Thesis: Orphan-franchise cash engine re-rated downward on gene-therapy scar tissue and CNP competition fear; Q2-26 quantified the competition as slow (~90% US VOXZOGO retention) and upgraded the Amicus assets to $2.6B combined peak. Market prices ~4.5% perpetual growth against 21% guided. P / FV (base): 0.55x · Spot: $64.55 · Base FV: $117.05 · Reviewed: 2026-08-06 · Call: Torque sleeve, base-modal, no exclusion gate

Bear (22%) — VOXZOGO revenue growth < 3% FY27 (vs +11% FY26 guide midpoint, anchored to company guidance); US VOXZOGO patient retention < 80% by YE2027 (vs ~90% reported at end-July 2026, company-disclosed); BMN 333 Phase 2/3 2027 update fails to show superiority to VOXZOGO on annualised growth velocity; non-GAAP operating margin < 36% FY28 (vs 36.4% Q2-26 actual).
Base (45%) — total revenue ≥ $4.35B FY27 (full-year Amicus plus organic; anchored to $3,875–3,925M FY26 guide); VOXZOGO franchise ≥ $1.10B FY27; VOXZOGO achondroplasia full approval by 2027-02-28 PDUFA AND hypochondroplasia approval by 2027-12-31; gross leverage < 2.5x by mid-2027 (company target restated 2026-08-06); non-GAAP operating margin ≥ 40% FY28.
Bull (25%) — total revenue ≥ $4.60B FY27; GALAFOLD plus POMBILITI+OPFOLDA combined ≥ $1.05B FY27 (vs ~$760M annualised Q2-26 run-rate ); non-GAAP diluted EPS ≥ $7.00 FY27 (vs $4.90–5.10 FY26 guide, against management's "substantially accretive in 2027"); non-GAAP operating margin ≥ 44% FY29.
Blue-sky (8%) — BMN 333 Phase 2/3 2027 data shows superiority to VOXZOGO on AGV AND supports dosing less frequent than weekly, establishing next-generation achondroplasia leadership; OR BMN 820 ACTION 3 (2028) hits its primary endpoint with a label covering the broad ~30,000-patient US FSGS population; OR credible takeout ≥ $130/sh.

Year-end
Bear $34.53 (−47%)
Base $117.05 (+81%)
Bull $168.33 (+161%)
Blue-sky $219.42 (+240%)
Prob-wtd $119.90 (+86%)
Catalyst risk (±%) ±11.3%
Live catalyst (±% · when) ±3% · Q3'26