Rule 425

Filed by Discovery Partners International, Inc. Pursuant to Rule 425

Under the Securities Act of 1933

and Deemed Filed Pursuant to Rule 14a-12

Under the Securities Exchange Act of 1934

Subject Company: Infinity Pharmaceuticals, Inc.

Commission File No. 333-134438

Additional Information about the Merger and Where to Find It

In connection with the proposed merger transaction between Infinity Pharmaceuticals, Inc. (“Infinity”) and Discovery Partners International, Inc. (“Discovery Partners”), on August 7, 2006, Discovery Partners filed with the Securities and Exchange Commission (the “SEC”) an amended registration statement that contains a proxy statement/prospectus, which registration statement has been declared effective by the Securities and Exchange Commission. Investors and securityholders of Discovery Partners and Infinity are urged to read the proxy statement/prospectus (including any amendments or supplements to the proxy statement/prospectus) regarding the proposed transaction because it contains important information about Discovery Partners, Infinity and the proposed transaction. Discovery Partners’ stockholders can obtain a free copy of the proxy statement/prospectus, as well as other filings containing information about Discovery Partners and Infinity, without charge, at the SEC’s Internet site (http://www.sec.gov). Copies of the proxy statement/prospectus can also be obtained, without charge, by directing a request to Discovery Partners International, Inc., 9640 Towne Centre Drive, San Diego, CA 92121, Attention: Investor Relations, Telephone: (858) 455-8600.

Participants in the Solicitation

Discovery Partners and its directors and executive officers and Infinity and its directors and executive officers may be deemed to be participants in the solicitation of proxies from the stockholders of Discovery Partners in connection with the proposed transaction. Information regarding the special interests of these directors and executive officers in the merger transaction is included in the proxy statement/prospectus referred to above. Additional information regarding the directors and executive officers of Discovery Partners is also included in Discovery Partners’ proxy statement for its 2006 Annual Meeting of Stockholders, which was filed with the SEC on April 6, 2006. This document is available free of charge at the SEC’s web site (http://www.sec.gov) and from Discovery Partners’ Investor Relations at the address listed above.

On August 16, 2006, Infinity made the presentation set forth below to a limited group of investors.


Introduction to Infinity
August 16, 2006


Forward-Looking Statements
Various statements in this presentation concerning our future expectations, plans and prospects
constitute forward-looking statements for the purposes of the safe harbor provisions under The
Private
Securities
Litigation
Reform
Act
of
1995.
Such
forward-looking
statements
include
statements regarding the proposed transaction with Discovery Partner International (DPI), DPI
and
the
combined
company's
net
cash
at
closing,
anticipated
cash
post-closing
and
projected period in which such cash will be available, the trading of the combined company's
shares on the
NASDAQ
National
Market,
the
potential
value
created
by
the
proposed
merger
for
DPI's
and Infinity's stockholders, the efficacy, safety, and intended utilization of
Infinity's product candidates, the results of discovery efforts and clinical trials, and plans
regarding regulatory filings, future research and clinical trials and current and future
collaborative activities. Actual results may differ materially from those indicated by such
forward-looking
statement
as
a
result
of
various
important
factors,
including
risks
related
to:
the
ability
of
DPI
and
Infinity
to
complete
the
proposed
transaction;
the
amount
of
DPI's
net
cash
at
closing;
the
availability
of
funds
to continue research and development
activities; the results of future clinical trials with respect to Infinity's product candidates and
compounds and Infinity's ability to successfully develop and commercialize product candidates;
the success of Infinity's collaborations and its ability to enter into additional collaborations;; the
timing and success of regulatory filings;; the scope of Infinity's patents and the patents of others;
competitive
factors
and
other
risks
and
uncertainties
more
fully
described
in
DPI's
filings
with
the
Securities
and
Exchange
Commission,
including
its
Registration
Statement
on
Form
S-4,
as
filed
on
May
24,
2006
and
subsequently
amended.
The
proposed
transaction
is
subject
to
customary
closing
conditions,
including
approval
of
DPI's
and
Infinity's
stock
holders.
Any forward-looking statements speak only as of the date made. Infinity undertakes no obligation
to publicly update any forward-looking statements, whether as a result of new information, future
events or otherwise.


