Infinity Reports Updated Phase 1 Data Showing Encouraging Clinical Activity of IPI-145 in B-Cell and T-Cell Lymphomas at ASCO

  Infinity Reports Updated Phase 1 Data Showing Encouraging Clinical Activity
  of IPI-145 in B-Cell and T-Cell Lymphomas at ASCO Annual Meeting and
  Announces Initiation of Phase 2 Clinical Study in Indolent Non-Hodgkin
  Lymphoma

 – Early Data Show that IPI-145 Is Well Tolerated and Has Activity in a Broad
   Range of B-Cell and T-Cell Lymphomas, with a 68 Percent Response Rate in
                       Indolent Non-Hodgkin Lymphoma –

– Rapid Onset of Clinical Activity Observed, with a Median Time to Response of
                                 1.8 Months –

2013 ASCO Annual Meeting

Business Wire

CHICAGO -- June 3, 2013

Infinity Pharmaceuticals, Inc. (NASDAQ: INFI) today announced updated Phase 1
data from an ongoing study of IPI-145, its potent, oral inhibitor of
phosphoinositide-3-kinase (PI3K)-delta and PI3K-gamma in patients with
relapsed/refractory lymphoma, a group of potentially fatal hematologic
malignancies, or blood cancers. Data from the study showed that IPI-145 was
well tolerated and clinically active in patients with B-cell or T-cell
lymphomas, including indolent non-Hodgkin lymphoma (iNHL), T-cell lymphoma,
mantle cell lymphoma (MCL) and Hodgkin lymphoma (HL). These findings were
presented today at the 2013 American Society of Clinical Oncology (ASCO)
Annual Meeting.

“I’m encouraged by the early data seen in this Phase 1 study of IPI-145. So
far, IPI-145 appears to be well tolerated, with responses seen across a broad
range of B-cell and T-cell lymphomas,” commented Steven Horwitz, M.D.,
assistant attending physician, department of medicine, Memorial
Sloan-Kettering Cancer Center, and an investigator for this trial. “Many
hematologic malignancies are difficult to treat and new agents are clearly
needed. Targeted therapies, including IPI-145, have the potential not only to
add therapeutic options for our patients but also to reduce or delay the need
for chemotherapy, possibly changing the way many of these malignancies are
treated.”

Infinity today also announced that its first Phase 2 study of IPI-145 in
hematologic malignancies, which is enabled by data from the Phase 1 trial, is
open for enrollment. This Phase 2, open-label, single-arm study is designed to
evaluate the safety and efficacy of IPI-145 dosed at 25 mg twice daily (BID)
in approximately 120 patients with refractory iNHL. In the Phase 1 study,
among the 19 patients with iNHL evaluable for activity, 13 patients (68
percent) responded, with three complete responses and 10 partial responses.
The majority of patients who responded were treated at doses ≤ 25 mg BID.

“Infinity is pleased to begin its first Phase 2 study of IPI-145 in patients
with indolent non-Hodgkin lymphoma, which is supported by the early,
encouraging, data from our ongoing Phase 1 study reported today at ASCO,”
stated Julian Adams, Ph.D., president of research and development at Infinity.
“Infinity believes IPI-145 has the potential to be the best-in-class PI3K
inhibitor for the treatment of blood cancers, and we are rapidly advancing
IPI-145 in the clinic with a goal of addressing significant medical needs.”

IPI-145 Data Presented at ASCO in Patients with Lymphoma

The presentation, “Preliminary safety and efficacy of IPI-145, a potent
inhibitor of phosphoinositide -3-kinase-δ,γ, in patients with
relapsed/refractory lymphoma” (Abstract #8518), includes 117 patients in the
total safety population, of which 68 patients with lymphoma were evaluable for
safety and 47 were evaluable for clinical activity.^1 All patients enrolled in
the study had advanced disease and had progressed during or were refractory
to, intolerant of, or ineligible for established therapy. Lymphoma patients
enrolled in the study had a median of four prior systemic therapies (range:
one to 13), and 46 (68 percent of) patients had at least three prior systemic
therapies.

