A New Approach for Potential Combined Chelation Therapy Using Mono- and Bis-Hydroxypyridinones

Abstract

Iron (Fe) overload diseases, such as β-thalassemia (thal) major and hemochromatosis, have been treated for several decades by chelating therapy with desferrioxamine (DFO). However, drawbacks associated with that drug led to the development of new chelating drugs. The 3-hydroxy-4-pyridinones emerged as highly effective Fe chelators, and deferiprone (L1) has been approved as a Fe chelating drug. The most recent strategy for Fe overload problems is based on the replacement of monotherapies by a combination therapy with both chelators. Following a similar chelating strategy, we present herein the results of animal tests with a combination of two different hydroxypyridinone-based chelators. Both are of the 3-hydroxy-4-pyridinone (HP) type, but with one and two HP chelating units, and extra functional groups to account for differentiation in their physicochemical and biological properties, namely chelating efficacy and bioavailability. Animal studies have shown that the simultaneous administration of this pair of HP chelators, under appropriate proportion, to metal-loaded mice, could speed up metal excretion. This may be rationalized by adjuvant and eventual synergistic effects, due to complementary accessibility of each chelator to different cellular compartments.

Keywords:

• Combination therapy
• Hydroxypyridinones
• Desferrioxamine (DFO)
• Deferiprone (L1)
• Chelating agents
• Iron (Fe) overload
• Iron chelators

Notes

*Presented at the 16^th International Conference on Chelation, Limassol, Cyprus, October 25–31, 2006.