Synaffix Announces $1 Billion Deal Expansion with Mersana

• Expanded deal focuses on Synaffix’s GlycoConnect™ site-specific ADC bioconjugation technology and adds license options for six new programs to existing deal
• Mersana currently developing two programs based on GlycoConnect™ site-specific ADC bioconjugation technology (XMT-1592 and XMT-1660)

Synaffix B.V., a biotechnology company focused on commercializing its clinical-stage platform technology for the development of antibody-drug conjugates (ADCs) with best-in-class therapeutic index, today announces the expansion of its license agreement with Mersana Therapeutics, Inc. (NASDAQ: MRSN), a clinical-stage biopharmaceutical company focused on discovering and developing a pipeline of antibody-drug conjugates (ADCs) targeting cancers in areas of high unmet medical need.

Under the expanded license agreement, Mersana will expand its access to Synaffix’s GlycoConnect™ site-specific ADC bioconjugation technology for six additional ADC targets. The license rights granted to Mersana are tied to specific ADC targets to be selected and provide non-exclusive access to deploy GlycoConnect™ site-specific ADC bioconjugation technology against the specified targets. Under the expanded deal, Synaffix is eligible to receive upfront and milestone payments on a per-target basis with a total potential deal value exceeding $1 billion plus royalties. This builds on the long-term relationship between the two companies announced in 2019.

About Mersana Therapeutics
Mersana Therapeutics is a clinical-stage biopharmaceutical company using its differentiated and proprietary ADC platforms to rapidly develop novel ADCs with optimal efficacy, safety and tolerability to meaningfully improve the lives of people fighting cancer. Mersana’s lead product candidate, upifitamab rilsodotin (UpRi), is a Dolaflexin ADC targeting NaPi2b and is being studied in UPLIFT, a single-arm registration strategy in patients with platinum-resistant ovarian cancer, as well as in UPGRADE, a Phase 1 umbrella study in combination with other ovarian cancer therapies. XMT-1592, Mersana’s second ADC product candidate targeting NaPi2b-expressing tumors, was created using Mersana’s customizable and homogeneous Dolasynthen platform and is in the dose escalation portion of a Phase 1 proof-of-concept clinical study. The Company’s early-stage programs include XMT-1660, a Dolasynthen ADC targeting B7-H4, as well as XMT-2056, a STING-agonist ADC developed using the Company’s Immunosynthen platform and targeting a novel epitope of human epidermal growth factor receptor 2 (HER2). In addition, multiple partners are using Mersana’s Dolaflexin platform to advance their ADC pipelines. The Company routinely posts information that may be useful to investors on the “Investors and Media” section of our website at www.mersana.com.