Mission
To develop targeted therapies for the treatment
of cancer and related conditions discovered
through the use of our innovative small
molecule drug technologies


Lead product candidate: IPI-504, a novel Hsp90 inhibitor
Two ongoing Phase I cancer studies in GIST and multiple myeloma
Phase II expected 2007
Pipeline of preclinical cancer drug candidates
Internally discovered and developed, chemistry platform
4 Pharma/Biotech corporate alliances
Amgen, J & J and Novartis (2)
Proven biotech leadership team
Expected cash runway post-DPI merger
~ $90+ million
Sufficient funds through 2007
Infinity Snapshot


Strategy
Drugs
Internally discovered, novel small molecules
Targets
“Well-credentialed, but not well-trodden”
Products
Opportunity for first-in class or fast follower best-in-class


Overview
Founded in late 2001 (~5 years old)
Team
Recognized biotechnology investor, business and R&D leaders
~115 employees (~55 PhD / MDs)
Alliance and Financing Strategy
Small molecule technology access alliances with Amgen, J&J and Novartis
Bcl-2 product alliance with Novartis
Public financing via Reverse Merger with Discovery Partners
IPI-504 –
lead proprietary oncology drug candidate (Hsp90)
Phase I in GIST and multiple myeloma commenced 2005
Phase II anticipated in 2007
Hedgehog pathway –
preclinical oncology candidate


Our Team: ~115 full-time employees
Infinity headcount
Biology/Clinical/Regulatory
36
Chemistry
50
Management & other
12
(~55 MD or PhDs)
R&D Total
98
Total
115
G&A
17
Well-balanced
Moderate near-term growth
anticipated
Primarily in “downstream”
disciplines (i.e. clinical,
regulatory, CMC/ADME/tox)


Leadership
Mr. Steven Holtzman, CEO
Millennium, DNX
Dr. Julian Adams, President & CSO
Millennium, ProScript
Boehringer
Ingelheim, Merck
Ms. Adelene Perkins, CBO
Transform, Genetics Institute,
Bain, GE
Dr. Michael Foley, VP Chemistry
Harvard ICCB, Glaxo, BMS
Dr. David Grayzel, VP Clinical Development
& Medical Affairs
Dyax,  Mass General Hospital
Dr. Vito Palombella, VP Discovery Biology
Syntonix, Millennium, ProScript
Dr. Jeffrey Tong, VP Corp & Prod Dev
McKinsey & Co, Harvard Center for
Genomics Research
Dr. Jim Wright, VP Pharm
Dev
Millennium, Alkermes, Boehringer
Ingelheim, Syntex, U. of Wisconsin


SAB –
Oncology & Chemistry
Co-chair: Stuart Schreiber, PhD -
Co-Director Broad Institute, Prof. of Chemistry and
Chemical Biology Harvard University
Co-chair: Rick Klausner, MD –
Column Group, former Head of the NCI
Arnie
Levine, PhD -
Institute for Advanced Study
Eric Lander, PhD -
Co-Director Broad Institute, Whitehead, MIT, Harvard
Todd Golub, MD -
DFCI, Broad Institute, Harvard, MIT
David Livingston, MD –
Professor of Medicine, Harvard Medical School, DFCI
Ken Anderson, MD -
Robert Kraft Prof. of Medicine Harvard Medical School, DFCI
Matthew Shair, PhD –
Professor of Chemistry, Harvard University
Vicki Sato, PhD –
former President Vertex Pharmaceuticals
Phil Needleman, PhD -
former Head of R&D Searle, Pharmacia


