SCHEDULE 13G/A

MERSANA THERAPEUTICS INC

Common Stock, $0.0001 par value per share · CUSIP: 59045L106

Event date: 2025-03-31

Reporting persons may disclose overlapping interests. Their amounts are shown individually and are not added into a filing total.

Filing-level shares

Unavailable

Percent of class

Unavailable

• Venrock Healthcare Capital Partners III, L.P.

  Shares: 3,574,325.00 · Class: 2.9%

• VHCP Co-Investment Holdings III, LLC

  Shares: 3,574,325.00 · Class: 2.9%

• Venrock Healthcare Capital Partners EG, L.P.

  Shares: 3,574,325.00 · Class: 2.9%

• VHCP Management III, LLC

  Shares: 3,574,325.00 · Class: 2.9%

• VHCP Management EG, LLC

  Shares: 3,574,325.00 · Class: 2.9%

• Nimish Shah

  Shares: 3,574,325.00 · Class: 2.9%

• Bong Y Koh

  Shares: 3,574,325.00 · Class: 2.9%

Amounts are as disclosed in this filing. Schedule type alone does not establish investment intent.