Chipscreen BioSciences announced that the CFDA had approved chidamide for the treatment of relapsed or refractory peripheral T-cell lymphoma (PTCL) in December 2014. The drug and Hengrui’s apatinib were the only two NCEs launched by domestic drug makers last year.
Chidamide (CS055/HBI-8000) is a HDAC1/2/3/10 inhibitor derived from entinostat (MS-27-275) which was first discoved by Mitsui Pharmaceuticals in 1999. Chipscreen holds worldwide IP rights to chidamide (patents: WO2004071400, WO2014082354).
Syndax Pharmaceuticals (NASDAQ: SNDX) is testing entinostat in breast cancer and NSCLC in pivotal trials. The FDA granted Breakthrough Therapy Designation to entinostat for advanced breast cancer in 2013. Eddingpharm in-licensed China rights to entinostat from Syndax in September 2013.
Chipscreen disclosed positive results from Phase II study of chidamide in relapsed or refractory PTCL at 2013 ASCO Annual Meeting. Out of 79 evaluable patients in the trial, 23 patients (29.1%) had confirmed responses (8 CR, 3 CRu, and 12 PR). The most common grade 3/4 AEs were thrombocytopenia (24%), leucocytopenia (13%), neutropenia(10%).
The FDA has approved three HDAC inhibitors, known as Zolinza (vorinostat), Istodax (romidepsin) and Beleodaq (belinostat), for the treatment of PTCL. Celgene priced Istodax at $12000-18000/month and reported annual sales of $54 million in 2013. The efficacy and safety profile of chidamide compares favorably with romidepsin.
Although a dozen of companies are developing generic vorinostat and romidepsin, no chemical 3.1 NDA has been submitted to the CFDA so far. Chipscreen will be the only domestic maker of HDAC inhibitor in the coming two years. Moreover, the company is testing chidamide in NSCLC and breast cancer in early clinical studies.
 Proc Natl Acad Sci USA. 1999, 96(8), 4592-4297.
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