Protagonist Announces Presentation of One-Year Phase 3 Data for ICOTYDE(TM) in Moderate-to-Severe Plaque Psoriasis at the 2026 American Academy of Dermatology (AAD) Annual Meeting

Rhea-AI Summary

Protagonist (Nasdaq:PTGX) reported one-year Phase 3 results for ICOTYDE in moderate-to-severe plaque psoriasis presented at AAD 2026 showing durable complete skin clearance, a favorable safety profile, and oral once-daily dosing. Adolescents: ~60% PASI100, 86% PASI90; 92% maintained PASI90 from Week 24 to 52.

ICOTYDE demonstrated increased PASI100 from Week 24 to Week 52, no new safety signals through Week 52, and lower overall adverse event and infection rates versus deucravacitinib through Week 24. J&J holds commercialization rights; Protagonist may receive tiered royalties and milestone payments.

Positive

• Adolescents: ~60% PASI100 at Week 52
• 86% PASI90 in adolescents at one year
• 92% of adolescent PASI90 responses maintained from Week 24 to Week 52
• Durable PASI100 increased from Week 24 to Week 52 in adults
• No new safety signals through Week 52
• Lower overall adverse event and infection rates vs deucravacitinib through Week 24

Negative

• No numeric adult PASI100 rate disclosed for Week 52 in the release
• Company retains development royalties; Johnson & Johnson controls commercialization and market execution

Key Figures

Adolescent PASI 100: Nearly 60% Adolescent PASI 90: 86% Maintained PASI 90: 92% +5 more

8 metrics

Adolescent PASI 100 Nearly 60% Adolescents with completely clear skin at one year (ICONIC-LEAD)

Adolescent PASI 90 86% Adolescents achieving PASI 90 at one year (ICONIC-LEAD)

Maintained PASI 90 92% Patients maintaining PASI 90 from Week 24 to Week 52

Phase 3 psoriasis studies 5 studies ICONIC-LEAD, TOTAL, ADVANCE 1 & 2, ASCEND in plaque psoriasis

FDA approval milestone $50 million Milestone to Protagonist on ICOTYDE U.S. approval

Future ICOTYDE milestones $580 million Additional potential milestones from Janssen collaboration

Cash & securities $646.0M Cash and marketable securities at Dec 31, 2025

Net loss 2025 $130.1M Full-year 2025 net loss

Market Reality Check

Price: $98.97 Vol: Volume 781,900 is below t...

normal vol

$98.97 Last Close

Volume Volume 781,900 is below the 20-day average of 972,880, suggesting no outsized trading response pre-announcement. normal

Technical Shares at $98.97 trade above the $73.92 200-day MA and 6.36% below the $105.69 52-week high.

Peers on Argus

PTGX fell 3.13% while key biotech peers showed smaller mixed moves (e.g., MIRM -...

PTGX fell 3.13% while key biotech peers showed smaller mixed moves (e.g., MIRM -1.1%, AKRO +0.24%). No peers appeared in the momentum scanner and there were no same-day peer headlines, pointing to a stock-specific move.

Previous Clinical trial Reports

5 past events · Latest: Jan 05 (Positive)

Same Type Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Jan 05	NDA submission	Positive	-3.4%	FDA NDA submission for rusfertide in PV with positive 52-week Phase 3 data.
Sep 17	Dermatology data	Positive	+1.1%	EADV data showing strong icotyde Phase 3 efficacy and PN-881 preclinical potency.
Jun 01	ASCO VERIFY data	Positive	+5.7%	ASCO plenary VERIFY results with improved response and hematocrit control in PV.
May 09	Psoriasis Phase 3	Positive	-2.2%	ICONIC-TOTAL Phase 3 data on difficult-to-treat psoriasis locations for icotyde.
Apr 23	ASCO plenary notice	Positive	+0.7%	Announcement of VERIFY Phase 3 rusfertide plenary presentation at ASCO 2025.

Pattern Detected

Clinical trial news has produced mixed reactions, with both positive and negative moves and a small average impact around the event date.

Recent Company History

Over the past year, Protagonist has repeatedly reported positive clinical milestones, including Phase 3 data and NDA activities for rusfertide and icotyde. Same-tag events such as VERIFY Phase 3 results in PV and multiple psoriasis datasets often highlighted strong efficacy and safety, yet one-day moves were modest (e.g., -3.44%, +5.65%, -2.16%). Today’s one-year ICOTYDE Phase 3 data fit this pattern of substantial clinical progress with historically variable short-term price reactions.

