Regeneron Confirms Active Talks to Expand Sanofi Alliance Beyond Dupixent While Detailing a Pivotal Fourth Quarter for Its C5 Franchise
Bernstein Healthcare Leaders and Disruptors Forum, September 23, 2026 — CFO Chris Fenimore and SVP Investor Relations Ryan Crowe outline pipeline catalysts, Dupixent's patent runway, and lingering caution on the LAG-3 melanoma program
Speaking at Bernstein's healthcare forum, Regeneron's finance chief Chris Fenimore and investor relations head Ryan Crowe used the session to confirm that discussions to expand the company's collaboration with Sanofi beyond Dupixent remain active, offered granular detail on the patent estate protecting Dupixent's roughly $24 billion run rate, and previewed a data-dense fourth quarter for the C5 complement franchise. The conversation also included a candid acknowledgment that the PD-1xVEGF bispecific class emerging in China poses a genuine long-term threat to Libtayo, and fresh caution around the company's LAG-3 melanoma program following a first-line trial that missed statistical significance earlier in 2026.
Sanofi Talks Move From Aspiration to Active Negotiation
The most consequential disclosure of the session concerned business development. Fenimore confirmed that the expansion talks both companies flagged on their respective second-quarter calls have progressed into "active discussions," a notable shift in tone from prior hedged language. "It makes a significant amount of sense as we talked about the value that's been generated for Dupixent in terms of the relationships with both providers, payers and then just the reputation of the brand amongst even the patient community to try and leverage what's been built between both parties," Fenimore said. No structure or asset scope was disclosed, but the framing suggests investors should expect an announcement rather than a continued holding pattern, particularly given that Regeneron has already retired the Sanofi development balance that historically weighed on its share of collaboration profits — a change that should lift earnings from the Sanofi partnership starting in the third quarter.
Dupixent's Patent Cliff Is Further Out Than Many Model, But Not as Far as the Headline Dates Suggest
Crowe provided the clearest public articulation yet of Dupixent's IP timeline. The composition-of-matter patent runs to March 2031 in the U.S., 2033 in Europe, and 2034 in Japan, with a layered estate of method-of-treatment, manufacturing, and formulation patents extending into the early-to-mid 2040s in some cases. The more immediate wrinkle: dosing patents covering asthma and atopic dermatitis begin expiring in the mid-2030s, which Crowe called "an important inflection potentially in terms of the runway for the exclusivity period." The company was explicit that it will litigate aggressively alongside Sanofi to push out biosimilar entry as long as possible, but declined to offer a "date certain" for when generic dupilumab actually reaches the U.S. market — a reminder that the composition-of-matter date is a ceiling, not a guarantee, on exclusivity.
C5 Franchise Faces a Loaded Fourth Quarter
Regeneron is heading into a data- and decision-heavy stretch for its complement C5 portfolio. A PDUFA date for cemdisiran, an siRNA targeting C5 for generalized myasthenia gravis, arrives in November, with Regeneron touting a differentiated profile requiring only four administrations per year. Separately, registration-enabling data in paroxysmal nocturnal hemoglobinuria is due in the fourth quarter, testing the cemdisiran-pozelimab combination head-to-head against AstraZeneca's eculizumab. Crowe flagged early Part A data showing 96% of patients reached normalized LDH levels versus roughly 80% on ravulizumab, but cautioned that the trial's second co-primary endpoint, transfusion avoidance, carries real risk because "not all transfusions are driven by intravascular hemolysis," the only mechanism C5 inhibition is expected to address. A geographic atrophy interim analysis is also due this quarter, testing systemic — rather than intravitreal — complement inhibition in an elderly, infection-vulnerable population; Crowe was measured on expectations, noting "systemic approaches in GA have historically been very challenging" and that the company would be satisfied simply landing "on trend" with approved intravitreal agents.
LAG-3 Melanoma Program Still Carries a Cloud
Crowe did not sugarcoat the disappointment from the first-line metastatic melanoma readout earlier this year, where the fianlimab-Libtayo combination showed more than five months of benefit over Merck's pembrolizumab but failed to reach statistical significance. The company is now in discussions with regulators about converting an ongoing head-to-head study against Bristol-Myers' Opdualag into a registration-enabling trial. More notably, Crowe flagged caution on the fully-enrolled adjuvant melanoma trial, whose data is expected late this year or in early 2027, given that Opdualag itself failed in that same adjuvant setting with a hazard ratio of essentially 1.0 versus Opdivo. "I'm a little cautious on the results here," Crowe said, a rare instance of a company pre-negatively-framing its own upcoming pivotal readout.
Libtayo's Quiet Strength — and the PD-1xVEGF Threat Regeneron Isn't Dismissing
Crowe called Libtayo "an overlooked product," pointing to greater than 30% year-over-year growth, with non-small cell lung cancer now contributing about 40% of U.S. sales and the drug holding the number two position in new-to-brand and total share in lung cancer — with new-to-brand share now exceeding Opdivo, Imfinzi, and Tecentriq combined. On the looming Keytruda loss of exclusivity, Crowe argued biosimilar impact typically concentrates on the reference product rather than adjacent competitors, and pointed to cross-trial data suggesting Libtayo may be superior in squamous cell lung cancer. But he was direct about the bigger structural risk: "We'd be blind not to acknowledge that PD-1 by VEGF is becoming — coming closer and closer to generating data in Western patients that could be potentially transformative for the space." Combined with next-generation ADCs, this marks one of the more explicit competitive risk acknowledgments from management on the call.
Factor XI: Two Antibodies, Deliberately Different Profiles
Regeneron is advancing two Factor XI antibodies into registration-enabling programs across roughly a half-dozen thrombotic conditions, from VTE prevention after knee surgery to atrial fibrillation to cancer-associated thrombosis. One antibody, targeting the catalytic domain, is expected to show best-in-class anticoagulation activity based on APTT and thrombin blockade assays — potentially exceeding Factor Xa inhibitors — without the bleeding risk tradeoff. A second antibody targets a different epitope (A2) and is designed as a functional Factor XII blocker, trading some potency for an even cleaner bleeding profile. Crowe framed the dual approach as filling out a total addressable market Regeneron estimates at $25 billion to $30 billion today, with roughly half of eligible patients currently undertreated due to bleeding fears. Initial Phase III VTE prevention data is expected in 2027, with short-duration Phase II atrial fibrillation data around mid-2027.
EYLEA HD Execution Remains Solid, But Biosimilar Pressure Is Building
EYLEA HD now represents roughly 60% of EYLEA franchise net sales, and Regeneron was the only innovative ophthalmology brand to grow share in the second quarter. Management cited real-world durability gains of nearly four additional weeks between treatments for patients switching from other therapies, following label enhancements for every-four-week dosing and an RVO indication added in late 2025. The company reiterated guidance for sequential demand growth in the low-to-mid teens in both the third and fourth quarters, while acknowledging that additional 2-milligram biosimilars are entering the market and will require continued commercial defense.
Capital Allocation Discipline and the Deals That Didn't Happen
Fenimore was unusually candid about business development misses, attributing some passed-on deals to disappointing diligence findings and others simply to valuation: "We've seen some of the announcements and some of the processes that we've been involved in and some of the values just really outstretched where we were able to get to." On capital returns, Regeneron repurchased $2 billion of stock in the first half of 2026, including $1.2 billion in the second quarter alone, funded by board reauthorizations of roughly $3 billion every 12 to 18 months, alongside a modest dividend program initiated in 2025 that pays out approximately $400 million annually.