Data Monitoring Committee Completes Review of 535 Patients in Celsion's Phase III ThermoDox(R) HEAT Study in Primary Liver Cancer

July 11, 2011

COLUMBIA, MD--(Marketwire - 07/11/11) - Celsion Corporation (NASDAQ:CLSN - News), a leading oncology drug development company, today announced that the independent Data Monitoring Committee (DMC) for the Company's multinational, double-blind, placebo-controlled, pivotal Phase III clinical study of ThermoDox® in combination with radio frequency ablation (RFA) for primary liver cancer (the HEAT study), has completed a review of 535 randomized patients and unanimously recommended that the study continue according to protocol. The Company also announced that enrollment in the HEAT study has reached 98% of the 600 patients necessary to ensure that its primary end point, progression free survival, can be achieved with statistical significance.The study's design and statistical plan incorporate a pre-planned interim efficacy analysis by the DMC (after patient enrollment is complete and 190 progression-free survival (PFS) events are realized in the study population) with the intent of evaluating safety, efficacy and futility to determine if there is overwhelming evidence of clinical benefit or a low probability of treatment success to continue, modify or terminate the study. Completion of the interim analysis is expected by the end of the third quarter of 2011."For the vast majority of patients, progression in unresectable primary liver cancer treated using conventional radio frequency ablation therapy occurs within one year, underscoring the urgent need for more effective treatment in first-line care," said Michael H. Tardugno, President and Chief Executive Officer of Celsion. "ThermoDox® is designed to concentrate doxorubicin in the margins surrounding the tumor, activating only in the presence of heat. Our data strongly indicate that the result is an increased treatment area which may extend the cure rate of RFA to larger, more locally advanced tumors. The HEAT study is poised to confirm this potential, with final data read out for the primary outcome measure expected in mid-2012."The DMC for the HEAT study is comprised of an independent group of medical and scientific experts with the responsibility for reviewing and evaluating patient safety and efficacy data from the Company's Phase III HEAT study. The DMC reviews study data at regular intervals with their primary responsibilities to ensure the safety of all patients enrolled in the study, the quality of the data collected, and the continued scientific validity of the study design.About Primary Liver CancerPrimary liver cancer is one of the most deadly forms of cancer and ranks as the fifth most common solid tumor cancer. The incidence of primary liver cancer is approximately 20,000 cases per year in the United States, approximately 40,000 cases per year in Europe and is rapidly growing worldwide at approximately 700,000 cases per year, due to the high prevalence of Hepatitis B and C in developing countries. The standard first-line treatment for liver cancer is surgical resection of the tumor; however, 90% of patients are ineligible for surgery. Radio frequency ablation (RFA) has increasingly become the standard of care for non-resectable liver tumors, but the treatment becomes less effective for larger tumors. There are few non-surgical therapeutic treatment options available as radiation therapy and chemotherapy are largely ineffective in the treatment of primary liver cancer.About ThermoDox® and the Phase III HEAT StudyThermoDox® is a proprietary heat-activated liposomal encapsulation of doxorubicin, an approved and frequently used oncology drug for the treatment of a wide range of cancers. In the HEAT Study, ThermoDox® is administered intravenously in combination with RFA. Localized mild hyperthermia (39.5 - 42 degrees Celsius) created by the RFA releases the entrapped doxorubicin from the liposome. This delivery technology enables high concentrations of doxorubicin to be deposited preferentially in a targeted tumor.For primary liver cancer, ThermoDox® is being evaluated in a 600 patient global Phase III study under an FDA Special Protocol Assessment. The study is designed to evaluate the efficacy of ThermoDox® in combination with Radio Frequency Ablation (RFA) when compared to patients who receive RFA alone as the control. The primary endpoint for the study is progression-free survival (PFS) with a secondary confirmatory endpoint of overall survival. A pre-planned, unblinded interim efficacy analysis will be performed by the independent Data Monitoring Committee when enrollment in the HEAT Study is complete and 190 PFS events are realized in the study population. Additional information on the Company's ThermoDox® clinical studies may be found at www.clinicaltrials.gov.About Celsion CorporationCelsion is a leading oncology company dedicated to the development and commercialization of innovative cancer drugs including tumor-targeting treatments using focused heat energy in combination with heat-activated drug delivery systems. Celsion has research, license, or commercialization agreements with leading institutions such as the National Institutes of Health, Duke University Medical Center, University of Hong Kong, the University of Pisa, and the North Shore Long Island Jewish Health System.For more information on Celsion, visit our website: http://www.celsion.com.Celsion wishes to inform readers that forward-looking statements in this release are made pursuant to the "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995. Readers are cautioned that such forward-looking statements involve risks and uncertainties including, without limitation, unforeseen changes in the course of research and development activities and in clinical trials by others; possible acquisitions of other technologies, assets or businesses; possible actions by customers, suppliers, competitors, regulatory authorities; and other risks detailed from time to time in the Company's periodic reports filed with the Securities and Exchange Commission.