AcelRx Top-line Data Show Primary Endpoint Achieved in Pivotal Phase 3 Study of Sufentanil NanoTab PCA System For Post-Operative

 AcelRx Top-line Data Show Primary Endpoint Achieved in Pivotal Phase 3 Study
    of Sufentanil NanoTab PCA System For Post-Operative Pain in Major Open
                          Abdominal Surgery Patients

- Patients experienced significantly greater reduction in pain as measured by
SPID-48 vs. placebo (p=0.001) -

- Adverse events in sufentanil-treated patients similar to placebo -

- AcelRx to conduct conference call and webcast tomorrow, March 5, at 8:30
a.m. EST (5:30 a.m. PST) to discuss top-line results -

PR Newswire

REDWOOD CITY, Calif., March 4, 2013

REDWOOD CITY, Calif., March 4, 2013 /PRNewswire/ --AcelRx Pharmaceuticals,
Inc. (Nasdaq: ACRX), a specialty pharmaceutical company focused on the
development and commercialization of innovative therapies for the treatment of
acute and breakthrough pain, today announced top-line data results
demonstrating that the first of two pivotal placebo-controlled Phase 3 studies
for its investigational sublingual Sufentanil NanoTab PCA (patient-controlled
analgesia) System met its primary endpoint. Adverse events reported in the
study were generally mild or moderate in nature and similar in both placebo
and treatment groups.


The primary endpoint evaluated pain intensity over the 48-hour study period
compared to baseline, or Summed Pain Intensity Difference (SPID-48), in
patients following major open abdominal surgery. Results demonstrated that
patients receiving sufentanil NanoTabs realized a significantly greater
SPID-48 during the study period than placebo-treated patients (p=0.001).
Secondary endpoint data also showed that 24 hours and 72 hours after first
dose, SPID was significantly greater in the sufentanil-treated patients than
in the placebo-treated patients (p<0.001 and p=0.004 respectively).

"These favorable results enable AcelRx to continue moving forward towards
submission of a New Drug Application (NDA) for the Sufentanil NanoTab PCA
System in the third quarter of this year," said Richard King, president and
CEO of AcelRx. "In the weeks ahead, our team will work with the FDA to
complete a pre-NDA meeting in support of this goal."

Phase 3 Study Results
Utilizing a randomized, double-blind, placebo-controlled design, this pivotal
Phase 3 study enrolled 178 adult patients at 13 U.S. sites for the treatment
of acute post-operative pain immediately following major abdominal surgery.
Patients were treated for post-operative pain for a minimum of 48 hours, and
up to 72 hours. Patients were randomized 2:1, with 119 patients randomized to
sufentanil and 59 to placebo treatment. Both treatments were delivered by the
patient, as needed, using the NanoTab System with a 20-minute lock-out
period. Patients in both groups could receive up to 2 mg morphine
intravenously per hour as a rescue medication, the primary purpose of this
rescue medication being to provide placebo-treated patients access to pain
medication to enable them to stay in the study as long as possible.
Pre-rescue pain scores were imputed to minimize the impact of this rescue
opioid on efficacy evaluations.

Eighty, or 70.2% of the sufentanil NanoTab-treated patients completed the
48-hour study period, compared to 30 (51.7%) placebo-treated patients.
Reasons for drop-out in the sufentanil- and placebo-treated groups were
adverse events (5.3% and 6.9% respectively), lack of efficacy (16.7% and 31.0%
respectively) and other (7.9% and 10.3% respectively). The primary endpoint
measure, SPID-48, was 105.6 for sufentanil-treated patients and 55.6 for
placebo-treated patients (p=0.001).