Investors
Venture Capitalists
Prospect Venture Partners
Venrock Associates
Advent Venture Partners
HBM BioVentures
Vulcan Ventures
Novartis BioVentures
Wellcome
Trust
POSCO BioVentures
Tallwood
Alexandria Equities
Lotus BioScience
Pharmaceutical Companies
Amgen
Novartis
J&J


Overview
Founded in late 2001 (~5 years old)
Team
Recognized biotechnology investor, business and R&D leaders
~115 employees (~55 PhD / MDs)
Alliance and Financing Strategy
Small molecule technology access alliances with Amgen, J&J and Novartis
Bcl-2 product alliance with Novartis
Public financing via Reverse Merger with Discovery Partners
IPI-504 –
lead proprietary oncology drug candidate (Hsp90)
Phase I in GIST and multiple myeloma commenced 2005
Phase II anticipated in 2007
Hedgehog pathway –
preclinical oncology candidate


DOS Small Molecule Technology: Discovery and Alliance Engine
Innovative small molecule platform, diversity oriented synthesis
(DOS), enables the creation of novel, “natural product-like”
synthetic drug candidates
Potential
to
access
previously
“undruggable”
drug
targets
Unique asset for:
Internal drug discovery
Value-accretive technology access alliances
N
O
O
H
R²
R³
N
O
R³
H
H
H
O
O
N
R
4
O
R
R2
R1
N
O
NR
4
O
R1
O
SR2
R3


Diversity Oriented Synthesis (DOS)
2004 –
2006:  > $65 million upfront/committed cash
Additional milestone and royalty potential
No license of proprietary Infinity product rights
Small Molecule Technology Access Alliances


Total payments         >$400M
Early product pipeline: Bcl-2 alliance with Novartis
Joint discovery of novel Bcl-2
targeted cancer drugs
Infinity participation in clinical
development (at NVS expense)
COLLABORATION
Infinity participation in US sales
effort (at NVS expense)
$30M
Upfront &
committed funds
FINANCIALS
Royalties on WW sales


Discovery
Preclinical
Start Clinical
Trials
Hsp90
(IPI-504)
Bcl2/Bcl-xL
2005
2007/2008*
100% owned
100% owned
Novartis
Non-exclusive
Amgen
Novartis
J&J
Small molecule drug technologies
Alliance and financing strategy: value retention
Hedgehog 
Pathway
(IPI-609)
2007*
*Planned


Reverse Merger
with
Discovery Partners International, Inc.
(NASDAQ: DPII)
•* * * * * * * * * * * * *  * * * *  * * * * * * * * * * * * * * * *
•* * * * * * * * * * * * *  * * * *  * * * * * * * * * * * * * * * *
•* * * * * * * * * * * * *  * * * *  * * * * * * * * * * * * * * * *


DPI reverse merger opportunity
Discovery Partners International
Publicly traded company on NASDAQ (DPII)
Cash position 1/1/06: > $83M
Board mandate (Q1, 2006):
Shut down existing business
Seek alternative, high-value biotech investment opportunity
DPI undertakes extensive evaluation of merger candidates
DPI selects Infinity as preferred partner


A financing event only –
NO
programs, employees, partnerships,
or obligations of DPI transferred to Infinity
DPI “invests”
cash and divests operating units
7/7/06: Sale of all DPI operating assets to Galapagos
If DPI cash between $70M and $75M, ownership:
DPII stockholders = 31%
Infinity stockholders = 69%
If cash above $75M or below $70M, adjustment applied
Expected reverse stock split at closing to lower share number and
increase share price
The reverse merger: a creative financing and access to
public markets


Lead clinical product in two ongoing Phase I cancer studies
Phase II expected 2007
Pipeline of preclinical cancer drug candidates
Internally discovered and developed, chemistry platform
4 Pharma/Biotech corporate alliances
Amgen, J & J and Novartis (2)
Proven biotech leadership team
Estimated approximately $90 million cash
Projected cash runway through 2007 and key value driving events
before any additional alliances or financing
Snapshot of Post-Merger Infinity (NASDAQ: INFI)