Historical Comparison

+0.4% avg move · In the last five clinical trial updates, PTGX’s average one-day move was 0.36%, with both rallies an...

clinical trial

+0.4%

Average Historical Move clinical trial

In the last five clinical trial updates, PTGX’s average one-day move was 0.36%, with both rallies and pullbacks, suggesting typically modest immediate reactions to even strong data.

Clinical-trial news shows steady advancement of rusfertide in PV and icotyde in psoriasis from pivotal VERIFY and ICONIC studies toward NDA submission, regulatory review, and broader dermatology presentations.

Regulatory & Risk Context

Active S-3 Shelf

Shelf Active

Active S-3 Shelf Registration 2025-08-06

The company has an effective S-3ASR shelf registration dated 2025-08-06 with no recorded usage to date, indicating capacity for future registered offerings without any disclosed takedowns so far.

Market Pulse Summary

This announcement highlights durable one-year Phase 3 efficacy and safety for ICOTYDE in moderate-to...

Analysis

This announcement highlights durable one-year Phase 3 efficacy and safety for ICOTYDE in moderate-to-severe plaque psoriasis, including high PASI 90 and PASI 100 rates and adolescent data from ICONIC-LEAD. It builds on a series of positive rusfertide and icotyde readouts over 2025–2026. Investors may watch upcoming commercialization by Johnson & Johnson, milestone realizations such as the $50 million payment, and further data from psoriatic arthritis and inflammatory bowel disease studies.

Key Terms

phase 3, il-23 receptor, pasi 100, pasi 90, +4 more

8 terms

phase 3 medical

"One-year Phase 3 data for ICOTYDE to be presented at AAD 2026"

Phase 3 is the late-stage clinical testing step for a new drug or medical treatment, where the product is given to large groups of patients to confirm effectiveness, monitor side effects, and compare it to standard care. Successful Phase 3 results are often the final scientific hurdle before regulators decide on approval and market launch—like passing a final exam before graduation—and can sharply change a company's valuation and future revenue prospects.

il-23 receptor medical

"ICOTYDE is the first and only targeted oral peptide designed to precisely block the IL-23 receptor"

A protein on the surface of certain immune cells that acts like a lock for the signaling molecule interleukin‑23 (IL‑23); when IL‑23 binds this receptor it turns on inflammation and immune activity. Investors care because drugs that block this receptor can calm harmful inflammation in diseases such as psoriasis and inflammatory bowel disease, so its role directly affects drug development prospects, regulatory success, and market value—think of therapies as keys or blockers that disable a problematic lock.

pasi 100 medical

"Rates of PASI 100 increased from Week 24 to Week 52 in the ICOTYDE treatment arms"

PASI 100 is a clinical-trial measure meaning a patient’s psoriasis has cleared completely, showing a 100% improvement on the Psoriasis Area and Severity Index. Think of it like a before-and-after photo where all visible signs of the condition are gone. For investors, PASI 100 signals a therapy’s top-level effectiveness claim, which can drive regulatory approval prospects, market adoption and a product’s commercial value.

pasi 90 medical

"86% achieved PASI 90, with 92% maintaining that response from Week 24 to Week 52"

PASI 90 is a clinical measure showing a 90% reduction in the size and severity of a patient’s psoriasis lesions compared with where they started, based on the Psoriasis Area and Severity Index (PASI). For investors, a drug or therapy that achieves PASI 90 signals very strong effectiveness—like shrinking a visible problem to almost nothing—which can boost the chances of regulatory approval, wider doctor use, higher pricing power and larger sales potential.

psoriatic arthritis medical

"Additional studies are also underway in psoriatic arthritis, ulcerative colitis, and Crohn's disease"

Psoriatic arthritis is a long-term inflammatory disease where the immune system causes both joint pain, swelling and stiffness and patches of scaly skin; think of it as the body’s defenses misfiring and damaging both skin and joints. It matters to investors because it defines a sizable, chronic patient population and drives demand for treatments, influencing drug development, regulatory approvals, pricing and healthcare spending.

ulcerative colitis medical

"Additional studies are also underway in psoriatic arthritis, ulcerative colitis, and Crohn's disease"

A long-term inflammatory disease that causes repeated sores and irritation in the large intestine, leading to symptoms such as abdominal pain, urgent diarrhea, and fatigue. For investors, it matters because the condition creates a steady need for effective treatments, influences the size of drug and medical-device markets, and makes clinical trial results, regulatory decisions and treatment approvals material to companies’ revenue prospects—like watching for fixes to a recurring leak in an important building system.

crohn's disease medical

"Additional studies are also underway in psoriatic arthritis, ulcerative colitis, and Crohn's disease"

