Chemoembolisation of Hepatocellular Carcinomas Not Subject to Interventive Care by Idarubicin-loaded Beads - IDASPHERE II

Overview

The most frequently used products in CHE are doxorubicin (36%), cisplatin (31%), and epirubicin (12%). But until recently, there were no obvious reasons to use one product over another. In fact, systemic chemotherapy is considered ineffective in HCC \[hepatocellular carcinoma\], which does not allow any argument in favour of the product. Moreover, 2 randomised trials comparing the molecules (doxorubicin vs. epirubicin) proved to be negative in terms of survival. Cytotoxicity of different anticancer agents on HCC cell lines have been compared in order to select the best candidate for CHE. Eleven chemotherapy molecules have been tested, including those more frequently used in CHE. Among them, idarubicin (an anthracycline) proved to be the most effective in vitro by far. The superiority of idarubicin (as opposed to doxorubicin) was noted especially on the SNU-449 line, which is known for its resistance to several chemotherapy agents. The best cytotoxicity of idarubicin can be explained by 2 mechanisms: 1) idarubicin has a better intracellular penetration than the other anthracyclines. This is probably due to its more considerable lipophily, facilitating thus its passage through the membrane made up of a double lipid layer, 2) idarubicin is resistant to the multidrug resistance system (MDR). The MDR mechanism, which is often noted in HCC, consists of membrane pumps transporting the molecule outside the cell. These two particularities could explain a more significant accumulation of idarubicin in the HCC cells, and thus better efficacy. It is interesting to note that orally administered idarubicin (5 mg/day for 21 days) has proved to be less toxic and is effective in HCC. Currently, idarubicin is used to treat leukaemia. Its toxicity profile (especially, haematological and cardiac) is known. On these grounds, A pilot study has been conducted in order to assess the tolerance and efficacy of lipiodol-based CHE using a 10 mg dose of idarubicin in 21 patients with unresectable HCC. These preliminary data reveal that CHE with idarubicin is effective and less toxic. Idarubicin can be loaded in microbeads. A phase I study (IDASPHERE) has been conducted on DC Beads® microbeads (300-500µm) loaded with idarubicin (dose increased from 5 to 25 mg). The DLT \[dose-limiting toxicity\] and MTD \[maximum tolerated dose\] have been determined in 21 patients using a CRM. The MTD of idarubicin was assessed at 10 mg. In our study, the idarubicin-loaded beads did not give rise to any specific toxicity-related problem. The 10 mg dose is compatible with the known toxicity profile of idarubicin: cumulative cardiotoxicity of doxorubicin is noted from 550 mg/m², whereas that of idarubicin is noted from 93 mg/m². There is thus a 5.9:1 ratio between their cumulative toxicities. The most frequently used dose (and also the weakest one) for the doxorubicin-based CHE is 50 mg. The equivalent of the idarubicin dose would thus be: 50 mg (doxorubicin) / 5.9 (doxorubicin/idarubicin ratio) = approx. 10 mg of idarubicin. It has been already demonstrated that hepatic extraction of idarubicin is better than those of doxorubicin and daunorubicin in an animal sarcoma model. In this study, AUC 0-48h and AUC 0-72h were 1.35 times higher with idarubicin, proving that its intra-hepatic penetration was 35% higher. The randomised phase II PRECISION V study compared conventional CHE (cCHE) with CHE by doxorubicin beads (DC Bead®) in patients with HCC. It is currently the largest randomised trial on CHE published. The PRECISION V data can be thus used to compare the other studies in terms of efficacy and tolerance. To continue our preliminary study and the phase I IDASPHERE study, investigators wish to assess thus the efficacy and confirm the tolerance of idarubicin-loaded beads for the CHE of HCC according to a protocol similar to PRECISION V, as part of a single-arm phase II study.