UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

(Rule 13d-102)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT

TO RULES 13d-1(b), (c), AND (d) AND AMENDMENTS THERETO FILED

PURSUANT TO RULE 13d-2(b)

(Amendment No. )¹

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

1              The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Pieris Pharmaceuticals, Inc., a Nevada corporation (the “Issuer”).

225 Franklin Street, 26th Floor

Boston, MA 02110

Biotechnology Value Fund, L.P. (“BVF”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

BVF I GP LLC (“BVF GP”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

Biotechnology Value Fund II, L.P. (“BVF2”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

BVF II GP LLC (“BVF2 GP”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

Biotechnology Value Trading Fund OS LP (“Trading Fund OS”)

PO Box 309 Ugland House

Grand Cayman, KY1-1104

Cayman Islands

Citizenship: Cayman Islands

BVF Partners OS Ltd. (“Partners OS”)

PO Box 309 Ugland House

Grand Cayman, KY1-1104

Cayman Islands

Citizenship: Cayman Islands

BVF GP Holdings LLC (“BVF GPH”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

BVF Partners L.P. (“Partners”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

BVF Inc.

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: Delaware

Mark N. Lampert (“Mr. Lampert”)

44 Montgomery St., 40th Floor

San Francisco, California 94104

Citizenship: United States

Each of the foregoing is referred to as a “Reporting Person” and collectively as the “Reporting Persons.”

Common Stock, $0.001 par value per share (the “Shares”)

720795202

As of the close of business on the date hereof, the Reporting Persons hold an aggregate of 85 shares of Series A Convertible Preferred Stock (the “Series A Preferred Stock”), convertible into an aggregate of 1,133 Shares. Each share of the Series A Preferred Stock is convertible into 13.34 Shares. The Series A Preferred Stock may not be converted if, after such conversion, the Reporting Persons would beneficially own, as determined in accordance with Section 13(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), more than 9.99% of the number of Shares then issued and outstanding (the “Conversion A Limitation”). As of the close of business on the date hereof, the Conversion A Limitation prohibits the conversion of all of the Series A Preferred Stock held by the Reporting Persons.

As of the close of business on the date hereof, the Reporting Persons hold an aggregate of 4,026 shares of Series B Convertible Preferred Stock (the “Series B Preferred Stock”), convertible into an aggregate of 53,706 Shares. Each share of the Series B Preferred Stock is convertible into 13.34 Shares. The Series B Preferred Stock may not be converted if, after such conversion, the Reporting Persons would beneficially own, as determined in accordance with Section 13(d) of the Exchange Act, more than 9.99% of the number of Shares then issued and outstanding (the “Conversion B Limitation”). As of the close of business on the date hereof, the Conversion B Limitation prohibits the conversion of all of the Series B Preferred Stock held by the Reporting Persons.

As of the close of business on the date hereof, the Reporting Persons hold an aggregate of 3,506 shares of Series C Convertible Preferred Stock (the “Series C Preferred Stock”), convertible into an aggregate of 46,770 Shares. Each share of the Series C Preferred Stock is convertible into 13.34 Shares. The Series C Preferred Stock may not be converted if, after such conversion, the Reporting Persons would beneficially own, as determined in accordance with Section 13(d) of the Exchange Act, more than 9.99% of the number of Shares then issued and outstanding (the “Conversion C Limitation”). As of the close of business on the date hereof, the Conversion C Limitation prohibits the conversion of all of the Series C Preferred Stock held by the Reporting Persons.

As of the close of business on the date hereof, the Reporting Persons hold an aggregate of 3,000 shares of Series D Convertible Preferred Stock (the “Series D Preferred Stock”), convertible into an aggregate of 40,020 Shares. Each share of the Series D Preferred Stock is convertible into 13.34 Shares. The Series D Preferred Stock may not be converted if, after such conversion, the Reporting Persons would beneficially own, as determined in accordance with Section 13(d) of the Exchange Act, more than 9.99% of the number of Shares then issued and outstanding (the “Conversion D Limitation”). As of the close of business on the date hereof, the Conversion D Limitation prohibits the conversion of all of the Series D Preferred Stock held by the Reporting Persons.

The Reporting Persons and certain Partners managed accounts (the “Partners Managed Accounts”) hold an aggregate of 5,000 shares of Series E Convertible Preferred Stock (the “Series E Preferred Stock”), convertible into an aggregate of 66,700 Shares. Each share of the Series E Preferred Stock is convertible into 13.34 Shares. The Series E Preferred Stock may not be converted if, after such conversion, the Reporting Persons would beneficially own, as determined in accordance with Section 13(d) of the Exchange Act, more than 9.99% of the number of Shares then issued and outstanding (the “Conversion E Limitation”). As of the close of business on the date hereof, the Conversion E Limitation prohibits the conversion of all of the Series E Preferred Stock held by the Reporting Persons and the Partners Managed Accounts.

The Reporting Persons and the Partners Managed Accounts hold an aggregate of 46,999 Tranche C Warrants (the “C Warrants”) exercisable into an aggregate of 46,999 Shares. The C Warrants have an exercise price of $532.05 per Share. The C Warrants may not be exercised if, after such exercise, the Reporting Persons would beneficially own, as determined in accordance with Section 13(d) of the Exchange Act, more than 9.99% of the number of Shares then issued and outstanding (the “C Warrants Blocker”). As of the close of business on the date hereof, the C Warrants Blocker prohibits the exercise of all of the C Warrants held by the Reporting Persons and the Partners Managed Accounts.