Status of Reverse Merger
Announce merger
File Initial S4
S-4 is Declared Effective
S-4 mailed to DPI and IPI Stockholders
Stockholder meeting/vote scheduled
Deal Closes, INFI publicly traded
April 12, 2006
July 11, 2006
August 7, 2006
August 9-10, 2006
September 12, 2006
Following successful vote


Overview
Founded in late 2001 (~5 years old)
Team
Recognized biotechnology investor, business and R&D leaders
~115 employees (~55 PhD / MDs)
Alliance and Financing Strategy
Small molecule technology access alliances with Amgen, J&J and Novartis
Bcl-2 product alliance with Novartis
Public financing via Reverse Merger with Discovery Partners
IPI-504 –
lead proprietary oncology drug candidate (Hsp90)
Phase I in GIST and multiple myeloma commenced 2005
Phase II anticipated in 2007
Hedgehog pathway –
preclinical oncology candidate


Novel Hsp90 inhibitor
Currently in 2 Phase I clinical trials:
GIST
Multiple myeloma
Ready for Phase II in 2007
Both IV (water-soluble) and oral
formulations
Infinity’s lead clinical product: IPI-504 (Hsp90 inhibitor)
Cl
-
IPI-504
OH
N
H
N
OH
O
OH
Me
O
O
O
O
NH
2
H
H
+


Heat Shock Protein 90 (Hsp90) is an emerging cancer
target
Hsp90 in cancer cells differs from
Hsp90 in normal cells*
Function of Hsp90 in cancer cells
General chaperone function
essential for protein homeostasis
Specific chaperone function
stabilization of oncogenic
proteins in key cell signaling
pathways
Preferential targeting to cancer
*Reference: Kamal
et al, Nature,
2003, 425,.407-410


Dependence
on Hsp90
Apoptosis
Tyrosine kinase
inhibitor
(e.g
Gleevec, Tarceva)
Oncogene
Cancer cell
survival &
proliferation
Resistance
mutations
Hsp90
inhibitor
Targeting specific oncogenic Hsp90 client proteins
Hsp90
inhibitor


Velcade
Gleevec / dasatinib
Investigational
Gleevec / Sutent
Herceptin
Tarceva
/ Erbitux
Sorafenib
/ Sutent
Sorafenib
Investigational
Targeted therapy
The emerging world of targeted cancer therapies
Indication
Myeloma
CML
AML
GIST
Breast (HER2+)
NSCLC
Renal cell
Melanoma
Prostate (PTEN -/-)
NF-
B
Bcr-Abl
Flt3
c-Kit
HER2
EGFR
VEGFR / HIF-1a
b-Raf
p-Akt
Molecular Target


The emerging world of targeted cancer therapies
NF-
B
Bcr-Abl
Flt3
c-Kit
HER2
EGFR
VEGFR / HIF-1a
b-Raf
p-Akt
Molecular Target
All are clients of Hsp90
Inhibiting Hsp90 affects the
stability of these targets


History of Geldanamycin analogs
17-AAG is a semi-synthetic natural
product, derived from Geldanamycin
17-AAG activity:
Potent & selective inhibitor of
Hsp90
Well-tolerated in humans (>400
patients tested in multiple
Phase I trials)
Removed chemical reactivity of
geldanamycin
Problems:
Highly insoluble
Sub-optimal DMSO-and
Cremophor
based formulations
Off-patent
O
N
H
H
N
O
Me
O
OH
Me
Me
O
Me
O
O
O
N
H
Me
Me
17-AAG


Novel chemical entity
Patient-friendly formulations
IV in two Phase I trials
Oral under development
Broad therapeutic potential
Strong intellectual property position
Phase II planned for 2007
Cl
-
Infinity’s lead clinical product: IPI-504 (HSP90 inhibitor)
IPI-504
OH
N
H
N
OH
O
OH
Me
O
O
O
O
NH
2
H
H
+


