(GALE) Abstracts Published, 2015 American Society of Clinical Oncology Announcement

• GALE-301 demonstrates promising preliminary efficacy data with a projected 78% reduction in relative risk of recurrence in the 1000 mcg dose cohort
• Leica Biosystem’s Bond Oracle HER2 Immunohistochemistry (IHC) System distinguishes HER2 1+ and 2+ expressions and supports its use as a companion diagnostic for NeuVax™ (nelipepimut-S)

PORTLAND, Ore., May 27, 2015  — Galena Biopharma, Inc. (Nasdaq:GALE), a biopharmaceutical company developing and commercializing innovative, targeted oncology therapeutics that address major medical needs across the full spectrum of cancer care, today announced two abstract publications at the American Society of Clinical Oncology (ASCO) 2015 Annual Meeting.

“The two abstracts published by ASCO provide meaningful advancements for both of our cancer immunotherapy programs, NeuVax and GALE-301,” said Mark W. Schwartz, Ph.D., President and Chief Executive Officer. “The use of Leica’s Bond Oracle HER2 IHC system ensures we have enrolled the specified HER2 1+/2+ patients for our Phase 3 NeuVax™ PRESENT trial and moves us further down the path of providing targeted, personalized medicine for these women. Meanwhile, the published preliminary data from our GALE-301 program is quite promising as it shows significant reduction of recurrences with our vaccine. We expect to present more mature data at a scientific conference this Fall, and we are currently evaluating the next steps to potentially advance GALE-301 into a randomized late-stage trial to prevent recurrence in ovarian and endometrial cancers.”

GALE-301

GALE-301 (E39) is a cancer immunotherapy targeting folate binding protein receptor-alpha to prevent ovarian and endometrial cancer recurrence in the adjuvant setting. In abstract #e14031, entitled, “Preliminary Results of the Phase I/IIa Dose Finding Trial of a Folate Binding Protein Vaccine (E39+GM-CSF) in Ovarian and Endometrial Cancer Patients to Prevent Recurrence,” data show that GALE-301 is well tolerated and elicits a strong and dose-dependent in vivo immune response. The trial is designed as a safety and dose optimization trial and is not powered for a disease free survival efficacy endpoint. However, early efficacy results from the trial are promising in the 1000 mcg dose cohort. Of the 51 patients enrolled in the trial, 29 were in the vaccinated group (15 patients at 1000 mcg vs. 14 patients at <1000 mcg) and 22 were in the control group. With 9.8 months median follow-up, the 1000 mcg dose group had only one clinical recurrence vs 11 in the vaccine group (6.7% vs. 50% CG, p = 0.01). Combining all dose groups, the complete response (CR) rate was 38% in the vaccine group vs. 50% in the control group (p = 0.41). Currently, the estimate for disease free survival at two years is 85.7% (1000 mcg dose group) vs. 19.2% for the control group (p = 0.09), for a 78% reduction in relative risk of recurrence. The full abstract can be found here.

NeuVax™ (nelipepimut-S) Companion Diagnostic

As part of the Phase 3 PRESENT (Prevention of Recurrence in Early-Stage, Node-Positive Breast Cancer with Low to Intermediate HER2 Expression with NeuVax Treatment) trial, Galena implemented central laboratory testing for all potential patients to confirm validated and robust entry criteria, and to ensure the enrollment of the targeted patient population. To improve accuracy and specificity for the HER2 1+ and 2+ status testing, and develop a companion diagnostic for NeuVax, the Leica Bond Oracle™ HER2 Immunohistochemistry (IHC) system has been incorporated as central HER2 screening for the PRESENT study.

In abstract #e11609, entitled, “Analytical Validation of BOND Oracle HER2 IHC System for Identifying Low to Intermediate HER2 Expressing Breast Cancer in NeuVax PRESENT Phase 3 Clinical Trial,” data demonstrate a direct correlation between cell line receptor load, quantitative measure of HER2 protein, and IHC score. The ability to discriminate HER2 protein expression at the low and intermediate levels in breast cancer tumors will identify patients for new treatments in development such as NeuVax. Specifically, the validation of the Bond Oracle HER2 IHC System to distinguish lower levels of HER2+ expressions supports its use as a companion diagnostic. The full abstract can be found here.

About GALE-301 (Folate Binding Protein)

GALE-301 (Folate Binding Protein (FBP)) is a cancer immunotherapy targeting the prevention of cancer recurrence in the adjuvant setting. GALE-301 targets folate binding protein receptor-alpha, a well-validated therapeutic target, is highly over-expressed in ovarian, endometrial and breast cancers. FBP is the source of immunogenic peptides that can stimulate cytotoxic T lymphocytes (CTLs) to recognize and destroy FBP-expressing cancer cells. GALE-301 consists of the FBP peptide(s) combined with the immune adjuvant, granulocyte macrophage-colony stimulating factor (GM-CSF). Galena has completed enrollment in a Phase 2a trial with GALE-301 in two gynecological cancers: ovarian cancer and endometrial adenocarcinomas (clinicaltrials.gov identifier: NCT01580696).

