Item 4 of the Schedule 13D is hereby amended by incorporating the following:

On February 21, 2024, at 9:00 a.m. (Beijing Time), an extraordinary general meeting of the shareholders of the Company was held at 1/F, Building 11, Zone 1, No. 8 Life Science Parkway, Changping District, Beijing, the People’s Republic of China. At the extraordinary general meeting, the shareholders of the Company authorized and approved the Merger Agreement, the Plan of Merger required to be registered with the Registrar of Companies of the Cayman Islands in connection with the Merger and the consummation of the transactions contemplated thereby, including the Merger.

On March 28, 2024, the Company and Merger Sub filed the Plan of Merger with the Registrar of Companies of the Cayman Islands, which was registered by the Registrar of Companies of the Cayman Islands as of March 28, 2024, pursuant to which the Merger became effective on March 28, 2024 (the “Effective Time”). As a result of the Merger, the Company became a wholly owned subsidiary of Parent.

The consummation of the Merger was financed through a combination of (i) rollover equity from the Rollover Shareholders, and (ii) cash contributions by the Sponsors in the amount of US$52.4 million. Due to certain logistics matters in relation to the equity rollover, two Rollover Shareholders (the “Electing Rollover Shareholders”) elected to pay to Parent an aggregate amount equal to the product of (x) the number of ADSs representing Shares such Electing Rollover Shareholders agreed to rollover pursuant to the Support Agreement, and (y) the Per ADS Merger Consideration, and will receive, through Depositary, such aggregate amount (excluding any fees, including ADS cancellation or termination fees, payable by such Electing Rollover Shareholders in accordance with the deposit agreement, dated June 18, 2020, entered into by and among the Company, the Depositary and all holders and beneficial owners of ADSs issued thereunder). As a result, the aggregate merger consideration paid by the Buyer Group and the ordinary shares of Parent that the Electing Rollover Shareholders received upon Effective Time remained the same.

At the Effective Time, each ordinary share issued and outstanding immediately prior to the Effective Time, other than the Excluded Shares (excluding certain Excluded Shares beneficially owned by the Electing Rollover Shareholders) and Shares represented by ADSs, was cancelled and ceased to exist in exchange for the right to receive US$0.272 per ordinary share in cash, and each ADS issued and outstanding immediately prior to the Effective Time (including certain rollover ADSs owned by the Electing Rollover Shareholders), together with the Shares represented by such ADSs, was cancelled and ceased to exist in exchange for the right to receive US$4.08 per ADS in cash. The aggregate amount of merger consideration paid for the rollover ADSs owned by the Electing Rollover Shareholders was borne by such Electing Rollover Shareholders and not Sponsors. At the Effective Time, the Excluded Shares (other than certain Excluded Shares beneficially owned by the Electing Rollover Shareholders in the form of ADSs), issued and outstanding immediately prior to the Effective Time, were cancelled and ceased to exist without payment of any consideration or distribution therefor.

As a result of the Merger, the ADS program for the ADSs will terminate and the ADSs will no longer be listed on any securities exchange or quotation system, including Nasdaq Global Market (“Nasdaq”), and the Company will cease to be a publicly traded company. The Nasdaq has filed an application on Form 25 with the SEC to remove the ADSs from listing on Nasdaq and withdraw registration of the Company’s registered securities under the  Act. The deregistration will become effective 90 days after the filing of Form 25 or such shorter period as may be determined by the SEC. The Company intends to suspend its reporting obligations under the Act by filing a certification and notice on Form 15 with the SEC. The Company’s reporting obligations under the Act will be suspended immediately as of the filing date of the Form 15 and will cease once the deregistration becomes effective. Accordingly, this Amendment No. 1 constitutes an exit filing for the Reporting Persons.