PIRS Pieris Pharmaceuticals Inc

(1) Excludes 1,567,000 shares of Common Stock underlying Series A Preferred Stock (defined in Item 4) currently not convertible due to the Conversion Limitation (defined in Item 4). As of the close of business on June 12, 2018, the Conversion Limitation limits the aggregate conversion of Series A Preferred Stock by the Reporting Persons to 0 out of the 2,907,000 shares of Common Stock underlying the Series A Preferred Stock owned by the Reporting Persons in the aggregate.

Excludes A Warrants (defined in Item 4) to acquire 854,800 shares of Common Stock owned by BVF as a result of the A Warrants Blocker (defined in Item 4). As of the close of business on June 12, 2018, the A Warrants Blocker limits the aggregate exercise of A Warrants by the Reporting Persons to 0 out of the 1,985,200 shares of Common Stock underlying the A Warrants owned by the Reporting Persons in the aggregate.

Excludes B Warrants (defined in Item 4) to acquire 427,400 shares of Common Stock owned by BVF as a result of the B Warrants Blocker (defined in Item 4). As of the close of business on June 12, 2018, the B Warrants Blocker limits the aggregate exercise of B Warrants by the Reporting Persons to 0 out of the 992,600 shares of Common Stock underlying the B Warrants owned by the Reporting Persons in the aggregate.

See Item 4(a) for a full description of the Reporting Person’s beneficial ownership.

(1) Excludes 1,021,000 shares of Common Stock underlying Series A Preferred Stock currently not convertible due to the Conversion Limitation. As of the close of business on June 12, 2018, the Conversion Limitation limits the aggregate conversion of Series A Preferred Stock by the Reporting Persons to 0 out of the 2,907,000 shares of Common Stock underlying the Series A Preferred Stock owned by the Reporting Persons in the aggregate.

Excludes A Warrants to acquire 560,400 shares of Common Stock owned by BVF2 as a result of the A Warrants Blocker. As of the close of business on June 12, 2018, the A Warrants Blocker limits the aggregate exercise of A Warrants by the Reporting Persons to 0 out of the 1,985,200 shares of Common Stock underlying the A Warrants owned by the Reporting Persons in the aggregate.

Excludes B Warrants to acquire 280,200 shares of Common Stock owned by BVF2 as a result of the B Warrants Blocker. As of the close of business on June 12, 2018, the B Warrants Blocker limits the aggregate exercise of B Warrants by the Reporting Persons to 0 out of the 992,600 shares of Common Stock underlying the B Warrants owned by the Reporting Persons in the aggregate.

See Item 4(a) for a full description of the Reporting Person’s beneficial ownership.

(1) Excludes 319,000 shares of Common Stock underlying Series A Preferred Stock currently not convertible due to the Conversion Limitation. As of the close of business on June 12, 2018, the Conversion Limitation limits the aggregate conversion of Series A Preferred Stock by the Reporting Persons to 0 out of the 2,907,000 shares of Common Stock underlying the Series A Preferred Stock owned by the Reporting Persons in the aggregate.

Excludes A Warrants to acquire 167,600 shares of Common Stock owned by Trading Fund OS as a result of the A Warrants Blocker. As of the close of business on June 12, 2018, the A Warrants Blocker limits the aggregate exercise of A Warrants by the Reporting Persons to 0 out of the 1,985,200 shares of Common Stock underlying the A Warrants owned by the Reporting Persons in the aggregate.

Excludes B Warrants to acquire 83,800 shares of Common Stock owned by Trading Fund OS as a result of the B Warrants Blocker. As of the close of business on June 12, 2018, the B Warrants Blocker limits the aggregate exercise of B Warrants by the Reporting Persons to 0 out of the 992,600 shares of Common Stock underlying the B Warrants owned by the Reporting Persons in the aggregate.

See Item 4(a) for a full description of the Reporting Person’s beneficial ownership.

(1) Excludes 319,000 shares of Common Stock underlying Series A Preferred Stock currently not convertible due to the Conversion Limitation. As of the close of business on June 12, 2018, the Conversion Limitation limits the aggregate conversion of Series A Preferred Stock by the Reporting Persons to 0 out of the 2,907,000 shares of Common Stock underlying the Series A Preferred Stock owned by the Reporting Persons in the aggregate.

Excludes A Warrants to acquire 167,600 shares of Common Stock owned by Trading Fund OS as a result of the A Warrants Blocker. As of the close of business on June 12, 2018, the A Warrants Blocker limits the aggregate exercise of A Warrants by the Reporting Persons to 0 out of the 1,985,200 shares of Common Stock underlying the A Warrants owned by the Reporting Persons in the aggregate.

Excludes B Warrants to acquire 83,800 shares of Common Stock owned by Trading Fund OS as a result of the B Warrants Blocker. As of the close of business on June 12, 2018, the B Warrants Blocker limits the aggregate exercise of B Warrants by the Reporting Persons to 0 out of the 992,600 shares of Common Stock underlying the B Warrants owned by the Reporting Persons in the aggregate.

See Item 4(a) for a full description of the Reporting Person’s beneficial ownership.

