New Real-World Evidence Presented by Organon at the American College of Rheumatology (ACR) Annual Meeting Evaluated a Large-Scale Switch to HADLIMA® (adalimumab-bwwd) Across United States Veterans Affairs Healthcare System

Organon (NYSE: OGN), a global healthcare company with a mission to deliver impactful medicines and solutions for a healthier every day, today announced the poster presentation of new real-world evidence at the American College of Rheumatology (ACR) Annual Meeting, held November 6-11, 2026 in Orlando, Florida. The poster evaluates the treatment, management, and economic impacts of transitioning patients from originator HUMIRA^® (adalimumab) to biosimilar HADLIMA^® (adalimumab-bwwd) within the United States (US) Department of Veterans Affairs (VA) Healthcare System.¹

The analysis demonstrated that a large-scale health system switch to HADLIMA was achieved with a 1.3% switchback rate over a 12-month follow-up period.¹ Though published rates vary, switchback rates from biosimilars to originator are frequently cited as 16-18% in the scientific literature.^2,3 Adherence metrics remained similar pre- and post-switch while generating cost savings for the healthcare system, with average per-patient pharmacy costs decreasing by $8,100 in the first year following the switch.¹ HADLIMA was exclusively selected by the VA to replace HUMIRA on its national formulary in 2024.⁴

“The findings demonstrate that a well-managed formulary transition to HADLIMA can deliver both continuity of care and economic savings,” said Jon Martin, US Commercial Lead, Biosimilars and Established Brands at Organon. “Real-world evidence at this scale is critical for showing that biosimilar adoption can support sustainable health systems while delivering confidence to doctors and patients alike. At Organon, we believe in the potential of biosimilars to expand patient access to effective treatments while potentially reducing the affordability burden on health care systems.”

The study analyzed electronic health records and administrative datasets from the Veterans Health Administration (VHA) Corporate Data Warehouse, including veterans who received any adalimumab treatment between October 1, 2015, and August 1, 2025, with at least one baseline clinical encounter.^1* Patients were categorized into three cohorts: originator HUMIRA only, HADLIMA only, or a switch cohort (transitioning from originator to HADLIMA).

• Of 58,407 total individuals identified, 16,322 veterans transitioned from the originator to HADLIMA. The switch cohort had a mean age of 60 years and was 87% male and 75% white.¹

• Rheumatoid arthritis (RA) represented the most common diagnosis (21.9%; n= 3577), followed by psoriatic arthritis (PsA; 8.4%; n= 1374), and ankylosing spondylitis (AS; 7.6%; n=1239).¹

• Within 12 months of follow-up, 1.3% of patients switched back from HADLIMA to the originator. Treatment adherence metrics remained similar pre- and post-switch.¹

• Across all indications in the switch cohort, mean per-patient pharmacy costs decreased by $8,100 in the first year following the switch.¹

• At the system level, the switch resulted in $132 million total estimated savings to the Veterans Affairs Healthcare System.¹

Poster presentation details

• Title: Real-World Evidence From the US Veterans Affairs Healthcare System of a Successful Switch to Biosimilar adalimumab-bwwd (Hadlima) from Originator adalimumab (Humira) Following a Formulary Change

• Presentation date & time: Monday, November 9, 2026, 10:30 AM to 12:30 PM ET

• Presenter: Ricardo Infante, Medical Affairs Lead, Organon

About HADLIMA^® (adalimumab-bwwd) Injection

HADLIMA is a tumor necrosis factor (TNF) blocker indicated for:

• Rheumatoid Arthritis: HADLIMA is indicated, alone or in combination with methotrexate or other non-biologic disease-modifying antirheumatic drugs (DMARDs), for reducing signs and symptoms, inducing major clinical response, inhibiting the progression of structural damage, and improving physical function in adult patients with moderately to severely active rheumatoid arthritis.

