Mersana Therapeutics -- $21M Series B Co-led by Fidelity Biosciences

Cambridge, MA, November 9, 2005 - Mersana, a privately-held cancer therapeutics company announced today that it has completed an oversubscribed $21 million financing. Fidelity Biosciences and ProQuest Investments led the round, with Rho Ventures and the company's previous investors participating, including PureTech Ventures, Cape Family Fund LLC, Harris & Harris Group, Inc., and Lansing Brown Investments LLC.

"We are pleased to announce this major round of financing from a top-tier syndicate of venture capital firms," said Julie Olson, Ph.D., President and CEO of Mersana. "We look forward to bringing new and effective cancer therapeutics to patients and the market," she concluded. Dr. Olson was Vice President of Licensing in Research and Development at Pfizer prior to joining the company. During her 18-year career at Pfizer, she played a variety of roles that included leading high throughput screening and chemistry, a therapeutic area research team, and licensing groups for both technology and clinical compounds.

With completion of the financing, Jay Moorin and Joyce Tsang, Partners at ProQuest Investments, Jason Rhodes, Principal, at Fidelity Biosciences, and Martin Vogelbaum, Partner, at Rho Ventures will join existing members Julie Olson and Charles Harris of Harris & Harris Group, Inc. on the Board of Directors.

For further information, contact Julie Olson or Pete Leone (Mersana COO) at 617-498-0020.