Biogen’s Acquisition of Apellis Strengthens Immunology and Rare Disease Portfolio While Accelerating Growth and Entry into Nephrology
Biogen Inc. and Apellis Pharmaceuticals (Nasdaq: APLS) have announced a definitive agreement under which Biogen will acquire Apellis in a transaction valued at approximately $5.6 billion upfront. The deal represents a major strategic step for Biogen as it continues to reshape its business and strengthen its presence in immunology, rare diseases, and specialty therapeutics.
Under the terms of the agreement, Biogen will purchase all outstanding shares of Apellis for $41.00 per share in cash at closing. In addition to the upfront payment, Apellis shareholders will receive a non-transferable contingent value right (CVR) for each share held. These CVRs provide the opportunity for additional payments of up to $4 per share, contingent on the future commercial performance of Apellis’ flagship ophthalmology product, SYFOVRE®. The structure of the deal reflects both immediate value and potential upside tied to long-term growth.
Strengthening Biogen’s Growth Portfolio
The acquisition is closely aligned with Biogen’s broader strategy to enhance its growth profile by adding innovative, revenue-generating assets in high-value therapeutic areas. By bringing Apellis into its portfolio, Biogen gains access to two commercially available, differentiated therapies—EMPAVELI® and SYFOVRE®—both of which target complement-mediated diseases, a rapidly advancing area of immunology.
Together, these products generated approximately $689 million in net sales in 2025 and are projected to grow at a mid-to-high teens rate annually through at least 2028. This immediate revenue contribution is expected to bolster Biogen’s financial performance while providing a platform for sustained long-term growth.
Apellis is widely recognized for its expertise in complement biology, an area of the immune system that plays a central role in inflammation and disease progression. Dysregulation of the complement cascade has been implicated in a range of rare and chronic conditions, making it an attractive target for therapeutic intervention.
Strategic and Leadership Perspectives
Christopher A. Viehbacher, President and Chief Executive Officer of Biogen, emphasized that the acquisition is a key milestone in the company’s ongoing transformation. He highlighted that the addition of Apellis strengthens Biogen’s position in immunology and rare diseases while complementing its existing portfolio.
Viehbacher also pointed to the synergy between the two organizations, noting that Apellis’ scientific expertise and commercial capabilities will enhance Biogen’s ability to maximize the potential of its newly acquired therapies. In particular, he underscored the opportunity to expand Biogen’s nephrology franchise, especially as it advances its late-stage asset felzartamab.
On the Apellis side, Cedric Francois, co-founder and Chief Executive Officer, described the transaction as a validation of the company’s scientific innovation and execution. He noted that Apellis has successfully developed and commercialized two transformative therapies and built a pipeline rooted in deep expertise in complement science.
Francois expressed confidence that Biogen’s global scale and experience will accelerate the reach and impact of these therapies, enabling them to benefit a larger patient population worldwide.
Overview of Key Products
EMPAVELI® (pegcetacoplan)
EMPAVELI® is a targeted therapy that inhibits complement component 3 (C3), a central protein in the complement cascade. By regulating excessive complement activation, the drug addresses underlying disease mechanisms rather than simply managing symptoms.
The therapy has received approval from the U.S. Food and Drug Administration for multiple indications, including rare kidney diseases such as C3 glomerulopathy (C3G) and primary immune-complex membranoproliferative glomerulonephritis (IC-MPGN), as well as paroxysmal nocturnal hemoglobinuria (PNH).
Clinical data from the Phase 3 VALIANT study demonstrated that EMPAVELI® significantly reduced proteinuria by 68%, stabilized kidney function, and promoted clearance of C3 deposits compared to placebo. The therapy is notable for its broad label, including use in both adult and adolescent patients, as well as those experiencing post-transplant disease recurrence.
Globally, EMPAVELI® is also marketed as Aspaveli® in certain regions, with Sobi retaining commercial rights outside the United States. Biogen has indicated it will continue to collaborate with Sobi following the acquisition.
SYFOVRE® (pegcetacoplan injection)
SYFOVRE® is an approved treatment for geographic atrophy (GA) secondary to age-related macular degeneration, a progressive and vision-threatening retinal disease. Like EMPAVELI®, it targets C3, providing comprehensive control over the complement cascade.
The therapy was approved based on results from the Phase 3 OAKS and DERBY studies, which demonstrated a meaningful reduction in the rate of lesion growth compared to sham treatment. Notably, the benefits increased over time, with the greatest effect observed between months 18 and 24 of treatment.
Long-term data from the GALE extension study further supported the therapy’s efficacy, showing that SYFOVRE® could delay disease progression by approximately 1.5 years in certain patient populations. The drug is currently approved in the United States and Australia, with additional regulatory activities ongoing.
Apellis has also completed a clinical trial evaluating a prefilled syringe formulation of SYFOVRE®, with plans to submit for regulatory approval in 2026. This innovation could improve patient convenience and expand the therapy’s accessibility.
Expanding Capabilities in Nephrology and Beyond
In addition to its commercial products, Apellis brings a well-established U.S. commercial infrastructure, including expertise in nephrology. This capability is expected to complement Biogen’s development efforts for felzartamab, a late-stage therapy currently being evaluated in Phase 3 trials for multiple kidney diseases.
