PTGX

EX-99.1

2 tm2613550d1_ex99-1.htm

EXHIBIT 99.1

Exhibit 99.1

Protagonist Reports First Quarter 2026 Financial Results and Provides Corporate Update

ICOTYDE™ (icotrokinra) approved by FDA in March for moderate-to-severe plaque psoriasis, triggering a $50 million milestone payment; Protagonist receives tiered royalties of 6% to 10% and is eligible for up to $580 million in future milestone payments

Rusfertide NDA accepted and granted Priority Review by FDA, with a Prescription Drug User Fee Act target action date in the third quarter of 2026

Protagonist exercised its rusfertide opt-out

right under the Takeda collaboration on April 28, triggering a $200 million opt-out fee payable to the Company; eligible for additional $200 million opt-out and $75 million milestone payments upon NDA approval, sales milestones of up to $775 million and worldwide royalties ranging from 14% to 29%

PN-881 (oral IL-17 antagonist peptide) Phase

1 study completion by mid-2026 and Phase 2 initiation anticipated by year-end; PN-477sc and PN-477o (sc and oral triple GLP/GIP/GICG agonist) Phase 1 initiation expected in mid-2026 and Q1 2027, respectively

Cash, cash equivalents and marketable securities of $620 million as of March 31, 2026, anticipated to provide cash runway through at least 2028

NEWARK,

Calif., May 5, 2026 – Protagonist Therapeutics (Nasdaq: PTGX) (“Protagonist” or “the Company”) today reported financial results for the first quarter ended March 31, 2026, and provided a corporate update.

“The first quarter of 2026 marked a series of landmark achievements for Protagonist, highlighted by the U.S. approval of ICOTYDE, FDA granting Priority Review for rusfertide, and advancement of our highly differentiated and fully-owned peptides PN-881 and PN-477,” said Dinesh V. Patel, Ph.D., the Company’s President and Chief Executive Officer. “These accomplishments, together with the additional financial resources afforded by our rusfertide opt-out election and future milestones and royalty payments from ICOTYDE and rusfertide, position Protagonist for meaningful near-, medium and long-term value creation through rapid progression of clinical stage assets and further expansion into new internal discovery programs. In addition, we look forward to implementing an efficient capital return strategy at the appropriate time.”

First Quarter 2026 Recent Developments and Upcoming Milestones

Rusfertide

On March 2, Takeda and Protagonist announced that the U.S. FDA accepted the New Drug Application for rusfertide and granted Priority Review. The application is supported by data from the positive 32-week primary analysis and 52-week results from the Phase 3 global randomized VERIFY study, as well as four-year efficacy and safety data from the Phase 2 REVIVE study and long-term extension THRIVE study. The FDA set a PDUFA goal date in August 2026.

On April 28, Protagonist announced that it exercised its right to opt out of the U.S. profit and loss sharing arrangement under the terms of its collaboration agreement with Takeda for rusfertide. The opt-out election triggers a $200 million payment to Protagonist, with an additional $200 opt-out fee and a separate $75 million milestone for FDA approval of rusfertide. The opt-out election also increases downstream economics payable to Protagonist, including up to $775 million in sales milestone payments and tiered worldwide royalties ranging from 14% to 29%. At $1.5 billion in annual net sales, the weighted-average royalty rate is approximately 21%, with the 29% tier applying to annual sales above $1.5 billion.

ICOTYDE™

(icotrokina)

On March 18, Protagonist announced that Johnson & Johnson received U.S. Food and Drug Administration approval for ICOTYDE for the treatment of moderate-to-severe plaque psoriasis in adults and pediatric patients 12 years of age and older who weigh at least 40 kg and are candidates for systemic therapy or phototherapy. The FDA approval triggered a $50 million milestone payment to Protagonist in the first quarter of 2026. Under the collaboration, Protagonist remains eligible to receive up to $580 million in potential additional regulatory and sales milestone payments, as well as tiered royalties ranging from 6% to 10% on global net sales with an approximate 7.25% weighted-average royalty rate at $4 billion in annual net sales and a 10% tier applying to the incremental annual sales above $4 billion. ICOTYDE is the first and only FDA-approved targeted oral peptide for moderate-to-severe plaque psoriasis

On March 28, Protagonist announced presentation of new one-year Phase 3 ICOTYDE results at the 2026 American Academy of Dermatology Annual Meeting. Data from the Phase 3 ICONIC-ADVANCE 1 and 2 and ICONIC-LEAD studies further supported the potential of ICOTYDE as a differentiated oral therapy for patients with moderate-to-severe plaque psoriasis, demonstrating durable efficacy and a favorable safety profile in a once-daily pill.

