GENFLEET-B - VOLUNTARY ANNOUNCEMENT GFH375 Granted with Second Breakthrough Therapy Designation, as The First KRAS G12D Inhibitor Monotherapy Included in China's Breakthrough Therapy Designation List for Pancreatic Cancer Treatment

GenFleet Therapeutics (Shanghai) Inc.

勁方醫藥科技(上海)股份有限公司

(A joint stock company incorporated in the People's Republic of China with limited liability)

(Stock Code: 2595)

VOLUNTARY ANNOUNCEMENT

GFH375 Granted with Second Breakthrough Therapy Designation, as The First KRAS G12D Inhibitor Monotherapy Included in China's Breakthrough Therapy

Designation List for Pancreatic Cancer Treatment

This announcement is made by GenFleet Therapeutics (Shanghai) Inc. (the "Company" or "GenFleet", together with its subsidiaries, the "Group") on a voluntary basis to inform the shareholders and potential investors of the Company about the latest business updates of the Group.

The board of directors of the Company (the "Board") is pleased to announce oral KRAS G12D (ON/OFF) inhibitor GFH375 has been granted with the Breakthrough Therapy Designation (BTD) by the Center for Drug Evaluation of China's National Medical Products Administration. The designation is intended for GFH375 monotherapy treating patients with KRAS G12D-mutant metastatic pancreatic cancer who have received at least one prior systemic therapy, representing China's first BTD inclusion of KRAS G12D inhibitor monotherapy for pancreatic cancer. Earlier this year, GFH375 became the first KRAS G12D inhibitor granted with China's BTD for treatment of non-small cell lung cancer. GenFleet's partner Verastem Oncology started overseas development of GFH375 (known as VS-7375 outside of China) in 2025, and VS-7375 was granted with US FDA's Fast Track Designation for the treatment of KRAS G12D-mutant pancreatic ductal adenocarcinoma across all lines of therapy.

GFH375 entered the world's first phase III registrational study of a KRAS G12D inhibitor monotherapy (GFH375X1301) in 2025. This is also the world's first registrational study of an oral KRAS G12D inhibitor, being conducted in approximately 40 clinical sites in China. GFH375 received clinical trial approval in China for a phase I/II trial in June 2024; the monotherapy data from treating solid tumors, pancreatic ductal adenocarcinoma and non-small cell lung cancer were selected as late-breaking abstracts and oral presentations at the ASCO, WCLC and ESMO annul meetings consecutively in 2025. Multiple monotherapy and combination trials of GFH375/VS- 7375 are currently underway in all lines of setting in China (by GenFleet) and outside of China (by Verastem).

"We are delighted that the product has received multiple regulatory designations in China and globally, vindicating the promising efficacy of GFH375 in various cancer types. In the clinical development of GFH375, we are deeply impressed with the urgent need for innovative targeted therapies among patients with pancreatic cancer and KRAS G12D mutations. GenFleet looks forward to the continued progress of GFH375's clinical programs to bring new treatment options for patients. We expect to disclose updated data from GFH375 trials across various indications at academic conferences this year." stated Yu Wang, M.D.,Ph.D., Chief Medical Officer of GenFleet.

Pancreatic cancer is among the most aggressive malignancies due to its rapid progression, high tumor heterogeneity and complex tumor microenvironment, with a 5year survival rate below 10%. RAS mutations occur in up to 90% of pancreatic cancer cases (with a KRAS G12D mutation ratio of approximately 40%). Patients with KRAS G12D mutations have significantly shorter overall survival and relapse-free survival compared to those with wild-type KRAS or other KRAS mutant subtypes. GenFleet's pipeline features top-tier selective and Pan RAS inhibitors, together with a bispecific antibody for cancer cachexia, which are poised to establish a novel targeted matrix for pancreatic cancer. The Company's collaborative project, "Research on the Pathogenesis of Pancreatic Cancer and a New Paradigm for Precise Clinical Diagnosis and Treatment", was successfully awarded a National Science and Technology Major Project in 2025.

About GFH375/VS-7375

GFH375 is an orally active, potent, highly selective small-molecule KRAS G12D (ON/OFF) inhibitor designed to target the GTP/GDP exchange, thereby disrupting the activation of downstream pathways and effectively inhibiting tumor cell proliferation. Preclinical studies demonstrated dose-dependent inhibition in models bearing KRAS G12D mutation; GFH375 also demonstrated low off-target risk in kinase selectivity and safety target assays. GenFleet entered into a discovery and development collaboration with Verastem to advance three novel oncology discovery programs related to RAS/MAPK pathway-driven cancers. The collaboration provides Verastem with an exclusive option to obtain a license for each of the three compounds in the collaboration after the successful completion of pre-determined milestones in a Phase I trial. Verastem selected GFH375/VS-7375, an oral KRAS G12D (ON/OFF) inhibitor, as its lead program from the collaboration, in December 2023 and the license for GFH375 that was exercised in January 2025 is the first one from this collaboration. The licenses would give Verastem development and commercialization rights outside of China while

GenFleet would retain rights inside of China.

Forward-looking Statements

Specific information in this announcement may contain or constitute forward-looking words that are not historical facts. They can be identified by using forward-looking terminology, such as "predict", "believe", "plan", "forecast", "expect", "will", "may", "should" and other words of similar meanings. Based on the management's current beliefs, plans, estimates and expectations of the Company's operation and market trends subject to changes beyond control, the forward-looking terminology reflects the Company's beliefs, plans, estimates and expectations of future development. Actual outcome in the future may differ significantly from forward-looking words owing to market, policy, and R&D uncertainties, among others. Subject to the above-mentioned uncertainties, the Company makes no expressed or implied guarantee as to the accuracy, completeness or feasibility of this presentation, and you are cautioned not to solely rely on such forward-looking words. Neither the company nor any of its directors, officers, employees, shareholders, agents, related parties, consultants or representatives will be liable to you or any other person for consequences resulting from using this presentation. Investors are advised to exercise due diligence with reference to the company's official disclosures for decision-making.

GLOSSARY OF TECHNICAL TERMS

"ASCO" American Society of Clinical Oncology

"BTD" Breakthrough Therapy Designation

"ESMO" European Society for Medical Oncology

"FDA" U.S. Food and Drug Administration

"KRAS" Kirsten RAS, a member of the RAS family of proteins

"MAPK" mitogen-activated protein kinase, a family of proteins

involved in transmitting signals from cell surface receptors

to the nucleus

"RAS" ras sarcoma, a family of proteins that are critical regulators

of cellular signaling pathways; it primarily includes HRAS,

KRAS, and NRAS

"WCLC" World Conference on Lung Cancer

Cautionary Statement required by Rule 18A.05 of the Rules Governing the Listing

of Securities on The Stock Exchange of Hong Kong Limited: The Company cannot guarantee that it will be able to develop, or ultimately market GFH375 successfully. Shareholders and potential investors of the Company are advised to exercise caution when dealing in the shares of the Company.

By order of the Board

GenFleet Therapeutics (Shanghai) Inc. Dr. Qiang LU

Chairman and Executive Director

Hong Kong, April 9, 2026