Mersana, GSK Ink $1.36B Biobuck Deal For Cancer-Focused Therapy

Mersana Therapeutics Inc MRSN announced a global collaboration that provides GSK plc GSK an exclusive option to co-develop and commercialize XMT-2056.
XMT-2056 is designed to activate the innate immune system through STING signaling in both tumor-resident immune cells and tumor cells.
Mersana expects to initiate a Phase 1 trial of XMT-2056 to investigate its potential in a range of HER2-expressing tumors. The FDA recently granted an orphan drug designation to XMT-2056 for gastric cancer.
Mersana will receive an upfront option purchase fee of $100 million. Mersana also is eligible to receive up to $1.36 billion in the form of an option exercise payment and development, regulatory and commercial milestone payments if GSK exercises its option.
Mersana has retained options to profit-share and to co-promote in the U.S.
Mersana held cash, cash equivalents, and marketable securities of $225.1 million at the end of Q2. The company expects that its available funds, together with the $100 million option payment due from GSK, will be sufficient to support its operating plan commitments into 1H of 2024.
Price Action: MRSN shares closed 14.3% higher at $6.00 during after-hours trading on Monday. GSK stock is down 0.37% at $40.16 during the premarket session on the last check Tuesday.