UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington,D.C. 20549

Form6-K

Report of Foreign Private Issuer

Pursuant to Rule 13a-16 or 15d-16

under the Securities Exchange Act of 1934

For the month of November 2025

Commission File Number: 001-42484

ASCENTAGE PHARMA GROUP INTERNATIONAL

(Translation of Registrant’s name intoEnglish)

68 Xinqing Road

Suzhou Industrial Park

Suzhou, Jiangsu

China

(Address of principal executive offices)

Indicate by check mark whether the registrantfiles or will file annual reports under cover of Form 20-F or Form 40-F. Form 20-F ☒ Form40-F ☐

EXPLANATORY NOTE

On November 19, 2025, AscentagePharma Group International issued a press release entitled “Ascentage Pharma to Participate in Three Upcoming Investor Conferencesin December 2025”. A copy of the press release is furnished as Exhibit 99.1 to this Report.

INDEX TO EXHIBITS

SIGNATURE

Pursuant to the requirementsof the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereuntoduly authorized.

Exhibit99.1

AscentagePharma to Participate in Three Upcoming Investor Conferences in December 2025

ROCKVILLE,MD. and SUZHOU, China, November 19, 2025 -- Ascentage Pharma Group International (NASDAQ: AAPG; HKEX: 6855) (“Ascentage Pharma”or the “Company”), a global, commercial stage, integrated biopharmaceutical company engaged in the discovery, developmentand commercialization of novel, differentiated therapies to address unmet medical needs in cancer, announced today that the Company’smanagement is scheduled to participate in three upcoming investor conferences in December 2025.

AboutAscentage Pharma Group International

AscentagePharma Group International (NASDAQ: AAPG; HKEX: 6855) (“Ascentage Pharma” or the “Company”) is a global, commercialstage, integrated biopharmaceutical company engaged in the discovery, development and commercialization of novel, differentiated therapiesto address unmet medical needs in cancer. The Company has built a rich pipeline of innovative drug products and candidates that includesinhibitors targeting key apoptotic pathway proteins, such as Bcl-2 and MDM2-p53, as well as next-generation kinase inhibitors.

AscentagePharma’s first approved product, Olverembatinib, is the first novel third-generation BCR-ABL1 inhibitor approved in China for the treatmentof patients with CML in chronic phase (CML-CP) with T315I mutations, CML in accelerated phase (CML-AP) with T315I mutations, and CML-CPthat is resistant or intolerant to first and second-generation TKIs. All indications are covered by the China National ReimbursementDrug List (NRDL). The Company is currently conducting an FDA-cleared, global registrational Phase III trial, or POLARIS-2, of Olverembatinibfor CML, as well as global registrational Phase III trials for patients with newly diagnosed Ph+ ALL and SDH-deficient GIST patients.

TheCompany’s second approved product, Lisaftoclax, is a novel Bcl-2 inhibitor for the treatment of various hematologic malignancies.Lisaftoclax is being commercialized in China following National Medical Products Administration (NMPA) approval for the treatment ofadult patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) who have previously received at least one systemictherapy including Bruton’s tyrosine kinase (BTK) inhibitors. The Company is currently conducting four global registrational PhaseIII trials: the FDA-cleared GLORA study of Lisaftoclax in combination with BTK inhibitors in patients with CLL/SLL previously treatedwith BTK inhibitors for more than 12 months with suboptimal response; the GLORA-2 study in patients with newly diagnosed CLL/SLL; theGLORA-3 study in newly diagnosed, elderly and unfit patients with acute myeloid leukemia (AML); and the GLORA-4 study in patients withnewly diagnosed higher-risk myelodysplastic syndrome (HR MDS), a study that was simultaneously cleared by the US FDA, the EMA of theEU, and China CDE.

Leveragingits robust R&D capabilities, Ascentage Pharma has built a portfolio of global intellectual property rights and entered into globalpartnerships and other relationships with numerous leading biotechnology and pharmaceutical companies, such as Takeda, AstraZeneca, Merck,Pfizer, and Innovent, in addition to research and development relationships with leading research institutions, such as Dana-Farber CancerInstitute, Mayo Clinic, National Cancer Institute and the University of Michigan. For more information, visit https://ascentage.com/

Forward-LookingStatements

Thispress release includes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and Section27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements, otherthan statements of historical facts, contained in this press release may be forward-looking statements, including statements that expressAscentage Pharma’s opinions, expectations, beliefs, plans, objectives, assumptions or projections regarding future events or futureresults of operations or financial condition.

Theseforward-looking statements are subject to a number of risks and uncertainties as discussed in Ascentage Pharma’s filings with theSEC, including those set forth in the sections titled “Risk factors” and “Special note regarding forward-looking statementsand industry data” in its Registration Statement on Form F-1, as amended, filed with the SEC on January 21, 2025, and the Form20-F filed with the SEC on April 16, 2025, the sections headed “Forward-looking Statements” and “Risk Factors”in the prospectus of the Company for its Hong Kong initial public offering dated October 16, 2019, and other filings with the SEC and/orThe Stock Exchange of Hong Kong Limited we made or make from time to time that may cause actual results, levels of activity, performanceor achievements to be materially different from the information expressed or implied by these forward-looking statements. The forward-lookingstatements contained in this presentation do not constitute profit forecast by the Company’s management.

Asa result of these factors, you should not rely on these forward-looking statements as predictions of future events. The forward-lookingstatements contained in this press release are based on Ascentage Pharma’s current expectations and beliefs concerning future developmentsand their potential effects and speak only as of the date of such statements. Ascentage Pharma does not undertake any obligation to updateor revise any forward-looking statements, whether as a result of new information, future events or otherwise.

Contacts

Investor Relations:

Stella Yang

Ascentage Pharma

Stella.Yang@ascentage.com

+1 (301) 792-6286

StephanieCarrington

ICR Healthcare

AscentageIR@icrhealthcare.com

+1 (646) 277-1282

MediaRelations:

Sean Leous

ICR Healthcare

AscentagePR@icrhealthcare.com

+1 (646) 866-4012