Treatment-emergent adverse events occurred in 64.0% of sufentanil-treated
patients and 67.2% of placebo-treated patients. Adverse events with an
occurrence greater than 5% in either the sufentanil group or the placebo group
were nausea (30.7% and 41.4% respectively), fever (14.9% and 8.6%
respectively), vomiting (8.8% and 6.9% respectively), itching (8.8% and 0.0%
respectively), oxygen saturation decrease (6.1% and 1.7% respectively), and
hypertension (2.6% and 5.2% respectively). Itching, a frequently observed
side effect of opioids, was the only adverse event that was significantly
different between the groups (p=0.017). All reported casesof itching in the
study were mild in nature. Only one patient (in the sufentanil group)
experienced a serious adverse event, which was determined to be unrelated to
the study drug by the investigator.

"These efficacy and safety results underscore the impact of the Sufentanil
NanoTab PCA System by potentially providing medical professionals a
non-invasive method to help relieve moderate-to-severe post-operative pain in
patients undergoing major surgical procedures, such as open abdominal
surgery," commented Pamela Palmer M.D., Ph.D., chief medical officer and
AcelRx co-founder. "We look forward to completing the full analysis of these
data and working with the FDA on the NDA for this important post-operative
pain advancement."

"The positive results to date for this, non-invasive approach for the
management of moderate-to-severe post-operative pain are intriguing and I look
forward to the complete study results for the entirety of this Phase 3
program," stated study investigator Dr. Tong-Joo Gan, Vice-Chair of the
Department of Anesthesiology at Duke University School of Medicine, Durham,

One additional pivotal Phase 3 double-blind, placebo-controlled study of the
Sufentanil NanoTab PCA System is underway. The study began in August 2012,
and is designed to enroll approximately 400 patients in a 3:1 randomization
following hip or knee replacement surgery at up to 35 sites. The primary
endpoint, SPID-48, is identical to the primary endpoint for the abdominal
surgery trial. We expect top-line results for this trial to be available in
the second quarter of 2013. Additional information can be found by visiting and using the identifier NCT01660763. 

About Post-Operative Pain

Acute pain management in the hospital, in particular post-operative analgesia,
remains a challenge for healthcare providers with up to 75% of patients
reporting inadequate pain relief following surgery. Inadequate treatment of
post-surgical pain can lead to decreased mobility, which increases the risks
for serious medical complications, including deep vein thrombosis and partial
lung collapse, potentially resulting in extended hospital stays. More than 30
million surgical procedures per year result in moderate to severe pain in the
U.S. and EU, with an additional 27 million procedures occurring in countries
with moderate to high per capita healthcare expenditures. The U.S., 5 main EU
countries and Japan represented $5.1 billion of acute pain treatment product
sales in 2008. Currently patients experiencing post-operative pain in the
hospital may have IV PCA treatment, typically utilizing morphine or
hydromorphone. However, there are deficiencies associated with the current
use of IV PCA that can negatively impact patient safety, well-being and
recovery. These include drug-related side effects associated with morphine or
hydromorphone, complications associated with IV delivery, and medication
delivery errors typically associated with misprogramming of the complex IV PCA

About the Sufentanil NanoTab PCA System
The NanoTab System is an investigational pre-programmed, non-invasive,
handheld system that allows post-operative patients to self-dose with
sublingual Sufentanil NanoTabs to manage their post-operative pain. The
NanoTab System is designed to address the limitations of IV PCA by offering:

  oA high therapeutic index opioid: The NanoTab System uses the high
    therapeutic index opioid sufentanil; it offers post-operative pain
    patients the potential for effective patient-controlled analgesia with a
    low incidence of drug-related side effects.
  oA non-invasive route of delivery of analgesia: The sublingual route of
    delivery used by the NanoTab System provides rapid onset of analgesia,
    therefore eliminating the risk of IV-related analgesic gaps and IV
    complications, such as catheter-related infections, associated with IV PCA
    delivery. In addition, because patients are not tethered to IV tubing and
    a pump for pain relief, the NanoTab System allows for ease of patient
  oA simple, pre-programmed PCA solution: The NanoTab System is
    pre-programmed, and thereby eliminates the risk of pump programming errors
    by healthcare providers.

