| Explanation of Responses: |
| (1) | The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person. |
| (2) | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $57.57 to $58.55, inclusive. The reporting person undertakes to provide to Deciphera Pharmaceuticals, Inc., any security holder of Deciphera Pharmaceuticals, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote. |
| (3) | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $58.58 to $59.57, inclusive. The reporting person undertakes to provide to Deciphera Pharmaceuticals, Inc., any security holder of Deciphera Pharmaceuticals, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote. |
| (4) | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $59.58 to $60.55, inclusive. The reporting person undertakes to provide to Deciphera Pharmaceuticals, Inc., any security holder of Deciphera Pharmaceuticals, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote. |
| (5) | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $55.42 to $56.41, inclusive. The reporting person undertakes to provide to Deciphera Pharmaceuticals, Inc., any security holder of Deciphera Pharmaceuticals, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote. |
| (6) | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $56.42 to $57.36, inclusive. The reporting person undertakes to provide to Deciphera Pharmaceuticals, Inc., any security holder of Deciphera Pharmaceuticals, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote. |
| (7) | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $57.42 to $58.33, inclusive. The reporting person undertakes to provide to Deciphera Pharmaceuticals, Inc., any security holder of Deciphera Pharmaceuticals, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote. |
| (8) | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $54.09 to $55.08, inclusive. The reporting person undertakes to provide to Deciphera Pharmaceuticals, Inc., any security holder of Deciphera Pharmaceuticals, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote. |
| (9) | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $55.09 to $56.08, inclusive. The reporting person undertakes to provide to Deciphera Pharmaceuticals, Inc., any security holder of Deciphera Pharmaceuticals, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote. |
| (10) | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $56.09 to $57.02, inclusive. The reporting person undertakes to provide to Deciphera Pharmaceuticals, Inc., any security holder of Deciphera Pharmaceuticals, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote. |
| (11) | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $57.10 to $57.21, inclusive. The reporting person undertakes to provide to Deciphera Pharmaceuticals, Inc., any security holder of Deciphera Pharmaceuticals, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote. |
| (12) | This stock option award was issued pursuant to Deciphera Pharmaceuticals, LLC's 2015 Equity Incentive Plan. The option vests in 16 equal quarterly installments at the end of each quarter following the vesting commencement date of March 1, 2014, subject to continued service through such dates. |