Cardiovascular effects of doxorubicin (Adriamycin) and 4-demethoxydaunorubicin (Idarubicin) in the conscious rat

Protective role of antioxidant vitamin E and catechin on idarubicin-induced cardiotoxicity in rats

Idarubicin is an anthracycline antibiotic extensively used in acute leukemia. In the present study we investigated whether vitamin E and catechin can reduce the toxic effects of idarubicin. Vitamin E (200 IU kg(-1) week(-1)), catechin (200 mg kg(-1) week(-1)), idarubicin (5 mg kg(-1) week(-1)), idarubicin + vitamin E (200 IU kg(-1) week(-1)), and idarubicin + catechin (200 mg kg(-1) week(-1)) combinations were given to male Sprague-Dawley rats weighing 210 to 230 g (N = 6/group). Idarubicin-treated animals exhibited a decrease in body and heart weight, a decrease in myocardial contractility, and changes in ECG parameters (P<0.01). Catechin + idarubicin- and vitamin E + idarubicin-treated groups exhibited similar alterations, but changes were attenuated in comparison to those in cardiac muscle of idarubicin-treated rats (P<0.05). Superoxide dismutase and catalase activity was reduced in the idarubicin-treated group (P<0.05). Glutathione peroxidase levels were decreased in the idarubicin-treated group (P<0.05) and reached maximum concentrations in the catechin- and catechin + idarubicin-treated groups compared to control (P<0.01). Malondialdehyde activity was decreased in the catechin + idarubicin-treated groups compared to control and increased in the other groups, reaching maximum concentrations in the vitamin E-treated group (P<0.01). In electron microscopy studies, swelling of the mitochondria and dilatation of the sarcoplasmic reticulum of myocytes were observed in the idarubicin-treated groups. In groups that were given idarubicin + vitamin E and idarubicin + catechin, the only morphological change was a weak dilatation of the sarcoplasmic reticulum. We conclude that catechin and vitamin E significantly reduce idarubicin-induced cardiotoxicity in rats.

Treatment of patients with high-grade non-Hodgkin's lymphoma aged over 70 years with an all-oral regimen combining idarubicin, etoposide and alkylators

In elderly patients age-specific comorbidity often reduces the possibility of administering intensive chemotherapy and of obtaining response to treatment. Therefore, chemotherapy must differ from that for non-elderly patients, while maintaining the primary goal of a complete clinical response. We treated 19 patients over the age of 70 years (median age 75 years, range 70-86) with stage II-IV high-grade non-Hodgkin's lymphoma (NHL) with a combination regimen including idarubicin plus etoposide and prednimustine (or chlorambucil+prednisone), all administered orally on an outpatient basis. The therapeutic schedule included six 5-day courses of idarubicin 20 mg/sqm on day 1 (or 10 mg/sqm on days 1 and 3 in the nine patients last treated), etoposide 60 mg/sqm/12 h days 2-5, prednimustine 60 mg/sqm days 2-5, G-CSF 300 microg/day from day+7 until PMN>1000/microl. In ten patients prednimustine was replaced by chlorambucil 10 mg/sqm, days 2-5, and prednisone 50 mg days 2-5, because of non-availability of the drug. Of the 19 patients submitted to this regimen 15 (79%) obtained a clinical response: eight reached a complete response (CR), and seven a partial response (PR). Hematologic toxicity was generally mild. Only three patients had to be hospitalised for infection. Except alopecia, non-hematologic toxicities were negligible. At a median follow-up of 16 months, five of eight patients who obtained CR relapsed (median CR duration 7 months). The actuarial median survival is 34 months (range 6-46). This study demonstrates the feasibility and efficacy of an all-oral regimen including idarubicin, plus etoposide and prednimustine (or chlorambucil+prednisone) in NHL patients aged over 70 years.

Comparison of doxorubicin- and MEN 10755-induced long-term progressive cardiotoxicity in the rat

