BioMarin Pharmaceutical Inc. (NASDAQ: BMRN) is ending 2025 with a bang. Shares surged on Friday, December 19, closing at $61.15—up 17.71% on the day—after the company announced a $4.8 billion all-cash acquisition of rare-disease peer Amicus Therapeutics. Trading volume spiked to roughly 18.5 million shares, far above BioMarin’s recent daily activity, underscoring how dramatically the market repriced the story in a single session. [1]
As of Sunday, December 21, 2025, the weekend narrative around BioMarin stock is dominated by that deal—and what it signals: a sharper pivot toward durable rare-disease commercial franchises, an attempt to reduce dependence on BioMarin’s fast-growing (but increasingly contested) achondroplasia drug Voxzogo, and a willingness to use the balance sheet to buy growth after a period of strategy resets. [2]
Below is a full roundup of the current news, plus the key forecasts and analyst talking points shaping BioMarin’s stock outlook as of 21.12.2025.
What happened to BioMarin stock this week
The price action has been unusually clean and catalyst-driven:
- Dec. 19 close: $61.15
- Day’s move: +17.71%
- Day’s range: Open ~$54.80; High ~$63.89; Low ~$54.39
- Volume: ~18.52M shares [3]
The move followed BioMarin’s announcement that it will acquire Amicus Therapeutics for $14.50 per share in cash, a 33% premium to Amicus’ prior close, with the transaction expected to close in Q2 2026. [4]
For additional context, BioMarin’s 52-week range has been roughly $50.76 to $73.51—so Friday’s close pushed the stock away from the lower end of its annual band, but still below highs. [5]
The headline: BioMarin to buy Amicus for $4.8 billion
Deal terms and financing (the “how”)
BioMarin will pay $14.50 per share for Amicus in an all-cash deal. The company plans to finance the purchase using about $2 billion in cash and around $3.7 billion in non-convertible debt. [6]
In its announcement, BioMarin also laid out a clear balance-sheet goal: it is targeting gross leverage below 2.5x within two years after close, alongside “strong cash flow generation” and an explicit commitment to deleveraging. [7]
What BioMarin is buying (the “what”)
Amicus brings two marketed rare-disease therapies and a late-stage clinical asset:
- Galafold (migalastat) for Fabry disease (an oral therapy)
- Pombiliti + Opfolda for Pompe disease (a combination regimen)
- U.S. rights to DMX-200, a Phase 3 asset for focal segmental glomerulosclerosis (FSGS), a rare kidney disease [8]
BioMarin said the two marketed medicines produced $599 million in combined net product revenue over the past four quarters, and it expects the acquisition to add revenue immediately after closing. [9]
Exclusivity and the Galafold patent overhang
A major part of the market’s comfort level with Fabry revenue durability is IP (intellectual property) visibility. Alongside the deal news, Amicus disclosed patent litigation settlements that pushed expected generic entry for Galafold in the U.S. out to early 2037; BioMarin’s deal materials likewise indicate U.S. exclusivity is expected through January 2037. [10]
Why investors cared: BioMarin is “buying back” growth credibility
To understand the stock’s reaction, you have to zoom out to BioMarin’s 2024–2025 corporate arc.
