X0306 4 2020-03-17 0 0001661998 Homology Medicines, Inc. FIXX 0001754067 Kelly Timothy P C/O HOMOLOGY MEDICINES, INC. ONE PATRIOTS PARK BEDFORD MA 01730 0 1 0 0 See Remarks Common Stock 2020-03-17 4 S 0 1315 13.0103 D 0 D The sale reported in the Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 20, 2018. Consists of 1,315 shares acquired under the Issuer's Employee Stock Purchase Plan on February 28, 2020. The price reported is a weighted average price. The shares were sold in multiple transactions at per share prices ranging from $12.60 to $13.48. The Reporting Person undertakes to provide upon request to the SEC staff, the Issuer, or any stockholder of the Issuer, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. Chief Technical Operations Officer /s/ Bradford Smith, Attorney-in-Fact for Timothy P. Kelly 2020-03-18