Conference Call
AcelRx will conduct a conference call and webcast tomorrow morning, March 5,
2013, at 8:30 a.m. Eastern time (5:30 a.m. Pacific time) to discuss the Phase
3 top-line results. To listen to the conference call, dial in approximately
ten minutes before the scheduled call to (800) 860-2442 for domestic callers,
(866) 605-3852 for Canadian callers, or (412) 858-4600 for international
callers. Those interested in listening to the conference call live via the
Internet may do so by visiting the Investor Relations section of the company's
website at

About AcelRx Pharmaceuticals, Inc.
AcelRx Pharmaceuticals, Inc. is a specialty pharmaceutical company focused on
the development and commercialization of innovative therapies for the
treatment of acute and breakthrough pain. AcelRx's lead product candidate,
the ARX-01 Sufentanil NanoTab PCA System, is designed to solve the problems
associated with post-operative intravenous patient-controlled analgesia which
has been shown to cause harm to patients following surgery because of the side
effects of morphine, the invasive IV route of delivery and the complexity of
infusion pumps. ARX-01 has successfully completed two of its three planned
Phase 3 clinical trials and a New Drug Application submission is planned for
the third quarter of 2013. AcelRx recently completed enrollment in a Phase 2
study for ARX-04, a sufentanil formulation for the treatment of
moderate-to-severe acute pain, funded through a grant from U.S. Army Medical
Research and Materiel Command, and top-line results are expected in the second
quarter of 2013. The company has two additional pain treatment product
candidates, ARX-02 and ARX-03, which have completed Phase 2 clinical
development. For additional information about AcelRx's clinical programs
please visit

Forward Looking Statements
This press release contains forward-looking statements, including, but not
limited to, statements related to the process and timing of anticipated future
clinical development of AcelRx Pharmaceuticals' product candidates, including
the release of sufentanil NanoTab PCA System top-line clinical trial data, the
release and anticipated timing of additional NanoTab System clinical trial
data, the potential submission of an NDA for NanoTab System and the timing
thereof, therapeutic and commercial potential of NanoTab System and the
anticipated timing and therapeutic and commercial potential of other AcelRx
Pharmaceuticals' product candidates. These forward-looking statements are
based on AcelRx Pharmaceuticals' current expectations and inherently involve
significant risks and uncertainties. AcelRx Pharmaceuticals' 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: the ability of AcelRx
Pharmaceuticals to successfully complete the clinical trials for the
sufentanil NanoTab System, that fact that subsequent analyses of the top-line
data may lead to different (including less favorable) interpretations of the
results than the analyses conducted to date or may identify important
implications of the study that are not reflected in these statements, or be
subject to differing interpretations by the regulatory agencies; the success,
cost and timing of all product development activities and clinical trials; the
uncertain clinical development process, including the risk that clinical
trials, have an effective design, enroll a sufficient number of patients, or
be completed on schedule, if at all; any delays or inability to obtain and
maintain regulatory approval of its product candidates in the United States
and Europe; its ability to obtain adequate clinical supplies of the drug and
device components of its product candidates; its ability to attract funding
partners or collaborators with development, regulatory and commercialization
expertise; its ability to obtain sufficient financing to complete registration
of its product candidates in the United States and Europe; the market
potential for its product candidates; the accuracy of AcelRx Pharmaceuticals'
estimates regarding expenses, capital requirements and needs for financing;
and other risks detailed in the "Risk Factors" and elsewhere in AcelRx
Pharmaceuticals' U.S. Securities and Exchange Commission filings and reports,
including its Current Report on Form 8-K filed with the SEC on December 7,
2012. AcelRx Pharmaceuticals undertakes no duty or obligation to update any
forward-looking statements contained in this release as a result of new
information, future events or changes in its expectations.

SOURCE AcelRx Pharmaceuticals, Inc.

Contact: Jim Welch, Chief Financial Officer, AcelRx Pharmaceuticals, Inc.,
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