CStone Pharmaceuticals Announces China Approval of Tibsovo® (Ivosidenib Tablets), the First IDH1 Inhibitor in the Country

TIBSOVO® is the world’s first and currently the only approved targeted therapy for the treatment of relapsed or refractory myelodysplastic syndromes (MDS) with IDH1 mutation.

Suzhou, China, November 14, 2023 — CStone Pharmaceuticals (HKEX: 2616) partner Servier announced that the U.S. Food and Drug Administration (FDA) has approved TIBSOVO® (ivosidenib tablets) for the treatment of IDH1-mutant relapsed or refractory (R/R) myelodysplastic syndromes (MDS). This marks the fifth indication for TIBSOVO® in the field of IDH1-mutant cancers. TIBSOVO® is also the world’s first and currently only targeted therapy approved for patients with relapsed or refractory MDS within this molecularly defined subgroup.

Based on the pivotal Phase I open-label clinical trial results of TIBSOVO® in IDH1-mutant relapsed or refractory MDS patients (n=18), the FDA approved this indication. The study results showed that in the TIBSOVO® treatment group, the complete response rate (CR) was 38.9%, and the overall response rate (ORR) was 83.3%. Additionally, the median time to achieve CR was 1.9 months (range: 1.0, 5.6). At the data cutoff date, the median duration of CR had not been reached (range: 1.9, 80.8+), while the median overall survival was 35.7 months (range: 3.7, 88.7*). Furthermore, among the 9 patients who were red blood cell or platelet transfusion-dependent at baseline, 66.7% (n=6) became transfusion-independent for any ≥56-day period post-baseline. Overall, treatment-related adverse events were consistent with the previously reported safety profile of TIBSOVO®.

In the United States, approximately 16,000 people are diagnosed with MDS each year.1 About 3.6% of MDS patients carry the IDH1 mutation,2 which is an early "driver" mutation.3 For MDS patients with the IDH1 mutation, their prognosis is generally associated with poorer overall outcomes and a higher risk of progression to acute myeloid leukemia (AML).2

TIBSOVO® has been granted Breakthrough Therapy Designation by the U.S. FDA for the treatment of adult patients with R/R myelodysplastic syndrome (MDS) harboring IDH1 mutations and has been awarded Priority Review status. Priority Review is typically granted to drugs that demonstrate significant improvements in the effectiveness or safety of the treatment, diagnosis, or prevention of serious conditions, and can expedite the approval process.

TIBSOVO® is a precision therapy targeting specific isocitrate dehydrogenase 1 (IDH1) mutations. TIBSOVO® has been approved in the United States, the European Union, Australia, the United Arab Emirates (UAE), and China.

In the United States, TIBSOVO® has been approved for the treatment of adult patients with relapsed or refractory AML harboring an IDH1 mutation, newly diagnosed adult AML patients with an IDH1 mutation (aged ≥75 years or with comorbidities ineligible for intensive induction chemotherapy), adult patients with relapsed or refractory MDS carrying an IDH1 mutation, and previously treated cholangiocarcinoma patients with an IDH1 mutation.

In China, TIBSOVO® has been approved for the treatment of adult patients with relapsed or refractory acute myeloid leukemia (AML) harboring susceptible IDH1 mutations.

Servier has granted CStone Pharmaceuticals exclusive rights to develop and commercialize TIBSOVO® in Greater China, including mainland China, Hong Kong, Taiwan, Macao, as well as Singapore.

Regarding NCT02074839 Clinical Trial 5

This is a Phase I open-label international study aimed at evaluating the safety, tolerability, and clinical activity of TIBSOVO® in patients with relapsed or refractory myelodysplastic syndromes harboring IDH1 mutations. The primary endpoint is the complete response (CR) plus partial response (PR) rate, with key secondary endpoints including the duration of CR+PR, the duration of transfusion independence, and the time to achieve transfusion independence.

About TIBSOVO® (Ivosidenib Tablets)

TIBSOVO® is an oral targeted inhibitor targeting the IDH1 mutant enzyme. TIBSOVO® has been approved by the National Medical Products Administration of China for the treatment of adult patients with relapsed or refractory acute myeloid leukemia carrying IDH1-susceptible mutations.

TIBSOVO® is approved by the FDA for use in patients with susceptible IDH1 mutations detected by an FDA-approved test, including:

Newly Diagnosed AML: As a single agent or in combination with azacitidine for the treatment of patients aged 75 years and older with newly diagnosed IDH1-mutated AML or adult patients with newly diagnosed IDH1-mutated AML who are ineligible for intensive induction chemotherapy due to comorbidities.

Relapsed or Refractory AML: For the treatment of adult patients with relapsed or refractory AML

Relapsed or Refractory MDS: For the treatment of adult patients with relapsed or refractory MDS

Locally Advanced or Metastatic Cholangiocarcinoma: For the treatment of adult patients with previously treated locally advanced or metastatic cholangiocarcinoma.

TIBSOVO® has been approved by the European Commission for two indications:

TIBSOVO® in combination with azacitidine is indicated for the treatment of adult patients with newly diagnosed AML who have IDH1 R132 mutations and are ineligible for standard induction chemotherapy.

TIBSOVO® monotherapy for adult patients with locally advanced or metastatic cholangiocarcinoma harboring an IDH1 R132 mutation who have received at least one prior systemic therapy

About Myelodysplastic Syndromes

Myelodysplastic Syndromes (MDS) are a group of diseases caused by abnormal differentiation of hematopoietic stem cells. In the United States, approximately 16,000 people are diagnosed with MDS each year. About 3.6% of MDS patients carry the IDH1 mutation, which is an early "driver" mutation. For MDS patients with the IDH1 mutation, the prognosis is typically associated with poorer overall outcomes and a higher risk of progression to acute myeloid leukemia (AML). Prior to the approval of TIBSOVO®, there were no targeted treatment options available for patients with this specific mutation.

About CStone Pharmaceuticals

CStone Pharmaceuticals (HKEX: 2616) is a biopharmaceutical company focused on the research, development, and commercialization of innovative immuno-oncology and precision treatments to address the significant unmet medical needs of cancer patients in China and globally. Established at the end of 2015, CStone Pharmaceuticals has assembled a management team with extensive experience in new drug discovery, clinical research, and commercial operations. With a core emphasis on combination therapies in immuno-oncology, the company has built a robust pipeline comprising 14 oncology drug candidates. To date, CStone Pharmaceuticals has received approval for 12 new drug applications for four innovative medicines. Several late-stage drug candidates are currently in pivotal clinical trials or at the registration stage. The vision of CStone Pharmaceuticals is to become a world-renowned biopharmaceutical company leading the way in conquering cancer.

For more information about CStone Pharmaceuticals, please visit: www.cstonepharma.com.

Editor: Bai Ji

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