A chronic inflammatory condition of the digestive tract in which the body's immune response causes repeated damage and irritation, leading to symptoms like abdominal pain, persistent diarrhea, weight loss and fatigue. It matters to investors because it creates ongoing demand for medications, medical devices and care services, shapes healthcare spending and insurance costs, and drives research and regulatory activity—think of it as a long-term market for treatments where an overactive security system attacks a vital pipeline.

license and collaboration agreement financial

"Under the license and collaboration agreement established in 2017 between Protagonist and Janssen"

A license and collaboration agreement is a contract where one party gives another the legal right to use intellectual property (like a drug formula, technology or brand) and both parties agree to work together to develop, make or sell the resulting product. For investors it matters because the deal spells out who pays, who controls development, how future sales and profits are split, and how risks and costs are shared—so it directly affects a company’s potential revenue, expenses and value, like a partnership for building and selling a new product.

AI-generated analysis. Not financial advice.

One-year Phase 3 data for ICOTYDE to be presented at AAD 2026 demonstrate lasting skin clearance and a favorable safety profile in a once daily pill for moderate-to-severe plaque psoriasis

Results further support the differentiated profile of ICOTYDE, the first and only IL-23 receptor targeted oral peptide

NEWARK, CA / ACCESS Newswire / March 28, 2026 / Protagonist Therapeutics, Inc. (Nasdaq:PTGX) ("Protagonist" or "the Company") today announced new one-year Phase 3 results for ICOTYDE^™ (icotrokinra) were presented at the 2026 American Academy of Dermatology (AAD) Annual Meeting. Data from the Phase 3 ICONIC-ADVANCE 1 and 2 and ICONIC-LEAD studies further support the potential of ICOTYDE as a differentiated oral therapy for patients with moderate-to-severe plaque psoriasis.

"The one-year Phase 3 results presented at AAD reinforce our belief that ICOTYDE by virtue of having IL-23 antagonist efficacy, a favorable safety profile and the convenience of a once-daily oral pill option, has the potential to meaningfully expand treatment options for people living with moderate-to-severe plaque psoriasis," said Dinesh V. Patel, Ph.D., President and Chief Executive Officer of Protagonist Therapeutics. "These findings highlight the power of Protagonist's peptide discovery platform and our ability to create highly differentiated oral medicines against clinically validated biological pathways."

ICOTYDE is the first and only targeted oral peptide designed to precisely block the IL-23 receptor, which underpins the inflammatory response in moderate-to-severe plaque PsO.

ICOTYDE was developed using Protagonist's proprietary peptide technology platform. The Company continues to invest in its discovery engine and development pipeline, with multiple programs moving towards proof-of-concept trials designed to produce therapeutics with clinically relevant competitive differentiation.

Under the license and collaboration agreement established in 2017 between Protagonist and Janssen Biotech, Inc., a Johnson & Johnson company, Johnson & Johnson is responsible for all commercial activities for ICOTYDE. ICOTYDE was jointly discovered by Protagonist and Johnson & Johnson scientists, with Protagonist having primary responsibility for the development of ICOTYDE through Phase 1, and Johnson & Johnson assuming responsibility for further development and commercialization.

ICONIC-ADVANCE 1 & ICONIC-ADVANCE 2

ICOTYDE demonstrated durable rates of complete skin clearance through Week 52 with no new safety signals identified. Rates of PASI 100 increased from Week 24 to Week 52 in the ICOTYDE treatment arms, and patients who switched from placebo to ICOTYDE at Week 16 achieved similar rates of complete skin clearance by Week 52 as those treated with ICOTYDE continuously for 52 weeks. The ICOTYDE adverse event profile through Week 52 was consistent with that observed through Weeks 16 and 24, and no new safety signal was identified through Week 52. ICOTYDE overall adverse event and infection rates were lower than deucravacitinib through Week 24.

ICONIC-LEAD

ICOTYDE also demonstrated sustained efficacy and a favorable safety profile in adolescents through Week 52. Nearly 60% of adolescents treated with ICOTYDE achieved completely clear skin at one year, and 86% achieved PASI 90, with 92% maintaining that response from Week 24 to Week 52. No new safety signals were identified over one year of treatment.

The pivotal ICONIC Phase 3 clinical development program includes five studies in plaque psoriasis: ICONIC-LEAD, ICONIC-TOTAL, ICONIC-ADVANCE 1, ICONIC-ADVANCE 2, and ICONIC-ASCEND. Additional studies are also underway in psoriatic arthritis, ulcerative colitis, and Crohn's disease.

