Krystal Biotech, Inc.

Insider Trading Arrangements

On February 3, 2026, John Thomas, our Executive Vice President, General Counsel, and Corporate Secretary, adopted a Rule 10b5-1 trading arrangement (the “Trading Plan”) that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act for the sale of up to 1,903 shares of our common stock, subject to certain conditions. The end date of the Trading Plan is December 31, 2026, subject to early termination in accordance with the terms of the Trading Plan, including upon completion of the sale of all of the shares of our common stock subject to the Trading Plan.

On March 9, 2026, Daniel Janney, one of ourdirectors, terminated a Rule 10b5-1 trading arrangement that was originally adopted on November 25, 2025. The Rule 10b5-1 trading arrangement was terminated during the Company’s unrestricted trading window and at a time when Mr. Janney was not in possession of material, non-public information about the Company.71,964 shares of our common stock were sold under the Rule 10b5-1 trading arrangement prior to termination of the arrangement.

During the three months ended March 31, 2026, other than as set forth above, no other director or officer (as that term is defined by the SEC in Rule 16a-1(f) under the Exchange Act)adopted orterminated a “Rule 10b5-1 trading arrangement” or a “non-Rule 10b5-1 trading arrangement,” as each term is defined in Item 408(a) of Regulation S-K.