Protagonist Reports Third Quarter 2023 Financial Results and Provides Corporate Update Five rusfertide abstracts accepted for oral and poster presentations at the 65 th ASH Annual Meeting and Exposition (ASH2023) Positiv

Reports Third Quarter 2023 Financial Results and Provides Corporate Update

rusfertide abstracts accepted for oral and poster presentations at the 65th ASH Annual Meeting and Exposition (ASH2023)

topline results from the Phase 2b FRONTIER 1 study of JNJ-2113 (formerly PN-235), the first- and only-in-class oral IL-23 receptor antagonist

peptide drug candidate for moderate-to-severe plaque psoriasis presented in July 2023

clinical development program advances with two Phase 3 studies in moderate-to-severe psoriasis and a Phase 2b study in moderately-to-severely

active ulcerative colitis (UC) commencing in Q4 2023; additional Phase 3 studies in psoriasis expected to begin in Q1 2024

cash runway through Q1 20261

Calif., November 2, 2023 - Protagonist Therapeutics (Nasdaq: PTGX) ("Protagonist" or "the

Company") today reported financial results for the third quarter ended September 30, 2023, and provided a corporate update.

quarter of 2023, Protagonist continued to make rapid progress with its key programs," said Dinesh V. Patel, Ph.D., the Company's

President and CEO. "Positive Phase 2b data from the FRONTIER 1 study with JNJ-2113, established it as a first- and only-in-class

oral IL-23 receptor antagonist peptide and triggered the decision to progress into several advanced studies for broad clinical development.

In October 2023, Janssen initiated two Phase 3 psoriasis studies, and a Phase 2b ulcerative colitis study, and plans to undertake additional

Phase 3 psoriasis studies in the first quarter of next year. The extraordinary pace of progress in multiple indications reflects strong

confidence in JNJ-2113's potential to have a meaningful impact on these and other diseases mediated by the IL-23 pathway."

Dr. Patel continued:

"We are equally excited about the potential of rusfertide, currently in the Phase 3 VERIFY study, to transform the treatment paradigm

for polycythemia vera. We are very pleased with the continuing level of enthusiasm among PV-treating physicians and patients participating

in the ongoing Phase 3 VERIFY study and look forward to sharing our latest findings in Polycythemia Vera and from our ongoing studies

through five oral and poster presentations at the upcoming ASH2023 Annual Meeting."

Based on $322.7 million in cash, cash equivalents and marketable securities as of September

30, 2023 and including expected $60.0 million in JNJ-2113 milestones.

Corporate Highlights

Poster presentations

At the 5th International

Congress on Myeloproliferative Neoplasms, held November 2-3, 2023, Dr. Naveen Pemmaraju presented a poster titled, "Summary of

Malignancies Observed Across 5 Open Label Clinical Trials of the Hepcidin Mimetic Rusfertide." The poster can be found on the Protagonist

corporate website at https://www.protagonist-inc.com/publications.

Third Quarter 2023 Financial Results

Therapeutics is a biopharmaceutical company with peptide-based new chemical entities (NCEs) rusfertide and JNJ-2113 (formerly PN-235)

in advanced stages of clinical development, both derived from the Company's proprietary technology platform. Protagonist and Janssen

scientists jointly discovered PN-235 (now known as JNJ-2113) as part of Protagonist's Interleukin-23 receptor (IL-23R) collaboration

with Janssen and followed it through IND-enabling pre-clinical and Phase 1 studies, with Janssen assuming responsibility for further

clinical development. Rusfertide, a mimetic of the natural hormone hepcidin, is the Company's lead drug candidate currently in a global

Phase 3 development program. The randomized portion of the Phase 2 REVIVE study was unblinded, showing positive results and is now complete,

with an open-label extension underway. The global Phase 3 VERIFY study of rusfertide in polycythemia vera is ongoing. Protagonist retains

all worldwide development and commercialization rights to rusfertide.

information on Protagonist, its pipeline drug candidates and clinical studies can be found on the Company's website at www.protagonist-inc.com.

Note on Forward-Looking Statements

press release contains forward-looking statements for purposes of the safe harbor provisions of the Private Securities Litigation Reform

Act of 1995. Forward-looking statements include statements regarding the potential benefits of rusfertide and JNJ-2113, our expectations

regarding the clinical development of JNJ-2113 and our potential receipt of milestone and royalty payments under our collaboration agreement

with Janssen. In some cases, you can identify these statements by forward-looking words such as "anticipate," "believe,"

"may," "will," "expect," or the negative or plural of these words or similar expressions. Forward-looking

statements are not guarantees of future performance and are subject to risks and uncertainties that could cause actual results and events

to differ materially from those anticipated, including, but not limited to, our ability to develop and commercialize our product candidates,

our ability to earn milestone payments under our collaboration agreement with Janssen, our ability to use and expand our programs to

build a pipeline of product candidates, our ability to obtain and maintain regulatory approval of our product candidates, our ability

to operate in a competitive industry and compete successfully against competitors that have greater resources than we do, and our ability

to obtain and adequately protect intellectual property rights for our product candidates. Additional information concerning these and

other risk factors affecting our business can be found in our periodic filings with the Securities and Exchange Commission, including

under the heading "Risk Factors" contained in our most recently filed periodic reports on Form 10-K and Form 10-Q filed with

the Securities and Exchange Commission. Forward-looking statements are not guarantees of future performance, and our actual results of

operations, financial condition and liquidity, and the development of the industry in which we operate, may differ materially from the

forward-looking statements contained in this press release. Any forward-looking statements that we make in this press release speak only

as of the date of this press release. We assume no obligation to update our forward-looking statements, whether as a result of new information,

future events or otherwise, after the date of this press release.

Consolidated Statements of Operations

in thousands except share and per share data)

(1) Amount includes non-cash stock-based compensation expense.

PROTAGONIST THERAPEUTICS, INC.

Stock-based Compensation

Selected Consolidated Balance Sheet Data