What happens when a challenger pays to educate patients but its biggest rival captures the sale? This highlights an interesting side of competitive DTC advertising: one company’s campaign can create demand for a rival’s treatment. Eli Lilly is promoting Ebglyss, a prescription treatment for moderate-to-severe atopic dermatitis. However, Sanofi believes those campaigns could also send patients toward Dupixent, the established market leader. This raises an important question for pharmaceutical marketers: Who gets the return when one brand grows the entire category?
Table of Contents
- Why Ebglyss Advertising Could Expand Eczema Treatment
- The Free-Rider Effect in Pharmaceutical Advertising
- Why Dupixent Could Benefit From Lilly’s Ebglyss Campaign
- How Pharma Marketers Can Measure the Real Winner
- Conclusion
- FAQ
Why Ebglyss Advertising Could Expand Eczema Treatment
Lilly’s Ebglyss received U.S. approval in September 2024 for eligible patients aged 12 and older. Its consumer campaign began in March 2025, adding another voice to the discussion about advanced eczema care. For example, someone relying on creams might not know that injectable treatments exist for certain cases. An Ebglyss advertisement could prompt a dermatology appointment, even without a firm brand preference.
During Sanofi’s October 30, 2026, earnings call, specialty-care leader Manuela Buxo estimated that advanced therapies reached only about 20% of the atopic dermatitis market. She argued that more education could bring patients into this treatment category. Crucially, Buxo predicted that Dupixent, with its leading share, would receive most of the benefit. That is Sanofi’s expectation, not proof of extra prescriptions generated by Lilly’s campaign.
Lilly reported Ebglyss revenue of $202 million in the third quarter of 2026, up 59% year over year. Meanwhile, Sanofi reported Dupixent sales of about €5.7 billion, up 34.8% at constant exchange rates. However, these totals are not directly comparable eczema sales because Dupixent treats several other conditions.
The Free-Rider Effect in Pharmaceutical Advertising
The free-rider effect occurs when one advertiser pays to build demand that a competitor can capture. In pharmaceuticals, the path from an advertisement to a prescription involves several decisions. First, a patient learns that another treatment may be possible. Next, a clinician assesses symptoms, medical history, risks, and available options. Insurance coverage, cost, and personal preferences then shape the choice. Consequently, the advertised brand does not necessarily become the prescribed brand.
Unlike most consumer advertising, prescription drug campaigns don’t always lead patients to the brand they first saw advertised. Instead, an advertisement may start a discussion that benefits other brands already familiar to the clinician. An established company may also offer well-known support services and smoother access pathways. Those advantages can convert new category awareness into prescriptions for the incumbent.
Still, spillover is not inevitable. Lilly can use its campaign to give patients a specific reason to ask about Ebglyss. Furthermore, promotional claims must reflect the evidence and communicate risks appropriately. The FDA’s Ebglyss drug information explains who the treatment is approved for and the trials behind that approval.
Why Dupixent Could Benefit From Lilly’s Ebglyss Campaign
Dupixent reached the U.S. market years before Ebglyss and now has a broad presence across inflammatory conditions. Therefore, many clinicians already know its treatment profile and patient support systems. When someone asks about advanced eczema care, that familiarity can matter. In effect, Lilly may generate the question while Dupixent remains a familiar answer.
However, Ebglyss offers another approved option for eligible patients with moderate-to-severe atopic dermatitis. Its advertising can help Lilly establish a distinct brand identity. Moreover, the right medicine depends on clinical needs, safety, coverage, and patient preferences, not advertising volume. An incumbent cannot assume every new consultation will produce a Dupixent prescription.
As Pharma Marketing Network has explored through distinctive healthcare brand assets, familiar cues can help people remember a brand. Yet a challenger needs more than attention to win against an established rival. It needs a credible reason for patients and clinicians to consider its treatment. People seeking professional guidance can also use Healthcare.pro to find healthcare providers.
How Pharma Marketers Can Measure the Real Winner
For challengers, the danger is confusing category growth with brand growth. Lilly’s advertising could encourage more eczema-related searches and doctor visits without delivering the same increase in Ebglyss prescriptions. Therefore, marketers should measure both new patients entering advanced treatment and each brand’s share of those starts. They should also distinguish first-time advanced therapy users from people switching products.
Useful signals include branded search, general eczema-treatment queries, patient surveys, and prescription starts. Where possible, teams can compare regions with different campaign exposure while adjusting for other influences. Meanwhile, formularies, out-of-pocket costs, and rival promotions can explain changes that advertising alone cannot. Rising sales after a campaign launch do not prove that the campaign caused them.
In addition, claims must remain accurate when competition gets aggressive. Pharma Marketing Network’s reporting on a competitive pharmaceutical advertising lawsuit shows how promotional disputes can become business risks. Ultimately, smart measurement connects awareness with verified treatment decisions rather than assuming every impression builds the advertised brand.
Conclusion
Lilly’s Ebglyss promotion may help more people discover advanced eczema treatment. However, Sanofi expects Dupixent to benefit because it already leads the market. For Lilly, the challenge is to expand awareness of advanced eczema treatments while giving patients a compelling reason to consider Ebglyss over its competitors. Until better evidence shows where new patients go, Sanofi’s free-rider theory remains a forecast, not a measured outcome.
FAQ
What is competitive DTC advertising?
It is prescription-drug advertising aimed at consumers when multiple brands compete for similar patients. These campaigns can increase awareness of both the advertised treatment and its competitors.
Why could Ebglyss ads help Dupixent?
An Ebglyss advertisement may lead someone to ask about advanced eczema care. Their clinician may then consider Dupixent or other suitable treatments based on medical needs and treatment options.
Has Sanofi proved a spillover benefit?
No. Sanofi has predicted that Dupixent will capture much of the growth, but it has not quantified prescriptions driven by Lilly’s advertisements. The actual impact remains uncertain.
How can pharmaceutical marketers reduce the free-rider effect?
They can explain meaningful brand differences, build stronger brand recognition, and measure new prescriptions alongside broader treatment awareness. Clear differentiation can help turn consumer interest into brand-specific demand.
This content is not medical advice. For any health issues, always consult a healthcare professional. In an emergency, call 911 or your local emergency services.
