Description: Filanesib, also known as ARRY-520, is a synthetic, small molecule targeting the kinesin spindle protein (KSP) with potential antineoplastic activity. KSP inhibitor ARRY-520 specifically inhibits KSP (kinesin-5 or Eg5), resulting in activation of the spindle assembly checkpoint, induction of cell cycle arrest during the mitotic phase, and consequently cell death in tumor cells that are actively dividing. Because KSP is not involved in postmitotic processes, such as neuronal transport, this agent does not cause the peripheral neuropathy that is often associated with tubulin-targeting agents. KSP is an ATP-dependent microtubule motor protein that is essential for the formation of bipolar spindles and the proper segregation of sister chromatids during mitosis.
Synonym: ARRY-520; ARRY 520; ARRY520; Filanesib.
IUPAC/Chemical Name: (S)-2-(3-aminopropyl)-5-(2,5-difluorophenyl)-N-methoxy-N-methyl-2-phenyl-1,3,4-thiadiazole-3(2H)-carboxamide.
Name: Filanesib (ARRY-520)
Chemical Formula: C20H22F2N4O2S
Exact Mass: 420.14315
Molecular Weight: 420.48
Elemental Analysis: C, 57.13; H, 5.27; F, 9.04; N, 13.32; O, 7.61; S, 7.6
In preclinical studies of multiple myeloma, ARRY-520 monotherapy has superior anti-tumor activity compared to VelcadeÂ® (bortezomib) or RevlimidÂ® (lenalidomide). Also, ARRY-520 combined with Velcade, including bortezomib-refractory models, showed synergistic activity in vivo and superadditive activity when combined with Revlimid. Apoptosis in myeloma cells treated with ARRY-520 requires loss of the short-lived survival protein Mcl-1, providing a likely mechanistic explanation for ARRY-520 activity. Further studies, including a single-agent Phase 2 study and combination trials in multiple myeloma, are planned. ARRY-520 inhibits kinesin spindle protein, or KSP, which plays an essential role in mitotic spindle formation. Like taxanes and vinca alkaloids, KSP inhibitors inhibit tumor growth by preventing mitotic spindle formation and cell division. However, unlike taxanes and vinca alkaloids, KSP inhibitors do not demonstrate certain side effects such as peripheral neuropathy and alopecia. ARRY-520 has demonstrated efficacy in preclinical hematological tumor models, with a 100.0% complete response rate observed in models of acute myeloid leukemia, or AML, and multiple myeloma, or MM. Treatment of MM models with ARRY-520 resulted in significant regression of tumors that had previously progressed after treatment with Velcade_ (bortezomib) or Revlimid_ (lenalidomide). In addition, ARRY-520 retained activity in a wide range of tumors resistant to other molecules with different mechanisms of action, such as the taxanes. Examination of pharmacodynamic activity in preclinical models reinforced that hematological cancers were among the most sensitive to ARRY-520. (Source: http://www.arraybiopharma.com/ProductPipeline/Cancer/KSP.asp).
On June 05, 2010, Array BioPharma Inc. announced the presentation of positive Phase 1 clinical data for its novel kinesin spindle protein (KSP) inhibitor, ARRY-520. The data, which were presented at the American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois, indicate that ARRY-520 was well tolerated and has shown encouraging preliminary results in the treatment of multiple myeloma. ARRY-520 is a novel, first-in-class, highly potent, selective KSP inhibitor currently advancing into a single-agent Phase 2 clinical trial and combination trials in patients with multiple myeloma.
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2: Tunquist BJ, Woessner RD, Walker DH. Mcl-1 stability determines mitotic cell fate of human multiple myeloma tumor cells treated with the kinesin spindle protein inhibitor ARRY-520. Mol Cancer Ther. 2010 Jul;9(7):2046-56. doi: 10.1158/1535-7163.MCT-10-0033. Epub 2010 Jun 22. PubMed PMID: 20571074.
3: Woessner R, Tunquist B, Lemieux C, Chlipala E, Jackinsky S, Dewolf W Jr, Voegtli W, Cox A, Rana S, Lee P, Walker D. ARRY-520, a novel KSP inhibitor with potent activity in hematological and taxane-resistant tumor models. Anticancer Res. 2009 Nov;29(11):4373-80. PubMed PMID: 20032381.
4: Kim KH, Xie Y, Tytler EM, Woessner R, Mor G, Alvero AB. KSP inhibitor ARRY-520 as a substitute for Paclitaxel in Type I ovarian cancer cells. J Transl Med. 2009 Jul 20;7:63. doi: 10.1186/1479-5876-7-63. PubMed PMID: 19619321; PubMed Central PMCID: PMC2719595.
5: Carter BZ, Mak DH, Woessner R, Gross S, Schober WD, Estrov Z, Kantarjian H, Andreeff M. Inhibition of KSP by ARRY-520 induces cell cycle block and cell death via the mitochondrial pathway in AML cells. Leukemia. 2009 Oct;23(10):1755-62. doi: 10.1038/leu.2009.101. Epub 2009 May 21. PubMed PMID: 19458629; PubMed Central PMCID: PMC3593228.