ThermaDox Shows Promise in Primary Liver Cancer
Treatment combines heat-activated doxorubicin and RFA
Positive preliminary results have been reported from a retrospective phase III analysis of ThermoDox (Celsion Corp.) in patients with primary hepatocellular carcinoma (HCC).
ThermoDox consists of a liposomal encapsulation of doxorubicin, an approved and frequently used oncology drug. Radiofrequency ablation (RFA) provides localized heat at mild hyperthermia temperatures (greater than 39.5 degrees Celsius), which releases the encapsulated doxorubicin from the liposomes, allowing high concentrations of the drug to be deposited preferentially in and around the targeted tumor.
ThermoDox is being investigated in the ongoing HEAT trial, a pivotal, phase III, double-blind, placebo-controlled study designed to evaluate the therapy’s safety and efficacy in 701 patients with non-resectable HCC. The trial’s primary endpoint is progression free survival (PFS), with a secondary confirmatory endpoint of overall survival (OS).
In January 2013, it was announced that ThermoDox in combination with RFA did not meet the HEAT trial's primary endpoint of PFS. Specifically, investigators determined that the study did not meet the goal of demonstrating persuasive evidence of clinical effectiveness that could form the basis for regulatory approval in the population chosen for the study. The patients were followed to the secondary endpoint, OS.
As of June 30, 2014, the latest quarterly analysis of OS in the HEAT trial demonstrated that the combination of ThermoDox and optimized RFA provided a 57% improvement in this endpoint compared with optimized RFA alone in a subgroup of patients (n = 285; 41% of the study cohort). The hazard ratio at this analysis was 0.639, with a P value of 0.037.
Data from the HEAT study and prior post hoc analyses were presented at several medical conferences over the past year, including the 2014 American Society of Clinical Oncology 50th Annual Meeting in June 2014; the 5th European Conference on Interventional Oncology in April 2014; the International Liver Cancer Association Annual Conference in September 2013; the European Conference on Interventional Oncology in June 2013; and the World Conference on Interventional Oncology in May 2013.
ThermoDox received both “fast track” and “priority review” designations from the FDA. The treatment also was granted “orphan drug” status for patients with HCC. Moreover, in recognition of the need for new treatment options in HCC, the National Cancer Institute recognized the HEAT study as a “priority clinical trial.”