Haemodynamic evaluation of two regimens of molsidomine in patients with chronic congestive heart failure

NCX-4040, a Unique Nitric Oxide Donor, Induces Reversal of Drug-Resistance in Both ABCB1- and ABCG2-Expressing Multidrug Human Cancer Cells

The emergence of multidrug resistance (MDR) in the clinic is a significant problem for a successful treatment of human cancers. Overexpression of various ABC transporters (P-gp, BCRP and MRP's), which remove anticancer drugs in an ATP-dependent manner, is linked to the emergence of MDR. Attempts to modulate MDR have not been very successful in the clinic. Furthermore, no single agent has been found to significantly inhibit their functions to overcome clinical drug resistance. We have previously shown that nitric oxide (^●NO) inhibits ATPase functions of ABC transporters, causing reversal of resistance to clinically active anticancer drugs. In this study, we have used cytotoxicity and molecular docking studies to show that NCX4040, a nitric oxide donor related to aspirin, inhibited the functions of ATPase which resulted in significant reversal of resistance to both adriamycin and topotecan in P-gp- and BCRP-expressing human cancer cell lines, respectively. We also used several other cytotoxic nitric oxide donors, e.g., molsidomine and S-nitroso glutathione; however, both P-gp- and BCRP-expressing cells were found to be highly resistant to these NO-donors. Molecular docking studies showed that NCX4040 binds to the nucleotide binding domains of the ATPase and interferes with further binding of ATP, resulting in decreased activities of these transporters. Our results are extremely promising and suggest that nitric oxide and other reactive species delivered to drug resistant tumor cells by well-designed nitric oxide donors could be useful in sensitizing anticancer drugs in multidrug resistant tumors expressing various ABC transporters.

Infusions with molsidomine and isosorbide-5-mononitrate in congestive heart failure: mechanisms underlying attenuation of effects

The use of nitrates for treatment of heart failure is encumbered by tolerance, caused by whatever mechanism, which has been reported only in a few instances with sydnonimines. Accordingly, we compared molsidomine (6 mg/h) and isosorbide-5-mononitrate (3.75 mg/h) with respect to maximal hemodynamic effects, rapidity and extent of attenuation, and underlying mechanisms by means of constant infusions over 24 h each in 15 patients with chronic congestive heart failure (NYHA II-III) with a placebo-controlled, double-blind, randomized, crossover protocol. Hemodynamic measurements and determinations of neurohormones were performed at baseline and at 2, 8, and 24 h after the beginning of infusions. With molsidomine, reductions of diastolic pulmonary artery pressure by 29% (p < 0.001), by 24% (p < 0.01), and by 24% (p < 0.01) versus placebo were found at 2, 8, and 24 h, which amounted to 19% (p < 0.01), 10% (NS), and 14% (NS) with the nitrate. Cardiac output was meaningfully affected only with molsidomine (+5%, NS, at 2 h; +9%, p < 0.05, at 8 h; and +15%, p < 0.05, at 24 h), as was systemic vascular resistance (-13%, p < 0.05; -9%, NS; and -18%, p < 0.01) at the corresponding times. Increases in renin activity amounted to 130% (p < 0.001), 117% (p < 0.001), and 112% (p < 0.001) with molsidomine, and to 14, 16%, and 0 (each NS) with the nitrate at the corresponding times. Hematocrit was reduced by 5% (p < 0.001), 7% (p < 0.001), and 12% (p < 0.01) with molsidomine and by 5% (NS), 5% (p < 0.05), and 5% (NS) with the nitrate. We conclude that neurohumoral counterregulation or fluid shift, which is even more pronounced with molsidomine despite longer-lasting effects, has no essential role in nitrate-tolerance development. With molsidomine, such a role cannot be ruled out, although alternatively, a fluid shift from arterial to the low-pressure arm of circulation during the later course of infusion would be even more likely.

Short- and long-term effects of molsidomine retard and molsidomine nonretard on exercise capacity and clinical status in patients with stable angina: a multicenter randomized double-blind crossover placebo-controlled trial

A multicenter, randomized, double-blind, crossover, placebo-controlled study was conducted in 90 isosorbide dinitrate responders showing stable angina to compare the efficacy of molsidomine retard, 8 mg b.i.d., with that of molsidomine, 4 mg t.i.d., for 6 weeks. Total work performance (workload x min) was significantly improved, compared with baseline and placebo until 8 and 12 h after molsidomine and molsidomine retard administration, respectively. ST-segment depression decreased significantly under the two treatments at 60 W as well as at maximal exercise. The rate-pressure product (heart rate x systolic blood pressure) decreased and increased significantly at submaximal and maximal exercise level, respectively. All these effects remained significant after 6-week treatment, with only the ST segment showing a nonsignificant tendency to improvement at maximal work. The frequency of anginal attacks and of sublingual nitroderivative-tablets consumption decreased significantly with molsidomine, 4 mg, and molsidomine retard, 8 mg. However, overall results showed that the latter form reduces myocardial ischemia more efficiently at submaximal exercise level, has a more prolonged effect on exercise tolerance, and maintains it at a somewhat higher level after 6-week treatment.

Clinical comparison of antiischemic efficacy of isosorbide dinitrate and molsidomine

In 16 patients with documented coronary artery disease, the extent and duration of acute antiischemic and hemodynamic effects of monotherapies with 120 mg of sustained-release isosorbide dinitrate once daily and 8 mg of sustained-release molsidomine 3 times daily were compared according to a randomized, double-blind, cross-over and placebo-controlled protocol including exercise testing for assessment of ST-segment depression (ST) at an identical workload and determination of plasma concentrations of both substances. Up to 8 h after dosing in the morning, more marked and sustained effects were observed with the nitrate (ST at 2 h, -82%; p < 0.001; at 8 h, -64%; p < 0.01) than with molsidomine (2 h, -68%; p < 0.001; at 8 h, -9%; NS). At 12 h, no more meaningful actions were detectable with isosorbide dinitrate (-13%, NS) despite plasma concentrations still within a range otherwise considered therapeutically effective, whereas with molsidomine, at 4 h after renewed dosing, this parameter was reduced by 38% (p < 0.01). However, therapeutic coverage over a 24-h period could be demonstrated on neither regimen, in the case of the nitrate because of the development of early tolerance, and in the case of molsidomine with its meaningfully shorter half-life because of the necessity of increasing the dosing frequency even further. No meaningful adverse effects were observed with either regimen. Nonresponders, overall a minority on one treatment, responded completely to the alternative regimen and vice versa.