About Ovarian/Endometrial Cancers

Ovarian cancer occurs in more than 40,000 women per year in the U.S. and is the most lethal gynecologic cancer. Despite the incidence of ovarian cancer being only approximately 20% of that of breast cancer, the number of patients who die from ovarian cancer is nearly 50% of that of breast cancer. Due to the lack of specific symptoms, the majority of ovarian cancer patients are diagnosed at later stages of the disease. These patients have their tumors routinely surgically debulked to minimal residual disease, and then are treated with platinum- and/or taxane-based chemotherapy. While most patients respond to this treatment regimen and become clinically free-of-disease, the majority of these patients will relapse, and once the disease recurs, treatment options are limited and successes of subsequent interventions drop dramatically.

Endometrial cancer is the most common gynecologic cancer and occurs in more than 46,000 women with more than 8,000 deaths in the U.S. annually. There are two basic types of endometrial cancer: endometrioid and papillary serous. The latter has a much more aggressive clinical course and the majority of these patients will die of this form of the disease.

About NeuVax™ (nelipepimut-S)

NeuVax™ (nelipepimut-S) is a first-in-class, HER2-directed cancer immunotherapy under evaluation to prevent breast cancer recurrence after standard of care treatment in the adjuvant setting. It is the immunodominant peptide derived from the extracellular domain of the HER2 protein, a well-established target for therapeutic intervention in breast carcinoma. NeuVax has been shown to bind to HLA-A2 and A3, as well as HLA-A24 and A26 molecules. The nelipepimut-S sequence stimulates specific CD8+ cytotoxic T lymphocytes (CTLs) following binding to specific HLA molecules on antigen presenting cells (APC). These activated specific CTLs recognize, neutralize and destroy, through cell lysis, HER2 expressing cancer cells, including occult cancer cells and micrometastatic foci. The nelipepimut-S immune response can also generate CTLs to other immunogenic peptides through inter- and intra-antigenic epitope spreading.

NeuVax is currently in an international, Phase 3 PRESENT (Prevention of Recurrence in Early-Stage, Node-Positive Breast Cancer with Low to Intermediate HER2 Expression with NeuVax Treatment) study under a Special Protocol Assessment (SPA) granted by the U.S. Food and Drug Administration (FDA). Additional information on the PRESENT trial can be found at www.neuvax.com (clinicaltrials.gov identifier: NCT01479244). Galena has two additional breast cancer studies ongoing with NeuVax in combination with trastuzumab (Herceptin®; Genentech/Roche): a Phase 2b trial in node positive and triple negative HER2 IHC 1+/2+ (clinicaltrials.gov identifier: NCT01570036); and, a Phase 2 trial in neoadjuvantly treated node positive and negative HER2 IHC 3+ patients not achieving a pathological complete response (pCR) or adjuvantly treated node positive HER2 IHC 3+ patients (clinicaltrials.gov identifier: NCT02297698).

About HER2 1+/2+ Breast Cancer

According to the National Cancer Institute, over 230,000 women in the U.S. are diagnosed with breast cancer annually. Of these women, only about 25% are HER2 positive (IHC 3+). NeuVax targets approximately 50%-60% of these women who are HER2 low to intermediate (IHC 1+/2+ or FISH < 2.0) and achieve remission with current standard of care, but have no available HER2-targeted adjuvant treatment options to maintain their disease-free status.

About Leica Biosystems

Leica Biosystems is a global leader in workflow solutions and automation, striving to advance cancer diagnostics to improve patients’ lives. Leica Biosystems provides anatomical pathology laboratories and researchers a comprehensive product range for each step in the pathology process, from sample preparation and staining to imaging and reporting. Leica’s easy-to-use and consistently reliable offerings help improve workflow efficiency and diagnostic confidence. The company is represented in over 100 countries. It has manufacturing facilities in 7 countries, sales and service organizations in 19 countries, and an international network of dealers. The company is headquartered in Nussloch, Germany. Further information can be found at www.LeicaBiosystems.com

About Galena Biopharma

Galena Biopharma, Inc. (Nasdaq:GALE) is a biopharmaceutical company developing and commercializing innovative, targeted oncology therapeutics that address major medical needs across the full spectrum of cancer care. Galena’s development portfolio ranges from mid- to late-stage clinical assets, including a robust immunotherapy program led by NeuVax™ (nelipepimut-S) currently in an international, Phase 3 clinical trial. The Company’s commercial drugs include Abstral® (fentanyl) Sublingual Tablets and Zuplenz® (ondansetron) Oral Soluble Film. Collectively, Galena’s clinical and commercial strategy focuses on identifying and advancing therapeutic opportunities to improve cancer care, from direct treatment of the disease to the reduction of its debilitating side-effects.  For more information, visit www.galenabiopharma.com.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Such statements include, but are not limited to, statements about the progress of the commercialization of Abstral® and development of Galena’s product candidates, including patient enrollment and preliminary results in our clinical trials, as well as statements about our expectations, plans and prospects. These forward-looking statements are subject to a number of risks, uncertainties and assumptions, including those identified under “Risk Factors” in Galena’s Annual Report on Form 10-K for the year ended December 31, 2014 and most recent Quarterly Reports on Form 10-Q filed with the SEC. Actual results may differ materially from those contemplated by these forward-looking statements. Galena does not undertake to update any of these forward-looking statements to reflect a change in its views or events or circumstances that occur after the date of this press release.

Abstral and NeuVax are trademarks of Galena Biopharma, Inc. All other trademarks are the property of their respective owners.

CONTACT: Remy Bernarda
         SVP, Investor Relations & Corporate Communications
         (503) 405-8258
         rbernarda@galenabiopharma.com