The Roctavian reset: exiting a gene-therapy growth story that didn’t land
In late October, BioMarin said it would divest/out-license Roctavian, its hemophilia A gene therapy, after commercial uptake lagged far behind early expectations. Reuters reported Roctavian faced headwinds including limited eligibility, reimbursement friction, and a $2.9 million list price; sales were reported at $3.5 million in 2023 and about $26 million in 2024. [11]
That decision mattered for sentiment because Roctavian had been a pillar of the company’s longer-term narrative—and when it fell away, the market became even more fixated on whether Voxzogo could keep carrying the growth story on its own. [12]
Voxzogo is still the engine—but competition is getting closer
BioMarin’s growth standout remains Voxzogo for achondroplasia. In 2024, Voxzogo generated $735 million in revenue (up 56% year over year), according to BioMarin’s full-year results. [13]
In BioMarin’s Q3 2025 update, the company reaffirmed its full-year 2025 Voxzogo revenue outlook of $900 million to $935 million, and noted treatment access across 55 countries at quarter-end, tracking toward availability in 60+ countries by 2027. [14]
But the competitive clock is ticking. The FDA extended its review timeline for Ascendis Pharma’s TransCon CNP (a would-be achondroplasia rival) after Ascendis submitted additional information related to a post-marketing requirement; Ascendis said it now expects an FDA decision on or before Feb. 28, 2026. [15]
The consequence: BioMarin’s stock had become increasingly “one-drug sensitive.” The Amicus acquisition directly addresses that market anxiety by adding new rare-disease revenue streams that fit BioMarin’s existing commercial wheelhouse. [16]
BioMarin’s fundamentals: the baseline numbers investors are anchoring to
2024 performance (the “starting point”)
BioMarin reported $2.854 billion in total revenue for full-year 2024, with strong profitability improvements year over year. In the same report, the company highlighted Enzyme Therapies revenue of $1.928 billion and Voxzogo revenue of $735 million. [17]
2025 guidance (the “near-term forecast”)
In the company’s Q3 2025 update, BioMarin raised the midpoint of its 2025 total revenue guidance to $3.15 billion to $3.20 billion, while keeping the Voxzogo outlook intact at $900 million to $935 million. [18]
BioMarin’s Q3 materials also show how one-time items can swing profit metrics: guidance for non-GAAP operating margin and non-GAAP diluted EPS was adjusted in connection with acquired in-process R&D charges from the Inozyme acquisition. [19]
Cash flow and balance-sheet flexibility (why BioMarin can do deals)
BioMarin reported $369 million in operating cash flow in Q3 2025 and $728 million year-to-date through Sept. 30, with total cash and investments at about $2.0 billion at quarter-end. [20]
That cash generation capacity is central to the Amicus thesis: the company is taking on substantial debt, but it’s also telling investors it intends to pay it down quickly while maintaining strategic flexibility. [21]
How big is the Amicus purchase relative to BioMarin?
BioMarin is not “Big Pharma big,” which is why this transaction is resonating so strongly with stock investors.
- BioMarin 2024 revenue: $2.854B [22]
- Amicus trailing-four-quarter net product revenue (two drugs): $599M [23]
At a high level, that means BioMarin is acquiring a revenue stream that (on a rough, apples-to-apples basis) is material relative to its current scale—while also adding a late-stage asset (DMX-200) that could become a future growth lever if Phase 3 results and regulatory pathways break favorably. [24]
That scale is also exactly why skeptics exist: a deal this size can help diversify growth, but it also raises execution risk (integration, commercial strategy, and debt service). [25]
Analyst and market commentary: broadly positive, but with real caveats
The bullish view: strategic fit + immediate revenue
Several major writeups converged on the same core point: this is a rare-disease bolt-on that matches BioMarin’s commercial infrastructure, particularly its enzyme-therapy experience, and it gives investors “more to talk about” than Voxzogo competition. [26]
BioMarin itself is projecting:
- Immediate revenue contribution post-close
- Accretion to non-GAAP diluted EPS within 12 months after close
- Substantial accretion beginning in 2027 [27]
The cautious view: debt + integration + “peak sales” debate
Even supportive analysts have flagged the obvious tension: BioMarin is making a “big bet on diversification,” and investors will debate the peak sales trajectory for Galafold and Pombiliti/Opfolda—especially as BioMarin layers on debt to buy those cash flows. [28]
BioMarin executives have argued the runway is meaningful. For example, commentary reported by Fierce Pharma noted management’s view that both Amicus drugs have potential to reach $1 billion in peak sales, and that Galafold growth could benefit from Fabry being underdiagnosed and undertreated. [29]
Where Wall Street targets cluster (and why they vary)
On the “numbers” side, one widely followed compilation (MarketBeat) characterized BioMarin as a “Moderate Buy” with an average price target around $88.61, while also noting recent rating changes including a December target cut by Leerink (from $82 to $60) and an October target cut by Barclays (from $86 to $80). [30]
The dispersion matters: it reflects how different analysts weight the same uncertainties—Voxzogo durability under competition, the pace and profitability of international expansion, and now the debt-funded integration of Amicus. [31]
The pipeline and upcoming catalysts: what could move BMRN next
BioMarin’s stock isn’t just about this acquisition headline; it’s also about what’s on deck into 2026.