IPI-504


IPI-504 competitive landscape for IV formulation
POTENCY
DELIVERY
CHEMICAL 
PROPERTIES
MTD
COMPOUND
COMPANY
17-DMAG
KOS-1022
~25-50 nM
IV 60–120
min
Chemically
reactive
alkylating
agent
<24 mg/m²
Kosan
17-AAG
KOS-953
~25-50 nM
IV 60-120 min
in Cremophor
Special tubing
Steroid
pretreatment
Emulsion
changes
distribution
and PK
Dose escalation
ongoing;
>
340 mg/m²
Kosan
Emulsion
changes
distribution
and PK
17-AAG
CNF-1010
~25-50 nM
IV 60 min
in lipid
emulsion
175 mg/m²
Biogen/
Conforma
Emulsion
changes
distribution
and PK
17-AAG
~25-50 nM
IV 60 min in
DMSO/Egg
220 mg/m²
Kosan
IPI-504
~25-50 nM
IV 30 min
Diffusion
controlled
distribution
Dose escalation
ongoing at
400 mg/m²
Infinity


IPI-504 competitive landscape for PO formulations
IPI-504 (same
molecule as IV)
17-DMAG
CNF-2024
Small Molecule
Small Molecule
Small Molecule
Compound
Company
Phase of Development
Infinity
Kosan
Biogen
Idec
Serenex
Novartis /
Vernalis
Synta
Pre-clinical
Phase I
Phase I
Preclinical
Preclinical
Preclinical
Novel small
molecules not
derived from
geldanamycin


Intellectual property protection for IPI-504
Composition of matter
Formulations (IV and PO)
Methods of making
Methods of using
Infinity has broad patent applications pending for IPI-504


IPI-504 Preclinical Data
*
*
*
*
*


Highly
responsive to
Hsp90 inhibition
T315I
T790M
T670I
Preclinical evidence of potential as salvage therapy
BCR-ABL
EGFR
KIT
Hsp90 Client
Disease
Drug
CML
NSCLC
GIST
Gleevec,
Dasatinib
Tarceva,
Iressa
Gleevec,
Sutent
Kinase
Inhibitor
Resistance
Mutation


CML / Bcr-Abl
Wild-type protein
Bcr
Abl
Non-cancer related
Protein status
Entity
Function
Hsp90-
dependent
Gain-of-function
mutant
Bcr-Abl
fusion
Constitutively
activated signaling
Drug-resistant
mutant
Bcr-Abl
(T315I)
TKI-resistant 
kinase


Gleevec-refractory primary CML cells sensitive to IPI-504
0
10
20
30
40
50
60
70
Pt 1
Pt 2 (T315I)
Pt 3
Control
0.5 uM IPI-504
2.0 uM IPI-504
Collaboration:
Kapil Bhalla, Moffitt Cancer Center


Placebo
Gleevec
IPI-504
0.0%
20.0%
40.0%
60.0%
80.0%
100.0%
15
17
19
21
23
25
27
29
31
33
Days
Oral IPI-504: survival benefit in Gleevec-resistant T315I
CML transplantation model
Collaboration: Shauguang
Li, Jackson Labs
Gleevec
2x daily, 100 mg/kg
IPI-504 oral MWF, 100 mg/kg (p=0.001)


Placebo
Gleevec
IPI-504
0.0%
20.0%
40.0%
60.0%
80.0%
100.0%
15
17
19
21
23
25
27
29
31
33
Days
Oral IPI-504: survival benefit in Gleevec-resistant T315I
CML transplantation model
Collaboration: Shauguang
Li, Jackson Labs
Gleevec
2x daily, 100 mg/kg
IPI-504 oral MWF, 100 mg/kg (p=0.001)


Placebo
Gleevec
IPI-504
0.0%
20.0%
40.0%
60.0%
80.0%
100.0%
15
17
19
21
23
25
27
29
31
33
Days
Oral IPI-504: survival benefit in Gleevec-resistant T315I
CML transplantation model
Collaboration: Shauguang
Li, Jackson Labs
Gleevec
2x daily, 100 mg/kg
IPI-504 oral MWF, 100 mg/kg (p=0.001)