Safety and Pharmacokinetics

Data presented today showed that IPI-145 was well tolerated, with a safety
profile consistent with co-morbidities seen in patients with advanced
hematologic malignancies. There have been no dose-related trends in adverse
events at the doses evaluated, from 8 mg BID to 75 mg BID, in the total safety
population or in patients with lymphoma. Among the 68 lymphoma patients
enrolled in this study, the most frequent adverse event was elevation in
transaminases (ALT/AST), which occurred in 21 patients (31 percent overall; 18
percent Grade 3 and one percent Grade 4). The majority of transaminase
elevations were primarily managed by dose interruptions and dose reductions.
Two (three percent of) patients discontinued treatment due to ALT/AST
elevations. Fifty-three percent of lymphoma patients remain on study.

Data also showed that IPI-145 is rapidly absorbed and demonstrates a linear
pharmacokinetic (PK) profile through 75 mg BID, with complete inhibition of
PI3K-delta and at least 50 percent inhibition of PI3K-gamma at doses ≥ 25 mg
BID.

Clinical Activity

IPI-145 showed clinical activity across a broad range of patients with
lymphomas, with responses observed in patients with iNHL, T-cell lymphoma, MCL
and HL. The onset of activity was rapid, with a median time to response of
under two months (range: 1.7 – 1.9). Clinical responses in patients with
lymphoma were as follows:

                                                                                     
                                                                                              Median
            Patients (n)            Best Observed Response (n)                          Time to
Diagnosis                                                                                     Response
                                        Complete     Partial      Stable      Progressive     in
            Treated   Evaluable   Response   Response   Disease   Disease       Months
                                                                                              (Range)
iNHL        26        19          3          10         4         2             1.8 (1.7
                                                                                              – 4.1)
T-cell      17        9           1          2          2         4             1.9 (1.7
lymphoma                                                                                      – 2.7)
MCL         9         6           1          3          1         1             1.8 (1.6
                                                                                              – 1.9)
HL          3         3           1          0          1         1             1.7 (NA)
aNHL*       13        10          0          0          4         6             (NA)
NA (not applicable)
*aNHL (aggressive non-Hodgkin lymphoma)
                                                                   

These data were presented in McCormick Place, E354a, in Chicago, Illinois, and
may also be found in the Publications Archive on Infinity’s website
http://www.infi.com/product-candidates-publications.asp.

Phase 2 Trial in iNHL

A Phase 2 study of IPI-145 in iNHL is now open for enrollment. This Phase 2,
multi-center, open-label, single-arm study is designed to evaluate the safety
and efficacy of IPI-145 dosed at 25 mg BID in approximately 120 patients with
iNHL (follicular lymphoma, marginal zone lymphoma, small lymphocytic lymphoma)
whose disease is refractory to combined rituximab and chemotherapy or
radioimmunotherapy. The primary endpoint of the study is response rate
according to the international working group criteria.^2

About the Phase 1 Trial of IPI-145 in Advanced Hematologic Malignancies

The Phase 1, open-label, dose-escalation trial of IPI-145 is designed to
evaluate the safety, PK and clinical activity of IPI-145 administered orally
BID in patients with advanced hematologic malignancies. The dose-escalation
portion of the study is complete, with the maximum tolerated dose defined at
75 mg BID. Infinity is continuing to evaluate IPI-145 in the following seven
expansion cohorts:

25mg BID expansion cohorts
1.  Relapsed/refractory CLL, iNHL and MCL
2.   Treatment-naïve CLL in high-risk patients (over age 65 or having a 17p
     deletion or p53 mutations)

75mg BID expansion cohorts
1.   Relapsed/refractory CLL, iNHL and MCL
2.   T-cell lymphomas
3.   Aggressive B-cell lymphomas
4.   Myeloid neoplasms
5.   Acute lymphoblastic leukemia

About Infinity’s PI3K Program in Blood Cancers

Infinity is developing IPI-145, a potent, oral inhibitor of Class I
phosphoinositide-3-kinase (PI3K)-delta and PI3K-gamma. The PI3Ks are a family
of enzymes involved in multiple cellular functions, including cell
proliferation and survival, cell differentiation, cell migration and
immunity.^3 The PI3K-delta and PI3K-gamma isoforms are preferentially
expressed in leukocytes (white blood cells), where they have distinct and
mostly non-overlapping roles in immune cell development and function.
Targeting PI3K-delta and PI3K-gamma may provide multiple opportunities to
develop differentiated therapies for the treatment of hematologic malignancies
and inflammatory diseases.