(1) Excludes 2,907,000 shares of Common Stock underlying Series A Preferred Stock currently not convertible due to the Conversion Limitation. As of the close of business on June 12, 2018, the Conversion Limitation limits the aggregate conversion of Series A Preferred Stock by the Reporting Persons to 0 out of the 2,907,000 shares of Common Stock underlying the Series A Preferred Stock owned by the Reporting Persons in the aggregate.

Excludes A Warrants to acquire 1,985,200 shares of Common Stock as a result of the A Warrants Blocker. As of the close of business on June 12, 2018, the A Warrants Blocker limits the aggregate exercise of A Warrants by the Reporting Persons to 0 out of the 1,985,200 shares of Common Stock underlying the A Warrants owned by the Reporting Persons in the aggregate.

Excludes B Warrants to acquire 992,600 shares of Common Stock as a result of the B Warrants Blocker. As of the close of business on June 12, 2018, the B Warrants Blocker limits the aggregate exercise of B Warrants by the Reporting Persons to 0 out of the 992,600 shares of Common Stock underlying the B Warrants owned by the Reporting Persons in the aggregate.

See Item 4(a) for a full description of the Reporting Person’s beneficial ownership.

(1) Excludes 2,907,000 shares of Common Stock underlying certain Series A Preferred Stock currently not convertible due to the Conversion Limitation. As of the close of business on June 12, 2018, the Conversion Limitation limits the aggregate conversion of Series A Preferred Stock by the Reporting Persons to 0 out of the 2,907,000 shares of Common Stock underlying the Series A Preferred Stock owned by the Reporting Persons in the aggregate.

Excludes A Warrants to acquire 1,985,200 shares of Common Stock as a result of the A Warrants Blocker. As of the close of business on June 12, 2018, the A Warrants Blocker limits the aggregate exercise of A Warrants by the Reporting Persons to 0 out of the 1,985,200 shares of Common Stock underlying the A Warrants owned by the Reporting Persons in the aggregate.

Excludes B Warrants to acquire 992,600 shares of Common Stock as a result of the B Warrants Blocker. As of the close of business on June 12, 2018, the B Warrants Blocker limits the aggregate exercise of B Warrants by the Reporting Persons to 0 out of the 992,600 shares of Common Stock underlying the B Warrants owned by the Reporting Persons in the aggregate.

See Item 4(a) for a full description of the Reporting Person’s beneficial ownership.

(1) Excludes 2,907,000 shares of Common Stock underlying Series A Preferred Stock currently not convertible due to the Conversion Limitation. As of the close of business on June 12, 2018, the Conversion Limitation limits the aggregate conversion of Series A Preferred Stock by the Reporting Persons to 0 out of the 2,907,000 shares of Common Stock underlying the Series A Preferred Stock owned by the Reporting Persons in the aggregate.

Excludes A Warrants to acquire 1,985,200 shares of Common Stock as a result of the A Warrants Blocker. As of the close of business on June 12, 2018, the A Warrants Blocker limits the aggregate exercise of A Warrants by the Reporting Persons to 0 out of the 1,985,200 shares of Common Stock underlying the A Warrants owned by the Reporting Persons in the aggregate.

Excludes B Warrants to acquire 992,600 shares of Common Stock as a result of the B Warrants Blocker. As of the close of business on June 12, 2018, the B Warrants Blocker limits the aggregate exercise of B Warrants by the Reporting Persons to 0 out of the 992,600 shares of Common Stock underlying the B Warrants owned by the Reporting Persons in the aggregate.

See Item 4(a) for a full description of the Reporting Person’s beneficial ownership.

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

255 State Street, 9th Floor
Boston, Massachusetts 02109

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

1 Sansome Street, 30 ^th Floor

San Francisco, California 94104

Citizenship: Delaware

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

1 Sansome Street, 30 ^th 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 Partners L.P. (“Partners”)

1 Sansome Street, 30th Floor

San Francisco, California 94104

Citizenship: Delaware

BVF Inc.

1 Sansome Street, 30 ^th Floor

San Francisco, California 94104

Citizenship: Delaware

Mark N. Lampert (“Mr. Lampert”)

1 Sansome Street, 30 ^th 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, par value $0.001 per share (the “Common Stock”)

720795 10 3

The Reporting Persons hold 2,907 shares of Series A Convertible Preferred Stock, (the “Series A Preferred Stock”) convertible for an aggregate of 2,907,000 shares of Common Stock. Each share of Series A Preferred Stock is convertible into 1,000 shares of Common Stock. 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 of Common Stock then issued and outstanding (the “Conversion Limitation”). As of the close of business on June 12, 2018, the Conversion Limitation limits the aggregate conversion of Series A Preferred Stock by the Reporting Persons to 0 out of the 2,907,000 shares of Common Stock underlying the Series A Preferred Stock owned by the Reporting Persons in the aggregate. In providing beneficial ownership described herein, the Reporting Persons have assumed that the Series A Preferred Stock owned by each of BVF, BVF2 and Trading Fund OS would not be converted due to the Conversion Limitation .

