Alnylam shares lag despite Q1 profit breakthrough as RNAi pioneer's valuation divides Wall Street

Alnylam Pharmaceuticals, the US biotech that has long been the standard-bearer for the RNA interference therapeutic class, has swung to a quarterly profit on the back of a surge in product sales, marking a watershed for a company whose unprofitable history has long unnerved more conservative investors. Yet the share price has so far failed to keep pace with the operational turnaround, leaving the market sharply divided over whether the stock now offers value or further valuation risk.

The Cambridge, Massachusetts-based group reported first-quarter net product revenues of more than $1bn, a 121 per cent year-on-year increase, and posted a net profit for the period — a transition from loss-making status that management has spent more than two decades building toward. Alnylam's market capitalisation stood at roughly $39.5bn in early May, with the stock trading at $297.93 ahead of last week's session.

Despite the scale of the operational shift, Alnylam shares have underperformed the broader biotech sector in recent months. The five-year total shareholder return of 131.6 per cent reflects the strong long-term compounding that has rewarded patient holders, but more recent performance has been weaker, prompting questions about whether the market has already priced in the company's commercial inflection — or whether sentiment has yet to catch up.

The rapid revenue acceleration has been driven principally by AMVUTTRA, the company's RNAi therapy for transthyretin amyloid cardiomyopathy, or ATTR-CM. Following its approval for the cardiomyopathy indication, AMVUTTRA has seen what Simply Wall St described as "rapid and robust uptake" in its first full quarter on the market, supported by near-universal first-line payer access and minimal patient out-of-pocket costs. Bulls argue that as diagnostic awareness of ATTR-CM continues to broaden, the addressable patient population will prove materially larger than current penetration rates suggest, supporting sustained double-digit revenue growth across Alnylam's RNAi franchise.

Bearish positioning is anchored on valuation. The stock currently trades at a price-to-earnings multiple of 73.9 times, well above the broader US biotech sector average of 17.3 times and a peer group average of 42 times. By comparison, Simply Wall St's own modelling implies a "fair" multiple of around 29.8 times. The dispersion captures the central tension in the Alnylam investment case: a discounted-cash-flow approach, anchored on aggressive forward earnings and pipeline expansion assumptions, suggests fair value of around $491.92 per share — implying upside of close to 40 per cent — while a multiples-based view points to clear valuation risk if commercial execution slips.

The risks to the bull case are familiar to followers of the stock. AMVUTTRA's pricing power could come under pressure if competing therapies — including Pfizer's tafamidis franchise and BridgeBio's Attruby — exert sustained downward pressure on first-line economics, while Alnylam's heavy reliance on TTR-targeting therapies leaves it exposed to any setback in payer scrutiny, label expansion or pipeline diversification. The company's longer-term growth case rests on the successful translation of its RNAi platform into therapeutic areas beyond the liver, where delivery technology has historically been the binding constraint.

For a company that pioneered an entirely new therapeutic modality — and which spent years burning cash to bring its first products through the regulatory gauntlet — the move into sustained profitability is a meaningful inflection. Whether the equity market chooses to reward Alnylam with a continued growth multiple, or to revert it toward more conventional biotech valuations, will determine whether the next leg of the company's story rewards holders to the same degree as the past five years.