Guselkumab (TREMFYA) for Plaque Psoriasis, Psoriatic Arthritis, Ulcerative Colitis and Crohn’s Disease

In recent months, the expensive injectable biologic drug guselkumab (TREMFYA) has frequently been promoted in direct-to-consumer television advertisements. In February 2026, the Food and Drug Administration (FDA) sent a warning letter to guselkumab’s manufacturer stating that one of the television advertisements “is false and misleading.” The FDA letter highlighted three claims in the advertisement and termed them “misleading because they suggest that ‘many people’ or ‘~1 out of 2 patients’ treated with Tremfya will achieve clinical remission at one year and maintain their remission through two years, when this is not the case.”[1]

What is guselkumab, and what is the evidence on its safety and effectiveness?

In 2017, the Food and Drug Administration (FDA) approved guselkumab to treat adult patients with moderate-to-severe plaque psoriasis who were also candidates for alternative therapies such as other drugs or phototherapy.[2] Subsequently, the FDA approved supplemental indications for adults with active psoriatic arthritis (2020),[3] moderately to severely active ulcerative colitis (2024)[4] and moderate to severely active Crohn’s disease (2025).[5] In 2025, the indications for guselkumab for plaque psoriasis and psoriatic arthritis were expanded to include children ages 6 and older who weigh at least 88 pounds.

The Table summarizes the clinical trial data in adults that appear on the FDA-approved label for guselkumab.[16]

Approximately 80%-90% of people with psoriasis have plaque psoriasis.[6] Plaque psoriasis is an autoimmune condition characterized by overactive skin cells that produce thick patches that can itch, bleed and be painful. About 2.6% of U.S. adults have plaque psoriasis.[7] Up to 30% of people with psoriasis also develop a related condition known as psoriatic arthritis that is characterized by joint inflammation.[8]

Ulcerative colitis and Crohn’s disease are chronic inflammatory bowel diseases that together affect about 1 in 250 people in the U.S.[9] Although Crohn’s diseases most commonly affects the end of the small intestine and beginning of the large intestine, it can cause inflammation throughout the gastrointestinal tract.[10] Ulcerative colitis typically causes inflammation of the large intestine (colon and rectum). Both ulcerative colitis and Crohn’s disease have autoimmune components.[11]

Guselkumab

Guselkumab is a human monoclonal antibody in a class of drugs known as anti-interleukin-23 antagonists (IL-23 inhibitors). IL-23 inhibitors are thought to treat autoimmune diseases by blocking one of several naturally occurring biochemical pathways involved in immune responses, including those leading to the proliferation of certain blood and skin cells.[12],[13] Guselkumab is not the first drug to act on these pathways. Moreover, there are other treatments, including methotrexate (JYLAMVO, RASUVO, TREXALL, XATMEP and generics) and tumor necrosis factor (TNF) inhibitors such as adalimumab (HUMIRA and biosimilars) or infliximab (REMICADE, ZYMFENTRA and biosimilars).

Guselkumab is available in prefilled single-dose syringes or injector pens.[14] Doses of 100-400 milligrams (mg) are self-administered subcutaneously (just below the skin) in the upper arm, abdomen or thigh; the drug can also be administered as an intravenous infusion. Before beginning treatment, patients should make sure that their vaccinations are current (to minimize treatment-related vulnerability to live vaccines) and have liver function tests (one of the treatment-related risks is hepatotoxicity). Induction is typically three 100-mg doses at weeks 0, 4 and 8. Maintenance dosing is usually the same or a lower dose every 8 weeks thereafter. People with psoriatic arthritis can continue using other drugs, such as methotrexate. Treatment with guselkumab costs more than $13,000 per 100-mg dose.[15]

Table. Summary of Clinical Trials Supporting Guselkumab’s Effectiveness

†Brand-name combination products were excluded.
*Designated as Limited Use
**Designated as Do Not Use
***The 80-milligram dose of simvastatin is designated as Do Not Use.

Notably, less than 5% of participants in the clinical trials supporting guselkumab were Black or African American.[17] In the U.S., Black patients are less likely than whites to receive biologic treatments for psoriasis and may be less familiar with these therapies.[18]

Safety

For psoriatic indications, the most common adverse reactions of guselkumab are upper respiratory infection, headache, injection site reactions, joint pain, bronchitis, diarrhea, gut inflammation, fungal infections and herpes simplex infections.[19] These adverse reactions were evident in at least 1% of those treated. The safety data are mostly based on 1,823 adults with moderate-to-severe plaque psoriasis, less than half of whom took the drug for one year or more. Salient treatment-group frequencies of adverse reactions were 16-week rates of upper respiratory infection (guselkumab 14.3%, adalimumab 10.7% and placebo 12.8%), headaches (4.6%, 1.0% and 3.3%, respectively) and tinea or herpes simplex infections (1.1%, 0.0% and 0.0%-0.5%, respectively).

