Sunesis Pharmaceuticals Presents Voreloxin Clinical Data at the American Society...

Sunesis Pharmaceuticals Presents Voreloxin Clinical Data at the American
Society of Clinical Oncology 2009 Annual Meeting

-- Conference Call Scheduled for Today, Monday June 1, at 1:00 PM ET to
Discuss ASCO Data Presentations --

SOUTH SAN FRANCISCO, Calif., June 1 /PRNewswire-FirstCall/ -- Sunesis
Pharmaceuticals, Inc. (Nasdaq: SNSS), announced today new data from three
ongoing clinical trials demonstrating that Sunesis' lead drug candidate,
voreloxin, shows promising safety and efficacy in acute myeloid leukemia (AML)
and in platinum-resistant ovarian cancer. These data were presented today and
this past weekend at the American Society of Clinical Oncology 2009 Annual
Meeting in Orlando. The presentations are available on the Sunesis website at
www.sunesis.com.

"We have made significant progress with our voreloxin program," said Daniel
Swisher, Chief Executive Officer of Sunesis. "Over 190 patients were enrolled
across the voreloxin trials in 2008. In AML, voreloxin, as a single agent or
when combined with cytarabine, has induced over 50 patients into a complete
remission to date. This positive momentum has carried into 2009 as we complete
our current studies, prepare for our End-of-Phase 2 meeting with the FDA and
complete our plans for entering into pivotal studies in AML."

Phase 2 Study of Single Agent Voreloxin in Newly Diagnosed Elderly AML
(REVEAL-1 Trial)

REVEAL-1 (Response Evaluation of VorEloxin in AmL) is a Phase 2 dose regimen
optimization study of single agent voreloxin in newly diagnosed elderly AML
patients who are unlikely to benefit from standard induction chemotherapy.
Interim clinical data from this study continue to show that voreloxin can
induce durable complete remissions.

-- In Schedule A (72 mg/m2 of voreloxin weekly for three weeks), 29
patients have been enrolled and treated.
-- 20 of 29 patients (69 percent) were 70 years of age or older.
-- The majority of patients had intermediate or unfavorable
cytogenetics.
-- 12 patients achieved a complete remission (CR) or complete
remission
without full platelet recovery (CRp) for an overall remission rate
of 41 percent.
-- Eight of 12 responders received one consolidation cycle of
voreloxin
and no responders received a second consolidation cycle.
-- Grade 3 or higher non-hematologic adverse events occurring in more
than 10 percent of patients include mucosal inflammation,
infections
and fatigue.
-- The 30-day all-cause mortality rate was 17 percent, which compares
favorably to standard induction chemotherapy. Infection was the
most
common cause of early mortality.
-- In Schedule B (72 mg/m2 of voreloxin dosed weekly for two weeks), 35
patients have been enrolled and treated.
-- 27 of 35 patients (77 percent) were 70 years of age or older.
-- The majority of patients had intermediate or unfavorable
cytogenetics.
-- Data from these patients suggest that Schedule B is better
tolerated. The incidence of Grade 3 or higher mucosal inflammation
has been reduced by more than 50 percent relative to Schedule A.
The
30-day all-cause mortality has also been reduced to 9 percent.
-- Anti-leukemic activity has been maintained. 10 patients achieved a
CR or CRp for an overall remission rate of 29 percent.
-- The number of responders receiving either one or two consolidation
cycles increased. All 10 responders received one consolidation
cycle
of voreloxin and seven of 10 responders received a second
consolidation cycle. While still too early to calculate, this may
contribute to an improved median duration of remission in Schedule
B
compared to Schedule A.
-- In Schedule C (72 mg/m2 of voreloxin dosed on days one and four), 28
patients have been enrolled and treated.
-- It is still too early for a complete remission evaluation, but
four
CRs and two CRps of 19 evaluable patients have been achieved to
date, while nine patients are too early to evaluate.
-- As with Schedule B, early data from patients suggest that Schedule
C
is better tolerated than Schedule A and activity has also been
maintained. The 30-day all-cause mortality is currently nine
percent
(two of 23).
-- Based on the current safety profile of 72 mg/m2 of voreloxin in
Schedule C as well as the ongoing Phase 1b/2 experience of 90
mg/m2
of voreloxin dosed on days one and four in combination with
cytarabine, an additional cohort of approximately 20 patients will
be enrolled at 90 mg/m2 in Schedule C.
-- The median duration of remission and the median overall survival have
not yet been reached in any schedule.
-- In Schedule A, five of 12 responders remain in remission for over
seven months while four have relapsed and three have withdrawn
from
remission follow-up.
-- In Schedule B, nine of 10 responders remain in remission to date.

