X0306 4 2019-12-16 0 0001711279 Krystal Biotech, Inc. KRYS 0001298711 Krishnan Suma C/O KRYSTAL BIOTECH, INC. 2100 WHARTON STREET, SUITE 701 PITTSBURGH PA 15203 1 1 1 0 Chief Operating Officer Common Stock 2019-12-16 4 S 0 7373 62.8444 D 1994089 D Common Stock 2019-12-16 4 S 0 7396 63.6235 D 1986693 D Common Stock 2019-12-16 4 S 0 5856 64.2782 D 1980837 D Common Stock 2019-12-16 4 S 0 322 65.6042 D 1980515 D Common Stock 2019-12-17 4 S 0 8138 59.8676 D 1972377 D Common Stock 2019-12-17 4 S 0 8799 60.461 D 1963578 D Common Stock 2019-12-17 4 S 0 891 61.7222 D 1962687 D Common Stock 2019-12-17 4 S 0 1834 62.7907 D 1960853 D Common Stock 2019-12-17 4 S 0 279 63.3472 D 1960574 D Common Stock 2019-12-18 4 S 0 1200 59.4893 D 1959374 D Common Stock 2019-12-18 4 S 0 1017 60.1921 D 1958357 D Common Stock 2019-12-18 4 S 0 900 61.2811 D 1957457 D Common Stock 2019-12-18 4 S 0 5756 62.6463 D 1951701 D Common Stock 2019-12-18 4 S 0 239 63.3143 D 1951462 D Common Stock 112162 I By trust Common Stock 1986462 I By spouse The sales reported were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person following discussions with the Compensation Committee and the Board of Directors. This transaction was executed in multiple trades ranging from $62.08 to $63.07. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. This transaction was executed in multiple trades ranging from $63.10 to $64.09. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. This transaction was executed in multiple trades ranging from $64.10 to $65.05. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. This transaction was executed in multiple trades ranging from $65.19 to $65.79. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. This transaction was executed in multiple trades ranging from $59.14 to $60.13. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. This transaction was executed in multiple trades ranging from $60.14 to $61.12. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. This transaction was executed in multiple trades ranging from $61.16 to $62.13. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. This transaction was executed in multiple trades ranging from $62.20 to $63.15. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. This transaction was executed in multiple trades ranging from $63.34 to $63.36. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. This transaction was executed in multiple trades ranging from $58.84 to $59.73. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. This transaction was executed in multiple trades ranging from $59.89 to $60.65. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. This transaction was executed in multiple trades ranging from $61.00 to $61.83. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. This transaction was executed in multiple trades ranging from $62.07 to $63.00. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. This transaction was executed in multiple trades ranging from $63.08 to $63.51. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth herein. Directly beneficially owned by the Krishnan Family Trust. The reporting person and her spouse are each joint beneficial owners of the trust with joint voting and investment control. Directly beneficially owned by Krish S. Krishnan, the spouse of the reporting person. /s/ Suma Krishnan 2019-12-18