Brian DeSchuytner

Date	Company	Security	Transaction	Code	Indirect	10b5-1	$Price	#Shares	$Value	#Remaining
16 Jan 25	MRSN Mersana Therapeutics	Common Stock	Sell	Dispose S	No	Yes	0.58	8,470	4.91 k	121,393
15 Jan 25	MRSN Mersana Therapeutics	Common Stock	Option exercise	Acquire M	No	No	0	14,583	0.00	129,863
15 Jan 25	MRSN Mersana Therapeutics	Common Stock	Option exercise	Acquire M	No	No	0	6,250	0.00	115,280
15 Jan 25	MRSN Mersana Therapeutics	RSU Common Stock	Grant	Acquire A	No	No	0	62,500	0.00	62,500
15 Jan 25	MRSN Mersana Therapeutics	Stock Option Common Stock	Grant	Acquire A	No	No	0.64	281,250	180.00 k	281,250
15 Jan 25	MRSN Mersana Therapeutics	RSU Common Stock	Option exercise	Dispose M	No	No	0	14,583	0.00	43,750
15 Jan 25	MRSN Mersana Therapeutics	RSU Common Stock	Option exercise	Dispose M	No	No	0	6,250	0.00	0
15 Jan 25	MRSN Mersana Therapeutics	Common Stock	Sell	Dispose S	No	Yes	0.63	2,331	1.47 k	109,030
14 Jan 25	MRSN Mersana Therapeutics	Common Stock	Option exercise	Acquire M	No	No	0	6,250	0.00	111,361
14 Jan 25	MRSN Mersana Therapeutics	RSU Common Stock	Option exercise	Dispose M	No	No	0	6,250	0.00	6,250

Data from 3, 4 and 5 filings. Values as filed, not updated for current price.