Under Protagonist's collaboration agreement with Johnson & Johnson, the Company is eligible to receive tiered royalties on net sales of ICOTYDE and additional future milestone payments. Protagonist believes the continued advancement of ICOTYDE highlights the strength of its oral peptide platform and its strategy of creating potentially best-in-class medicines through internal innovation and strategic partnerships.

About ICOTYDE^™ (icotrokinra)

ICOTYDE (icotrokinra) is the first and only targeted oral peptide designed to precisely block the IL-23 receptor, which underpins the inflammatory response in moderate-to-severe plaque PsO. ICOTYDE binds to the IL-23 receptor with high affinity and demonstrated potent inhibition of IL-23 signaling in human T cells. Clinical significance of these findings are unknown.

ICOTYDE is currently approved in the U.S. for the treatment of adults, and pediatric patients 12 years of age and older who weigh at least 40 kg, with moderate-to-severe plaque PsO who are candidates for systemic therapy or phototherapy. Patients on ICOTYDE take one pill, once a day with water upon waking, 30 minutes prior to eating food.

ICOTYDE is also currently in Phase 3 studies for active psoriatic arthritis, moderately to severely active ulcerative colitis and moderately to severely active Crohn's disease.

ICOTYDE was jointly discovered by Protagonist and Johnson & Johnson scientists and is being developed and commercialized by Johnson & Johnson. The approval of ICOTYDE triggers a $50 million milestone payment to Protagonist. Protagonist is also eligible for 6 - 10% upward tiering royalties on worldwide net sales, as well as additional regulatory and sales milestone payments of up to $580 million.

About Plaque Psoriasis
Plaque psoriasis (PsO) is a chronic immune-mediated disease resulting in overproduction of skin cells, which causes inflamed, scaly plaques that may be itchy or painful. It is estimated that 8 million Americans and more than 125 million people worldwide live with the disease. Nearly one-quarter of all people with plaque PsO have cases that are considered moderate-to-severe. On Caucasian skin, plaques typically appear as raised, red patches covered with a silvery white buildup of dead skin cells or scale. On skin of color, the plaques may appear darker and thicker, and more of a purple, gray, or dark brown color. Plaques can appear anywhere on the body, although they most often appear on the scalp, knees, elbows, and torso. Living with plaque PsO can be a challenge and impact life beyond a person's physical health, including emotional health, relationships, and handling the stressors of life. Psoriasis on highly visible areas of the body or sensitive skin, such as the scalp, hands, feet, and genitals, can have an increased negative impact on quality of life.

About Protagonist

Protagonist Therapeutics is a discovery through late-stage development biopharmaceutical company. The Company's proprietary peptide technology platform enables de novo discovery of peptide therapeutics. Two novel peptides derived from Protagonist's proprietary discovery platform are at or near commercialization. ICOTYDE^™ (icotrokinra) is approved in the U.S. 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 who are candidates for systemic therapy or phototherapy. ICOTYDE is the first and only targeted oral peptide that precisely blocks the Interleukin-23 receptor (IL-23R) licensed to Janssen Biotech, Inc., a Johnson & Johnson company. ICOTYDE was jointly discovered by Protagonist and Johnson & Johnson scientists, with Protagonist having primary responsibility for the development of ICOTYDE through Phase 1, and Johnson & Johnson assuming responsibility for further development and commercialization. An NDA for rusfertide, a first-in-class hepcidin mimetic peptide that is being co-developed with Takeda Pharmaceuticals pursuant to a worldwide license and collaboration agreement entered in 2024, is under priority review with the FDA. Protagonist holds an option to co-commercialize rusfertide in the U.S. through a 50/50 profit and loss share structure or can opt-out of this structure. The Company also has a number of preclinical stage drug discovery programs addressing clinically and commercially validated targets including an oral IL-17 peptide antagonist, obesity dual and triple agonists, an oral hepcidin functional mimetic, and the recently announced IL-4 and amylin programs.

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

Cautionary Note on Forward-Looking Statements

This 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 ICOTYDE and potential revenue from the Company's collaboration with Johnson & Johnson. 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 agreements with Janssen and Takeda, 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.

Investor Relations Contact

Corey Davis, Ph.D.
LifeSci Advisors
cdavis@lifesciadvisors.com
+1 212 915 2577

Media Relations Contact

Virginia Amann
ENTENTE Network of Companies
virginiaamann@ententeinc.com
+1 833 500 0061 ext 1

ICOTYDE^™ INDICATION AND IMPORTANT SAFETY INFORMATION
What is the most important information I should know about ICOTYDE?