• Juvenile Idiopathic Arthritis: HADLIMA is indicated, alone or in combination with methotrexate, for reducing signs and symptoms of moderately to severely active polyarticular juvenile idiopathic arthritis in patients 2 years of age and older.

• Psoriatic Arthritis: HADLIMA is indicated, alone or in combination with non-biologic DMARDs, for reducing signs and symptoms, inhibiting the progression of structural damage, and improving physical function in adult patients with active psoriatic arthritis.

• Ankylosing Spondylitis: HADLIMA is indicated for reducing signs and symptoms in adult patients with active ankylosing spondylitis.

• Crohn’s Disease: HADLIMA is indicated for the treatment of moderately to severely active Crohn’s disease in adults and pediatric patients 6 years of age and older.

• Ulcerative Colitis: HADLIMA is indicated for the treatment of moderately to severely active ulcerative colitis in adult patients.

Limitations of Use:

The effectiveness of HADLIMA has not been established in patients who have lost response to or were intolerant to tumor necrosis factor (TNF) blockers.

• Plaque Psoriasis: HADLIMA is indicated for the treatment of adult patients with moderate to severe chronic plaque psoriasis who are candidates for systemic therapy or phototherapy, and when other systemic therapies are medically less appropriate. HADLIMA should only be administered to patients who will be closely monitored and have regular follow-up visits with a physician.

• Hidradenitis Suppurativa: HADLIMA is indicated for the treatment of moderate to severe hidradenitis suppurativa in patients 12 years of age and older.

• Uveitis: HADLIMA is indicated for the treatment of non-infectious intermediate, posterior, and panuveitis in adult and pediatric patients 2 years of age and older.

SELECTED SAFETY INFORMATION

SERIOUS INFECTIONS

Patients treated with adalimumab products, including HADLIMA, are at increased risk for developing serious infections that may lead to hospitalization or death. Most patients who developed these infections were taking concomitant immunosuppressants such as methotrexate or corticosteroids.

Discontinue HADLIMA if a patient develops a serious infection or sepsis.

Reported infections include:

• Active tuberculosis (TB), including reactivation of latent TB. Patients with TB have frequently presented with disseminated or extrapulmonary disease. Test patients for latent TB before HADLIMA use and during therapy. Initiate treatment for latent TB prior to HADLIMA use.

• Invasive fungal infections, including histoplasmosis, coccidioidomycosis, candidiasis, aspergillosis, blastomycosis, and pneumocystosis. Patients with histoplasmosis or other invasive fungal infections may present with disseminated, rather than localized, disease. Antigen and antibody testing for histoplasmosis may be negative in some patients with active infection. Consider empiric anti-fungal therapy in patients at risk for invasive fungal infections who develop severe systemic illness.

• Bacterial, viral, and other infections due to opportunistic pathogens, including Legionella and Listeria.

Carefully consider the risks and benefits of treatment with HADLIMA prior to initiating therapy in patients:

• with chronic or recurrent infection

• who have been exposed to TB

• with a history of opportunistic infection

• who resided in or traveled in regions where mycoses are endemic

• with underlying conditions that may predispose them to infection

Monitor patients closely for the development of signs and symptoms of infection during and after treatment with HADLIMA, including the possible development of TB in patients who tested negative for latent TB infection prior to initiating therapy.

• Do not start HADLIMA during an active infection, including localized infections.

• Patients older than 65 years, patients with co-morbid conditions, and/or patients taking concomitant immunosuppressants may be at greater risk of infection.

• If an infection develops, monitor carefully and initiate appropriate therapy.

• Drug interactions with biologic products: A higher rate of serious infections has been observed in rheumatoid arthritis (RA) patients treated with rituximab who received subsequent treatment with a TNF blocker. An increased risk of serious infections has been seen with the combination of TNF blockers with anakinra or abatacept, with no demonstrated added benefit in patients with RA. Concomitant administration of HADLIMA with other biologic DMARDs (eg, anakinra or abatacept) or other TNF blockers is not recommended based on the possible increased risk for infections and other potential pharmacological interactions.

