X0306 4 2016-05-16 0 0001621227 Adaptimmune Therapeutics PLC ADAP 0001661908 Sigal Charles Elliott 32 BREARLY ROAD PRINCETON NJ 08540 1 0 0 0 Ordinary Shares with a nominal value of GBP0.001 per share 2016-05-16 4 P 0 15000 1.50 A 269100 I Shares held by Sigal Family Investments, LLC Ordinary Shares with a nominal value of GBP0.001 per share 2016-05-17 4 P 0 15000 1.53 A 284100 I Shares held by Sigal Family Investments, LLC Ordinary Shares with a nominal value of GBP0.001 per share 2016-05-18 4 P 0 15000 1.55 A 299100 I Shares held by Sigal Family Investments, LLC Ordinary Shares with a nominal value of GBP0.001 per share 52938 D Dr. Sigal is a manager of Sigal Family Investments, LLC. Dr. Sigal may be deemed to have voting and investment power over the shares held by Sigal Family Investments, LLC. Dr. Sigal disclaims beneficial ownership of such shares except to the extent of any pecuniary interest therein. The 15,000 Ordinary Shares are represented by 2,500 American Depositary Shares ("ADSs") which are held by Sigal Family Investments, LLC. Each ADS represents six Ordinary Shares of Adaptimmune Therapeutics plc. The price of $1.50 per Ordinary Share was derived from the purchase price paid on May 16, 2016, of $8.98 per ADS, divided by six. The 269,100 Ordinary Shares comprise (i) 254,100 Ordinary Shares, and (ii) 15,000 Ordinary Shares represented by 2,500 ADSs. The price of $1.53 per Ordinary Share was derived from the purchase price paid on May 17, 2016, of $9.18 per ADS, divided by six. The 284,100 Ordinary Shares comprise (i) 254,100 Ordinary Shares, and (ii) 30,000 Ordinary Shares represented by 5,000 ADSs. The price of $1.55 per Ordinary Share was derived from the purchase price paid on May 18, 2016, of $9.30 per ADS, divided by six. The 299,100 Ordinary Shares comprise (i) 254,100 Ordinary Shares, and (ii) 45,000 Ordinary Shares represented by 7,500 ADSs. The 52,938 Ordinary Shares are represented by 8,823 ADSs. /s/ Charles Elliott Sigal 2016-05-18