In addition to the Series A Preferred Stock, the Reporting Persons hold 1,985,200 Tranche A Warrants (the “A Warrants”) exercisable for an aggregate of 1,985,200 shares of Common Stock. The A Warrants have an exercise price of $2.00 per share and expire on June 8, 2021. The A 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 of Common Stock then issued and outstanding (the “A Warrants Blocker”). As of the close of business on June 12, 2018, the A Warrants Blocker limits the aggregate exercise of A Warrants by the Reporting Persons to 0 out of the 1,985,200 shares of Common Stock underlying the A Warrants owned by the Reporting Persons in the aggregate. In providing beneficial ownership described herein, the Reporting Persons have assumed the A Warrants owned by each of BVF, BVF2 and Trading Fund OS and held in certain Partners managed accounts (the “Partners Managed Accounts”) would not be exercised due to the A Warrants Blocker.

In addition to the Series A Preferred Stock and A Warrants, the Reporting Persons hold 992,600 Tranche B Warrants (the “B Warrants”) exercisable for an aggregate of 992,600 shares of Common Stock. The B Warrants have an exercise price of $3.00 per share and expire on June 8, 2021. The B 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 of Common Stock then issued and outstanding (the “B Warrants Blocker”). As of the close of business on June 12, 2018, the B Warrants Blocker limits the aggregate exercise of B Warrants by the Reporting Persons to 0 out of the 992,600 shares of Common Stock underlying the B Warrants owned by the Reporting Persons in the aggregate. In providing beneficial ownership described herein, the Reporting Persons have assumed the B Warrants owned by each of BVF, BVF2 and Trading Fund OS and held in the Partners Managed Accounts would not be exercised due to the B Warrants Blocker.

As of the close of business on June 12, 2018, (i) BVF beneficially owned 2,558,773 shares of Common Stock, excluding (a) 1,567,000 shares of Common Stock upon the conversion of Series A Preferred Stock held by it, (b) 854,800 shares of Common Stock issuable upon the exercise of A Warrants held by it, and (c) 427,400 shares of Common Stock issuable upon the exercise of B Warrants held by it; (ii) BVF2 beneficially owned 2,108,048 shares of Common Stock, excluding (a) 1,021,000 shares of Common Stock issuable upon the conversion of Series A Preferred Stock held by it, (b) 560,400 shares of Common Stock issuable upon the exercise of A Warrants held by it, and (c) 280,200 shares of Common Stock issuable upon the exercise of B Warrants held by it; and (iii) Trading Fund OS beneficially owned 308,720 shares of Common Stock, excluding (a) 319,000 shares of Common Stock issuable upon the conversion of Series A Preferred Stock held by it, (b) 167,600 shares of Common Stock issuable upon the exercise of A Warrants held by it, and (c) 83,800 shares of Common Stock issuable upon the exercise of B Warrants held by it.

Partners OS, as the general partner of Trading Fund OS, may be deemed to beneficially own the 308,720 shares of Common Stock beneficially owned by Trading Fund OS.

Partners, as the general partner of BVF, BVF2, the investment manager of Trading Fund OS, and the sole member of Partners OS, may be deemed to beneficially own the 5,626,295 shares of Common Stock beneficially owned in the aggregate by BVF, BVF2 and Trading Fund OS, including 650,754 shares of Common Stock held in the Partners Managed Accounts, and excluding (a) 402,400 shares of Common Stock issuable upon the exercise of A Warrants held in the Partners Managed Accounts and (b) 201,200 shares of Common Stock issuable upon the exercise of B Warrants held in the Partners Managed Accounts.

BVF Inc., as the general partner of Partners, may be deemed to beneficially own the 5,626,295 shares of Common Stock beneficially owned by Partners.

Mr. Lampert, as a director and officer of BVF Inc., may be deemed to beneficially own the 5,626,295 shares of Common Stock 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 of Common Stock owned by another Reporting Person. Partners OS disclaims beneficial ownership of the shares of Common Stock beneficially owned by Trading Fund OS. Each of Partners, BVF Inc. and Mr. Lampert disclaims beneficial ownership of the shares of Common Stock 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 53,989,427 shares of Common Stock outstanding, as of May 25, 2018, which is the total number of shares of Common Stock outstanding as reported in the Issuer’s Definitive Proxy Statement on Form DEF 14A filed with the Securities and Exchange Commission on June 14, 2018.

As of the close of business on July 12, 2018, (i) BVF beneficially owned approximately 4.7% of the outstanding shares of Common Stock, (ii) BVF2 beneficially owned approximately 3.9% of the outstanding shares of Common Stock, (iii) Trading Fund OS beneficially owned less than 1% of the outstanding shares of Common Stock (iv) Partners OS may be deemed to beneficially own less than 1% of the outstanding shares of Common Stock, and (v) each of Partners, BVF Inc. and Mr. Lampert may be deemed to beneficially own approximately 10.4% of the outstanding shares of Common Stock (1.2% of the outstanding shares of Common Stock 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.

Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the shares of Common Stock beneficially owned by BVF, BVF2, Trading Fund OS, and the Partners Managed Accounts.

Not Applicable.

See Exhibit 99.1 to the Schedule 13G filed with the Securities and Exchange Commission on June 17, 2016.

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: July 12, 2018