MALIGNANCY

Lymphoma and other malignancies, some fatal, have been reported in children and adolescent patients treated with TNF blockers, including adalimumab products. Postmarketing cases of hepatosplenic T-cell lymphoma (HSTCL), a rare type of T-cell lymphoma, have been reported in patients treated with TNF blockers, including adalimumab products. These cases have had a very aggressive disease course and have been fatal. The majority of reported TNF blocker cases have occurred in patients with Crohn’s disease or ulcerative colitis and the majority were in adolescent and young adult males. Almost all of these patients had received treatment with azathioprine or 6-mercaptopurine concomitantly with a TNF blocker at or prior to diagnosis. It is uncertain whether the occurrence of HSTCL is related to use of a TNF blocker or a TNF blocker in combination with these other immunosuppressants.

• Consider the risks and benefits of HADLIMA treatment prior to initiating or continuing therapy in a patient with known malignancy.

• In clinical trials, more cases of malignancies were observed among adalimumab-treated subjects compared to control subjects.

• Non-melanoma skin cancer (NMSC) was reported during clinical trials for adalimumab-treated subjects. Examine all patients, particularly those with a history of prolonged immunosuppressant or psoralen and ultraviolet A (PUVA) therapy, for the presence of NMSC prior to and during treatment with HADLIMA.

• In adalimumab clinical trials, there was an approximate 3-fold higher rate of lymphoma than expected in the general U.S. population. Patients with chronic inflammatory diseases, particularly those with highly active disease and/or chronic exposure to immunosuppressant therapies, may be at higher risk of lymphoma than the general population, even in the absence of TNF blockers.

• Postmarketing cases of acute and chronic leukemia were reported with TNF blocker use. Approximately half of the postmarketing cases of malignancies in children, adolescents, and young adults receiving TNF blockers were lymphomas; other cases included rare malignancies associated with immunosuppression and malignancies not usually observed in children and adolescents.

HYPERSENSITIVITY

Anaphylaxis and angioneurotic edema have been reported following adalimumab administration. If a serious allergic reaction occurs, stop HADLIMA and institute appropriate therapy.

HEPATITIS B VIRUS REACTIVATION

Use of TNF blockers, including HADLIMA, may increase the risk of reactivation of hepatitis B virus (HBV) in patients who are chronic carriers. Some cases have been fatal.

Evaluate patients at risk for HBV infection for prior evidence of HBV infection before initiating TNF blocker therapy.

Exercise caution in patients who are carriers of HBV and monitor them during and after HADLIMA treatment.

Discontinue HADLIMA and begin antiviral therapy in patients who develop HBV reactivation. Exercise caution when resuming HADLIMA after HBV treatment.

NEUROLOGIC REACTIONS

TNF blockers, including adalimumab products, have been associated with rare cases of new onset or exacerbation of central nervous system and peripheral demyelinating diseases, including multiple sclerosis, optic neuritis, and Guillain-Barré syndrome.

Exercise caution when considering HADLIMA for patients with these disorders; discontinuation of HADLIMA should be considered if any of these disorders develop.

HEMATOLOGIC REACTIONS

Rare reports of pancytopenia, including aplastic anemia, have been reported with TNF blockers. Medically significant cytopenia has been infrequently reported with adalimumab products.

Consider stopping HADLIMA if significant hematologic abnormalities occur.

CONGESTIVE HEART FAILURE

Worsening and new onset congestive heart failure (CHF) has been reported with TNF blockers. Cases of worsening CHF have been observed with adalimumab products; exercise caution and monitor carefully.

AUTOIMMUNITY

Treatment with adalimumab products may result in the formation of autoantibodies and, rarely, in development of a lupus-like syndrome. Discontinue treatment if symptoms of a lupus-like syndrome develop.

IMMUNIZATIONS

Patients on HADLIMA should not receive live vaccines.

