Mersana Therapeutics delivered strong second quarter results, marked by promising clinical data for its lead candidate, Emi-Le, particularly in triple-negative breast cancer (TNBC) and adenoid cystic carcinoma, driving ongoing dose expansion efforts.

• Emi-Le demonstrated a 31% objective response rate in B7-H4 high tumor expression patients during the recent ASCO and ESMO presentations.
• The drug showed a heightened response rate of 56% in a poor-prognosis subgroup with adenoid cystic carcinoma, reinforcing its potential across various tumor types.
• Enrollment for the Emi-Le Phase I expansion is proceeding well, with over 45 patients already enrolled, and initial data expected in the second half of 2025.
• Mersana anticipates significant market potential for Emi-Le, particularly among post-topoisomerase 1 patients, as evolving treatment standards create substantial unmet needs.
• The company achieved a $15 million milestone with partner GSK related to its HER2-targeting Immunosynthen ADC, XMT-2056, currently in Phase I trials.