Mersana Therapeutics, Inc., announced today that the U.S. Patent and Trademark Office has granted three new U.S. patents, further strengthening its intellectual property (IP) position in next-generation antibody-drug conjugate (ADC) technologies that utilize the Fleximer® polymer. U.S. Patent No. 8,808,679 provides coverage for anti-tumor payloads and customized linkers utilized in Mersana’s Dolaflexin™ conjugation platform. U.S. Patent No. 8,815,226 expands Mersana’s IP portfolio to encompass Fleximer platform technology that is optimized to create ADCs with antibody alternatives. The third patent, U.S. Patent No. 8,821,850, provides broad coverage for Fleximer-based ADCs and use thereof. Together with U.S. Patent No. 8,685,383, which issued earlier this year, the claims of these patents provide Mersana with expansive IP protection for its innovative, highly differentiated platform technologies.

“Mersana’s strong intellectual property position provides a comprehensive ADC solution for our internal pipeline as well as our partners’ programs by covering proprietary payloads, Fleximer polymer linker technology, and conjugation to antibodies or antibody alternatives,” said Eva M. Jack, Chief Business Officer of Mersana Therapeutics. “Our ability to create ADCs with full length antibodies and a variety of antibody alternatives, payloads, and linkers, demonstrates our technology’s inherent flexibility and our leading position among companies with next-generation ADC technologies. We are committed to the ongoing advancement of Fleximer-based ADCs to address unmet needs and improve patient outcomes.”

About Fleximer® Antibody-Drug Conjugate Technology

Mersana’s next-generation Fleximer® antibody-drug conjugate (ADC) technology is based on the company’s proprietary biodegradable polymer system, known as Fleximer, and a wide variety of linkers that allow for the attachment of an extensive range of anti-tumor payloads to Fleximer. As an example, once loaded with drug(s), Fleximer is then attached through a stable linker that is different from the drug linker(s) to the antibody or antibody alternative to create a Fleximer-ADC. Mersana’s novel linker systems are designed to be stable in the bloodstream and to release the drug payloads once inside the targeted cell. Mersana’s Fleximer-ADC technology provides several key advantages over currently available approaches, including: the ability to deliver diverse payloads; the opportunity to significantly increase drug loading per antibody; significantly improved physicochemical properties and facile manufacturing. Mersana’s proprietary polymer payload platforms include Dolaflexin™, an auristatin-polymer conjugate; Vindeflexin™, a vindesine-polymer conjugate; and Cytoflexin™, a tubulysin-polymer conjugate.

About Mersana Therapeutics

Mersana Therapeutics engineers antibody-drug conjugates (ADCs) that maximize the potential of new and established therapeutic classes. Mersana is developing, with select pharmaceutical partners, a portfolio of next-generation Fleximer® ADCs with superior properties not found with current ADC technologies. The company is also advancing its own pipeline of Fleximer-ADCs with best-in-class potential to address unmet needs and improve patient outcomes in multiple oncology indications.

Media Contacts

 For Mersana:
 MacDougall Biomedical Communications
 Kari Watson or Charles Liles
 kwatson@macbiocom.com or cliles@macbiocom.com
 +1 781 235 3060