Deferitazole magnesium

Liver biopsy was long considered the reference standard for measuring liver iron concentration. However, its high sampling variability and invasive nature make it poorly suited for serial analyses. To demonstrate the fallibility of liver biopsy, we use serial estimates of iron chelation efficiency (ICE) calculated by R2 and R2* MRI liver iron concentration (LIC) estimates as well as by simulated liver biopsy (over all physically reasonable sampling variability) to compare the robustness of these three techniques.

R2, R2*, transfusional volume, and chelator compliance were obtained from 49 participants in a phase II clinical trial of deferitazole over two years. Liver biopsy LIC results were simulated using sampling errors of 0%, 10%, 20%, 30%, 40% and iron assay variability of 12%. LIC estimates by R2, R2*, and simulated biopsy were used to calculate ICE over time. Bland-Altman limits of agreement were compared across observation intervals of 12, 24, and 48 weeks.

At 48 week intervals, LIC estimates by R2, R2* and "perfect" liver biopsy had comparable accuracy in predicting ICE; both MRI methods were superior to any physically realizable liver biopsy (sampling error 10% or higher). LIC by R2* demonstrated the most robust ICE estimates at monitoring intervals of 24 and 12 weeks, but this difference did not remain significant at 48 week intervals.

MRI relaxometry is superior to liver biopsy for serial LIC observations, such as used in the care of tranfusional siderosis patients, and should also be considered the new standard of LIC determination for regulatory purposes. Among relaxometry techniques, LIC estimates by R2* are more robust for tracking changes in iron balance over intermediate time scales (<=24 weeks).

Reducing the transmission of the malarial parasite by Anopheles mosquitoes using drugs or vaccines remains a main focus in the efforts to control malaria. Iron chelators have been studied as potential antimalarial drugs due to their activities against different stages of the parasite. The iron chelator FBS0701 affects the development of Plasmodium falciparum early gametocytes and lowers blood-stage parasitemia. Here, we tested the effect of FBS0701 on stage V gametocyte infectivity for mosquitoes. The incubation of stage V gametocytes for up to 3 days with increasing concentrations of FBS0701 resulted in a significant dose-related reduction in mosquito infectivity, as measured by the numbers of oocysts per mosquito. The reduction in mosquito infectivity was due to the inhibition of male and female gametocyte activation. The preincubation of FBS0701 with ferric chloride restored gametocyte infectivity, showing that the inhibitory effect of FBS0701 was quenched by iron. Deferoxamine, another iron chelator, also reduced gametocyte infectivity but to a lesser extent. Finally, the simultaneous administration of drug and gametocytes to mosquitoes without previous incubation did not significantly reduce the numbers of oocysts. These results show the importance of gametocyte iron metabolism as a potential target for new transmission-blocking strategies.