The delayed functional cardiotoxic effects of repeated treatment with the new disaccharide anthracycline MEN 10755 and doxorubicin (1.5 mg/kg, i.v., once a week for 5 consecutive weeks) were investigated in the rat. Changes were assessed (2 days and 4 and 13 weeks after the last treatment) in ECG morphology, hemodynamics, in vivo left ventricular contractile responses to beta-adrenergic stimulation, and histopathology of both atria and ventricles. Doxorubicin induced significant and progressive prolongation of the QalphaT interval starting 2 days after suspension of treatment. At 4 and 13 weeks after the last treatment, the ECG showed a further progressive and significant impairment. MEN 10755 induced alterations similar in nature but of lesser severity compared with doxorubicin. In addition, MEN 10755-induced prolongation of the QalphaT interval was not progressive, being similar at 4 and 13 weeks after the last treatment. Although the hemodynamics were only slightly affected by both anthracyclines, a nearly complete ablation of isoprenaline-induced enhancement of ventricular function was observed 4 and 13 weeks after the last treatment with doxorubicin, whereas only mild, if any, reduction was detected in rats receiving MEN 10755. Histopathologic investigations indicated that both anthracyclines produced qualitatively similar alterations in ventricular myocytes. However, only with doxorubicin did these changes show a progression with a further significant worsening at 13 weeks as compared with 4 weeks after the last treatment. In addition, atrial lesions were evident in doxorubicin-treated rats, but not in rats receiving MEN 10755. In conclusion, an equimyelotoxic regimen of MEN 10755 produced, as compared with doxorubicin, lesser ECG alterations, smaller impairment of the ventricular response to adrenergic stimulation, and less severe myocyte lesions. Unlike doxorubicin, the histologic and functional cardiotoxic effects induced by MEN 10755 were not progressive. Further investigations are warranted to define the pharmacodynamic and/or pharmacokinetic mechanism(s) underlying the different cardiotoxic profile exhibited by the two anthracyclines.

Intensive chemotherapy of poor prognosis myelodysplastic syndromes (MDS) and acute myeloid leukemia following MDS with idarubicin and cytarabine

Forty patients with high risk myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) preceded by MDS were treated with intensive induction and consolidation chemotherapy in a prospective multicenter pilot study. They were given two cycles of cytarabine 100 mg/m with 12-h intervals on days 1-7 and idarubicin 12 mg/m2 on days 5-7, both intravenously. Patients who were in remission after these two cycles were given two further cycles of cytarabine on days 1-5 and idarubicin on day 5. No maintenance treatment was given. Eleven out of 19 MDS patients (58%) and 10 out of 21 AML patients (48%), in total 21 out of 40 patients (53%), entered remission. Eight patients underwent allogeneic bone marrow transplantation. The follow-up time was 13-48 (median 33) months. At the time of the analysis, seven patients survived, four patients with MDS all of whom had been treated with bone marrow transplantation (three in continuous remission), and three patients with AML treated with chemotherapy only (two in continuous remission). The median survival of the patients treated with chemotherapy only was 12 months, with the median progression-free survival being 8 months. In view of the poor prognostic factors of the patients, the remission rate was satisfactory, but the responses as well as the survival were short. The post-remission treatment needs to be improved.

Results of conventional-dose cytosine arabinoside and idarubicin in elderly patients with acute myeloid leukemia

Conventional-dose Ara-C (200 mg/m2 d 1-5) combined with idarubicin (12 mg/m2 d 1-3) was employed as remission induction and consolidation therapy in 23 elderly AML patients with a median age of 66 years (range, 60-75) with AML according to the FAB criteria (M1 n = 3, M2 n = 10, M4 n = 6, M5 n = 2, M6 n = 2), eligible for the study. In seven patients earlier MDS had been documented by previous bone marrow aspirates. The CR rate after one induction course was 65% (15/23). Toxicity was acceptable, with four patients dying during the chemotherapy-induced hypoplasia (4/23). Although 80% of the CR patients received two additional cycles of Ara-C and idarubicin as consolidation therapy, only two patients are still in continuous complete remission more than 12 months after achieving CR. The median disease-free survival of the CR patients was 11.5 months and the median survival of the entire group was 10 months. We conclude that conventional dose Ara-C/idarubicin is an effective protocol for inducing complete remission in elderly patients with AML, but that consolidation therapy consisting of two courses of the same regimen does not produce a relevant rate of long-term disease-free survival.

Cardiotoxic effects and the influence on the beta-adrenoceptor function of doxorubicin (Adriamycin) in the rat

The possible relationship between the effect of the anthracycline-cytostatic doxorubicin (Dox) on the cardiac beta-adrenoceptor function in vitro and the development of delayed cardiotoxicity in vivo has been investigated in the rat. Dox (10(-5)-10(-4) M) blocked the chronotropic effect of isoprenaline on isolated atria in a competitive manner. Treatment with a single dose of Dox 5 mg/kg intravenously caused marked ECG changes manifested by progressive prologations of the Q alpha T and S alpha T-intervals, which amounted to 37% and 58% respectivity 5 weeks after the medication. At this time no beta-blocking action was detectable when tested on the isolated atria in the same rats. The results indicate that the delayed cardiotoxicity induced by Dox is not mediated by an interference with the cardiac beta-adrenoceptor function.