Pixantrone (maleate) (Synonyms: BBR 2778)

Cell experiment:

Briefly, cells seeded into 96-well plates are treated with increasing concentrations of either pixantrone or doxorubicin for 72 hours. After this time, MTS reagent is added to cells and incubated at 37°C for a further 4 hours. Cell proliferation is then determined by measuring the absorbance at 490 nm. All data points are normalized to untreated cells. All treatments are performed in triplicate and performed a minimum of 3 times[1].

Animal experiment:

Mice[3]To evaluate the potential cardiotoxicity of Pixantrone in doxorubicin-pretreated mice, doxorubicin 7.5 mg/kg is administered intravenously every 7 days for 3 weeks (1 cycle) to a group of CD1 females. Six weeks later, these mice receive either 0.9% saline (vehicle), doxorubicin 7.5 mg/kg, Pixantrone 27 mg/kg, or mitoxantrone 3 mg/kg intravenously every 7 days for 3 weeks (2 cycles). Animals are sacrificed after the first cycle at 8 weeks, and after the second cycle at 16 weeks. In addition, to evaluate the potential cardiotoxicity of Pixantrone as a single agent compared with doxorubicin and mitoxantrone, CD1 female mice receive a single or a double cycle of vehicle, doxorubicin 7.5 mg/kg, Pixantrone 27 mg/kg, or mitoxantrone 3 mg/kg. These animals are sacrificed after the first and second cycles (at 8 and 16 weeks, all groups), during week 14 (Pixantrone-treated group only) and during week 22 (Pixantrone- and vehicle-treated groups)[3].Rats[4]For the studies on Pixantrone efficacy on EAMG, TAChR-immunized rats are randomly assigned to different treatment groups: 1) preventive Pixantrone group, starting 4 days after immunization, with 16.25 mg/kg Pixantrone, administered i.v. via tail vein, once a week for three times; 2) therapeutic Pixantrone group, starting 4 wk after immunization, with 16.25 mg/kg Pixantrone, administered i.v. via tail vein, once a week for three times; 3) therapeutic MTX group (1.2 mg/kg, i.v. via tail vein, once a week for three times); and 4) vehicle group (sterile saline, i.v. via tail vein, once a week for three times). The doses of Pixantrone and MTX used in this study are in both cases equal to one-fourth of the LD10 for single i.v. injection in rats. Treatment assignation is performed at day 4 after TAChR immunization (preventive schedule) in coincidence of the acute phase of EAMG, or at onset of clinical signs (therapeutic schedule), which occurs after 4 wk. Animals are sacrificed after deep anesthesia obtained by carbon dioxide; low-grade anesthesia with chloral hydrate administered i.p. is used for TAChR immunization and drug treatments[4].

References:

[1]. Beeharry N, et al. Pixantrone induces cell death through mitotic perturbations and subsequent aberrant cell divisions. Cancer Biol Ther. 2015;16(9):1397-406.
[2]. Hasinoff BB, et al. Mechanisms of Action and Reduced Cardiotoxicity of Pixantrone; a Topoisomerase II Targeting Agent with Cellular Selectivity for the Topoisomerase IIα Isoform. J Pharmacol Exp Ther. 2016 Feb;356(2):397-409.
[3]. Cavalletti E, et al. Pixantrone (BBR 2778) has reduced cardiotoxic potential in mice pretreated with doxorubicin: comparative studies against doxorubicin and mitoxantrone. Invest New Drugs. 2007 Jun;25(3):187-95.
[4]. Ubiali F, et al. Pixantrone (BBR2778) reduces the severity of experimental autoimmune myasthenia gravis in Lewis rats. J Immunol. 2008 Feb 15;180(4):2696-703.