roctaviandurability calibration hit
biomarin · severe hemophilia A · 4-yr durability warrantyknowable at deal datethe warranty turns on 3 metrics — factor level · bleeding · resumption; its modelled basis was 2%/yr → 7.8% cumulative over 4yr (ICER 2022)
finnegas output (read per trigger definition)switching basis: ~16.7% by yr4 (band 10.8–23.8%), ~2.3× the 7.8% assumed · strict 3-criteria clinical loss: 8.3% — the answer swings ~2× with the definition
what actually happenedswitching / resumption 24/134 ≈ 17.9% by yr4 (inside the band) · strict clinical composite 9.0% (Santos 2025) · product withdrawn, ~$240M commercial restructuring
the honest claima retrospective calibration hit on the durability trigger, priced per definition — not a forward prediction; the ~$240M that vaporised sat on the commercial axis we refuse to price, and the refusal is the read that came true in dollars
buyer takeawayunder-priced ~2.3× on the switching basis it was written against — and we price the trigger definition, not one printed rate, because it moves the answer 2×; the independent, audit-trailed read they lacked