-- More than half of all patients in Schedules A and B have survived
more than six months.

"Voreloxin's anti-leukemic activity in this previously untreated, older adult
patient population with AML is promising," said Robert K. Stuart, M.D.,
Professor of Medicine, Division of Hematology/Oncology, Department of
Medicine, Medical University of South Carolina, and an investigator in the
study. "I am encouraged by the complete remissions observed thus far in
patients who are unlikely to benefit from standard induction therapy.
Additionally, the convenience of a ten minute injection is an added benefit
for both staff and patients."

Phase 1b/2 Study of Voreloxin in Combination with Cytarabine in
Relapsed/Refractory AML

Researchers also presented interim data from an ongoing Phase 1b/2 clinical
trial testing voreloxin in combination with cytarabine. The Phase 1b/2 trial
is designed to evaluate the safety, pharmacokinetics and anti-leukemic
activity of escalating doses of voreloxin when administered on days one and
four with cytarabine given either as a continuous infusion of 400 mg/m2 daily
for five days (CIV Schedule) or as a two hour IV bolus of 1 g/m2 daily for
five days (Bolus Schedule).

-- The Phase 1 dose escalation in both the CIV and Bolus Schedules has
been
completed with a maximum tolerated dose/recommended Phase 2 dose of 80
mg/m2 and 90 mg/m2, respectively.
-- Between both schedules, 57 relapsed or refractory patients have
been
enrolled and treated in the dose escalation.
-- In the Phase 1 portions of this study, infection related
toxicities
were the most common Grade 3 or higher adverse events. The overall
incidence of Grade 3 or higher mucosal inflammation was 11 percent
when patients from both the CIV and Bolus Schedules are combined.
-- In the dose escalation, nine of 39 patients (23 percent) in the
CIV
Schedule and four of 18 patients (22 percent) in the Bolus
Schedule
achieved a CR or CRp. Responders included first relapse, second
relapse, primary refractory and relapsed/refractory patients.
-- In the CIV Schedule dose escalation, six of nine responders to
date
have had a remission of at least eight months and a third of
responders went on to receive a bone marrow transplant.
-- It is too early to evaluate remission duration in the Bolus
Schedule
dose escalation.
-- Across both the CIV and Bolus Schedules, a total of 14 patients
with
primary refractory AML were enrolled and treated with a voreloxin
dose of 80 mg/m2 or higher. Five of 14 of these patients achieved
a
CR or CRp for an overall CR or CRp rate of 36 percent, which
compares favorably relative to expected remission rates in this
AML
population of approximately 10 to 15 percent.
-- In Phase 2, 16 AML patients in first relapse were enrolled in the CIV
Schedule.
-- Infection related toxicities were the most common Grade 3 or
higher
adverse events and no Grade 3 or higher mucosal inflammation was
observed.
-- Six CRs and one CRp were achieved for an overall CR or CRp rate of
44 percent, which compares favorably relative to the expected
single
agent cytarabine remission rate of approximately 20 percent. Five
first relapse AML patients were enrolled in the dose escalation in
the CIV Schedule at a dose of 80 mg/m2 or higher, of whom none
achieved a CR or CRp.
-- Three of seven responders had an initial remission, or CR1, of
less
than 12 months, and to date, five of seven responders remain in
remission.

-- In the Bolus Schedule, both first relapse and primary refractory
patients are currently being enrolled in Phase 2.

"Voreloxin has demonstrated anti-leukemic activity when administered in
combination with both continuous infusion and bolus cytarabine," said Jeffrey
Lancet, M.D, Assistant Professor and Section Chief of the Leukemia Program,
Division of Hematologic Malignancies at the H. Lee Moffitt Cancer Center &
Research Institute, and an investigator in this voreloxin/cytarabine
combination study in AML. "Voreloxin has induced remissions in several
difficult to treat AML patient populations, including relapsed, primary
refractory and relapsed/refractory AML patients. I look forward to the final
results of this study and the continued clinical investigation of voreloxin."

