Chidamide (trade name: Epidaza^®) is a new molecular entity drug exclusively discovered by the company with a novel mechanism. It is the world's first subtype-selective histone deacetylase (HDAC) inhibitor and the first oral therapeutic drug approved for the treatment of peripheral T-cell lymphoma and advanced hormone receptor-positive breast cancer, belonging to the class of epigenetic modulators.

Chidamide acts on epigenetics-related targets—histone deacetylases (subtypes 1, 2, and 3 of Class I and subtype 10 of Class IIb). Histone deacetylases (HDACs) are a class of proteases that play a crucial role in chromosomal structural modification and gene expression regulation. As an HDAC inhibitor, Chidamide exerts its effects by inhibiting the biological activity of HDACs, thereby inducing changes in the gene expression of multiple signaling pathways involved in tumorigenesis (i.e., epigenetic changes).

Specifically, the general mechanisms of action of Chidamide primarily include:   ① Directly inhibiting the tumor cell cycle and inducing apoptosis;   ② Inducing and activating natural killer (NK) cell- and antigen-specific cytotoxic T lymphocyte (CTL)-mediated tumor killing effects;   ③ Inhibiting phenotypic transformation of tumor cells and the pro-drug resistance/pro-metastasis activity in the tumor microenvironment.

Chidamide has been included in the National Reimbursement Drug List under the routine Category B reimbursement program. In mainland China and Macao, Chidamide has been approved for the treatment of peripheral T-cell lymphoma (PTCL), breast cancer, and diffuse large B-cell lymphoma (DLBCL). In Japan, it has been approved for adult T-cell leukemia (ATL) and PTCL, while in Taiwan, China, it has been approved for breast cancer.

The Company and its partners are exploring the global development of "HDAC Inhibitor + IO" as a next-generation combination approach for cancer immunotherapy. The international multicenter Phase III clinical trial in melanoma has met its primary endpoint, while the Phase III clinical trial in China for colorectal cancer has completed patient enrollment. The clinical trial application for NW001, the world's first epigenetic immune-modulating antibody conjugate (EIMAC), has also been accepted for review.

Figure: Molecular Anti-tumor Mechanisms of Action of Chidamide (Epidaza) 

Commercialization Status:

• In December 2014, it was approved in China for the treatment of patients with relapsed or refractory peripheral T-cell lymphoma (PTCL) who had received at least one prior systemic chemotherapy, filling a gap in this treatment area in the country.
• In July 2017, it was included in the National Medical Insurance Drug List, benefiting more patients.
• In November 2019, it was approved in China in combination with an aromatase inhibitor for the treatment of postmenopausal patients with locally advanced or metastatic breast cancer that is hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative, and has relapsed or progressed after endocrine therapy. It was first confirmed that HDAC inhibitors in combination with other targeted drugs can effectively overcome tumor drug resistance, making it the world's first epigenetic modulator approved for the treatment of solid tumors.
• In June 2021, it was approved in Japan as a monotherapy for the treatment of adult patients with relapsed or refractory (R/R) T-cell leukemia (ATL).
• In December 2021, Chidamide received its second approval in Japan—as a monotherapy for the treatment of patients with relapsed or refractory peripheral T-cell lymphoma.
• In March 2023, it was approved in Chinese Taiwan, for the treatment of postmenopausal patients with locally advanced or metastatic breast cancer that is hormone receptor-positive and human epidermal growth factor receptor 2 (HER2)-negative, and has relapsed or progressed after endocrine therapy (in combination with exemestane).
• In April 2024, it was approved in China in combination with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) for the treatment of treatment-naive patients with MYC- and BCL2-positive diffuse large B-cell lymphoma (DLBCL).
• In January 2025, the diffuse large B-cell lymphoma (DLBCL) indication of Chidamide was included in the NRDL for the first time, becoming the only oral innovative drug for first-line DLBCL treatment covered by medical insurance.
• In January 2026, Chidamide was officially included in the National Reimbursement Drug List (NRDL) under routine Category B;
• In January 2026, Chidamide was approved for marketing in Macao, China.

Global Pipeline of Investigational Indications:

• Advanced melanoma (first-line): The international multicenter Phase III clinical trial of Chidamide in combination with nivolumab, led by our international partner HUYABIO, achieved positive topline results. Median progression-free survival (mPFS) was 11.7 months in the treatment arm, representing a statistically significant and clinically meaningful improvement over 7.4 months in the control arm.
• Advanced MSS/pMMR colorectal cancer (second-line or later): The Phase III trial of Chidamide in combination with sintilimab and bevacizumab has completed patient enrollment and entered the treatment follow-up period. This indication has received Breakthrough Therapy Designation from the CDE, and results from the preceding CAPability-01 study were published in Nature Medicine.
• Treatment-naïve PTCL-TFH: The Phase III trial of Chidamide in combination with CHOP has begun enrolling patients and is expected to further strengthen Chidamide's leading position in the PTCL field.
• Other exploratory studies: The Company is conducting multiple investigator-initiated clinical studies evaluating Chidamide as a monotherapy or in combination with immunotherapy for hematologic malignancies and solid tumors.