NSCLC / EGFR
Wild-type protein
EGFR
Ligand-dependent
RTK
Protein status
Entity
Function
Hsp90-
dependent
Gain-of-function
mutant
EGFR
(
exon19 or
L858R)
Ligand-
hypersensitive RTK
Drug-resistant
mutant
EGFR
(
exon19 or
L858R + T790M)
TKI-resistant,
ligand
hypersensitive RTK


0
500
1000
1500
2000
2500
3000
3500
4000
12
15
19
22
26
27
32
Days Post-Implant
IPI-504 Vehicle, IP
Gefitinib Vehicle, PO
100mpk Gefitinib, PO
100mpk IPI-504, IP
100mpk
IPI-504
2X
weekly
IP;
100mpk
Gefitinib
daily
PO
for
3
weeks
21%
difference
in
tumor
volumes
between
vehicle
and
Gefitinib
treated
groups
(p=0.54)
69% difference in tumor volumes between vehicle and IPI-504 treated groups (p=0.009)
69%
Non small cell lung cancer xenograft with T790M EGFR
Tarceva/Iressa-resistance mutation


GIST / Kit
Wild-type protein
Kit
Ligand-dependent
RTK
Protein status
Entity
Function
Hsp90-
dependent
Gain-of-function
mutant
c-Kit
Ligand-independent
RTK
Drug-resistant
mutant
c-Kit (T670I)
TKI-resistant,
ligand-independent
RTK


GIST: Gleevec-resistant cells more sensitive to IPI-504
GIST 882*
Gleevec-Sensitive
(primary: exon
13, K642E)
10
100
1000
10
20
30
40
50
10000
60
70
Compounds concentrations (nM)
10
100
1000
10
20
30
40
50
10000
10000
60
70
Compounds concentrations (nM)
IPI-504 : EC50 = 121 +/-
21 nM
IM :        EC50 = 147 +/-
42 nM
Gleevec-
Resistant
(primary: exon
11, V560D +
Gleevec resistance: exon
17, D820A)
10
100
1000
5
15
25
35
45
55
65
75
85
Compounds concentrations (nM)
IPI-504
Imatinib
GIST 48*
IPI-504 : EC50 = 54 +/-
7 nM
IM : 25% inhibition @ 10uM
Collaboration:
Fletcher, Demetri, DFCI


IPI-504 Clinical Development Strategy
*
*
*
*


Development and registration of IPI-504 in hematologic
malignancies and solid tumors
Preclinical support  for broad role of Hsp90
Early human proof-of-concept with rapid path to registration
Strong scientific rationale
Trials targeted to homogenous patient population (disease-focused)
Surrogate marker
Rapid patient accrual
Single-agent activity in refractory setting (potential for expedited
approval)
In parallel, initiate broader development for larger indications
(additional diseases, combination therapy, front-line therapy)
IPI-504 Clinical Development Strategy


Principal Investigator:
Dr. George Demetri, DFCI
Objectives:
Safety, PK, dose-ranging
Establish Phase II dose
Surrogate marker of response:
PET scans
Solid Tumor
Gastrointestinal Stromal Tumors
(Gleevec-resistant)
Schedule / status:
Days 1, 4, 8, 11 of 21 day
Continuing dose escalation
Current ongoing phase I clinical trials
Principal Investigator:
Dr. Paul Richardson, DFCI
Dr. Sundar Jagannath, SVCCC
Dr. David Siegel, HUMED
Objectives:
Safety, PK, dose-ranging
Establish Phase II dose
Surrogate marker of response:
M protein levels
Hematologic
Multiple Myeloma
(relapsed, refractory)
Schedule / status:
Days 1, 4, 8, 11 of 21 day
Continuing dose escalation


