CVac Shows Clear Trend for Overall Survival Benefit in Second Remission Ovarian Cancer in Phase II Study

SYDNEY, AUSTRALIA--(May 19, 2015) - Prima BioMed Ltd (ASX: PRR) (NASDAQ: PBMD)

• Final Data from the CAN-003 Phase II trial after 5 years of data collection
• Final Overall Survival data provided at least 16 months benefit for second remission ovarian cancer patients ("second remission patients") using CVac™  
• Follows Progression Free Survival data showing 8 month benefit for second remission patients

Prima BioMed Ltd (ASX: PRR) (NASDAQ: PBMD) ("Prima" or the "Company") is pleased to announce that the final CVac data from the Phase II CAN-003 ovarian cancer clinical trial has shown a trend for a clinically meaningful improvement in Overall Survival ("OS") over standard of care ("SOC") in second remission patients.

In the group of second remission patients (n=20), the median for standard of care ("SOC") patients was 25.53 months, which is consistent with current literature. By comparison, for patients treated with CVac a median has still not yet been reached after 42 months with study completion and closure. This suggests a striking improvement with a hazard ratio¹ = 0.17 (95%CI: 0.02, 1.44; p=0.07). This implies at least a 16 months median survival advantage for second remission patients when treated with CVac.

Lucy Turnbull, Chairman of Prima BioMed, commented: "This final clinical data for CVac is most encouraging for cancer patients in second remission. We sincerely thank all patients and medical staff who have participated in the trial over the last five years. Our concerted focus will now be to find a development partner to make CVac widely available to cancer sufferers around the world."

This data is consistent with the statistically significant Progression Free Survival ("PFS") data for second remission patients from CAN-003 announced in May 2014 with a median PFS for CVac of greater than 12.91 months, compared to a median PFS of 4.94 months for the control group (hazard ratio=0.32; p=0.04). This implies an eight month median PFS advantage for second remission patients treated with CVac.

For first remission patients, the final CAN-003 data suggests a positive trend in favour of CVac patients with no median reached in either the CVac or SOC group (current hazard ratio= 0.65 (95%CI: 0.17, 2.42); p=0.52).

Marc Voigt, Prima's Chief Executive Officer, said: "The CAN-003 data has shown a consistent and sustained trend for improvement over the years in Progression Free Survival and also Overall Survival. The positive effect of cellular therapies and the high quality of life of treated patients support the potential for further developing CVac under license through an industry partner."

About the CAN-003 clinical trial

CAN-003² is a 63-patient phase 2 study evaluating the effects of CVac, as compared to an observational standard of care arm (SOC), in epithelial ovarian cancer patients in complete remission after first or second line treatment. In accordance with the protocol design, the first seven patients on the trial were all assigned to receive CVac in order to test the comparability of product manufacturing in a new facility.

The subsequent 56 patients were randomized 1:1 to either the CVac group or observational standard of care (SOC) and included in the intent-to-treat analysis. 36 patients were in first remission (19 patients were assigned to CVac and 17 to SOC) and 20 patients were in second remission (10 patients were each assigned to CVac or SOC). Final PFS data was analysed after thorough quality control reviews of investigator-evaluated progression and appropriate censoring of data from patients who had not progressed during the study.

The primary objectives of the trial were to determine the safety of CVac administration and to determine CVac's effect on progression-free survival. Secondary objectives of the trial were to determine CVac's effect on overall survival and to evaluate host immunologic responses to CVac.

¹ The ratio of survival in one group as compared with survival in another. A hazard ratio of 0.17 means that the risk of death at a specific timepoint is reduced by 83% for patients receiving CVac compared to those receiving SOC.

² See NCT01068509 at www.clinicaltrials.gov.

About CVac^™

CVac, an autologous cancer vaccine in which a patient's dendritic cells are primed ex vivo with a mannan+MUC1 fusion protein, was Prima BioMed's original lead product between 2001 and 2015. Prima BioMed announced in February 2015 that it had ceased recruiting into outstanding CVac clinical trials. The company is currently seeking partnership arrangements for further development.

About Prima BioMed

Prima BioMed is a globally active biotechnology company that is striving to become a leader in the development of immunotherapeutic products for the treatment of cancer. Prima BioMed is dedicated to leveraging its technology and expertise to bring innovative treatment options to market for patients and to maximize value to shareholders.

Prima's pipeline of products includes IMP321 based on the LAG-3 immune control mechanism which plays a vital role in the regulation of the T cell immune response. IMP321 is its most clinically advanced product, a T cell immunostimulatory factor (APC activator) for cancer chemoimmunotherapy which has completed early Phase II trials. A number of additional LAG-3 products including antibodies for immune response modulation in autoimmunity and cancer are being developed by large pharmaceutical partners.

Prima BioMed is listed on the Australian stock exchange, on the NASDAQ in the US. For further information please visit www.primabiomed.com.au

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