Most of the common adverse reactions found for guselkumab as a psoriasis treatment were also observed in trials of the drug for ulcerative colitis and Crohn’s disease.[20] Additionally, ulcerative colitis treatment with guselkumab was associated with fatigue, fever and rash, and Crohn’s disease treatment was associated with abdominal pain. Overall, these adverse reactions occurred in at least 3% of patients treated for ulcerative colitis or Crohn’s disease. For patients with ulcerative colitis, one trial found that by week 44, serious infections occurred in 0.8% of those treated with 100-200-mg guselkumab compared to none of those treated with placebo. Crohn’s disease treatment for 48 weeks in 330 participants who received the highest studied doses of guselkumab (400-mg induction, 100-200-mg maintenance) showed abdominal pain rates of 12% to 14%, compared with 6.8% for placebo, and fatigue rates of 2.6% to 3.5% compared with no reported cases for placebo.

What You Can Do

If you suffer from a disease guselkumab is approved for, discuss with your clinician the choice of treatments. Although the drug may help relieve symptoms,[21] there are adverse reactions, especially increased risk of infections. Moreover, there are less expensive alternatives such as phototherapy and topical vitamin D for psoriasis, as well as methotrexate and TNF inhibitors for the conditions for which guselkumab is approved.[22],[23]
 

References

[1] FDA Letter to Johnson & Johnson International, Inc. February 6, 2026. https://www.fda.gov/media/191066/download  Accessed April 10, 2026.

[2] Janssen Biotech. Label: guselkumab (TREMFYA). July 2017. https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/761061s000lbl.pdf.  Accessed April 6, 2026.

[3] Janssen Biotech. Label: guselkumab (TREMFYA). July 2020. https://www.accessdata.fda.gov/drugsatfda_docs/label/2020/761061s007lbl.pdf. Accessed April 6, 2026.

[4] Janssen Biotech. Label: guselkumab (TREMFYA). September 2024. https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/761061s021lbl.pdf. Accessed April 6, 2026.

[5] Janssen Biotech. Label: guselkumab (TREMFYA). September 2025. https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/761061s026lbl.pdf. Accessed April 7, 2026.

[6] Cleveland Clinic. Plaque psoriasis. April 25, 2022. https://my.clevelandclinic.org/health/diseases/22842-plaque-psoriasis. Accessed April 6, 2026.

[7] Armstrong AW, Mehta MD, Schupp CW, et al. Psoriasis prevalence in adults in the United States. JAMA Dermatol. 2021;157(8):940-946.

[8] Harvard Health Publishing. Psoriatic arthritis. April 1, 2026. https://www.health.harvard.edu/bones-and-joints/psoriatic-arthritis-a-to-z. Accessed April 6, 2026.

[9] Cleveland Clinic. Ulcerative colitis. November 5, 2023. https://my.clevelandclinic.org/health/diseases/10351-ulcerative-colitis. Accessed April 6, 2026.

[10] Centers for Disease Control and Prevention. Crohn’s disease basics. June 21, 2024. https://www.cdc.gov/inflammatory-bowel-disease/about/crohns-disease-basics.html. Accessed April 6, 2026.

[11] Braverman J. Crohn’s Disease: symptoms, causes, and treatment. WebMD. December 12, 2024.  https://www.webmd.com/ibd-crohns-disease/crohns-disease/digestive-diseases-crohns-disease. Accessed April 6, 2026.

[12] Janssen Biotech. Label: guselkumab (TREMFYA). September 2025. https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/761061s028s029lbl.pdf. April 6, 2026.

[13] Naik PP. Adverse effects of anti-interleukin-23 agents employed in patients with psoriasis: A systematic review. Dermatology. 2022;238(5):886-896.

[14] Janssen Biotech. Label: guselkumab (TREMFYA). September 2025. https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/761061s028s029lbl.pdf. Apri l6, 2026.

[15] GoodRx. Tremfya, guselkumab, 1ml of 100mg/ml (1 injector). https://www.goodrx.com/tremfya. Accessed April 13, 2026.

[16] Ibid.

[17] Strober B, Coates LC, Lebwohl MG, et al. Long-term safety of guselkumab in patients with psoriatic disease: an integrated analysis of eleven phase II/III clinical studies in psoriasis and psoriatic arthritis. Drug Saf. 2024;47(1):39-57.

[18] Takeshita J, Eriksen WT, Raziano VT, et al. Racial differences in perceptions of psoriasis therapies: implications for racial disparities in psoriasis treatment. J Invest Dermatol. 2019 Aug;139(8):1672-1679.e1.

[19] Janssen Biotech. Label: guselkumab (TREMFYA). September 2025. https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/761061s028s029lbl.pdf. April 6, 2026.

[20] Ibid.

[21] -------. Drugs for plaque psoriasis. The Medical Letter on Drugs and Therapeutics. 2024;1712:66:153-60.

[22] Feldman SR, Bhutani T. Chronic plaque psoriasis in adults: overview of management. UpToDate. February 2026.

[23] Cohen RD, Stein AC. Management of moderate to severe ulcerative colitis in adults. UpToDate. February 2026.