Antibody binding capacity for evaluation of MDR-related proteins in acute promyelocytic leukemia: Onset versus relapse expression.

BACKGROUND: Multidrug resistance (MDR) remains a major obstacle for successful treatment in cancer, in particular in acute leukemia. In acute promyelocytic leukemia (APL), the high sensitivity to anthracyclines appears to be attributable to the low frequency of MDR proteins overexpression at onset even if 30% of patients still relapse and become resistant to therapy. In attempt to explain different blast cell sensitivity, we studied the expression of PGP, MRP1, MRP2, and LRP in 45 cases of APL, comparing onset of disease with relapse. METHODS: PGP, LRP, and MRP on bone marrow or peripheral blood blast cells were evaluated by flow cytometry using the MRK-16, LRP-56, MRP-m6, and MRP2 antibodies and results expressed by the mean fluorescence index (MFI). The antibody binding capacity (ABC) for each MDR protein was also calculated. RESULTS: At diagnosis, only 2 of 45 patients overexpressed PGP and 1 overexpressed LRP. PGP and LRP overexpressing cases significantly grew up during disease progression and at second relapse mean PGP MFI and mean LRP MFI were significantly higher than at onset (P = 0.001 and P = 0.008, respectively). By analyzing ABC, the same trend was more evident because a significant increment of PGP and LRP was observed at second (P = 0.002 and P = 0.002, respectively), but even at first relapse (P = 0.018 and P = 0.002, respectively). No changes were demonstrated in MRP1 and MRP2 expression in any phase of disease considered. CONCLUSIONS: Our data confirm the low expression at diagnosis of proteins related to development of drug resistance in APL. The evidence of a relative easy induction of PGP and LRP, but not of MRP, can be useful in choosing drugs to employ for consolidation or rescue therapy.

Disposition of liposomal daunorubicin during cotreatment with cytarabine in patients with leukaemia.

OBJECTIVE: To investigate the pharmacokinetics and pharmacodynamics of liposomal daunorubicin (DaunoXome) 80 or 100 mg/m(2) on days 1, 2 and 3 coadministered with standard or high-dose cytarabine to patients with poor-risk acute leukaemia. DESIGN: Unblinded pharmacokinetic-pharmacodynamic study. PARTICIPANTS: Twenty-three adult patients with acute leukaemia. METHODS: Blood, bone marrow and urine samples were collected at appropriate intervals on days 1-6. Total daunorubicin and daunorubicinol concentrations in plasma, bone marrow, peripheral blood cells and urine were measured by high performance liquid chromatography. RESULTS: Liposomal daunorubicin exhibited a markedly different pharmacokinetic behaviour from the free drug due to a slow distribution of the liposomal moiety into the body. The ratio of area under the concentration-time curve (AUC) for metabolite to parent drug was lower for liposomal daunorubicin than for free daunorubicin, mainly due to higher concentrations of the parent drug in plasma, whereas daunorubicinol exposure was more or less comparable, if not higher. After liposomal daunorubicin at both 80 and 100 mg/m(2), total daunorubicin concentrations in leukaemic cells were at least similar to those observed for free daunorubicin, and significant accumulation was also observed in bone marrow blast cells. Nineteen of 23 patients obtained a complete remission, although 13 had P-glycoprotein-overexpressing blast cells. Grade 3-4 mucositis was found only in three patients with very high AUCs for total daunorubicin and daunorubicinol. CONCLUSIONS: Liposomal daunorubicin at both 80 and 100 mg/m(2) in combination with cytarabine may represent a valid treatment for high-risk acute leukaemia. Liposomal daunorubicin may be helpful in overcoming multidrug resistance, since it shows significant accumulation into tumour target cells, irrespective of P-glycoprotein expression. The tolerability profile suggests that toxicity may be related to exposure to both the parent drug and the metabolite.

Clinical characteristics, prognostic factors and multidrug-resistance related protein expression in 36 adult patients with acute promyelocytic leukemia.

UNLABELLED: We report on a single-center experience about the characteristics and outcome of 36 acute promyelocytic leukemia (APL) patients observed at our Department of Hematology between 1990 and 2002. The expression, of multidrug-resistance (MDR) associated proteins (PGP, LRP, MRP1) was also analyzed. There were 12 males and 24 females (median age 37 yr), 89% (32 of 36) with classic morphology, and 11% (four of 36) with a microgranular variant. Risk class (according to GIMEMA/PETHEMA): 25% (nine of 36) high risk (HR), 53% (nineteen of 36) intermediate risk (IR), 22% (eight of 36) low risk (LR). PGP, LRP, and MRP1 expression at onset and at first relapse was low. CD33 antigen expression was high in all cases. The patients were treated according to GIMEMA protocols (LAP0389 and AIDA) including ATRA in induction in 75% (27 of 36) of cases and 94% (34 of 36) achieved a complete remission (CR) after induction therapy while 6% (two of 36) died early (DDI) of hemorrhage. OUTCOME: 71% (24 of 34) of evaluable patients remain in CR at a median follow-up of 57 months (range 4-158 months) while 29% (10 of 34) relapsed at a median time of 12 months (range 8-43 months) and, of them, eight of 10 died early. The majority of patients that relapsed were in high-risk group. The overall survival (OS) of the whole population at 32 months was 66% and the DFS at 42 months was 62%. A statistically significant difference in terms of DFS was observed between HR and IR/LR patients (P = 0.04 by log-rank). DFS was not affected by age, sex, Hb levels, karyotype, and BCR isoform. At conclusion, our data confirm that despite the high rate of success with ATRA plus chemotherapy as induction (more than 90% of CR), about 30% of APL patients have a relapse (without a long-lasting second remission) and underline the importance of patient stratification in distinct risk groups at diagnosis in order to better adapt the type and intensity of treatment (risk-adapted therapy). Taking into account the high expression of CD33 and the low expression of MDR proteins in APL, new and investigational approaches like gemtuzumab-ozogamicin, with or without ATRA and other new drugs, should be strongly considered expecially in HR APL.

Endogenous endophthalmitis following disseminated fungemia due to Fusarium solani in a patient with acute myeloid leukemia.

We report the case of a young man with a resistant acute myeloid leukemia (AML) who developed a disseminated fungemia due to Fusarium solani involving the skin and lungs, during the neutropenic phase following a chemotherapy course. Despite continuous therapy with liposomal amphotericin B, he developed a bilateral endophthalmitis that rapidly evolved to complete blindness. The patient underwent two procedures of vitrectomy, with detection of F. solani in the vitreous fluid, and continued antifungal therapy, without any recovery of visual acuity. When he eventually died due to recurrence of leukemia and hemorrhagic shock, autopsy revealed a diffuse fusarial involvement of the central nervous system.