APLS Stock Soars 140% Today – Here’s Everything To Know About Apellis' Massive $5.6B Deal With Biogen

• Biogen stated Apellis shareholders will also receive two contingent value rights as part of the all-cash deal.
• This entitles Apellis shareholders to receive two payments of $2 per share, contingent on Syfovre meeting certain annual global net sales thresholds.
• Biogen stated that the Apellis acquisition will add two commercialized medicines in differentiated immunology and rare diseases to its growth portfolio: Empaveli and Syfovre.

Apellis Pharmaceuticals Inc. (APLS) shares soared 140% in Tuesday’s pre-market trade after Biogen Inc. (BIIB) announced that it has agreed to acquire the company in a $5.6 billion deal.

Biogen stated that the acquisition of Apellis will bolster its rare-disease treatment portfolio and accelerate its expansion into nephrology.

Retail sentiment on Stocktwits around Apellis Pharmaceuticals trended in the ‘bullish’ territory with message volumes at ‘high’ levels at the time of writing.

Biogen shares were down nearly 3% at the time of writing.

Biogen stated that Apellis shareholders will also receive two contingent value rights (CVRs) as part of the all-cash deal, entitling the holder to receive two payments of $2 per share, contingent on certain annual global net sales thresholds for Syfovre being met.

What Does Apellis Bring To The Table?

Biogen stated that the Apellis acquisition will add two commercialized medicines in differentiated immunology and rare diseases to its growth portfolio: Empaveli and Syfovre.

Syfovre is the first and only FDA-approved therapy for geographic atrophy (GA) secondary to age-related macular degeneration (AMD). The regulator approved Empaveli in 2025 as the first treatment for C3 glomerulopathy (C3G) or primary immune complex membranoproliferative glomerulonephritis (IC-MPGN) in patients aged 12 years and older.

Biogen Highlights Revenue, Earnings Boost From Apellis Acquisition

Biogen stated that Empaveli and Syfovre will boost its topline immediately, noting that these two treatments achieved combined net sales of $689 million in 2025 and expect them to grow in the mid-to-high teens at least through 2028.

“Consistent with our strategy, this acquisition immediately advances Biogen’s ongoing transformation. The addition of Apellis expands our growth portfolio in immunology and rare disease with two approved, best-in-class medicines that complement our existing portfolio and bolsters our near-and long-term growth potential,” said Biogen CEO Christopher A. Viehbacher.

The company added that the Apellis acquisition is expected to be increasingly accretive to Biogen’s diluted earnings per share (EPS) starting in 2027. Biogen stated that it plans to update the full-year 2026 guidance when it reports its first-quarter (Q1) earnings.

APLS stock is down 32% year-to-date, while BIIB stock is up 7%. The S&P Biotech ETF (XBI) is up 41% over the past 12 months, while the Vanguard Small-Cap Index Fund ETF (VB) is up 15%.

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