X0603 D LIVE 0001442836 MERSANA THERAPEUTICS INC 840 MEMORIAL DRIVE CAMBRIDGE MA 02139 617-498-0020 DELAWARE None None Corporation true Julie A. Olson 840 Memorial Drive Cambridge MA 02139 Executive Officer Director Peter Leone 840 Memorial Drive Cambridge MA 02139 Executive Officer Nicholas G. Bacopoulous 840 Memorial Drive Cambridge MA 02139 Director C. Clarke Boyd 840 Memorial Drive Cambridge MA 02139 Director Joyce Tsang 840 Memorial Drive Cambridge MA 02139 Director Martin Vogelbaum 840 Memorial Drive Cambridge MA 02139 Director Thomas Beck 840 Memorial Drive Cambridge MA 02139 Director Biotechnology Decline to Disclose 06 false 2010-01-19 false true false 0 3500000 2500000 1000000 false 7 0 0 0 false MERSANA THERAPEUTICS INC /s/ Julie A. Olson Julie A. Olson President & CEO 2010-02-25