Fennec Pharmaceuticals Ord Shs T.FRX

ADHEREX REPORTS

[IBTryinIt]

FIRST PATIENT ENROLLED IN PHASE 2 STUDY OF

ENILURACIL IN METASTATIC BREAST CANCER

Research Triangle Park, NC, April 27, 2011 - Adherex Technologies Inc. (TSX:AHX, Pink

ShADHEREX REPORTS eets: ADHXF), a biopharmaceutical company focused on the development of eniluracil and 5-

fluorouracil today announced the enrollment of the first patient in the Phase 2 clinical trial for

Metastatic Breast Cancer comparing the oral regiment of Eniluracil + 5-Fluorouracil (5-FU) and

Leucovorin versus Capecitabine (Xeloda®).

The comparative study intends to enroll 140 patients at approximately 20 clinical sites in the United

States and Russia in the next 12 to 14 months. It plans to enroll 80 patients in the eniluracil/5-

FU/leucovorin arm and 60 in the capecitabine arm. All agents are administered orally as tablets.

Eligible patients have been previously treated with an anthracycline and a taxane during

neoadjuvant, adjuvant, or first-line therapy for metastatic disease. Patients, who have disease

progression while being treated with capecitabine, may be eligible to crossover to receive

eniluracil/5-FU/leucovorin treatment.

"The goal of the trial is to show superior antitumor activity and tolerability for eniluracil/5-

FU/leucovorin," said Tom Spector, PhD, Chief Scientific Officer of Adherex and principal inventor

of the treatment. "After many years of clinical research, we now believe that we have the optimal

doses and schedule to achieve these goals."

The primary endpoint of the trial is progression-free survival. The secondary endpoints include the

overall toxicity (including hand-foot syndrome), antitumor response rate, disease control rate,

duration of response, and time-to-treatment response. Patients receiving eniluracil (40 mg)/5-FU

(30 mg/m2)/leucovorin (30 mg) are treated once per week for three consecutive weeks per month.

Patients receiving capecitabine are treated with 1000 mg/m2 every 12 hours for 14 days every three

weeks.

"It is an absolute privilege to be a part of this international study," said Dr. Edgardo Rivera,

Medical Director for Banner MD Anderson Cancer Center and Principal Investigator for the study,

"I look forward to how this may impact the future treatment of Metastatic Breast Cancer."

About Eniluracil/5-FU/leucovorin

Eniluracil is a mechanism-based inactivator of DPD, the enzyme that rapidly breaks down 5-FU.

Accordingly, eniluracil increases the 5-FU elimination half-life from about 15 minutes to 5 hours

and enables 5-FU to be administered orally, making it 100% orally bioavailable. In addition,

eniluracil prevents the formation of α-fluoro-β-alanine (F-Bal), the 5-FU-breakdown product. F-Bal

appears to cause hand-foot syndrome, neurotoxicity, and also decreases the antitumor activity of

5-FU in laboratory animals. Furthermore, because DPD is present in variable levels, the highly

variable and nonlinear pharmacokinetics of 5-FU become predictable and linear when DPD is

inactivated by eniluracil in cancer patients.

The weekly regimen used in the current Phase 2 trial is based on a Phase 1 eniluracil/5-

FU/leucovorin trial that produced durable tumor responses and no hand-foot syndrome in advanced

colorectal cancer patients who were refractory to intravenous 5-FU/leucovorin. In a similar Phase 2

study with capecitabine, no tumor responses occurred and 87% of the patients experienced handfoot

syndrome, a painful condition that may require dosing interruptions and dose reductions. The

eniluracil/5-FU/leucovorin regimen for metastatic breast cancer uses two modifications of the Phase

1 regimen. The eniluracil dose is increased to 40 mg to minimize neurotoxicity and is administered

the night before 5-FU to prevent high eniluracil:5-FU ratios that interfere with the antitumor

activity.

About Metastatic Breast Cancer

Breast cancer is the second leading cause of cancer related death among women, according to the

National Cancer Institute. In 2010, NCI estimated that 207,090 women were diagnosed with breast

cancer, while 39,840 women likely died from the disease. FDA-approved therapies used to treat

late-stage, refractory breast cancer include Xeloda (capecitabine) for patients with breast cancer

resistant to paclitaxel and anthracycline-containing chemotherapy; Ixempra (ixabepilone) for

patients with late-stage disease after failure of an anthracycline, taxane and Xeloda; Ixempra plus

Xeloda for patients with late-stage disease after failure of anthracycline- and taxane-based

chemotherapy; Halaven (eribulin mesylate) for patients with metastatic breast cancer who have

received at least two prior chemotherapy regimens for late-stage disease.

Except for historical information described in this press release, all other statements are forwardlooking.

Forward-looking statements are subject to certain risks and uncertainties inherent in the

Company's business that could cause actual results to vary, including such risks that regulatory

clinical and guideline developments may change, scientific data may not be sufficient to meet

regulatory standards or receipt of required regulatory clearances or approvals, clinical results may

not be replicated in actual patient settings, protection offered by the Company's patents and patent

applications may be challenged, invalidated or circumvented by its competitors, the available

market for the Company's products will not be as large as expected, the Company's products will

not be able to penetrate one or more targeted markets, revenues will not be sufficient to fund further

development and clinical studies, the Company may not meet its future capital needs, and its ability

to obtain additional funding, as well as uncertainties relative to varying product formulations and a

multitude of diverse regulatory and marketing requirements in different countries and

municipalities, and other risks detailed from time to time in the Company's filings with the

Securities and Exchange Commission including its Annual Report on Form 10-K for the year ended

December 31, 2010. Adherex Technologies, Inc. disclaims any obligation to update these forwardlooking

statements except as required by law.

For a more detailed discussion of related risk factors, please refer to our public filings available at

www.sec.gov and www.sedar.com.

For further information, please contact:

Rosty Raykov

Chief Executive Officer

Adherex Technologies Inc.

T: [phone]