Phase 2 Study of Single Agent Voreloxin in Women with Platinum-Resistant
Ovarian Cancer

Updated clinical data from the Phase 2 study of single agent voreloxin in
women with platinum-resistant ovarian cancer were also presented at the ASCO
2009 Annual Meeting. Platinum resistance is defined as progression within six
months of completing platinum-based chemotherapy or progression while on
platinum-based chemotherapy. Patients may have received up to three prior
platinum regimens plus one additional non-platinum cytotoxic regimen.
Approximately a third of the study patients have also failed prior treatment
with Doxil(R).

-- Three dose cohorts of voreloxin have been studied, 48 mg/m2 given
every
three weeks (N=65), 60 mg/m2 given every four weeks (N=37) and 75
mg/m2
given every four weeks (N=35). Enrollment completed in December of
2008.
16 patients in the 60 mg/m2 and 75 mg/m2 cohorts remain on study.
-- Data from this trial show encouraging durable anti-tumor activity
across
all three dose cohorts. The overall response rate (ORR), as measured
by
GOG RECIST criteria, was eleven percent for each of the three dosing
cohorts: two complete responses (CR) and five partial responses (PR)
in
cohort A (48 mg/m2 q3 weeks), two CRs and two PRs in cohort B (60
mg/m2
q4 weeks) and four PRs in cohort C (75 mg/m2 q4 weeks).
-- 74 patients (52 percent) experienced disease control, defined as an
objective response or stable disease for 12 weeks or more.
-- The median progression free survival (PFS) for cohort A was 82 days.
The
preliminary median PFS for cohorts B and C is 84 days and 109 days,
respectively. There was a significant difference in PFS among the 3
dose
cohorts (p = 0.019). PFS was significantly longer in the 60 and 75
mg/m2
cohorts vs. 48 mg/m2, suggesting a benefit to higher voreloxin doses.
-- Four PRs were achieved in the 44 women who were Doxil(R) failures for
an
ORR of nine percent and 28 (64 percent) achieved disease control.
-- The preliminary median PFS in these Doxil(R) failure patients is 90
days. PFS was not statistically different from those who had not
failed
Doxil(R).
-- Overall, the adverse event profile was similar across cohorts and
voreloxin was generally well-tolerated. Grade 3 or higher adverse
events
occurring in more than 10 percent of patients include neutropenia,
febrile neutropenia, and anemia.

-- The incidence of febrile neutropenia was increased in cohort C (75
mg/m2
q4 weeks), and was clinically manageable and within the range of other
commonly used and approved agents in ovarian cancer.

"Voreloxin continues to demonstrate promising clinical activity in a vastly
underserved patient population," said Robert P. Edwards, M.D., Professor of
Obstetrics, Gynecology, and Reproductive Sciences and Vice Chair of the
Division of Gynecologic Oncology at the University of Pittsburgh, and an
investigator for the Phase 2 clinical trial. "I am encouraged by the
preliminary data, including the activity in patients that are resistant or
refractory to both platinum-based chemotherapy and Doxil(R)."

Conference Call Information

Sunesis management, joined by voreloxin clinical investigators, will host a
conference call to discuss the voreloxin clinical data presented at the ASCO
2009 Annual Meeting today, Monday, June 1, 2009, at 1:00 p.m. ET / 10:00 a.m.
PT. Individual and institutional investors can access the call via
1-877-856-1961 (U.S. and Canada) or +1-719-325-4787 (international). To access
the live audio webcast or the subsequent archived recording, visit the
"Investors and Media - Calendar of Events" section of the Sunesis website at
www.sunesis.com. The webcast will be recorded and available for replay on the
company's website until June 15, 2009.

About Voreloxin

Voreloxin is a first-in-class anticancer quinolone derivative, or AQD, a class
of compounds that has not been used previously for the treatment of cancer.
Voreloxin both intercalates DNA and inhibits topoisomerase II, resulting in
replication-dependent, site-selective DNA damage, G2 arrest and apoptosis.
Voreloxin is currently being evaluated in a Phase 2 clinical trial (known as
the REVEAL-1 trial) in previously untreated elderly AML patients and in a
Phase 1b/2 clinical trial combining voreloxin with cytarabine for the
treatment of patients with relapsed/refractory AML, as well as in an ongoing
Phase 2 single agent trial in platinum-resistant ovarian cancer.