Pediatric patients, if possible, should be brought up to date with all immunizations before initiating HADLIMA therapy.

Adalimumab is actively transferred across the placenta during the third trimester of pregnancy and may affect immune response in the in utero-exposed infant. The safety of administering live or live-attenuated vaccines in infants exposed to adalimumab products in utero is unknown. Risks and benefits should be considered prior to vaccinating (live or live-attenuated) exposed infants.

ADVERSE REACTIONS

The most common adverse reactions in adalimumab clinical trials (>10%) were: infections (e.g., upper respiratory, sinusitis), injection site reactions, headache, and rash.

Before prescribing HADLIMA, please read the Prescribing Information, including the Boxed Warning about serious infections and malignancies. The Medication Guide and Instructions for Use also are available.

About Organon

Organon (NYSE: OGN) is a global healthcare company with a mission to deliver impactful medicines and solutions for a healthier every day. With a portfolio of over 70 products across Women’s Health and General Medicines, which includes biosimilars, Organon focuses on addressing health needs that uniquely, disproportionately, or differently affect women, while expanding access to essential treatments in over 140 markets.

Headquartered in Jersey City, New Jersey, Organon is committed to advancing access, affordability, and innovation in healthcare. Learn more at http://www.organon.com and follow us on LinkedIn, Instagram, X, YouTube, TikTok and Facebook.

Cautionary Note Regarding Forward-Looking Statements

This press release includes “forward-looking statements” within the meaning of the safe harbor provisions of the US Private Securities Litigation Reform Act of 1995, including statements regarding Organon’s presentation of data at the ACR Annual Meeting and the potential benefits of biosimilars. Forward-looking statements may be identified by words such as “will,” “can,” “potential,” “potentially,” “believe,” or words of similar meaning. These statements are based upon the current beliefs and expectations of Organon’s management and are subject to significant risks and uncertainties. If underlying assumptions prove inaccurate, or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements. Factors that could cause results to differ materially from those described in the forward-looking statements can be found in Organon’s filings with the SEC, including Organon’s most recent Annual Report on Form 10-K and subsequent SEC filings, available at the SEC’s Internet site (www.sec.gov). Organon undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise, except as required by law.

© 2026 Organon group of companies. All rights reserved. ORGANON and the ORGANON Logo are trademarks of the Organon group of companies.

*The types of immunologic condition being treated are defined by multiple ICD-10-CM diagnosis codes from 12 months before to 30-days after the index date.

REFERENCES

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1 Goodall G, Liu H, Willis C, et al. Real-world evidence from the US Veterans Affairs Healthcare System of a successful switch to biosimilar adalimumab-bwwd (Hadlima) from originator adalimumab (Humira) following a formulary change. Poster presented at: American College of Rheumatology (ACR) Convergence; November 6–11, 2026; Orlando, FL.

2 Fitzgerald T, Melsheimer R, Lafeuille MH, et al. Switching and discontinuation patterns among patients stable on originator infliximab who switched to an infliximab biosimilar or remained on originator infliximab. Biologics. 2021;15:1-15. doi:10.2147/BTT.S285610

3 Farrar KG, Masters NB, Do D, et al. Real-world switching and switch-back patterns among patients transitioning from adalimumab to biosimilars in the United States (February 2023 to August 2025). J Manag Care Spec Pharm. 2026;32(7):1-8. doi:10.18553/jmcp.2026.32.7.856

4 Organon Announces HADLIMA™ (adalimumab-bwwd) Has Been Exclusively Selected by the US Department of Veterans Affairs (VA), Replacing HUMIRA on Its National Formulary. Organon. February 20, 2024. Accessed October 20, 2026. https://www.organon.com/supplier-guides/news/organon-announces-hadlima-adalimumab-bwwd-has-been-exclusively-selected-by-the-us-department-of-veterans-affairs-va-replacing-humira-on-its-national-formulary/

US-ADA-111212 11/26

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