• Infections. Medicines that interact with the immune system, such as ICOTYDE, may lower your ability to fight infections and may increase your risk of infections. Your healthcare provider may check you for infections and tuberculosis (TB) before starting treatment and may treat you for TB before you begin treatment with ICOTYDE if you have a history of TB or have active TB. Your healthcare provider should watch you closely for signs and symptoms of TB during and after treatment with ICOTYDE.

Tell your healthcare provider right away if you have any infection or have symptoms of an infection, including:

fever, sweat, or chills cough shortness of breath blood in your mucus (phlegm) muscle aches

warm, red, or painful skin or sores on your body different from your psoriasis weight loss diarrhea or stomach pain burning when you urinate or urinating more often than normal

Before taking ICOTYDE, tell your healthcare provider about all of your medical conditions, including if you:

• have an infection that does not go away or that keeps coming back.

• have tuberculosis (TB) or have been in close contact with someone with TB.

• have recently received or are scheduled to receive an immunization (vaccine). Avoid receiving live vaccines during treatment with ICOTYDE.

• have kidney problems.

• are pregnant or plan to become pregnant. It is not known if ICOTYDE can harm your unborn baby.

Pregnancy Safety Study. There is a pregnancy safety study for women who take ICOTYDE during pregnancy. The purpose of this study is to collect information about the health of you and your baby. If you are pregnant or become pregnant during treatment with ICOTYDE, you can report your pregnancy by calling 1-800-526-7736 or visiting www.ICOTYDE.com.

• are breastfeeding or plan to breastfeed. It is not known if ICOTYDE passes into your breast milk. Talk to your healthcare provider about the best way to feed your baby during treatment with ICOTYDE.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

What are the possible side effects of ICOTYDE?

ICOTYDE may cause serious side effects. See "What is the most important information I should know about ICOTYDE?"

The most common side effects of ICOTYDE include:

headache nausea cough

fungal infection tiredness

These are not all the possible side effects of ICOTYDE. Call your doctor for medical advice about side effects. You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch, or call 1-800-FDA-1088.

How should I take ICOTYDE?

• Take ICOTYDE exactly as your healthcare provider tells you to take it.

• Take ICOTYDE 1 time a day when you wake up on an empty stomach with water. Wait at least 30 minutes after taking ICOTYDE before eating food.

• If you have difficulty swallowing tablets, ICOTYDE can be dispersed in water. For more information, please read the Medication Guide.

• If you miss a dose of ICOTYDE, take the dose as soon as you remember and go back to your regular schedule the next day.

Please read the full Prescribing Information, including Medication Guide, for ICOTYDE and discuss any questions that you have with your doctor.

SOURCE: Protagonist Therapeutics

View the original press release on ACCESS Newswire

FAQ

What did Protagonist announce about ICOTYDE one-year Phase 3 results (PTGX) at AAD 2026?

ICOTYDE showed durable skin clearance and a favorable safety profile through one year. According to Protagonist, PASI100 rates rose from Week 24 to Week 52 and no new safety signals were identified through Week 52, supporting a differentiated oral IL-23 receptor targeted peptide.

How effective was ICOTYDE in adolescents at one year in the Phase 3 data for PTGX?

Adolescents achieved high clearance: nearly 60% PASI100 and 86% PASI90 at Week 52. According to Protagonist, 92% of adolescents maintained PASI90 from Week 24 to Week 52, indicating sustained responses over one year.

What safety findings were reported for ICOTYDE through Week 52 in the PTGX Phase 3 program?

No new safety signals were identified through Week 52, and overall adverse event and infection rates were lower vs deucravacitinib through Week 24. According to Protagonist, the adverse event profile through Week 52 was consistent with earlier weeks.

Does Johnson & Johnson handle commercialization of ICOTYDE following the PTGX announcement?

Yes, Johnson & Johnson is responsible for commercialization of ICOTYDE under the 2017 collaboration agreement. According to Protagonist, J&J will manage all commercial activities while Protagonist may receive tiered royalties and future milestone payments.

Which ICONIC Phase 3 studies support the ICOTYDE results announced by Protagonist (PTGX)?

The one-year data come from ICONIC-ADVANCE 1, ICONIC-ADVANCE 2 and ICONIC-LEAD studies. According to Protagonist, these pivotal Phase 3 trials are part of a five-study ICONIC program in plaque psoriasis.

How does ICOTYDE’s mechanism differ and why does Protagonist highlight it in the PTGX release?

ICOTYDE is an oral peptide that precisely blocks the IL-23 receptor, a distinct mechanism among oral agents. According to Protagonist, this IL-23 receptor targeting underpins its differentiated clinical profile and potential therapeutic advantage.