safety (no drug related diarrhea); linear pharmacokinetics

Phase II GBM study proceeding after reaching interim assessment

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Response Three Years after Initiation(Two Years after Last AR-67 Infusion)

Pre-treatment / Baseline 3/3/08 Three years later 2/28/11

AR-67 Phase I, Subject 21 17

Market Potential

Compound Indication US IncidenceAR-42 NSCLC 220,000

prostate 240,000

AML 12,900bladder cancer

69,000multiple myeloma

20,500cranial/spinal tumors

13,000AR-12 breast cancer 232,000

NSCLC 220,000AR-67 GBM 10,000

colorectal cancer 140,000

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Upcoming Milestones

Expand AR-42 Phase I/II study into solid tumors of interest

Complete AR-12 Phase I enrollment; identify indications for Phase II testing

Complete AR-67 Phase II GBM study enrollment

Initiate AR-67 Phase II colorectal cancer study

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Reasons to Invest in Arno

Promising & differentiated oncology pipeline

Efficient, well-defined clinical/regulatory pathway with planned near term inflection points and potential expedited global registration programs

Senior management has record of success in oncology

New roadmap to value creation 20