IPI-145, Infinity’s lead product candidate, is currently progressing in a
Phase 2 study in patients with indolent non-Hodgkin lymphoma (iNHL) and in a
Phase 1 study in patients with advanced hematologic malignancies. An
investigator-sponsored Phase 1b, open-label, dose-escalation study of IPI-145
in patients with B-cell NHL, CLL and T-cell lymphoma in combination with
rituximab (a monoclonal antibody therapy), bendamustine (a chemotherapy) or
both rituximab and bendamustine is also open for enrollment.

Additionally, Infinity is conducting preclinical studies of IPI-443, its
second oral PI3K-delta and PI3K-gamma inhibitor. IPI-443 has a distinct
biochemical profile from IPI-145 and also has the potential to treat
hematologic malignancies and inflammatory diseases.

About Infinity Pharmaceuticals, Inc.

Infinity is an innovative biopharmaceutical company dedicated to discovering,
developing and delivering best-in-class medicines to people with
difficult-to-treat diseases. Infinity combines proven scientific expertise
with a passion for developing novel small molecule drugs that target emerging
disease pathways. Infinity’s programs focused on the inhibition of
phosphoinositide-3-kinase and heat shock protein 90 are evidence of its
innovative approach to drug discovery and development. For more information on
Infinity, please refer to the company’s website at www.infi.com.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of
The Private Securities Litigation Reform Act of 1995. Such forward-looking
statements include those regarding the Company’s expectations about: progress
in clinical trials of its PI3K program; its ability to execute on its
strategic plans; and the therapeutic potential of PI3K inhibition, IPI-145 and
IPI-443. Such statements are subject to numerous important factors, risks and
uncertainties that may cause actual events or results to differ materially
from the company’s current expectations. For example, there can be no
guarantee that Infinity will report data in the time frames it has estimated,
that any product candidate Infinity is developing will successfully complete
necessary preclinical and clinical development phases, or that development of
any of Infinity’s product candidates will continue. Further, there can be no
guarantee that any positive developments in Infinity’s product portfolio will
result in stock price appreciation. Management’s expectations and, therefore,
any forward-looking statements in this press release could also be affected by
risks and uncertainties relating to a number of other factors, including the
following: Infinity’s results of clinical trials and preclinical studies,
including subsequent analysis of existing data and new data received from
ongoing and future studies; the content and timing of decisions made by the
U.S. FDA and other regulatory authorities, investigational review boards at
clinical trial sites and publication review bodies; Infinity’s ability to
obtain and maintain requisite regulatory approvals and to enroll patients in
its clinical trials; unplanned cash requirements and expenditures; development
of agents by Infinity’s competitors for diseases in which Infinity is
currently developing or intends to develop its product candidates; and
Infinity’s ability to obtain, maintain and enforce patent and other
intellectual property protection for any product candidates it is developing.
These and other risks which may impact management’s expectations are described
in greater detail under the caption “Risk Factors” included in Infinity’s
quarterly report on Form 10-Q filed with theSecurities and Exchange
Commission (SEC) onMay 7, 2013, and other filings filed by Infinity with
theSEC. Any forward-looking statements contained in this press release speak
only as of the date hereof, and Infinity expressly disclaims any obligation to
update any forward-looking statements, whether as a result of new information,
future events or otherwise.

^1  Data reported as of the April 29, 2013, data cutoff.
^2   Cheson et al (2007) Revised response criteria for malignant lymphoma. J.
     Clin Oncol 25:579-586.
     Weinberg RA (2007) Cytoplasmic signaling circuitry programs many of the
^3   traits of cancer. In Jeffcock E, Zayatz E, and Mickey RK (Eds.) The
     biology of cancer (pp. 179-183). New York, NY: Garland Science, Taylor &
     Francis Group.

Contact:

Infinity Pharmaceuticals, Inc.
Jaren Irene Madden, 617-286-6264 (mobile)
Jaren.Madden@infi.com
http://www.infi.com
 
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