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Pixantrone (rINN; trade name Pixuvri) is an experimental antineoplastic (anti-cancer) drug, an analogue of mitoxantrone with fewer toxic effects on cardiac tissue. It acts as a topoisomerase II poison and intercalating agent. The code name BBR 2778 refers to pixantrone dimaleate, the actual substance commonly used in clinical trials.
Random screening at the US National Cancer Institute of a vast number of compounds provided by the Allied Chemical Company led to the discovery of ametantrone as having significant tumor activity. Further investigation regarding the rational development of analogs of ametantrone led to the synthesis of mitoxantrone, which also exhibited marked anti-tumor activity Mitoxantrone was considered as an analog of doxorubicin with less structural complexity but with a similar mode of action. In clinical studies, mitoxantrone was shown to be effective against numerous types of tumors with less toxic side effects than those resulting from doxorubicin therapy. However, mitoxantrone was not totally free of cardiotoxicity. A number of structurally modified analogs of mitoxantrone were synthesized and structure-activity relationship studies made. BBR 2778 was originally synthesized by University of Vermont researchers Miles P. Hacker and Paul A. Krapcho and initially characterized in vitro for tumor cell cytotoxicity and mechanism of action by studies at the Boehringer Mannheim Italia Research Center, Monza, and University of Vermont, Burlington. Other studies have been completed at the University of Texas M. D. Anderson Cancer Center, Houston, the Istituto Nazionale Tumori, Milan, and the University of Padua. In the search for novel heteroanalogs of anthracenediones, it was selected as the most promising compound. Toxicological studies indicated that BBR 2778 was not cardiotoxic, and US patents are held by the University of Vermont. An additional US patent application was completed in June 1995 by Boehringer Mannheim, Italy.
Novuspharma, an Italian company, was established in 1998 following the merger of Boehringer Mannheim and Hoffmann-La Roche, and BBR 2778 was developed as Novuspharma's leading anti-cancer drug, pixantrone. A patent application for the injectable preparation was filed in May 2003.
In 2003, Cell Therapeutics, a Seattle biotechnology company, acquired pixantrone through a merger with Novuspharma.
Animal studies demonstrated that pixantrone does not worsen pre-existing heart muscle damage, suggesting that pixantrone may be useful in patients pretreated with anthracyclines. While only minimal cardiac changes are observed in mice given repeated cycles of pixantrone, 2 cycles of traditional anthracyclines doxorubicin or mitoxantrone result in marked or severe heart muscle degeneration.
Clinical trials substituting pixantrone for doxorubicin in standard first-line treatment of patients with aggressive non-Hodgkin's lymphoma, had a reduction in severe side effects when compared to patients treated with standard doxorubicin-based therapy. Despite pixantrone patients receiving more treatment cycles, a three-fold reduction in the incidence of severe heart damage was seen as well as clinically significant reductions in infections and thrombocytopenia, and a significant reduction in febrile neutropenia. These findings could have major implications for treating patients with breast cancer, lymphoma, and leukemia, where debilitating cardiac damage from doxorubicin might be prevented. Previous treatment options for multiply relapsed aggressive non-Hodgkin lymphoma had disappointing response rates.
The completed phase II RAPID trial compared the CHOP-R regimen of Cyclophosphamide, Doxorubicin, Vincristine, Prednisone, and Rituximab to the same regimen, but substituting Doxorubicin with Pixantrone. The objective was to show that Pixantrone was not inferior to Doxorubicin and less toxic to the heart.
Pixantrone was shown to have potentially reduced cardiotoxicity and demonstrated promising clinical activity in these phase II studies in heavily pretreated non-Hodgkin lymphoma patients.
The phase III EXTEND (PIX301) randomized clinical trial studied pixantrone to see how well it works compared to other chemotherapy drugs in treating participants with relapsed non-Hodgkin's lymphoma. The complete response rate in pixantrone treated with pixantrone has been significantly higher than in those receiving other chemotherapeutic agents for treatment of relapsed/refractory aggressive non-Hodgkin lymphoma.
Pixantrone also reduces the severity of experimental autoimmune myasthenia gravis in Lewis rats, and in vitro cell viability experiments indicated that Pixantrone significantly reduces amyloid beta (A beta(1-42)) neurotoxicity, a mechanism implicated in Alzheimer's disease.
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