What Is Driving Biogen’s Recent Drop and What Comes Next
It is a pretty wild thought that the same company you see on a stock ticker was actually cofounded by a group that included two different scientists who both went on to win Nobel Prizes. Walter Gilbert and Phillip Sharp were part of that original “brain trust,” and while you would think that kind of genius DNA would make for a smooth ride, Biogen stock (NASDAQ: BIIB) has been a total rollercoaster lately. After a strong start to February 2026 where it hit highs around $202, the stock has since lost its steam, sliding down to about $172 as of early April. For anyone watching their portfolio, it has been a bit of a reality check that even the smartest companies in the room can hit a rough patch.
Why the Drop Since February?
The main reason for the slide from those February peaks is not that the company is failing, but rather that the market is just being incredibly impatient. When Biogen reported its fourth quarter results on February 6, the stock initially popped because the numbers were actually pretty good. However, once the hype died down, investors started obsessing over the legacy side of the business. Biogen is currently in the middle of a massive pivot, trying to move away from its old multiple sclerosis drugs which are getting hurt by cheaper generic competition.
Even though new drugs are growing, the old ones are shrinking fast. Management warned that total revenue for 2026 will likely decline by a mid single digit percentage because those older treatments are losing ground so quickly. On top of that, there is some extra noise in the financials right now. Just this week, Biogen flagged a $34 million research and development charge for the first quarter of 2026, which is expected to shave about $0.19 off its earnings per share. In a market that is already nervous, these little hits to the bottom line tend to send fair weather investors running for the exits.
Recent Results and the Leqembi Factor
If you ignore the falling sales of the old drugs, the actual performance of Biogen’s new portfolio is pretty impressive. In the last quarter of 2025, the company reported revenue of $2.28 billion which beat what analysts expected. Their adjusted earnings came in at $1.99 per share, which was a huge beat compared to the $1.61 the experts were looking for. The real star of the show was Leqembi, their new Alzheimer’s treatment. Sales for that drug hit $134 million in that quarter, proving that there is real demand for it even if the rollout feels a bit slow to some.
Another bright spot was Skyclarys, a drug for a rare neurological disease, which brought in $133 million. Together, the new products Biogen has launched since 2023 are finally starting to pull their weight. The problem is that while these new hits are growing, they are still fighting to cover the holes left by the shrinking multiple sclerosis business, which used to be a $3 billion powerhouse. It is a classic race against time and right now the market is worried the old business is dying faster than the new one can grow.
What is Next and the $5.6 Billion Bet
The big news moving forward is Biogen’s massive $5.6 billion acquisition of Apellis Pharmaceuticals which was just announced on March 31, 2026. This is a huge all in bet on immunology and rare diseases. Biogen is basically buying its way into more immediate revenue as Apellis already has products like Syfovre on the market making hundreds of millions of dollars. The goal is to make the company earnings look much better by 2027, but in the short term, it means Biogen has to deal with the costs of a big merger.
For the rest of 2026, Biogen is sticking to its guns with an earnings guidance of $15.25 to $16.25 per share. The next big date to watch is May 7, 2026, when they are expected to report their first quarter results. If they can show that Leqembi sales are still accelerating and that the Apellis deal won’t be too messy, the stock could easily find its footing again. It is definitely a transition year and while the drop to $172 hurts, the company is basically trying to rebuild its entire engine while the plane is still flying.
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