Therapeutic mechanism of combined oral chelation therapy to maximize efficacy of iron removal in transfusion-dependent thalassemia major - a pilot study.

OBJECTIVES: Three iron chelators are used to treat transfusion-dependent beta-thalassemia: desferrioxamine (DFO), deferasirox (DFX), and deferiprone (DFP). Compliance is low for DFO as it cannot be administered orally. Combined administration of DFP and DFX is orally available, however, the therapeutic mechanism is unknown. This pilot study investigated the iron removal mechanisms of DFX and DFP treatment in patients with transfusion-dependent thalassemia major. METHODS: Each patient received three treatments sequentially: (1) DFX monotherapy, (2) DFP monotherapy, and (3) DFX/DFP combination therapy with a four-day washout period between each treatment. Urine and stool specimens were collected to determine the primary outcome of iron excretion volumes. RESULTS: The mean iron excretion was seven times higher after combination therapy with DFX and DFP. Monotherapies also increased excretions volumes, though to a significantly lesser degree. Combined administration of DFX and DFP achieves maximum iron removal in transfusion-dependent thalassemia major compared to monotherapy with either drug. CONCLUSIONS: We suggest combination therapy in chronic severe iron overload cases, especially for patients in poor compliance with DFO/DFP combination therapy or those exhibiting poor iron removal from DFX or DFP monotherapy.

MJ-66 induces malignant glioma cells G2/M phase arrest and mitotic catastrophe through regulation of cyclin B1/Cdk1 complex.

Malignant gliomas are among the most devastating cancers as they are resistant to many kinds of treatment. Despite recent advances in the diagnosis and treatment, the prognosis of patients remains very poor and the development of new drug is urgently needed. Here, we report that a synthetic quinazolinone analog 2-(naphthalene-1-yl)-6-pyrrolidinyl-4-quinazolinone (MJ-66) induced glioma cell death. Immunofluorescence staining showed that MJ-66-induced cell death was associated with multinucleated phenotype and multipolar spindles that were typical characteristics of mitotic catastrophe. Flow cytometry analysis revealed that MJ-66 caused glioma cell cycle arrest at G2/M phase and increased the proportion of polyploidy cells. Western blotting indicated that the expression of cyclin B1, Cdk1 pY15 and Cdk1 increased after treatment with MJ-66. MJ-66 effectively inhibited tumor growth and induced apoptosis in the xenograft animal model of U87 human glioma cells. Together, these results suggest that MJ-66 inhibited malignant gliomas growth through inducing mitotic catastrophe by interference with G2/M cell cycle checkpoint which may open a new avenue for the treatment of malignant gliomas.

Combined versus monotherapy or concurrent therapy for treatment of thalassaemia.

A combined deferasirox (DFX) and deferiprone (DFP) treatment protocol for relieving thalassemia patients' iron-overload was designed and the pharmacokinetic study was performed by LC-MS/MS. For this open-label, randomized trial, eight patients were recruited and randomly allocated to different treatment regimens: (A) monotherapy with single oral dose of DFX 30 mg/kg, (B) monotherapy with DFP 80 mg/kg/day, twice daily, (C) combined therapy with DFX and DFP (DFX 30 mg/kg for first dose, DFP 40 mg/kg 7 hours later, and DFP 40 mg/kg after another 7 h) and (D) concurrent therapy with DFX 30 mg/kg and DFP 80 mg/kg. Descriptive statistics evaluated pharmacokinetic parameters, AUC0-t, AUC0-inf, Cmax, Tmax, T1/2 and MRT. A positive pharmacokinetic drug interaction was observed in combined therapy. In case of DFX, combined therapy tallied about 2-fold larger than monotherapy in AUC, 1.5-fold larger in Cmax, 1 h longer in Tmax, but 1 h shorter in T1/2. Regarding DFP, most such parameters of combined therapy concurred with monotherapy. Conversely, negative drug interaction was observed in concurrent therapy. With DFX, concurrent therapy attained 1.2- to 2.2-fold lower than monotherapy in AUC0-t and Cmax, 0.6-h shorter in Tmax, and 3-fold longer in T1/2. With DFP, concurrent therapy proved approximately 2-fold larger than monotherapy in AUC and Cmax, 2.5-fold longer in T1/2, and 1.4-fold longer in MRT. Follow-up of subjects' clinical examinations and subjective symptoms showed no adverse events. Our findings showed the combined therapy had advantages, safe, convenient and painless for patients, over the existing concurrent therapy with deferoxamine (DFO) and DFX.

Development of a fast LC-MS/MS assay for the determination of deferiprone in human plasma and application to pharmacokinetics.

A fast and accurate liquid chromatography/tandem mass spectrometric (LC-MS/MS) assay was first developed and validated for the determination of deferiprone in human plasma. The analytes were extracted with acetonitrile from only 50 µL aliquots of human plasma to achieve the protein precipitation. After extraction, chromatographic separation of analytes in human plasma was performed using a Synergi Fusion-RP 80A column at 30 °C. The mobile phase consisted of methanol and 0.2% formic acid containing 0.2 mM EDTA (60:40, v/v). The flow rate of the mobile phase was 0.8 mL/min. The total run time for each sample analysis was 4 min. Detection was performed using electrospray ionization in positive ion multiple reaction monitoring mode by monitoring the precursor-to-parent ion transitions m/z 140.1 → 53.1 for deferiprone and m/z 143.1 → 98.1 for internal standard. A linear range was established from 0.1 to 20 µg/mL. The limit of detection was determined as 0.05 µg/mL. The validated method was estimated for linearity, recovery, stability, precision and accuracy. Intraday and interday precisions were 4.3-5.5 and 4.6-7.3%, respectively. The recovery of deferiprone was in the range of 80.1-86.8%. The method was successfully applied to a pharmacokinetic study of deferiprone in six thalassemia patients.