CStone announces positive registrational study of the first-in-class drug ivosidenib in Chinese patients with relapsed or refractory acute myeloid leukemia, and NDA has been accepted by the China NMPA and considered for Priority Review

Ivosidenib (TIBSOVO®,the brand name in the U.S.) is the first isocitrate dehydrogenase 1 (IDH1) inhibitor in China that has demonstrated its efficacy and manageable safety in patients with relapsed or refractory acute myeloid leukemia (R/R AML)

The National Medical Products Administration (NMPA) of China has accepted the new drug application (NDA) of TIBSOVO® (ivosidenib tablets) for the treatment of adults with R/R AML with a susceptible IDH1 mutation and this NDA has been considered for priority review

SUZHOU,China,Aug. 3,2021 -- CStone Pharmaceuticals ("CStone",HKEX: 2616),a leading biopharmaceutical company focused on researching,developing,and commercializing innovative immuno-oncology therapies and precision medicines,today announced that the China registrational study CS3010-101 of TIBSOVO® (ivosidenib tablets) has met the pre-specified endpoints in Chinese patients with relapsed or refractory acute myeloid leukemia (R/R AML) with a susceptible IDH1 mutation. The results demonstrated efficacy and manageable safety of TIBSOVO® (ivosidenib tablets),which were consistent with previously reported data from the global study population. Detailed data of this registrational study will be reported at an international academic conference in the near future.

Meanwhile,CStone announced that the National Medical Products Administration (NMPA) of China has accepted the new drug application (NDA) of TIBSOVO® (ivosidenib tablets) in adult patients with R/R AML who have a susceptible IDH1 mutation and this NDA has been considered for priority review.

Professor Wang Jianxiang from the Institute of Hematology & Blood Diseases Hospital,Chinese Academy of Medical Sciences,the principal investigator of the CS3010-101 study,said,"In the field of AML treatment,we are facing urgent clinical treatment needs,especially for R/R AML patients with a susceptible IDH1 mutation,currently there is no targeted therapy available on the market in China. Congratulations on the success of the registrational study of TIBSOVO® (ivosidenib tablets) in Chinese patients with R/R AML and we look forward to its early approval and launch in China,which will bring new hope for AML patients."

Dr. Jason Yang,Chief Medical Officer of CStone,"We are glad that TIBSOVO® (ivosidenib tablets) demonstrated efficacy and manageable safety in Chinese patients with R/R AML. TIBSOVO® (ivosidenib tablets) is our fourth product with an NDA,after GAVRETO®,AYVAKIT®,and sugemalimab,bringing the total number of our NDAs or sNDAs to seven. We will work closely with the NMPA,aiming to make this innovative drug available to Chinese patients as soon as possible."

In 2020,TIBSOVO® (ivosidenib tablets) was selected in the list of thethird batchofOverseas New Drugs Urgently Needed In Clinical Settings by the Center for Drug Evaluation,NMPA,and granted for fast-track designation. As a potent and highly selective first-in-class oral IDH1 inhibitor,TIBSOVO® (ivosidenib tablets) was also recommended by the 2020 edition of the CSCO Guidelines for Diagnosis and Treatment of Hematological Malignancies due to its proven clinical advantages.

Currently,TIBSOVO® (ivosidenib tablets) is the only targeted therapy approved in the U.S. by the FDA for the treatment of AML patients with a susceptible IDH1 mutation. TIBSOVO® (ivosidenib tablets) is also approved in the U.S. as monotherapy for the treatment of adults with susceptible IDH1-mutant relapsed or refractory acute myeloid leukemia (AML) and for adults with newly diagnosed susceptible IDH1-mutant AML who are ≥75 years old or who have comorbidities that preclude the use of intensive induction chemotherapy. TIBSOVO® (ivosidenib tablets) is commercialized in the U.S. by Servier Pharmaceuticals.

About acute myeloid leukemia

Acute myeloid leukemia (AML) is the most common leukemia in adults. It is a rapidly progressing disease with a high incidence in the elderly. In the United States,there are about 20,000 new cases each year,and the five-year survival rate is about 29%. The incidence of AML in China is 1.4/100,000 in men and 1.2/100,000 in women[1],and about 6-10% of patients with AML carry IDH1 mutations. Somatic IDH1 mutation results in the accumulation of oncometabolite 2-HG which impairs differentiation of hematopoietic stem cells into mature blood cells,contributing to oncogenesis. Along with the aging of the population,the incidence of AML has been increasing over the years,and elderly patients and R/R AML patients have a poor prognosis.

About CS3010-101 China Bridging Study

CS3010-101 is an ongoing phase I,multi-center,single-arm study in China,which aims to evaluate the pharmacokinetic (PK),pharmacodynamics (PD),safety,and clinical efficacy of orally administrated ivosidenib in Chinese adults with R/R AML with a susceptible IDH1 mutation. And as the bridging study of the global pivotal AG120-C-001 study,it provides data on R/R AML patients in China.

About TIBSOVO® (ivosidenib tablets)

Servier is a global independent pharmaceutical Group governed by a Foundation. In the field of oncology,Servier conducts activities in research,development,and commercialization of therapeutic solutions in different diseases including AML. Servier and CStone entered into a collaboration and license agreement for the development and commercialization of TIBSOVO® (ivosidenib tablets) in some territories including Mainland China.

TIBSOVO® (ivosidenib tablets) is currently approved in the U.S. since 2018 as monotherapy for the treatment of adults with susceptible IDH1-mutant relapsed or refractory acute myeloid leukemia (AML). In 2019,the indication was extended by the U.S. FDA to include the treatment of newly diagnosed susceptible IDH1-mutant AML adult patients who are ≥75 years old or who have comorbidities that preclude the use of intensive induction chemotherapy.

The U.S. FDA has granted Breakthrough Therapy Designation for TIBSOVO® (ivosidenib tablets) in combination with azacytidine for this supplemental indication and Breakthrough Therapy Designation for TIBSOVO® (ivosidenib tablets) for the treatment of adult patients with relapsed and refractory myelodysplastic syndrome (MDS) with a susceptible IDH1 mutation.

About CStone

CStone Pharmaceuticals (HKEX: 2616) is a biopharmaceutical company focused on researching,and commercializing innovative immuno-oncology and precision medicines to address the unmet medical needs of cancer patients in China and worldwide. Established in 2015,CStone has assembled a world-class management team with extensive experience in innovative drug development,clinical research,and commercialization. The company has built an oncology-focused pipeline of 15 drug candidates with a strategic emphasis on immuno-oncology combination therapies. Currently,CStone has received three drug approvals in Greater China,including two in Mainland China and one in Taiwan. CStone's vision is to become globally recognized as a world-renowned biopharmaceutical company by bringing innovative oncology therapies to cancer patients worldwide.

This TIBSOVO® (ivosidenib tablets) NDA is the third NDA acceptance of CStone in 2021,after GAVRETO® (pralsetinib) in patients with metastatic RET-mutant medullary thyroid cancer and RET fusion-positive thyroid cancer,and AYVAKIT® (avapritinib) in patients with PDGFRA D842V-mutant gastrointestinal stromal tumor in Hong Kong,China. GAVRETO® and AYVAKIT® were approved by the China NMPA and commercially launched in Mainland China. AYVAKIT® was also approved for launch by the Taiwan Food and Drug Administration for adults with unresectable or metastatic GIST who have a PDGFRA D842V mutation.

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

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[1] Miranda-Filho,A.,et al.,Epidemiological patterns of leukaemia in 184 countries: a population-based study. 2018. 5(1): p. e14-e24