Alnylam Reports Strong 2025 Revenue Growth Amid Persistent Execution and Compliance Risks

What happened

Alnylam Pharmaceuticals announced robust fourth quarter and full-year 2025 financial results, with total net product revenues nearing $3 billion, an 81% year-over-year increase driven by the landmark approval of AMVUTTRA for ATTR-CM. However, the DeepValue report highlights that this growth masks underlying vulnerabilities, including a subpoena on government price reporting and distributor fee arrangements that threaten net pricing stability. Recent market sensitivity was evident in a Q4 2025 preannouncement where AMVUTTRA sales of $827 million fell short of expectations, underscoring fragility in quarterly cadence. Despite operational improvements, such as Q3 2025 operating income of $368 million, the company faces intensifying competition from BridgeBio's Attruby and potential payer policy shifts that could curb new patient starts. Investors are now scrutinizing whether Alnylam can deliver on its FY2026 guidance of $4.9B to $5.3B in combined net product revenues while navigating these headwinds.

Implication

The strong 2025 revenue growth confirms AMVUTTRA's commercial traction but does not mitigate the deep-seated risks from pricing and regulatory scrutiny that could compress profitability. The subpoena on government price reporting poses a direct threat to net sales if it escalates, potentially forcing structural changes to discount practices across key products. Competitive pressures are rising, with BridgeBio's Attruby gaining prescriber share, which may erode Alnylam's new-start momentum in ATTR-CM and necessitate higher rebates. Quarterly revenue misses, even if minor, signal expectation fragility that could trigger stock volatility and multiple compression, as seen in recent price reactions. Therefore, while the long-term growth narrative remains plausible, the path is fraught with non-linear risks that favor a patient approach, aligning with the DeepValue 'WAIT' rating for better risk-adjusted returns.

Thesis delta

The 2025 results reinforce the growth thesis but do not alter the core risk profile identified in the DeepValue report, which centers on execution precision and compliance outcomes. The thesis remains unchanged: Alnylam must consistently hit quarterly targets and safeguard net pricing to justify its valuation, with any deviation likely to exacerbate downside scenarios. Investors should continue monitoring the next two quarters for cadence proof and updates on the subpoena, as these are the primary drivers of any future shift in investment outlook.