Phase I dose escalation for IPI-504 (GIST)
1 cycle = 21 days
4 doses (days 1, 4, 8, 11 followed by 10 days off)
Phase I schedule
25%
500
6
33%
400
5
33%
300
4
50%
225
3
66%
150
2
100%
90
1
Escalation over
previous dose
Dose (mg/m2)
Group


Near-term sequence of additional clinical indications
(2006/2007)
Resistance
Mutation
Disease
PI
T. Lynch
T. Kipp, CLL
consortium
Matsui, Smith /
Bhalla
NSCLC
CLL
CML
Tarceva-R
(T790M )
Zap-70
T315I
Focused trials would determine IPI-504 activity in patients with known resistance to
targeted therapy
If positive, trials provide opportunity to rapidly advance to market
Additional indications to follow
Site
MGH
UCSD
JHU, Moffitt


Overview
Founded in late 2001 (~5 years old)
Team
Recognized biotechnology investor, business and R&D leaders
~115 employees (~55 PhD / MDs)
Alliance and Financing Strategy
Small molecule technology access alliances with Amgen, J&J and Novartis
Bcl-2 product alliance with Novartis
Public financing via Reverse Merger with Discovery Partners
IPI-504 –
lead proprietary oncology drug candidate (Hsp90)
Phase I in GIST and multiple myeloma commenced 2005
Phase II anticipated in 2007
Hedgehog pathway –
preclinical oncology candidate


Potential for first-in-class systemic hedgehog inhibitor
Proprietary NCE’s
Systemic (sub-cu and oral) products
Lead molecule (IPI-609) in advanced preclinical development
First in man expected in 2007
Broad anti-cancer potential
Strong data supporting pancreatic, metastatic prostate,
SCLC, others
Single agent activity
Potential for synergy with standards of care
Infinity’s Hedgehog program


History of cyclopamine –
chemical discovery
1950’s
Lambs born in Idaho with cyclopic
features (defect in development of
left-right asymmetry)
USDA determines that pregnant
ewes grazed on the plant Veratrum
californicum
Cyclopamine
identified as the
teratogenic substance in V.
californicum
Purified cyclopamine given to
animals recapitulates cyclopic
features and other birth defects
V. californicum
cyclopamine


History of hedgehog –
genetics
40 years later (1980’s to today)
Genes are discovered that control
embryonic development and pattern
formation
One such gene is called “hedgehog”
Hedgehog mutations in the Drosophila
fruit fly result in cyclopia
Hedgehog function in humans related
to development of the pancreas, gut,
and other elements of GI tract


Cyclopamine chemistry meets hedgehog genetics
Chemistry
The chemical cyclopamine
results in cyclopic animals
Genetics
Mutation of hedgehog pathway
results in cyclopic animals
Might the chemical cyclopamine interact
with genes in the hedgehog pathway?
YES


Cyclopamine is a smoothened antagonist
*Chen et al., 2002 G&D
16:2743
Cyclopamine
Normal
Cancer


Cancers have hijacked components of the hedgehog
pathway
#
ON = active repressor of Smo
* Mutation in Patched
1
Hahn et al., 1996, Cell
85: 841
2
Bale & Yu, 2001, Human Molec. Genetic. 10: 757 (review)
3
Berman et al., 2002 Science
297: 1559
4
Berman et al., 2003 Nature
425: 846
5
Kayed et al., 2004 Int. J. Cancer
110: 668
6
Thayer et al., 2003 Nature
425: 851
7
Karhadkar et al., 2004 Nature, 431: 707
8
Fan et al., 2004 Endocrinology
145: 3961
9
Watkins et al., 2003, Nature
422: 313
10
Sicklick  2005 ASCO; Mohini, 2005 AACR
11
Kubo et al., 2004 Cancer Res. 64
:6071
State
Normal
Basal cell carcinoma*
1,2
Medulloblastoma*³
Pancreatic cancer
4,5,6
Prostate cancer
7,8
Small cell lung cancer
9
Hepatocellular cancer
10
Breast Cancer
11
Smoothened
OFF
ON
ON
ON
ON
ON
ON
ON
Patched
#
ON
Mutant -
OFF
Mutant -
OFF
OFF
OFF
OFF
OFF
OFF
Hedgehog
OFF
OFF
OFF
Turned ON
Turned ON
Turned ON
Turned ON
Turned ON
Frequency
---
95%
30-40%
100%
100%
50%
n/a
100%