The integration of Apellis’ field teams and operational capabilities is anticipated to enhance Biogen’s readiness for future product launches, particularly in the nephrology space. Upon closing, a significant proportion of Apellis employees are expected to join Biogen, further strengthening the combined organization.
Financial Structure and Value Creation
The transaction is structured to deliver both immediate and long-term value. The upfront cash payment represents an 86% premium to Apellis’ 90-day volume-weighted average stock price and a 35% premium to its 52-week high, reflecting strong confidence in the company’s assets and growth potential.
The CVR component provides additional upside tied to SYFOVRE®’s commercial success. Shareholders may receive:
- $2 per share if SYFOVRE® achieves $1.5 billion in annual global net sales between 2027 and 2030
- An additional $2 per share if sales reach $2 billion within the same period
- Alternatively, a single $4 payment if the $2 billion threshold is achieved in 2031
This structure aligns incentives between Biogen and Apellis shareholders while mitigating risk.
Biogen expects the acquisition to enhance its revenue and earnings per share (EPS) growth, with increasing accretion anticipated starting in 2027. The deal is also expected to contribute meaningfully to Biogen’s non-GAAP EPS compound annual growth rate through the end of the decade.
To finance the acquisition, Biogen plans to use a combination of cash and debt. The company has indicated that it expects to fully deleverage by the end of 2027, maintaining financial flexibility for future investments.
Transaction Process and Timeline
The acquisition will be executed through a tender offer, followed by a second-step merger to acquire any remaining shares. The transaction has been approved by the boards of directors of both companies and is subject to customary closing conditions, including regulatory approvals.
Biogen expects the deal to close in the second quarter of 2026. Following completion, the company will integrate Apellis’ operations and update its financial guidance accordingly.
Advisory Support
The transaction is being supported by leading financial and legal advisors. Lazard is serving as Biogen’s financial advisor, with Cravath, Swaine & Moore LLP and Arnold & Porter providing legal counsel. Apellis is being advised by Evercore, with legal support from Wachtell, Lipton, Rosen & Katz and WilmerHale.
Broader Industry Implications
The acquisition highlights ongoing consolidation within the biopharmaceutical industry, particularly in areas such as immunology and rare diseases. Companies are increasingly seeking to acquire innovative assets and platforms that can drive growth and address unmet medical needs.
Complement biology, in particular, has emerged as a promising area of research, with applications across a wide range of conditions. By acquiring Apellis, Biogen positions itself at the forefront of this field, with the potential to expand into additional indications over time.
The planned acquisition of Apellis Pharmaceuticals represents a transformative step for Biogen, reinforcing its strategic focus on high-growth therapeutic areas and strengthening its commercial portfolio. With the addition of EMPAVELI® and SYFOVRE®, Biogen gains immediate revenue, scientific expertise, and a platform for future innovation.
As the company continues its transformation, the integration of Apellis is expected to enhance its ability to deliver innovative therapies to patients while driving long-term value for shareholders. The transaction underscores the importance of strategic investment in cutting-edge science and the critical role of collaboration in advancing healthcare.
About Geographic Atrophy (GA)
Geographic atrophy (GA) is an advanced form of age-related macular degeneration and a leading cause of blindness worldwide, impacting more than one million Americans and five million people worldwide.1,2 It is a progressive and irreversible disease caused by the growth of lesions, which destroys the retinal cells responsible for vision. Vision loss caused by GA severely impairs independence and quality of life by making it difficult to participate in daily activities. While rates of progression vary between patients, on average, it takes 2.5 years for GA lesions to start impacting the fovea, which is responsible for central vision.3
About C3 Glomerulopathy (C3G) and Primary Immune-Complex Membranoproliferative Glomerulonephritis (IC-MPGN)
C3G and primary IC-MPGN are rare and debilitating kidney diseases that can lead to kidney failure. Excessive C3 deposits are a key marker of disease activity, which can lead to kidney inflammation, damage, and failure. Approximately 50% of people living with C3G and primary IC-MPGN suffer from kidney failure within five to 10 years of diagnosis, requiring a burdensome kidney transplant or lifelong dialysis therapy.4-6 Additionally, approximately 90% of patients who previously received a kidney transplant will experience disease recurrence.7
About SYFOVRE® (pegcetacoplan injection)
SYFOVRE® (pegcetacoplan injection) is the first-ever approved therapy for geographic atrophy (GA) secondary to AMD. By targeting C3, SYFOVRE is designed to provide comprehensive control of the complement cascade, part of the body’s immune system. SYFOVRE is approved in the United States for the treatment of GA secondary to age-related macular degeneration.
About EMPAVELI®/Aspaveli® (pegcetacoplan)
EMPAVELI®/Aspaveli® (pegcetacoplan) is a targeted C3 therapy designed to regulate excessive activation of the complement cascade, part of the body’s immune system, which can lead to the onset and progression of many serious diseases. It is the first treatment approved in the United States for C3 glomerulopathy (C3G) or primary immune complex membranoproliferative glomerulonephritis (IC-MPGN) in patients 12 years of age or older, to reduce proteinuria.
EMPAVELI/Aspaveli® is also approved for the treatment of adults with paroxysmal nocturnal hemoglobinuria (PNH) in the United States, European Union, and other countries globally, and for the treatment of C3G and primary IC-MPGN in the European Union and other countries globally. EMPAVELI is being evaluated for the treatment of additional rare diseases.
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