1) Deal progress and regulatory clearance
The Amicus acquisition is expected to close in Q2 2026, pending customary approvals. Some analysts cited in coverage have suggested antitrust risk is likely manageable, but the closing timeline still matters for near-term modeling. [32]
2) Voxzogo competitive timeline (Feb. 2026 is a key window)
The FDA’s delayed decision on Ascendis’ TransCon CNP—now expected by Feb. 28, 2026—will remain a major overhang/inflection point for BioMarin’s flagship growth driver. [33]
3) BioMarin’s internal pipeline readouts (2026-heavy calendar)
From BioMarin’s Q3 2025 corporate update, notable expected milestones include:
- BMN 401 (ENPP1 deficiency): initial pivotal data readout anticipated 1H 2026, with potential launch cited for 2027
- BMN 333 (long-acting CNP): Phase 2/3 study dosing expected to begin 1H 2026
- Voxzogo hypochondroplasia: pivotal data expected 1H 2026 [34]
Separately, BioMarin’s earlier acquisition of Inozyme added INZ-701 (enzyme replacement therapy) to the enzyme-therapies portfolio, and industry coverage has pointed to Phase 3 data timing as another 2026 watch item. [35]
4) Earnings and guidance updates
With a major M&A announcement now in the mix, investors will be watching BioMarin’s next earnings cycle for:
- Updated capital allocation priorities
- Any revisions to 2026 expectations and longer-term margin targets
- Integration planning assumptions and deleveraging cadence [36]
The bottom line for BioMarin stock as of Dec. 21, 2025
As of 21.12.2025, BioMarin’s stock story has shifted quickly from “How long can Voxzogo outrun competition?” to a broader (and more classic) biotech question: Can management execute a debt-financed roll-up of adjacent rare-disease cash flows while still investing in the next wave of growth? [37]
The Amicus deal gives BioMarin:
- Two marketed assets with meaningful scale (relative to BioMarin’s size)
- A clearer diversification plan anchored in enzyme/rare metabolic diseases
- A more credible bridge toward 2030 growth messaging—if integration and deleveraging go to plan [38]
But it also raises the stakes:
- $3.7B in new debt is not trivial
- Voxzogo competition is still coming into focus in early 2026
- Market enthusiasm now needs follow-through in execution and numbers [39]
References
1. www.investing.com, 2. www.barrons.com, 3. www.investing.com, 4. www.reuters.com, 5. www.nasdaq.com, 6. www.reuters.com, 7. investors.biomarin.com, 8. www.reuters.com, 9. investors.biomarin.com, 10. www.biopharmadive.com, 11. www.reuters.com, 12. www.biospace.com, 13. www.biomarin.com, 14. investors.biomarin.com, 15. www.biospace.com, 16. www.biopharmadive.com, 17. www.biomarin.com, 18. investors.biomarin.com, 19. investors.biomarin.com, 20. investors.biomarin.com, 21. investors.biomarin.com, 22. www.biomarin.com, 23. investors.biomarin.com, 24. www.reuters.com, 25. www.biopharmadive.com, 26. www.biopharmadive.com, 27. investors.biomarin.com, 28. www.biopharmadive.com, 29. www.fiercepharma.com, 30. www.marketbeat.com, 31. www.marketbeat.com, 32. www.reuters.com, 33. www.biospace.com, 34. investors.biomarin.com, 35. investors.biomarin.com, 36. investors.biomarin.com, 37. www.biospace.com, 38. investors.biomarin.com, 39. www.reuters.com