Cyclopamine validates Hedgehog as a cancer target
Cyclopamine is a plant natural
product produced by Veratrum
californicum
Cyclopamine activity:
Potent inhibitor of
Smoothened
Highly active in pancreatic,
prostate, small cell lung
cancer animal models
Drawbacks:
Insoluble
Caustic formulations
Off-patent
HO
O
HN
H
H
H
H
H


Infinity’s lead Hedgehog pathway inhibitors
Novel candidates based on cyclopamine
On mechanism
Superior to cyclopamine:
More chemically stable
More potent
More soluble
Most advanced candidate (IPI-609) in late-preclinical development
First in man 2007
i.v., s.c., or oral formulations
Better oral bioavailability
Better tumor PK


IPI-609 competitive landscape
CUR-61414 –
Curis
and Genentech Hedgehog antagonist
Highly insoluble: not suitable for systemic administration
Topical formulation failed in Phase 1 Basal Cell Carcinoma trial; failure
attributed to formulation, not pathway
Curis
and Genentech
have expressed continued interest in the
Hedgehog pathway for systemic agents


Intellectual property protection for IPI-609
Novel scaffold for IPI-609 and analogs with patent applications
pending
We believe there are no patents preventing us from marketing
IPI-609 or its analogs


0
200
400
600
800
1000
1200
1400
1600
31
36
41
46
51
56
61
Days
Vehicle
IPI-609 10 mpk/day
IPI-609 efficacious in PC-3 prostate xenograft


IPI-609 slows tumor growth rates
0
200
400
600
800
1000
1200
30
35
40
45
50
55
60
Day
Linear Fit
Bivariate Fit of P 10 By Day
200
400
600
800
1000
1200
30
35
40
45
50
55
60
Day
Linear Fit
Bivariate Fit of VP 6 By Day
Median vehicle-treated
animals
Median IPI-609 treated
animals


Clinical development strategy of hedgehog pathway
inhibitors
Strong scientific rationale supports targeting of cancers dependent
on the Hedgehog pathway
Pancreatic
Small cell lung
Metastatic prostate
Metastatic breast
Ovarian
Others (medulloblastoma, glioma, basal cell carcinoma, etc.)
Identify a rapid path to registration
Potential for sole agent activity or
Combination with a single Standard of Care


Key Principal Investigator relationships established
Pancreatic cancer
Manuel Hidalgo, MD  Johns Hopkins
(PCRT –
Dan Van Hoff, MD)
Small cell lung cancer
Charles Rudin, MD Johns Hopkins
Prostate cancer
Phil Kantoff, MD DFCI
Howard Scher, MD MSKCC
Chris Logothetis, MD MD
Anderson
Prostate Consortium
Breast
Max Wicha, MD U of Michigan
Heme malignancies
Doug Smith, MD Johns Hopkins
Bill Matsui, MD Johns Hopkins
Kapil Bhalla, MD Moffitt Cancer Ctr


Infinity Pharmaceuticals
Summary
*
*
*
*
*
*


Product Pipeline
IPI-504: Complete Phase I trials
Publish First Clinical Data
IPI-504: Expect to initiate Phase II in 2007
Hedgehog Pathway: Expect to initiate
Phase I in 2007
Successful alliance execution (Novartis, J&J, Amgen)
At least one new corporate alliance
Financing event
Year-end
cash
runway:
12-24
months
2006/Early 2007 Goals, Achievements and Anticipated News Flow
NVS -
Bcl
Pending
DPII merger
AMGN
extension
Expected
at EORTC
11/7/06