As of the close of business on the date hereof, (i) BVF beneficially owned 137,592 Shares, excluding (a) 27,787 Shares underlying the Series B Preferred Stock held by it, (b) 23,958 Shares issuable upon the conversion of the Series C Preferred Stock held by it, (c) 23,465 Shares issuable upon the conversion of the Series D Preferred Stock held by it, (d) 35,617 Shares issuable upon the conversion of the Series E Preferred Stock held by it, and (e) 23,966 Shares issuable upon the exercise of the C Warrants held by it, (ii) BVF2 beneficially owned 107,264 Shares, excluding (a) 22,131 Shares underlying the Series B Preferred Stock held by it, (b) 19,276 Shares issuable upon the conversion of the Series C Preferred Stock held by it, (c) 14,380 Shares issuable upon the conversion of the Series D Preferred Stock held by it, (d) 24,905 Shares issuable upon the conversion of the Series E Preferred Stock held by it, and (e) 19,283 Shares issuable upon the exercise of the C Warrants held by it, and (iii) Trading Fund OS beneficially owned 9,312 Shares, excluding (a) 1,133 Shares issuable upon the conversion of the Series A Preferred Stock held by it, (b) 3,788 Shares issuable upon the conversion of the Series B Preferred Stock held by it, (c) 3,535 Shares issuable upon the conversion of the Series C Preferred Stock held by it, (d) 2,174 Shares issuable upon the conversion of the Series D Preferred Stock held by it, (e) 2,147 Shares issuable upon the conversion of the Series E Preferred Stock held by it, and (e) 3,536 Shares issuable upon the exercise of the C Warrants held by it.

BVF GP, as the general partner of BVF, may be deemed to beneficially own the 137,592 Shares beneficially owned by BVF.

BVF2 GP, as the general partner of BVF2, may be deemed to beneficially own the 107,264 Shares beneficially owned by BVF2.

Partners OS, as the general partner of Trading Fund OS, may be deemed to beneficially own the 9,312 Shares beneficially owned by Trading Fund OS.

BVF GPH, as the sole member of each of BVF GP and BVF2 GP, may be deemed to beneficially own the 244,856 Shares beneficially owned in the aggregate by BVF and BVF2.

Partners, as the investment manager of BVF, BVF2 and Trading Fund OS, and the sole member of Partners OS, may be deemed to beneficially own the 257,622 Shares beneficially owned in the aggregate by BVF, BVF2 and Trading Fund OS and held in the Partners Managed Accounts, including 3,454 Shares held in the Partners Managed Accounts, and excluding (a) 4,028 Shares issuable upon the exercise of the Series E Preferred Stock held in the Partners Managed Accounts, and (b) 214 Shares issuable upon the exercise of C Warrants held in the Partners Managed Accounts.

BVF Inc., as the general partner of Partners, may be deemed to beneficially own the 257,622 Shares beneficially owned by Partners.

Mr. Lampert, as a director and officer of BVF Inc., may be deemed to beneficially own the 257,622 Shares beneficially owned by BVF Inc.

The foregoing should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of any Shares owned by another Reporting Person. BVF GP disclaims beneficial ownership of the Shares beneficially owned by BVF. BVF2 GP disclaims beneficial ownership of the Shares beneficially owned by BVF2. Partners OS disclaims beneficial ownership of the Shares beneficially owned by Trading Fund OS. BVF GPH disclaims beneficial ownership of the Shares beneficially owned by BVF and BVF2. Each of Partners, BVF Inc. and Mr. Lampert disclaims beneficial ownership of the Shares beneficially owned by BVF, BVF2 and Trading Fund OS and held in the Partners Managed Accounts, and the filing of this statement shall not be construed as an admission that any such person or entity is the beneficial owner of any such securities.

The following percentages are based on 1,320,240 Shares outstanding as of May 9, 2024, which is the total number of Shares outstanding as reported in the Issuer’s Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on May 15, 2024.

As of the close of business on the date hereof, (i) BVF beneficially owned approximately 10.4% of the outstanding Shares, (ii) BVF2 beneficially owned approximately 8.1% of the outstanding Shares, (iii) Trading Fund OS beneficially owned less than 1% of the outstanding Shares, (iv) BVF GP may be deemed to beneficially own approximately 10.4% of the outstanding Shares, (v) BVF2 GP may be deemed to beneficially own approximately 8.1% of the outstanding Shares, (vi) Partners OS may be deemed to beneficially own less than 1% of the outstanding Shares, (vii) BVF GPH may be deemed to beneficially own approximately 18.5% of the outstanding Shares, and (viii) each of Partners, BVF Inc. and Mr. Lampert may be deemed to beneficially own approximately 19.5% of the outstanding Shares (less than 1% of the outstanding Shares are held in the Partners Managed Accounts).

See Cover Pages Items 5-9.

See Cover Pages Items 5-9.

See Cover Pages Items 5-9.

See Cover Pages Items 5-9.

Not Applicable.

BVF GP, BVF GPH, Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the Shares beneficially owned by BVF. BVF2 GP, BVF GPH, Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the Shares beneficially owned by BVF2. Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the Shares beneficially owned by Trading Fund OS and held in the Partners Managed Accounts.

Not Applicable.

See Exhibit 99.1.

Not Applicable.

By signing below each of the undersigned certifies that, to the best of its knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

SIGNATURE

After reasonable inquiry and to the best of his knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

Dated: May 17, 2024