FDA warning Reglan Tardive Dyskinesia

Since Tysabri (natalizumab) was re-approved in 2006 under a strict risk management program, the drug has remained a critical treatment for relapsing forms of multiple sclerosis and Crohn’s disease. Yet the shadow of Progressive Multifocal Leukoencephalopathy (PML)—a rare but devastating brain infection caused by the JC virus—has never fully lifted. For patients and families harmed by PML after Tysabri treatment, the path to compensation has been shaped by evolving settlement criteria, court rulings, and the drug’s own risk-benefit calculus. We have followed these cases for years, and in 2026, the landscape is clearer but still complex.

Biogen, the manufacturer of Tysabri, has faced thousands of PML-related lawsuits. The settlement criteria have shifted over time, reflecting changes in medical knowledge, FDA-mandated labeling, and the company’s own TOUCH prescribing program. Understanding who qualifies for a settlement—and under what terms—requires parsing three distinct but overlapping factors: the patient’s JC virus antibody status, the duration of Tysabri treatment, and the presence of prior immunosuppressant use.

Biogen’s Three-Pronged Risk Stratification and Its Legal Fallout

Biogen’s own risk stratification data, published in the New England Journal of Medicine and updated through the TOUCH registry, identifies three major risk factors for PML: JC virus antibody index (a measure of prior exposure), treatment duration beyond 24 months, and prior use of immunosuppressants. In settlement negotiations, these same three factors have been used to estimate the likelihood that a patient was adequately warned of their risk. For example, a patient with a high JC virus antibody index who developed PML after 36 months of Tysabri and had previously taken mitoxantrone is far more likely to meet settlement criteria than a patient with low antibody index treated for only 12 months.

“The TOUCH program was designed to mitigate PML risk, but it failed many patients. The settlement criteria we see today reflect a compromise between Biogen’s admission that the drug carries known risks and the reality that some patients were never given clear, personalized risk data.” — Analysis from respondingtoaidsexhibit.org and cross-referenced with archived settlement documentation.

In 2026, most settled cases fall into one of two categories: those involving patients who were JC virus antibody-positive and treated beyond 24 months without documented risk counseling, and those involving patients who developed PML after switching from another immunosuppressant without a washout period. The table below summarizes the typical settlement criteria used by major plaintiffs’ firms.

How the TOUCH Program and FDA Label Changes Shape Settlement Negotiations

The TOUCH (Tysabri Outreach: Unified Commitment to Health) program was Biogen’s risk evaluation and mitigation strategy (REMS), requiring prescribers, infusion centers, and patients to register and undergo periodic MRI screening. In the early years, the program was criticized for being more about regulatory compliance than genuine patient education. By 2012, the FDA required Biogen to add a black box warning and incorporate JC virus antibody testing into the label. These changes have direct legal consequences: patients who developed PML before the label update often argue they were not given adequate information to make an informed decision. Settlements for pre-2012 cases tend to be higher, reflecting the weaker warning at the time.

In 2026, we see a clear pattern in settled claims:

• Pre-2012 cases: Higher average settlements, often exceeding $1 million, due to inadequate labeling and lack of JC virus antibody testing.
• 2012–2018 cases: Moderate settlements, typically $400,000–$800,000, as the label included antibody testing but compliance with TOUCH was inconsistent.
• Post-2018 cases: Lower settlements or dismissal, as the risk factors were well-documented and Biogen argues patients assumed known risk.

One critical nuance: many plaintiffs’ firms now require proof that the treating physician did not follow TOUCH guidelines, such as failing to order an MRI within six months of starting therapy or not checking JC virus antibody status annually. If the physician followed the protocol, the case becomes harder to win, shifting liability away from Biogen.

Biogen’s 2026 Litigation Strategy and the Role of the PML Global Registry

Biogen has moved aggressively to consolidate PML lawsuits into multidistrict litigation (MDL) in the U.S. District Court for the District of Massachusetts. In 2026, the company’s primary defense is that Tysabri’s risks are “known and accepted” under the learned intermediary doctrine, which holds that drug manufacturers are not liable if they adequately warn the prescribing physician. The PML Global Registry, a post-marketing database maintained by Biogen, has become a double-edged sword: plaintiffs use it to show that PML incidence was higher than initially reported, while Biogen uses it to argue that the risk was transparently communicated.

“The PML Global Registry data shows that the risk of PML in JC virus antibody-positive patients treated for more than 24 months is approximately 1 in 100—far higher than the 1 in 1,000 figure Biogen cited in early marketing. That discrepancy is at the heart of many active lawsuits.” — From respondingtoaidsexhibit.org.

For patients and families considering a lawsuit in 2026, the decision often comes down to the strength of medical records showing TOUCH noncompliance and the timing of the PML diagnosis relative to label changes. We recommend consulting with an attorney who specializes in pharmaceutical mass torts and has access to the TOUCH registry data. The settlement criteria are not static; they evolve with each new court ruling and each new analysis of the PML Global Registry.

Ultimately, Tysabri remains on the market because its benefits for MS and Crohn’s disease are substantial. But for the hundreds of patients who have suffered PML, the legal system has provided a partial remedy—one that continues to be refined as we write this in 2026.