ENSPIRIT Trial to Continue as Planned Following Completion of the First of Two Interim Futility Analyses

BOTHELL, WA, USA and VANCOUVER, Canada I August 21, 2014 I OncoGenex Pharmaceuticals, Inc. (NASDAQ: OGXI) announced today that the Phase 3 ENSPIRIT trial, evaluating custirsen in the treatment of non-small cell lung cancer (NSCLC), is continuing as planned per the recommendation of the Independent Data Monitoring Committee (IDMC) based upon completion of the first interim futility analysis.

“While the results of the study remain blinded to OncoGenex and Teva, we are very pleased that ENSPIRIT has passed this important early interim futility analysis,” said Scott Cormack, President and CEO of OncoGenex. “We remain strong in our belief that targeting mechanisms of treatment resistance is a critical path forward in the fight against cancer and we continue to actively pursue this approach through the two ongoing Phase 3 trials of custirsen and the seven Phase 2 trials of apatorsen in four tumor types.”

The Phase 3 ENSPIRIT trial is an international, randomized, open-label trial designed to evaluate a survival benefit for custirsen in the treatment of advanced or metastatic non-small cell lung cancer in 1,100 patients who have progressed after initial chemotherapy treatment. Patients are randomized to receive custirsen plus docetaxel or docetaxel alone. Patient enrollment to ENSPIRIT was initiated by Teva in September 2012. Two interim futility analyses are planned for stopping the trial. The first of these two futility analyses has now been completed which allows for acceleration of further enrollment. A second futility analysis will be conducted later in the trial. The U.S. Food and Drug Administration (FDA) has granted Fast Track designation for the evaluation of custirsen in the ENSPIRIT trial.

Custirsen is also being evaluated in the ongoing Phase 3 AFFINITY trial with second-line chemotherapy in men with metastatic castrate-resistant prostate cancer. The expected timing of AFFINITY results is based on a pre-specified number of death events, however the Company currently expect final results to be announced in late 2015 or early 2016.

About Custirsen

Custirsen is an experimental drug that is designed to block the production of the protein clusterin, which may play a fundamental role in cancer cell survival and treatment resistance. Clusterin is upregulated in tumor cells in response to treatment interventions such as chemotherapy, hormone ablation and radiation therapy and has been found to be overexpressed in a number of cancers, including prostate, lung, breast and bladder. Increased clusterin production has been linked to faster rates of cancer progression, treatment resistance and shorter survival duration. By inhibiting clusterin, custirsen is designed to alter tumor dynamics, slowing tumor growth and resistance to partner treatments, so that the benefits of therapy, including survival, may be extended.

As part of Phase 1 and Phase 2 clinical trials, custirsen was administered to 294 patients with various types of cancer. The majority of adverse events were mild. The most common adverse events associated with custirsen consisted of flu-like symptoms. The most common serious adverse events (SAE) associated with custirsen were febrile neutropenia, fever, pleural effusion, and dyspnea. Each SAE event was observed in approximately 2%-4% of patients. In the Phase 3 SYNERGY trial in men with metastatic CRPC, adverse events observed were similar to custirsen’s known adverse event profile.

About OncoGenex

OncoGenex is a biopharmaceutical company committed to the development and commercialization of new therapies that address treatment resistance in cancer patients. OncoGenex has a diverse oncology pipeline, with each product candidate having a distinct mechanism of action and representing a unique opportunity for cancer drug development. OncoGenex and Teva Pharmaceutical Industries Ltd. (NYSE: TEVA) have entered a global collaboration and licensing agreement to develop and commercialize OncoGenex’ lead drug candidate, custirsen. Custirsen is currently in Phase 3 clinical development as a treatment in men with metastatic castrate-resistant prostate cancer and in patients with advanced, unresectable non-small cell lung cancer. Apatorsen is in Phase 2 clinical development and OGX-225 is currently in pre-clinical development. More information is available at www.OncoGenex.com and at the company’s Twitter account https://twitter.com/OncoGenex_IR.

SOURCE: OncoGenex