X0306 4 2018-12-26 0 0001622229 Unum Therapeutics Inc. UMRX 0001734419 Ettenberg Seth C/O UNUM THERAPEUTICS INC. 200 CAMBRIDGE PARK DRIVE, SUITE 3100 CAMBRIDGE MA 02140 0 1 0 0 Chief Scientific Officer Common Stock 2018-12-26 4 M 0 11485 0.18 A 11485 D Common Stock 2018-12-26 4 S 0 11485 4.0476 D 0 D Stock Option (Right to Buy) 0.18 2018-12-26 4 M 0 11485 0.00 D 2025-01-28 Common Stock 11485 352115 D The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $4.00 to $4.36, inclusive. The reporting person undertakes to provide to Unum Therapeutics Inc., any security holder of Unum Therapeutics 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. 25% of the shares vests on September 3, 2015, and the remaining shares shall vest in 36 equal monthly installments thereafter, subject to the Reporting Persons continuous service with the Issuer. /s/ Amoli Pandya, as Attorney-in-Fact 2018-12-28