Biogen acquires Apellis Pharmaceuticals for USD5.6B to fuel immunology growth

USA—Biogen has moved to strengthen its immunology portfolio by acquiring Apellis Pharmaceuticals, paying USD41 per share in cash, with the total transaction valued at approximately USD5.6 billion. 

This deal signals Biogen’s commitment to addressing near-term revenue pressures while positioning itself for future growth in kidney disease treatments.

Strategic acquisition adds proven revenue generators.

The acquisition grants Biogen access to two already-marketed medications that generated USD 689 million in sales last year.

Syfovre, a drug treating geographic atrophy affecting the eye, contributed USD587 million of that total, while Empaveli, approved for rare kidney diseases, strengthened Apellis’s commercial position.

Empaveli received FDA clearance last year for two kidney conditions: complement 3 glomerulopathy and primary immune complex membranoproliferative glomerulonephritis.

The drug earned its initial approval in 2021 for paroxysmal nocturnal hemoglobinuria, a rare blood disorder.

Apellis shareholders will receive additional compensation through contingent value rights of up to USD4 per share, contingent on Apellis products meeting certain sales milestones.

The transaction is expected to close during the second quarter, with the majority of Apellis’s approximately 740 employees anticipated to join Biogen.

The company will continue collaborating with its partner Sobi on Empaveli’s international commercialization.

Closing a near-term revenue gap

Biogen CEO Chris Viehbacher explained the strategic rationale behind the acquisition, emphasizing that while the company maintains confidence in its late-stage pipeline spanning neurology and immunology, those drugs won’t meaningfully contribute to growth until around 2028.

Rather than absorb the risks of phase 3 trials or strain its balance sheet with an expensive acquisition, Biogen pursued a company with products already generating revenue or launching imminently.

Viehbacher characterized the move as fundamentally an immunology play and indicated Biogen has concluded its significant M&A efforts for the foreseeable future.

CFO Robin Kramer projected that combined revenue from Syfovre and Empaveli will expand at mid- to high-teen percentages annually for at least the next two years.

The company will revise its 2026 financial guidance when reporting first-quarter earnings.

Building momentum in two critical markets

Adam Keeney, Biogen’s head of corporate development, highlighted Syfovre’s substantial market opportunity, noting that approximately 1.5 million patients in the United States have geographic atrophy.

Although competition exists—especially from Astellas’s rival drug Izervay, FDA-approved in 2023—Keeney expressed confidence that Syfovre’s position as a leading treatment, along with Biogen’s well-established commercial strength, will realise the drug’s full sales potential.

For Empaveli, the acquisition provides Biogen with a commercial foundation supporting its broader nephrology strategy.

The drug positions itself as a launchpad for Biogen’s investigational felzartamab, currently in late-stage trials across three kidney disease indications.

Biogen expects to announce its first phase 3 results for felzartamab during the first half of 2027.

Stabilizing after recent growth

Biogen announced the acquisition shortly after reporting its first annual sales increase since 2019, with 2025 revenue climbing 2 percent to USD9.9 billion.

However, the company projects a mid-single-digit sales decline for 2026, forecasting annual revenue between USD9.3 billion and USD9.5 billion.

Apellis shares surged more than 100 per cent on the acquisition announcement, while Biogen’s stock declined 4 per cent by midmorning Tuesday.