About Acute Myeloid Leukemia

AML is a rapidly progressing cancer of the blood characterized by the
uncontrolled proliferation of immature blast cells in the bone marrow. The
Leukemia and Lymphoma Society estimates that over 13,000 new cases of AML were
diagnosed and approximately 9,000 deaths from AML occurred in the U.S. during
2007. AML is generally a disease of older adults, and the median age of a
patient diagnosed with AML is about 67 years. A majority of elderly patients
are not considered candidates for standard induction therapy or decline
therapy, resulting in an acute need for new treatment options.

About Ovarian Cancer

In the United States, ovarian cancer remains the leading cause of death from
gynecologic malignancies and is the fifth leading cause of cancer death
overall in women behind lung, breast, colorectal and pancreatic cancers.
According to the American Cancer Society, in 2008 there were an estimated
21,650 new cases and more than 15,000 deaths from ovarian cancer in the U.S.
alone. Following frontline treatment, recurrence rates among ovarian cancer
patients are high. Treatment options remain limited following relapse, and
overall long-term survival has not changed significantly over the past 40
years, with five-year survival rates at less than 30 percent.

About Sunesis Pharmaceuticals

Sunesis is a biopharmaceutical company focused on the development and
commercialization of new oncology therapeutics for the treatment of solid and
hematologic cancers. Sunesis has built a highly experienced cancer drug
development organization committed to advancing its lead product candidate,
voreloxin, in multiple indications to improve the lives of people with cancer.
For additional information on Sunesis Pharmaceuticals, please visit
http://www.sunesis.com.

This press release contains forward-looking statements, including without
limitation statements related to the potential safety and efficacy and
commercial potential of voreloxin, the efficacy and benefits of voreloxin as
compared to currently available treatments, planned additional clinical
testing and development efforts and the timing of interactions with regulatory
authorities . Words such as "shows," "suggest," "will," "promising,"
"activity," "demonstrated," "encouraged," "preliminary," "continues" and
similar expressions are intended to identify forward-looking statements. These
forward-looking statements are based upon Sunesis' current expectations.
Forward-looking statements involve risks and uncertainties. Sunesis' actual
results and the timing of events could differ materially from those
anticipated in such forward-looking statements as a result of these risks and
uncertainties, which include, without limitation, risks related to Sunesis'
need for additional funding, the risk that Sunesis' drug development
activities could be halted significantly or delayed for various reasons, the
risk that Sunesis' clinical trials for voreloxin may not demonstrate safety or
efficacy or lead to regulatory approval, the risk that preliminary data and
trends may not be predictive of future data or results, the risk that Sunesis'
nonclinical studies and clinical trials may not satisfy the requirements of
the FDA or other regulatory agencies, risks related to the conduct of Sunesis'
clinical trials, including the pace of enrollment, risks related to the
manufacturing of voreloxin and the risk that Sunesis' proprietary rights may
not adequately protect voreloxin. These and other risk factors are discussed
under "Risk Factors" and elsewhere in Sunesis' Annual Report on Form 10-K/A
for the year ended December 31, 2008, its quarterly report on Form 10-Q for
the quarter ended March 31, 2009 and other filings with the Securities and
Exchange Commission. Sunesis expressly disclaims any obligation or undertaking
to release publicly any updates or revisions to any forward-looking statements
contained herein to reflect any change in the company's expectations with
regard thereto or any change in events, conditions or circumstances on which
any such statements are based.

SUNESIS and the logo are trademarks of Sunesis Pharmaceuticals, Inc. All other
trademarks are the property of their respective owners.

Investor Contact: Media Contact:
Sunesis Pharmaceuticals, Inc. Sunesis Pharmaceuticals, Inc.
Eric Bjerkholt Dan Weinseimer
650-266-3717 650-266-3739

SOURCE Sunesis Pharmaceuticals, Inc.

For investors, Eric Bjerkholt, +1-650-266-3717, for media, Dan Weinseimer,
+1-650-266-3739, both of Sunesis Pharmaceuticals, Inc.