William Blair & Company, LLC. Exhibit 1 ARIAD Pharmaceuticals, Inc. Sum-of-Parts Fair Value (dollars in thousands) Drug Peak Sales Stage of Development Estimated Launch Date Probability of Commercialization Percentage of Sales to Company Probability. Adjusted NPV Value per Share Percentage of Fair Value Iclusig-CML 9746.822 Marketed January 2013/ 100% 100% $1,843,975 $9.85 83.4% Worldwide July 2013 AP28113—ALK* NSCLC S280918 Phase Ifl I 1-12 2016 81% 100% $325,268 $1.74 14.7% Worldwide Subtotal $2,189,243 $11.59 98.2% Net Cash at Yearend 2014 $63,406 $0.34 2.9% Net Present Value of additional Gain (Loss)' ($22,727) ($0.12) (1.0%) Sum-of-Parts Fair Value $2,209,922 $11.81 100.0% - Includes costs nal *Golly reined to programs above Sources. Company reports and %ma'am Emir 8 Company. L L.C. estimates 5 I Y. Katherine Xu, Ph.D. CONFIDENTIAL - PURSUANT TO FED. R. CRIM. P. 6(e) CONFIDENTIAL DB-SDNY-0 106554 SDNY_GM_00252738 EFTA01450729