SUZHOU, China, July 26th, 2021 – The partner of CStone Pharmaceuticals (“CStone”, HKEX: 2616), Genetron Holdings Limited (“Genetron Health” or the “Company”, NASDAQ:GTH) announced that its AYVAKIT^® (avapritinib) companion diagnostic (CDx) kit, developed in partnership with CStone Pharmaceuticals has entered the priority review and approval process under the National Medical Products Administration (NMPA) in China.

The test kit is the first companion diagnostic product developed in China to go through the NMPA’s accelerated review channel. This channel expedites the review of qualified medical devices that are deemed urgent and necessary, so that they can be applied sooner in clinical settings.

During the process, the Center for Medical Device Evaluation (CMDE) under the NMPA carries out a priority technical review, working closely with the company to expedite the process. Provincial food and drug authorities also make the review of the product a priority throughout their registered quality management systems. The product then goes through a priority administrative processes under the National Medical Products Administration, which approves the product at the end.

Gastrointestinal stromal tumor (GIST) patients with human platelet-derived growth factor receptor alpha (PDGFRA) gene mutations lack effective treatment drugs. AYVAKIT^® has demonstrated remarkable efficacy and acceptable safety in Chinese patients with unresectable or metastatic GIST harboring PDGFRA exon 18 mutations, including D842V. As a proprietary companion diagnostics for AYVAKIT^®, the CDx kit can be used to effectively detect PDGFRA D842V gene mutation in GIST patients, providing accurate molecular diagnosis for targeted drug application which may translate into durable clinical benefits for these patients.

The AYVAKIT^® CDx test kit is based on a real-time PCR fluorescent probe, specific primers, Taqman probes, and highly specific Taq enzymes to detect gene mutations. This enables the test kit to detect mutations with higher specificity and sensitivity in DNA samples. A clinical study utilizing the test kit was carried out at the Beijing Cancer Hospital, Harbin Medical University Cancer Hospital and Shanghai Tenth People's Hospital, demonstrating data on par with that of the Sanger sequencing method and exhibiting total concordance rate of over 99%.

"I am very pleased that the AYVAKIT^® companion diagnostics test kit has entered the NMPA priority review and approval process, distinguishing itself through innovative, original technology and strong performance data. The development of such companion diagnostics products can enable doctors to choose more suitable, targeted drugs for patients, while lowering the costs of drug development, accelerating the development process, and improving drug safety and effectiveness. Genetron Health is committed to exploring more innovative pathways for the development of new drugs and companion diagnostics, providing more choices for patient care," said Sizhen Wang, Co-Founder and CEO of Genetron Health.

“Precision medicine is one of CStone's core strategies. As the world's first therapeutic approved for GIST based on driver mutations, AYVAKIT^® was approved by the NMPA in March 2021 after passing the NMPA’s priority review process. Molecular diagnosis has become imperative for GIST patients. I am very pleased that the AYVAKIT^® companion diagnostic kit has also entered the priority review process. I look forward to the early approval of this diagnostic kit, so that more GIST patients in China can benefit from precision treatment,” said Dr. Archie Tse, Chief Scientific Officer of CStone.

About AYVAKIT^® (avapritinib)

AYVAKIT^® (avapritinib) is a kinase inhibitor approved by the China National Medical Products Administration (NMPA) for the treatment of adults with unresectable or metastatic GIST harboring the PDGFRA exon 18 mutation, including PDGFRA D842V mutations.

The U.S. Food and Drug Administration (FDA) has approved AYVAKITTM for the treatment of two indications: adults with advanced systemic mastocytosis (SM), including aggressive SM (ASM), SM with an associated hematological neoplasm (SM-AHN) and mast cell leukemia (MCL), and adults with unresectable or metastatic GIST harboring a PDGFRA exon 18 mutation, including PDGFRA D842V mutations.

This medicine is approved by the European Commission under the brand name AYVAKYT^® for the treatment of adults with unresectable or metastatic GIST harboring the PDGFRA D842V mutation.

AYVAKIT^®/AYVAKYT^® is not approved for the treatment of any other indication in the U.S., Europe or Greater China, or for any indication in any other jurisdiction by any other health authority.

Blueprint Medicines is developing AYVAKIT^® globally for the treatment of advanced and non-advanced SM. The FDA granted breakthrough therapy designation to AYVAKIT^® for the treatment of advanced SM, including the subtypes of ASM, SM-AHN, and MCL, and for the treatment of moderate to severe indolent SM.

About CStone

CStone Pharmaceuticals (HKEX: 2616) is a biopharmaceutical company focused on researching, developing, 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.

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

About Genetron Holdings Limited

Genetron Holdings Limited (“Genetron Health” or the “Company”) (Nasdaq:GTH) is a leading precision oncology platform company in China that specializes in cancer molecular profiling and harnesses advanced technologies in molecular biology and data science to transform cancer treatment. The Company has developed a comprehensive oncology portfolio that covers the entire spectrum of cancer management, addressing needs and challenges from early screening, diagnosis and treatment recommendations, as well as continuous disease monitoring and care. Genetron Health also partners with global biopharmaceutical companies and offers customized services and products. For more information, please visit ir.genetronhealth.com.

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