Entity Information

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Economic entity name	IMMUNOGEN INC
CIK	0000855654
Accession number	0001558370-16-008099
Generator	Merrill
SEC filing page	http://www.sec.gov/Archives/edgar/data/855654/000155837016008099/0001558370-16-008099-index.htm
XBRL Instance	http://www.sec.gov/Archives/edgar/data/855654/000155837016008099/imgn-20160630.xml
XBRL Cloud Viewer	https://edgardashboard.xbrlcloud.com/flex/viewer/XBRLViewer.html#instance=http://www.sec.gov/Archives/edgar/data/855654/000155837016008099/imgn-20160630.xml