Biogen Stock Slides on Q3 Beat as Guidance Cut Shocks Investors

Ticker: BIIB (Nasdaq) – trading in the mid-$140s on Oct. 30, 2025 (last close $147.86 on Oct 29) ^[1], about 2.6% lower after-hours on Oct. 30 ^[2].
Q3 Results: Revenue $2.53 B (+3% YoY) and adjusted EPS $4.81, comfortably beating estimates ($2.34 B and $3.88 EPS) ^[3]. Launch-product revenue jumped 67% (Alzheimer’s, rare and depression drugs) ^[4].
Guidance: 2025 non-GAAP EPS now $14.50–$15.00, below prior $15.50–16.00 ^[5]. Full-year revenue expected roughly flat at +0–1% (vs. prior “flat”) ^[6]. The cut includes an anticipated ~$1.25/sh R&D charge in Q4 ^[7].
Key Products: Alzheimer’s antibody Leqembi sales were ~$121 M in Q3 (+~80% YoY) ^[8]. Skyclarys (Friedreich’s ataxia) brought in $133 M (+30%) ^[9]. Multiple sclerosis portfolio held steady (+1%) with Vumerity demand offsetting generic erosion ^[10].
Recent News: On Oct. 24, Biogen licensed Vanqua Bio’s oral C5aR1 antagonist (inflammatory disorders) for up to $1.06 B ^[11]. Pipeline highlights include full enrollment of two Phase 3 lupus trials (litifilimab) and a filed high-dose Spinraza with FDA PDUFA date April 3, 2026 ^[12].
Analyst Consensus: MarketBeat shows a Hold consensus with an average price target ~$180.7 (≈22% above current) ^[13]. Investors eye Biogen’s need to offset its aging MS drugs with new therapies.

Biogen Inc. (Nasdaq: BIIB) is a leading neuroscience biotech known for multiple sclerosis and rare-disease therapies ^[14]. On Oct. 30, 2025 the stock dipped after a mixed earnings release. The company beat Q3 expectations – adjusted EPS $4.81 vs. $3.88 est and $2.53 B revenue vs. $2.34 B est ^[15] – but lowered its full-year outlook. Biogen now expects 2025 non-GAAP EPS of $14.50–$15.00 (previously $15.50–16.00), citing an anticipated ~$1.25 per-share charge in Q4 for recent R&D deals ^[16] ^[17].

CEO Chris Viehbacher spun the quarter positively, noting “we delivered another quarter of strong financial performance driven by … momentum in our launch products [and] resilience in our MS franchise” ^[18]. Indeed, Biogen’s newer products performed well: Alzheimer’s treatment Leqembi saw global sales of about $121 M (up 82% YoY) ^[19] and rare-disease drugs like Skyclarys ($133 M, +30%) and Zurzuvue ($55 M) continue to grow ^[20]. However, Biogen’s core multiple sclerosis line held nearly flat (+1%) as U.S. demand for Vumerity rose but Tecfidera (now generic) declined overseas ^[21].

Meanwhile Biogen announced a strategic deal on Oct. 24: an exclusive license to Vanqua Bio’s experimental C5aR1 inflammation drug for up to $1.06 B ^[22], expanding its immunology pipeline. The company also reported progress in its pipeline – for example, two Phase 3 trials of the lupus drug litifilimab are now fully enrolled with data expected by H2 2026, and Biogen has resubmitted a high-dose Spinraza (nusinersen) filing (with a PDUFA date set for April 3, 2026) ^[23]. These moves underline Biogen’s focus on growing new franchises as its older drugs face patent cliffs.

Expert Commentary: Some analysts remain cautious. As Wedbush’s Laura Chico recently warned, “we continue to anticipate shares will be under pressure absent a more clearly articulated strategy for top-line growth” ^[24]. Her view reflects concern that Biogen must prove its new products can fill revenue gaps. By contrast, CEO Viehbacher emphasized operational strength in his statement (quoted above) – reflecting a mix of optimism and realism among experts. Stifel analysts note key near-term catalysts are lecanemab (now called Leqembi) trial data and competition in Alzheimer’s, which will influence investor sentiment.

Analyst Outlook & Forecast: On balance, Wall Street’s outlook on BIIB is moderate. MarketBeat data show 31 analysts with a consensus Hold rating and an average price target of ~$180.7 ^[25]. Some believe there is upside if Biogen’s launches continue to exceed expectations. Others point to headwinds. For example, Needham and Citigroup have trimmed 2025 projections amid uncertainty around new indications. Overall, analysts expect roughly flat revenue in 2025 (following several years of declines), reflecting the tug-of-war between legacy drugs and new launches.

Biotech Sector Context: Biogen’s performance comes as the broader biotech sector shows mixed signals. TechStock² (ts2.tech) reports the Nasdaq Biotech Index recently hit a one-year high (~5,007) after surging ~2.6% on Oct. 1 amid optimism around AI-driven drug discovery ^[26]. However, TechStock² also notes biotech as a whole underperformed in early 2025 (healthcare stocks down ~5% YTD while the S&P 500 gained ~7%) ^[27]. Valuations in biotech remain at multi-decade lows – a setup some investors view as attractive “on the rebound” ^[28]. In this environment, Biogen’s stock is influenced not just by its own news, but by these sector-wide trends.

Looking ahead, BIIB investors will watch how the company balances R&D investments with revenue growth. Its recent guidance cut and deals like the Vanqua license show a willingness to spend on the pipeline. If upcoming trial results (e.g. Alzheimer’s and lupus drugs) are positive and product sales continue to climb, Biogen’s longer-term outlook could improve. For now, however, analysts remain cautious, noting that “absent a more clearly articulated strategy” Biogen’s shares could stay under pressure ^[29], even as the company touts strong quarter results.

Sources: Official financial reports and news (Biogen IR, Reuters) and analysis from financial news outlets ^[30] ^[31] ^[32] ^[33] ^[34] ^[35] ^[36] ^[37].