Wholly-Owned Clinical and Discovery Prog

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): February 25, 2026

PROTAGONIST THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

Delaware

001-37852

98-0505495

(State or other jurisdiction

of incorporation)

(Commission

File Number)

(IRS Employer

Identification No.)

Protagonist Therapeutics, Inc.

7707 Gateway Blvd., Suite 140

Newark, California 94560-1160

(Address of principal executive offices, including zip code)

(510) 474-0170

(Registrant’s telephone number, including area code)

Not Applicable

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading Symbol(s)

Name of each exchange on which

registered

Common Stock, par value $0.00001

PTGX

The Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

Item 2.02. Results of Operations and Financial Condition.

On February 25, 2026, Protagonist Therapeutics, Inc. reported its financial results for the fourth quarter and full year ended December 31, 2025. A copy of the press release titled “Protagonist Reports Fourth Quarter and Full Year 2025 Financial Results and Provides Corporate Update” is furnished pursuant to Item 2.02 as Exhibit 99.1 hereto and is incorporated herein by reference.

Item 9.01  Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.

Description

99.1

Press release, dated February 25, 2026, titled “Protagonist Reports Fourth Quarter and Full Year 2025 Financial Results and Provides Corporate Update.”

104

Cover Page Interactive Data File (embedded within the Inline XBRL document).

The information in this report, including the exhibit hereto, shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of Section 11 and 12(a)(2) of the Securities Act of 1933, as amended. The information contained herein and in the accompanying exhibit shall not be incorporated by reference into any filing with the U.S. Securities and Exchange Commission made by Protagonist Therapeutics, Inc., whether made before or after the date hereof, regardless of any general incorporation language in such filing.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Protagonist Therapeutics, Inc.

Dated: February 25, 2026

By: /s/ Asif Ali

Asif Ali

Chief Financial Officer

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): November 6, 2025

PROTAGONIST THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

Delaware

001-37852

98-0505495

(State or other jurisdiction

of incorporation)

(Commission

File Number)

(IRS Employer

Identification No.)

Protagonist Therapeutics, Inc.

7707 Gateway Blvd., Suite 140

Newark, California 94560-1160

(Address of principal executive offices, including zip code)

(510) 474-0170

(Registrant’s telephone number, including area code)

Not Applicable

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading Symbol(s)

Name of each exchange on which

registered

Common Stock, par value $0.00001

PTGX

The Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

Item 2.02. Results of Operations and Financial Condition.

On November 6, 2025, Protagonist Therapeutics, Inc. reported its financial results for the quarter ended September 30, 2025. A copy of the press release titled “Protagonist Reports Third Quarter 2025 Financial Results and Provides Corporate Update” is furnished pursuant to Item 2.02 as Exhibit 99.1 hereto and is incorporated herein by reference.

Item 9.01  Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.

Description

99.1

Press release, dated November 6, 2025, titled “Protagonist Reports Third Quarter 2025 Financial Results and Provides Corporate Update.”

104

Cover Page Interactive Data File (embedded within the Inline XBRL document).

The information in this report, including the exhibit hereto, shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of Section 11 and 12(a)(2) of the Securities Act of 1933, as amended. The information contained herein and in the accompanying exhibit shall not be incorporated by reference into any filing with the U.S. Securities and Exchange Commission made by Protagonist Therapeutics, Inc., whether made before or after the date hereof, regardless of any general incorporation language in such filing.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Protagonist Therapeutics, Inc.

Dated: November 6, 2025

By: /s/ Asif Ali

Asif Ali

Chief Financial Officer