Biogen's SMA Breakthrough: Higher-Dose Nusinersen Could Drive Long-Term Growth and Justify Immediate Investment

The field of spinal muscular atrophy (SMA) treatment has long been a proving ground for biotechnology innovation, and Biogen's (NASDAQ: BIIB) recent data on its higher-dose nusinersen (SPINRAZA) regimen underscores its position as a leader in this space. With transformative trial results from the DEVOTE and NURTURE studies, coupled with ongoing regulatory reviews, Biogen is poised to expand its dominance in SMA therapy. This creates a compelling investment case for those willing to bet on its long-term prospects.

A Transformative Dose Regimen: Beyond Incremental Improvements

The DEVOTE Part C trial, which evaluated 38 patients previously treated with the standard 12 mg dose of nusinersen for over four years, revealed meaningful motor function gains after transitioning to a higher-dose regimen (50 mg loading dose followed by 28 mg maintenance doses). Non-ambulatory patients saw an average improvement of +2.5 points on the Hammersmith Functional Motor Scale-Expanded (HFMSE), a statistically significant outcome. Even ambulatory patients, a harder-to-treat group, showed improvement. These results are critical because they demonstrate that nusinersen can continue to deliver benefits in long-term patients—a population where disease progression often plateaus.

The NURTURE trial, which tracked presymptomatic infants over eight years, further solidifies nusinersen's efficacy. With 92% of participants achieving independent walking and none requiring permanent ventilation, the data reinforces the importance of early intervention. This cohort's neurofilament light chain (NfL) levels—a biomarker of neurodegeneration—dropped sharply post-treatment, offering a measurable indicator of treatment success. Together, these studies establish a clear therapeutic pathway: early treatment with the standard dose to prevent disease onset, followed by a higher-dose regimen to sustain or enhance gains in chronic cases.

Regulatory Momentum and Market Potential

Biogen's applications for the higher-dose regimen are under review in the U.S., EU, Japan, and other markets. While no approval timelines are yet specified, the FDA and EMA's acceptance of the submissions marks a significant milestone. If approved, the regimen could carve out a new revenue stream for Biogen, addressing a gap in existing SMA treatments.

The SMA market is projected to grow rapidly, driven by early diagnosis, expanded access, and pipeline innovations. With SPINRAZA already approved in over 70 countries and used by 14,000+ patients, Biogen's existing footprint provides a strong base. The higher-dose regimen, if approved, could extend the product's lifecycle, reduce patient attrition, and even attract new patients who were previously deemed untreatable.

Investment Thesis: A Catalyst-Driven Opportunity

The data from DEVOTE and NURTURE, combined with regulatory momentum, positions Biogen as a beneficiary of multiple near- and long-term catalysts:

1. Near-Term Catalysts:
2. Regulatory decisions on the higher-dose regimen in key markets could arrive within the next 12–18 months. Positive outcomes would validate Biogen's pipeline and likely boost stock valuation.

3. Analysts have set a median price target of $196 for BIIB, with some firms like RBC Capital and H.C. Wainwright advocating “buy” ratings.

4. Long-Term Growth:

5. The SMA pipeline is robust, with over 10 ongoing trials (including Phase III studies for salanersen, another SMA candidate). This diversification reduces reliance on any single asset.
6. The higher-dose regimen's potential to improve outcomes in long-term patients could expand SPINRAZA's addressable market, driving recurring revenue through maintenance doses.

Risks to Consider

• Regulatory Delays: While the higher-dose application is under review, delays or unfavorable decisions could pressure the stock.
• Competitor Threats: Roche's risdiplam (Evrysdi) and Sarepta's SRP-5051 offer alternatives, though Biogen's early clinical lead and established brand remain advantages.

Conclusion: A Strategic Buy with SMA's Future in Mind

Biogen's nusinersen data represents a paradigm shift in SMA treatment, combining early intervention success with sustained benefits in chronic cases. With regulatory reviews advancing and a clear path to market expansion, the stock offers a rare combination of near-term catalysts and long-term growth potential. For investors seeking exposure to a transformative biotech story, BIIB's current valuation—trading at ~25x forward earnings—appears reasonable given its SMA leadership and pipeline depth.

The SMA space is no longer about incremental progress; it's about redefining what's possible. Biogen's latest data suggests it's leading the charge—and investors who act now may secure a position in a market set to redefine itself for years to come.