Amendment: SEC Form SCHEDULE 13D/A filed by Athira Pharma Inc.

The address of the principal business office of PXV II is 51 Astor Place 10th Floor, New York, NY 10003.

The principal business of PXV II is to invest in securities.

During the last five years, PXV II has not been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).

During the last five years, PXV II has not been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree of final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws, other than the previously announced settlement order entered into by Perceptive Advisors with the Securities and Exchange Commission dated September 6, 2022 (File No. 3-21031).

PXV II is a Delaware limited partnership.

Item 3 of the Schedule 13D is amended and supplemented as follows: The shares of Common Stock and Warrants purchased by the Master Fund and PXV II pursuant to the Securities Purchase Agreement described in Amendment No. 4 to the Schedule 13D and set forth in Item 5(c) of this Amendment No. 5 were purchased using the working capital of the Master Fund and PXV II for an aggregate purchase price of $19,998,167.53.

Item 4 of the Schedule 13D is amended and supplemented as follows: The information set forth in Item 6 of this Amendment No. 5 is incorporated by reference to this Item 4.

Item 5 of the Schedule 13D is amended and supplemented as follows: The information set forth in rows 11 and 13 of the cover pages to this Schedule 13D is incorporated by reference. The percentages set forth in row 13 are based on an aggregate of 9,300,434 shares of Common Stock outstanding, consisting of (i) 3,943,887 shares of Common Stock outstanding as of November 5, 2025, as disclosed by the Issuer in its Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (the "SEC") on November 6, 2025, and (ii) 5,356,547 shares of Common Stock issued in the Private Placement.

The information set forth in rows 7 through 10 of the cover pages to this Schedule 13D is incorporated by reference. Mr. Edelman's cover page includes 9,728 shares of Common Stock that may be acquired upon the exercise of vested options awarded to Mr. Edelman in connection with his role as a director of the Issuer. As of the date hereof, the Beneficial Ownership Limitation does not permit the Master Fund or PXV II to exercise any of their Warrants.

On December 18, 2025, the Master Fund and PXV II acquired 989,270 shares and 329,756 shares of Common Stock, respectively, at a purchase price of $6.35 per share, 1,372,935 and 457,645 Pre-Funded Warrants, respectively, at a purchase price of $6.349 per share, 3,838,583 and 1,279,526 Series A Warrants and 3,543,307 and 1,181,101 Series B Warrants, respectively, pursuant to the transactions contemplated by the Securities Purchase Agreement. Except for the transactions described in this Item 5(c), none of the Reporting Persons has effected any transaction in shares of Common Stock since the filing of Amendment No. 4 to the Schedule 13D, filed with the Securities and Exchange Commission on December 22, 2025.

Item 6 of the Schedule 13D is amended and supplemented as follows: In connection with the closing of the transactions contemplated by the Securities Purchase Agreement, on December 23, 2025, the Master Fund and PXV II entered into a registration rights agreement (the "Registration Rights Agreement") with the Issuer pursuant to which the Issuer agreed to prepare and file a registration statement to register the resale of the shares of Common Stock and shares underlying Warrants purchased pursuant to the Securities Purchase Agreement within thirty calendar days after the date of the Closing and to use reasonable best efforts to have the registration statement declared effective at the earliest possible date but no later than the earlier of (a) seventy-five calendar days after the filing date if the SEC notifies the Issuer that it will review the registration statement and (b) the fifth business day after the Issuer is notified by the SEC that the registration statement will not be reviewed or will not be subject to further review. If the Issuer fails to meet certain of the requirements in the Registration Rights Agreement following the Closing, the Issuer will pay liquidated damages to the Master Fund and PXV II as provided in the PIPE Registration Rights Agreement. The foregoing description of the Registration Rights AGreement is qualified in its entirety by reference to the full text of the agreement, a copy of which is included as Exhibit 8 hereto.

Item 7 of the Schedule 13D is hereby amended and supplemented as follows: Exhibit 7 Joint Filing Agreement Exhibit 8 Form of Registration Rights Agreement (incorporated by reference to Exhibit 4.5 to the Issuer's Current Report on Form 8-K/A filed with the Securities and Exchange Commission on December 18, 2025)