Verdict: Justified

Key finding: Q3 beat (revenue $1.458B vs $1.43B; TTR franchise $1.15B, +59% y/y), but management now expects 2026 TTR sales at the low end of $4.2–4.5B. That implies a roughly flat to −3% Q4 versus Q3 (my estimate). It is the second disappointment in a row after the July guidance cut, with new Q4 headwinds: the 340B rule, UnitedHealth's Medicare Advantage policy, and a lower net price. The stock fell to a new 52-week low.

Scorecard

Ticker Rev last Q ($M) Rev YoY last Q Rev YoY prior Q Gross margin (last Q, trend) Op margin EPS last Q vs yr ago P/S Mkt cap 1-mo price %
ALNY (Q3-26) 1,458.1 +16.7% +66.9% — (Q2 76.9%, down from 81.9%) 29.1% (non-GAAP) 16.26* vs 1.84 4.9x $24.6B −9.0% to 10/28; −28.1% incl. today
BBIO (Q2-26) 222.4 +101.2% +66.8% 93.2% (flat) −48.1% −0.78 vs −0.95 20.3x $14.0B +6.3%
IONS (Q2-26) 267.9 −40.7% +87.0% 99.0% (flat) −38.2% −0.69 vs 0.68 8.6x $7.5B −1.5%
NTLA (Q2-26) 7.7 −46.2% −9.5% — — −0.80 vs −0.98 31.9x $1.9B +16.6%

*Includes a ~$1.9B non-cash tax benefit (US valuation-allowance release).

ALNY is the quality leader of the TTR group: the only profitable one and the cheapest on sales (4.9x). But its growth is slowing hard: total revenue went from +66.9% to +16.7% y/y, partly because Q3-25's total revenue was itself up 149%. Product revenue still grew +52% and TTR +59%. Peers: BBIO (Attruby) and IONS (Wainua, with AstraZeneca) compete in ATTR. NTLA is in-vivo gene editing for ATTR.

Move

Catalyst

Q3 2026 results (10/29, before the open):
- AMVUTTRA $1,130.4M (+65% y/y). Total TTR $1,150.0M (+59% y/y, +12% q/q). Rare (GIVLAARI + OXLUMO) $142.0M (+12%). Net product revenue $1,291.9M (+52%). Total revenue $1,458.1M (+17%).
- Guidance reiterated (TTR $4.2–4.5B, net product $4.7–5.1B, collaborations and royalties $575–625M), but TTR is expected at the low end.
- My estimate: year-to-date TTR is about $3.08B (Q1 derived as about $0.90B), so the low end implies Q4 TTR of about $1.11–1.12B, against $1.15B in Q3.
- Q3 itself was helped by a $17M inventory build (channel inventory up from 19 to 21 days) and about $10M of one-time Medicaid gross-to-net benefit.
- Management on the call:
- The field expansion is "not yet translating into demand at the pace that we anticipated."
- Q4 headwinds: 340B ordering (final rule expected "in the coming weeks", effective 1/1/2027, a "meaningful portion of our business"); UnitedHealth's Medicare Advantage policy (effective 10/1); a lower US net price in Q4.
- No 2027 guidance until mid-February.
- Positives:
- ATTR-CM prescriptions are up nearly 40% y/y. New-to-brand share has stayed above 30%; total TTR prescription share is 24%. About 80% of prevalent ATTR-CM patients are untreated.
- Cash $3.6B. Non-GAAP operating income $425M (−11% y/y).
- GAAP net income of about $2.2B is mostly the ~$1.9B tax item, which also inflated the $16.26 EPS "beat" against $1.74.
- Pipeline:
- Triton-CM enrollment was raised by 500 to about 2,250 patients to protect statistical power; launch still about 2030.
- The next-generation TTR silencer shows over 95% knockdown with twice-yearly dosing.
- Huntington's (bersoeran): 60–64% mutant HTT reduction in the spinal fluid; a pivotal study is planned for 2027.

Sector

Risks

Judgement

Justified. The beat came from one-time items (the tax benefit, the inventory build, Medicaid gross-to-net). What matters is the outlook: Q4 TTR implied flat to down, three new pricing and access headwinds, demand conversion "not at the pace we anticipated," and no 2027 visibility until February. For a stock priced as a compounder, a stall in sequential growth justifies a repricing. The business isn't broken: TTR is still +59% y/y, new-patient share is above 30%, 80% of patients are untreated, and the company is profitable with $3.6B cash. But the near-term growth story that held the multiple has broken twice, and the stock broke its July low.

Sources