X0306 4 2020-10-12 0 0001503802 Karyopharm Therapeutics Inc. KPTI 0001364719 Kauffman Michael C/O KARYOPHARM THERAPEUTICS INC. 85 WELLS AVENUE NEWTON MA 02459 1 1 0 0 Chief Executive Officer Common Stock 2020-10-12 4 M 0 1424 0.033 A 757913 I By Spouse Common Stock 2020-10-12 4 M 0 6076 0.033 A 763989 I By Spouse Common Stock 2020-10-12 4 S 0 7500 14.891 D 756489 I By Spouse Common Stock 555122 D Stock Option (right to buy) 0.033 2020-10-12 4 M 0 1424 0.00 D 2020-10-31 Common Stock 1424 0 I By Spouse Stock Option (right to buy) 0.033 2020-10-12 4 M 0 6076 0.00 D 2020-10-31 Common Stock 6076 0 I By Spouse These transactions were effected pursuant to a Rule 10b5-1 trading plan adopted by the spouse of the reporting person. Represents the weighted average sale price. These shares were sold in multiple transactions at prices ranging from $14.71 to $15.16, inclusive. The spouse of the reporting person undertakes to provide upon request by the U.S. Securities and Exchange Commission staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price. This option, representing a right to purchase a specified number of shares, vested as to 25% of the shares on November 1, 2011, and the remaining 75% vested in 36 equal monthly installments thereafter. /s/Christopher B. Primiano, Attorney-in-Fact for Michael Kauffman 2020-10-14